The method of obtaining bleached pulp and method for delignification and bleaching of lignocellulosic material (options)

 

(57) Abstract:

The inventive method of obtaining bleached pulp and method of delignification and bleaching of lignocellulosic pulp and its variants without the use of chlorine gas by partial delignification weight permanganate number, approximately 10 or less and a viscosity of more than about 10 or less and a viscosity of more than about 13 SP; then delignification partially delignification mass to some effective amount of ozone for a time sufficient to obtain essentially delignification mass having a permanganate number of about 5 or less, a viscosity of more than about 5 or less, a viscosity of more than about 10 and a white GE at least about 50%. Received essentially delignification pulp bleaching additive such bleach as chlorine dioxide or peroxide to obtain a finished product having a whiteness of at least about 65%, and preferably from 70 to 90%. Due to the fact that in the process there is no chlorine gas, it is possible to regenerate the filtrate from all stages except stage treatment with chlorine dioxide, if this stage is available is. the 116 C.p. f-crystals, 30 tab., 5 Il.

The invention relates to a method for producing bleached pulp, and to a new and environmentally acceptable method for the delignification and bleaching of lignocellulosic pulp, which eliminates the need to use chlorine gas and it turns out the pulp of acceptable strength. The application of this method also allows you to reduce the number of substances that pollute the environment.

Part of the wood consists of two main components, this fibrous hydrocarbon or cellulosic portion and a fibrous component. Polymer chain, forming a fibrous cellulosic portion of the wood, oriented the same way and form strong associative ties with neighboring chains. Lint-free piece of wood contains a three-dimensional polymeric material, consisting mainly of phenylpropane units, also called lignin, some of the lignin is between cellulose fibers, through their strong bond, but most of the lignin is distributed within the fibers.

So wood can be used in the manufacture of paper, it should first of all grind to a fibrous mass. Similar weight to depict the sheet of paper. For the conversion of wood into a fibrous mass, it is subjected to physical or chemical treatment, or their combined action to change the chemical form of wood and give the finished product the desired properties. So, there are two basic methods of obtaining wood fibrous mass is a mechanical and chemical methods. By machining the wood is separated into individual fibers. During the chemical processing of wood chips are cooked with chemical solutions to dissolve a portion of the lignin and delete it. The most widely used methods of chemical treatment can be classified as: (1) the method of cooking soda; (2) sulfite method of cooking, and (3) the sulphate process or the Kraft process; the latter method has been most widely used, well-known various modifications, described in detail below.

The method of cooking soda are well known. It used sodium hydroxide (NaOH), acting as the active reagent, softening the lignin and contributing to its destruction. Sulfite method of cooking is also well known (see, for example, "Handbook of technology in the pulp and paper", Chapter 6 "Sulfite cooking" (TAPPI, USA).

Main x is its variation. In accordance with the basic sulfate method of cooking that is described in the "Handbook of technology in the pulp and paper", Chapter 7 "Kraft process" (TAPPI, USA), are cooking wood chips in an aqueous solution of sodium hydroxide (NaOH) and sodium sulfide (Na2S). This method has proven a highly effective when cooking southern softwoods, as well as when cooking free-cutting of wood species, namely Northern deciduous and coniferous species. Use the Kraft process, as a rule, allows to obtain relatively high-strength material, as when using the cellulose component of the wood is exposed to less destruction.

Various modifications of the Kraft process can achieve even less degradation of the polymer structure cellulose fibers, so that the strength of the resulting paper is higher than with standard Kraft process. One of the modified methods of sulfate pulping call method "extended delignification", it covers a lot of modified Kraft process, for example, additive chemicals in strictly determined sequence or at different points in the digester or in different periods of time, or uninstall and then under the Nina while softening chemical action cooking solutions on the pulp fibers. Another modification of the Kraft process is the process by which sulfate cooking the liquor add a small amount of anthraquinone to accelerate the delignification and to limit the impact on pulp fibers.

Besides them, there are many other methods of delignification, for example, a modified continuous cooking on Kamyur (MCC) described C. A. Kortelainen and E. A. Balunda in TAPPI, vol 68 (II), 70 (1985); the method of rapid replacement by heating Belua (RDI) described R. S. Grant in TAPPI, vol 66 (3), 120 (1983); and cooking with cold blowing Sands, described by B. Peterson and B. Ernerfeldt in "Pulp and paper", volume 59 (II), 90 (1985).

In the cooking of wood on the main or modified Kraft process formed suspension, painted in a dark color and so-called brown mass. The dark color of unbleached pulp is attributed to the fact that during cooking is deleted, not the entire lignin, it is chemically modified forms of the chromophore group. To lighten unbleached mass, i.e., to make it suitable for use as printing or writing paper, you must continue to remove the residual lignin due to the additive delignification materials and by the chemical preframe the corruption.

However, usually upon completion of the chemical treatment carried out during the cooking of wood, and prior to the bleaching of the pulp mass is placed in a single blow tank. In the blow tank relieve the pressure created during the initial chemical treatment of lignocellulosic material, and separating the fibrous mass. The obtained fibrous mass is subjected to multiple washings to remove combinations of residual chemicals and soluble materials (such as lignin), separated from the fibrous material during cooking. Very often the pulp mass is subjected to several sorts, designed to separate unground wood for further processing (perevalki, mechanical grinding, and so on).

After washing, get the remainder, usually called black liquor, it is collected, concentrated and then environmentally friendly way calcined in the recovery boiler. The technology for the collection, concentration and combustion of black liquor is a typical and well-known.

The process of delignification and bleaching is performed on the washed fibrous mass during several stages, using selected combinations of chemicals. The wound is to regroupements, and the number of such combinations and permutations are almost endless. Therefore, to simplify further explanations of various processes and systems applicable letter codes, which we will use to describe the apply of specific reagents and sequence of steps.

Further, where convenient, we will use the following letter codes:

C chlorination reaction with gaseous chlorine in an acidic environment;

E alkaline processing dissolution of reaction products with NaOH;

Eaboutoxidative-alkaline processing dissolution of reaction products with NaOH and oxygen;

D chlorine dioxide reaction with ClO2in the acidic environment;

P peroxide reaction with peroxide in an alkaline environment;

O oxygen reaction with gaseous oxygen in an alkaline environment;

ABOUTmmodified uniform oxygen alkaline processing pulp small or medium concentration, followed by the reaction of concentrated mass with oxygen;

Z ozone reaction with ozone;

Zmhomogeneous reaction with ozone;

C/D of a mixture of chlorine and chlorine dioxide;

H hypochlorite reaction with hypochlorite in an alkaline solution.

ABOUTmand Zmare modificat for delignification and bleaching of wood pulp used chlorine gas.

Although chlorine gas is an effective bleaching agent, however, it is difficult to apply, and it is potentially dangerous to equipment and personnel. For example, in the wastewater coming from the processes of chlorine bleaching, as by-products of these processes contains a large amount of chlorides. Under the influence of chlorides equipment quickly corrode, making the manufacture of such installations have to send expensive materials. However, the presence of chlorides inside the unit prevents recirculation of leachate at the completion of phase chlorination system with a closed cycle, if you do not use the recovery system with complex and therefore expensive modifications. But the concept of the potential environmental impact of chlorinated organic compounds contained in the composition of the effluent and recognized toxic to humans and animals according to the decisions of the United States Agency for environmental protection, has undergone significant changes in terms of more stringent requirements and standards, compliance with which may not be possible using standard methods of bleaching and pollution control of the environment.

chlorine and chlorine-containing compounds in multi-step processes of bleaching lignocellulosic material. An additional factor complicating attempts, is the need to uphold the highest level of white fibrous semi-finished product.

Therefore, efforts were focused on development of such a bleaching process, in which instead of chlorine-containing substances for mass bleaching apply oxygen. The use of oxygen allows for the recycling of wastewater from this stage along with a significant decrease in the number of used chlorine gas. It was proposed several processes of bleaching and delignification of wood pulp with oxygen, for example, U.S. patent N 2926114, CL 162/16 for 1960 and N 3024158 on CL 162/17 for the 1962 U.S. patent N 3274049 on CL 162/65 for 1966 United States patent N 3384533 on CL 162/65 for the 1968 U.S. patent N 3423282 in class. D 21 C 9/10 (162/65) for 1969 and other U.S. patent N 3661699 in class. D 21 C (162/65) for the 1972 publication of P. Christensen, "the Bleaching of sulphate mass with hydrogen peroxide", Norsk Skoqindustri, 268-271 (1973).

In U.S. patent N 4806203 in class. D 21 C 3/26 (162/19) for 1989 suggests ways preliminary alkaline treatment of pulp prior to oxygen delignification.

However, the use of oxygen cannot be considered fully satisfactory solution to the problems associated with ispolzovanny chlorine, making use of standard methods of delignification with oxygen allows only a limited extent to reduce the permanganate number of the pulp before disproportionate, i.e., unacceptable effects on cellulose fibers. In addition, upon completion of the oxygen delignification residual lignin typically removed by the methods of the chlorine bleaching to get fully bleached mass; however, used a much smaller amount of chlorine. However, even with such small concentrations of chlorine due to the closed working cycle soon reached unacceptable levels of concentration of corrosive chlorides.

To avoid using bleach with chlorine, offered to remove the residual lignin using ozone. First, the ozone seemed to be the ideal material for bleaching lignocellulosic materials, however, extremely high oxidative properties of ozone and its relatively high cost, until recently, severely limited the development of a satisfactory processes ozone bleaching of lignocellulosic materials, and especially the southern conifers. Ozone readily reacts with lignin, effectively reducing permanganate, and significantly reduces the strength of the pulp. However, ozone is extremely sensitive to the process parameters like pH, affecting its oxidative and chemical stability, making these changes can significantly alter the reactivity of ozone in respect of lignocellulosic materials.

From the beginning of our century, when the first recognized delignification properties of ozone, many researchers were important and ongoing work on the development of industrial acceptable method of bleaching lignocellulosic materials using ozone. The result of this work led to numerous articles and patents, which have been reported attempts to implement the ozone bleaching in non-industrial scale. For example, in U.S. patent N 2466633, CL 162/65 for 1949 described the bleaching process in which ozone is passed through the pulp mass, where the absolute humidity is maintained within the range of from 25 to 55% and a pH of 4 to 7.

Other proposals for bleaching without the use of chlorine is described in the publication of S. Rotenberg, D. Robinson and D. Jianbo "Bleaching of oxygen-containing pulp mass by using ozone", TAPPI, 182-185 (1975) Z, ZeZ, Zp and ZPa (Pa peracetic acid); and in the publication of R. Toseland "Bleaching tech">

In U.S. patent N 4196043, D 21 C 9/10 (162/30K) for 1980, the disclosed multi-stage method of bleaching, which also made an attempt to get rid of the use of chlorine compounds; it contains examples specifically related to hardwood species. Specialists are well aware that hardwoods can be bleached easier for many coniferous species. Proposed there, the method is characterized by the use of from one to three stages using the Kraft process pulp ozone bleaching and finishing alkaline hydrogen peroxide, with each stage separated by alkaline extraction. A similar sequence can be abbreviated to describe how ZEZEP. In accordance with this method, the effluent from each stage is collected and recycled for use in the operations bleaching, preferably at an earlier stage. The patent also describes the so-called backflow of sewage.

However, despite all the studies to date are not aware of any industrially feasible method for the production of lignocellulosic mass through the ozone bleaching, especially southern softwood; there are only reports of numerous failures.

Objectives the bleaching, to resolve the previously encountered difficulties listed above, with the exception of chlorinated organic compounds, as well as minimization of colors and biological oxygen demand for the production of high-grade bleached pulp in an industrial scale.

The essence of the invention.

The technical result of the invention is to provide a multi-stage delignification and bleaching of lignocellulosic pulp without the use of bleach with chlorine to greatly reduce or exclude the environment while optimizing the physical properties of the pulp method, effective from the point of view of energy and costs. This invention can be used with almost all wood, including difficult for the bleaching of soft southern conifers.

The method according to this invention consists of three or more of the steps within the phases and between different possible variations. All these stages can be described as follows.

In the first stage is the delignification of wood chips in lignocellulosic mass using one of the known chemical processes of cooking, then removed is usually carried out screening mass, to remove the fiber bundles, not divided during cooking. Stage delignification spend so from softwood to get the pulp mass with permanganate number from 20 to 24 (preferably 21), the viscosity in solution cupriethylenediamine ("ETS") from approximately 21 to 28 and the whiteness of about from 15 to 25. From solid hardwoods USA usually get the pulp mass with permanganate number from 10 to 14 (preferably 12,5) and SED viscosity of approximately 21-28.

Possible variants of realization of the first stage are not limited to:

a) sulphate cooking using a continuous or cyclical stages;

b) continuous sulfate cooking with extended delignification in a staged addition of alkali and final counter-current cooking;

C) cyclic sulfate cooking with extended delignification and application of methods for rapid displacement of liquor and cold blowing; or

g) sulphate cooking with the use of anthraquinone to achieve extended delignification using a continuous or cyclic stage.

Mentioned above in paragraphs b) and C) methods of extended delignification can contain for example technological methods specific type of lignocellulosic material can also be used above soda and sulfite processes.

On the second step of the method is the oxygen delignification for the further removal of lignin is not accompanied by a significant loss of strength of the cellulose fibers. In this step may be performed by removing the leaching of dissolved organic matter and alkali for recycling and regeneration. Upon completion of the oxygen delignification also sort of pulp.

On stage oxygen delignification permangante number of pulp with high concentration is reduced at least about 45% (O) and 60% (for Omwithout noticeable damage to the pulp components. Moreover, the ratio of permanganate number and viscosity usually decreases at least by 25% When processing the pulp is achieved permanganate number is equal to or less than 10, in the processing of pulp from softwood using ABOUTmeasily achievable permanganate number from 7 to 10 and a viscosity approximately equal to or more than 13. In the processing of pulp from hardwoods after stage oxygen delignification is achieved permanganate number from 5 to 8 and a viscosity approximately equal to or more than 13.

Possible the tion, where is the oxygen - alkali treatment of the mass with a low, medium or high concentration pulp (O); or

b) preferred alkali treatment at a concentration of mass from low to medium, i.e., less than about 10 weight. then for the mass with a high concentration (i.e., more than about 20 weight.) should oxygen treatment (Om).

As pulp, whiteness which may not exceed 35% of the NORTH (often called porublennoy weight), you can use a lot of processed up to 2 stages.

On the third step of the method is acidic bleaching gaseous ozone (Z or Zm) subject to certain process parameters to achieve highly selective removal and bleaching of lignin for minimum damage to the pulp. The process parameters include chelating agents for control of metal ions, pH control, control of particle size, control the consistency of the mass, ozone concentration and contact between the gas and the pulp mass. Prior treatment with ozone for pulp mass may be added chelating agents, such as oxalic acid, diethylenetriaminepentaacetic acid (DTRA) or atrend is th a pH from 1 to 4, by doing this before the start of the third stage. With this objective, the pulp mass, you can add a sufficient amount of acidic material, also preferably, the consistency of the mass was in the range of from 35 to 45 wt. and flakes of fibers, it is desirable to give the approximate size of 5 mm or less, carrying it to the stage of the ozone delignification. It also includes stage leaching of dissolved organic substances for recycling and regeneration.

During the processing phase ozone, it is desirable that the temperature of the mass was maintained equal to normal or at least below about 120oF (48,9oC). Ozone can act as ozonoterapia gas, which could include for example oxygen or air. If you are using a mixture of oxygen with ozone, it is preferable that the ozone concentration from about 1 to about 8. while in the mixture of ozone with air permissible concentration from about 1 to about 4. Moving delignification mass inside the reaction tank is carried out so that ozone had a uniform impact on all its particles.

It was found that the pulp with permanganate more than about 10 after the second stage is not Peremoga level requires a large amount of ozone, which is usually undesirable effect on the properties of cellulose fibres. If otnerwise the pulp with permanganate number less than 10, use a lower concentration of ozone and there is a slight destruction of cellulose. The product obtained in stage ozonation of pulp from coniferous or deciduous, permanganate number of about 5 or less than 5, and usually ranges from 3 to 4 (preferably 3,5), the viscosity is greater than 10, and white CE is at least 50% (usually coniferous wood approximately 54% and above, deciduous 63% and above).

Possible options for the implementation of the third method are not limited to:

a) processing of acidified mass in countercurrent contact with the ozone in the oxygen-containing gas or air; or

b) treating the acidified mass in contact with a parallel stream of ozone in oxygen-containing gas or air.

Then may be additional stage bleaching for making pulp and the desired weight of the fully bleached state, when the brightness level reaches approximately 70-95% with the use of one of the well-proven processes of bleaching and the donkey which should peroxide stage with flushing, i.e., ER;

b) typical stage be and washing, followed by standard treatment with chlorine dioxide with flushing, that is, ED;

in typical stage be and washing, followed by standard treatment with chlorine dioxide by washing, then re-bucking and treatment with chlorine dioxide, i.e., EDED; or

g) stage be reinforced or oxygen, or oxygen and hydrogen peroxide, followed by standard treatment with chlorine dioxide, i.e., (Eabout)D or (E'orD.

As an additional option, the implementation stage can be implemented in connection mainly delignification mass with a sufficient quantity of alkaline material in an aqueous-alkaline solution at a certain time and at a certain temperature in accordance with the available quantity of alkaline material to dissolve a substantial proportion of lignin remaining in the pulp. Then an aqueous-alkaline solution can be extracted to remove virtually all dissolved lignin.

Upon completion of the stage be delignification pulp mass can be directed to an additional stage bleaching to improve its whiteness, at least up to 70% In the number of preferred otah implementation (Eabout)D, (E'orD or EDED. In a variant ED filtrate obtained after treatment with chlorine dioxide cannot be sent to recycling for chemical recovery without treatment due to the presence of inorganic chlorides. However, the filtrate is the only loss from the process, and therefore achieved a significant decrease in the volume of wastewater, the presence of chlorinated organic compounds, COD and D. It is possible to reach values of the amount of the colorant is less than 2 pounds per ton, D5less than 2 pounds per ton, and total organic chlorides less than 2 and preferably less than 0.8. In addition, the filtrate after treatment with chlorine dioxide can be used for membrane filtration, which will allow complete recycling. In a variant of the EP on stage bleaching no formation of chlorinated materials and almost all liquid effluents can be recycled and regenerated, allowing it turns out the process without sewage.

In Fig. 1 in the form of a block diagram showing the preferred methods according to this invention, while the solid line shows the flow of the pulp, and the dashed line the wastewater stream; Fig.2 the preferred method for this image is sustained fashion devices for ozone in Fig.2 in section, made along the line C-C of Fig.5 - comparison of flows of recycling and waste in different ways of processing cellulose.

The invention relates to new ways of delignification and bleaching of pulp, allowing to minimize the degree of destruction of the cellulose fraction of the wood and therefore to obtain a product having mechanical properties suitable for the production of paper and different products. For convenience in understanding the improvements achieved using the inventive method of delignification and bleaching, below you will find the definition of several parameters involved at different stages in all processes of delignification and bleaching.

Throughout the description the following definitions are used.

Under the "consistency" refers to the amount of cellulose fibers in the suspension, expressed as a percentage of the total weight of the absolutely dry fiber and water. It is sometimes called the concentration of the pulp. The consistency of the mass depends on the work used dewatering equipment and its type. In the subsequent definitions are definitions given by Rydholm in the publication "digester" Interscience Publishers, 1965, S. 862-863, and Monogr and, 1963, S. 186-187.

The concept of "low consistency" includes the range from 6% is typically from 3 to 5% of Such suspension to conventional centrifugal pump pump, get it by using thickeners and filters without wringer rolls.

The concept of "average consistency" includes the range from approximately 6 to 20% cut-off point within this range is the value of 15% to Obtain a consistency of less than 15% by using filters. Such consistency has mass, leaving drum vacuum filter system, brown stock washing and bleaching system. The consistency of the suspension coming from the washing machine, whether vacuum filter for washing cellulose or apparatus for washing after bleaching, is from 9 to 15% If the consistency of more than 15% for dehydration requires dewatering shafts. Rudholm believes that the normal range for the average consistency equal to 10-18% while Rapson indicates 9-15% Slurry can be pumped by special machines, although at high temperatures and under pressure it is a homogeneous liquid phase.

The term "greater consistency includes a range of more than 20 and up to 50% Rudholm considers the usual range of 25 to 35% according to Rapson 20-35And the liquid phase, and pulp mass can be build only on very short distances.

Further, in the present description the term "cooking" is used in its ordinary sense, pointing to the cooking of lignocellulosic material to obtain the unbleached pulp. The concept of cooking includes the Kraft process, as well as the Kraft process using anthraquinone, the cooking is achieved delignification.

The term "modified Kraft process" includes extended delignification and all other modified Kraft processes except for the Kraft process using anthraquinone, because this process has acquired a special status and is known by a specific name. Under the concept of extended delignification is not covered stage oxygen delignification, following the completion of cooking; it is preferable to call the first phase of the delignification process for bleaching or lightening the weight.

Then there are mentioned two main types of measurements used to determine completion of boiling process or bleaching, is "the degree of delignification" and "white" pulp. The concept of the degree of delignification is typically used in connection with the process of cooking and the initial stages of bleaching. On measures the pam bleaching. The ratio of white is usually used in connection with the bleaching process, as it becomes more accurate as svetlenija pulp, when the reflectivity is increased.

There are several methods of measuring the degree of delignification, but many of them are just variations of the permanganate test. Under normal permanganate test turns out permanganate number (K), i.e. the number of cubic centimeters decinormal permanganate solution of potassium absorbed by one gram of absolutely dry mass under certain conditions. Permanganate number is determined by the standard TAPPI test T-214.

There are also several methods of measuring the white pulp. This option is usually the measure of reflectivity, and its value is expressed in percentage on a certain scale. The standard method is white CE, expressed as a percentage of the maximum white CE, determined by TAPPI standard method TRD-103.

In addition, in the appropriate places will use a letter code described above in the section "Background to the invention"; throughout the detailed description he manganates number, viscosity and white, obtained using the proposed method of cooking, delignification and bleaching will show the ability of this method to improve the degree of removal of lignin from the pulp while minimizing the resulting destruction of cellulose.

Upon completion of stage oxygen delignification before the bleach plant has partially delignification weight with permanganate number from about 5 to 10, preferably from 7 to 10 for the growing U.S. softwood and from 5 to 7 for deciduous. The viscosity of the partially delignification mass of approximately greater than 10, usually about 13 and preferably at least 14 (for the mass of the softwood) or 15 (deciduous). Partially delignification material had good strength and desired viscosity and therefore could withstand exposure to ozone. Partially delignification mass was exposed to ozone for further delignification mass, resulting in a permanganate number of mass was decreased to approximately 3-4 for both coniferous and deciduous species, with the white mass was increased at least up to 50-70% of The pulp from softwood was usually achieved white will bring ulaznoj mass was achieved by bucking and additional bleaching with chlorine dioxide or hydrogen peroxide.

For ease of understanding the present invention and Fig.1 in schematic form shows the various stages that are used in cooking, delignification and bleaching of the pulp according to the invention. As can be seen from Fig.1, the present invention proposes a multi-step process in which:

(a) carry out the cooking of lignocellulosic material, and used in cooking chemicals can be regenerated and re-used using known methods;

(b) washed pulp for the removal of chemical waste from the cooking solution with residual lignin and, as a rule, sorted pulp mass to remove those bundles of fibers that will not be separated during cooking;

(C) carry oxygen-alkali delignification of the pulp (i.e., On or ABOUTm);

(g) partially washed delignification mass obtained in step (b), for the removal of dissolved organic compounds;

optionally, at this point you can sort and send for recycling at least a portion of the wastewater from this stage to a preceding stage;

(d) carry out helatoobrazovateli and acidification pulp for binding of metal ions and pH adjustment to a specified level;

(g) washed with ozonated mass, directing in recycling at least a portion of the wastewater from this stage to the preceding;

(C) carry out the alkaline treatment to remove residual lignin;

(and) wash the treated mass, recycle at least a portion of the wastewater to the preceding stage;

(K) adding a second bleaching reagent (i.e., D or P for lightening and whitening mass);

(l) washed clarified a lot for getting bleached product, the whiteness of which is approximately 70-90% and

(m) recycle at least a portion of the wastewater from the bleaching of P to the previous stage; or drain the waste water from the bleaching D or after appropriate treatment, recycle wastewater to the previous stage.

1. Cooking

The first step in the method according to this invention, which can be applied procedures, contributing to the removal of lignin from lignocellulosic materials while minimizing the destruction of cellulose, is cooking. The specific method of cooking used in this invention largely depends on the type of lignocellulosic material and more specifically to the type of wood used as a source material. From Phi is well-known methods. After this phase is usually followed by washing to remove most of the dissolved organic compounds and cooking chemicals for recycling and regeneration, as well as the sorting stage in which the pulp passes through a sorting device for removing those bundles of fibers that did not split during cooking.

Practically all varieties of wood, you can use the Kraft process, since the resulting material has acceptable physical properties, although the color of unbleached lot darker.

Depending on the source of lignocellulosic material, the results obtained on a typical Kraft process, can be improved by applying the method of extended delignification or Kraft process with addition of anthraquinone. This method is preferable when it is necessary to obtain a higher degree of reduction of the permanganate number of the pulp without undesirable deterioration of its strength and viscosity properties.

When using the Kraft process with addition of anthraquinone specific number of anthraquinone in the cooking solution should be at least about 0.01 wt. when calculating on the absolutely dry weight vivariums wood, floor and helps to remove lignin, without causing a harmful effect on the strength properties of the residual cellulose. In addition, the additional costs of anthraquinone partially offset by cost savings on chemicals in the later stages Zm, E, D or p

Alternatively or additions to the Kraft process using anthraquinone you can also use the methods of extended delignification of Kamyur, Belua or Sands proposed for boilers periodic cooking. These methods also allow you to remove more lignin from the pulp during cooking, without causing a harmful effect on the desired mechanical properties of the residual pulp.

2. Oxygen delignification

The next step in the method according to this invention is part of the process of bleaching, which focused primarily on the removal of residual lignin from the treated unbleached pulp. In accordance with the method according to this invention, at this stage is the stage oxygen delignification. At this stage removes oxygendemand materials, they can, like cooking solution, collect, concentrate, and then in an environmentally responsible manner ignited in a typical recovery boiler. As can be seen from the gnificance can be so which contributes to the destruction of large quantities of residual lignin in unbleached weight without exerting undesirable deterioration of its viscosity. In General, the described method is implemented by treating the unbleached pulp coming from the stage cooking with consistency from low to medium, with such a quantity of alkali required for stage oxygen delignification in order to ensure smooth flow of alkali and then increase the consistency and delignification to large quantities. The most preferred vysokochastotnaya delignification, but instead you can also use low - or srednekonkurentnyh oxygen delignification.

Stage vysokokonkurentnoj delignification should preferably be conducted in the presence of aqueous alkaline solution when the consistency of the mass from approximately 25 to 35%, preferably approximately 27% of Such improved method (Om) removes at least 60% of the residual lignin from unbleached pulp compared to 45-50% removed during typical stages of oxygen delignification, there is no previously inevitable deterioration in the relative viscosity. Due to the nature of the modified process

In the processing stage of the modified basic oxygen process (Om) is essentially uniform connection wood pulp, preferably unbleached pulp from the Kraft process, with an aqueous alkaline solution while maintaining the consistency of the mass is at least equal to about 10% and preferably less than 5 wt. Preferably, the aqueous alkaline solution is present in a quantity sufficient to obtain about 0.5 to 4 wt. active after alkali thickening in the calculation of absolutely dry unbleached weight, even more preferably a value of approximately 2.5% active alkali on weight after thickening calculated according to completely dry unbleached weight.

At this stage, the aqueous alkaline solution is evenly distributed throughout nizkochastotnoi mass, when all fibres unbleached pulp should feel evenly action of the alkaline solution. Quite unexpectedly it was found that the treated similarly unbleached weight mostly not delignified on the stage of processing, however, the delignification of unbleached pulp at a later stage vysokokonkurentnoj delignification more effective than the unbleached pulp, processed at high consistency in shch a typical alkali vysokokonkurentnoj mass and excluded from the accompanying inhomogeneous oxygen delignification.

It is desirable that in the homogeneous phase distribution was part of the uniform connection weight aqueous alkaline solution of at least about 1 min, and preferred not more than about 15 minutes, you Can assume that the processing time less than 1 min, usually not enough to achieve a uniform distribution, whereas the processing time more than 5 minutes will not give significant benefit.

Alkaline treatment of the mass according to the invention can be implemented in a wide temperature range. Practice has shown that processing can be performed at a temperature from about room temperature up to approximately 150oF (65,6oC), while the most preferred temperature is from 90 to 150oF (32,3 65,6oC). Can be used both atmospheric and high pressure. The processing stage is complete when the aqueous alkaline solution is evenly distributed throughout nizkochastotnoi mass. The aqueous-alkaline solution present on the stage of processing may vary within wide limits in accordance with the specific process parameters of the delignification reaction. An effective amount of the alkaline solution will depend primarily on, the. Preferably, the number of aqueous alkaline solutions was part of the sodium hydroxide solution with a concentration of approximately from 20 to 120 g/L. This solution is mixed with nizkochastotnoi mass, so that the concentration of alkaline material in the mixture was approximately between 6.5 and 13.5 g/l, preferably about 9 g/L.

If the processing time is from 5 to 15 minutes at the consistency of the mass from 3 to 5% and a temperature of from 120 to 150oF (48,9-65,6oC) when the specified concentration of the alkaline material, achieved its uniform distribution throughout the unbleached pulp.

In accordance with a preferred implementation of the present invention, aqueous alkali hydroxide solution is added to nizkochastotnoi mass in such a quantity that is sufficient to obtain approximately from 15 to 30 wt. sodium hydroxide calculated according to absolutely dry mass. Can also be used, and other alkaline solutions with equivalent content, e.g., white liquor from the typical cycle of the Kraft process with regeneration.

After step nizkochastotnoi alkaline processing consistency of the processed mixture is increased to no less than 20% and preferably OI mass removal from the liquid. Originally formed mass is unbleached weight, and at least part of the liquid obtained from the alkaline solution at the stage of increasing the consistency of the pulp, recycle on stage alkaline processing.

Next on vysokokonkurentnoj mass is oxygen delignification. To have an effect on the delignification can be used known methods of dissolution of gaseous oxygen in the liquid phase vysokokonkurentnoj mass. In accordance with this invention may be any of the known methods. However, it is desirable that when the oxygen delignification according to this invention was applied gaseous oxygen pressure of approximately 80 to 100 pounds per square inch in the liquid phase vysokokonkurentnoj mass, and the temperature of the mass is maintained in the range of about 90 to 130oC. the Average contact time vysokokonkurentnoj mass with gaseous oxygen, it is desirable to maintain approximately 20 to 60 minutes

If you follow the preferred process according to this invention, it is possible after stage oxygen delignification to reduce permanganate number, at least 60% by Attali is possible to achieve reduction in the permanganate number approximately 50% before the destruction of the cellulose. Thus, the proposed method allows to increase the delignification of at least 20% in comparison with typical delignification processes, i.e., from 50 to 60% reduction of the permanganate number of the incoming mass. With minimal destruction of the cellulose could be reduced by 70% or more. The fact that the destruction of the cellulose does not occur, is evident from the minimal changes in the viscosity of the mass to be processed according to this invention.

In the early stage oxygen delignification permanganate number of the weight is in the range from 10 to 26 depending on the type of wood (for example, when cooking on Kraft approximately 10-14, preferably of 12.5 for hardwood, softwood, from 20 to 24, preferably 21), whereas after oxygen delignification permanganate number is usually in the range from 5 to 10.

In Fig. 2 in schematic form showing the processing method according to this invention. Using the steps depicted preferred scheme that allows to extract the maximum benefit from this invention. Wood chips 2 is fed to the digester 4, which is cooked in the cooking solution, such as sodium hydroxide or sodium sulfide. From the cooking site 4 post is processed in the wash installations which preferably includes blow tank 10 and the washing apparatus 12 which removes residual working solution contained in the mass. The most famous different ways in brown stock washing, for example diffusion washing, rotary washing under pressure, horizontal filtering and dilution and extraction. All these methods are within the scope of this invention. In addition, very often is the brown stock screening both before and after a washing step to remove large pieces of unground wood for special handling.

Next, the washed wood served in obrabotannoy installation 14, where it is treated with an alkaline solution, while its consistency is maintained at less than about 10% and preferably less than 5% of the Process according to the invention also comprises means for supplying fresh caustic 16 to the machining stage to maintain the desired level. The treated mass 18 serves on spustitelny installation 20, which increases the consistency of the mass, for example, by pressing, at least 20 wt. and preferably from 25 to 35% of the Liquid 22 to be removed from the centrifuge 20, it is desirable to return the item is received in the thickener 20, send in the reactor 26 for oxygen delignification, where it is in contact with gaseous oxygen 28. Delignification unbleached mass, preferably 30 to pass through the blow tank 32 and to direct next to the second leaching installation 34, where the mass is washed with water to remove dissolved organic compounds and to produce high quality slightly coloured mass 36. Preferably at least part effluent 38 with a washing step to return in the wash installation 12 for use in it. In turn, the waste water 13 with a wash installation 12 can be recycled separately or together with affluent 38, or part of it to blow the tank 10 or line of black liquor 6. Partially delignification mass obtained at the stage oxygen delignification, can be sorted to remove bundles of fibers, not previously divided, for further processing, such as mechanical pulping. From there the mass 36 can be used for subsequent finishing stages to get fully bleached product.

In accordance with a preferred method according to this invention, is shown in Fig. 2, for the most successful application of ozone bleaching in which abode and vysokokonkurentnoj delignification (Om) described above. As noted above, when using softwood such a combination results in a mass of permanganate number of about 10 or less, preferably 9, and a viscosity of more than 13. Alternatively, you can also brew of wood by the Kraft process with addition of anthraquinone, followed by a stage of a typical oxygen delignification (i.e., About when is vysokochastotnaya alkaline treatment followed by vysokochastotnaya oxygen delignification), resulting in mass with similar properties. Instead of cooking the Kraft process with addition of anthraquinone processes could be used for extended delignification followed by the step standard oxygen delignification to obtain mass with the desired properties. Also very effective, though less preferred from the standpoint of increased costs is the combination of the Kraft process technology extended delignification, for example, processes of Kamyur MSS, Belua RDN and Sands, described in the introductory part of this description, followed by a typical oxygen delignification.

You can use various combinations of the stages of cooking and designlogo stage.

To apply typical cooking by Kraft in the framework of the present invention with the subsequent typical oxygen delignification generally undesirable, except for some hardwoods like aspen, relatively easy delignification and bleaching, as listed standard technologies usually requires a greater amount of ozone during ozone treatment, which is accompanied by great destruction of cellulose.

Thanks to the application of the present invention, it is possible to reduce the consumption of ozone if the use of several alternative methods, such as standard Kraft process, followed by the modified stage oxygen delignification (Om), or modified Kraft process with extended delignification (for example, the processes of Kamyur MSS, Belua RDN and Sands), followed by a stage of a typical oxygen delignification (O), or Kraft process with addition of anthraquinone, followed by a stage of a typical oxygen delignification (O) above.

An even greater reduction in the consumption of ozone can be achieved if we use the modified Kraft process with extended delignification (Kamyur MSS, Belua RDN and Sands with addition of anthraquinone and with extended delignification (Kamyur MSS, Belua of the RDI or Sands) with the subsequent stage of a typical oxygen delignification (O). In the case of the use of all these technological solutions in a single process, i.e., the Kraft process with addition of anthraquinone with extended delignification (Kamyur MSS, Belua of the RDI or Sands) with the subsequent stage of the modified oxygen delignification (phase Omit is possible to additionally reduce the consumption of ozone. In turn decrease the amount of ozone allows you to maintain the viscosity of the mass at an acceptable level.

The above advantages of the above-described modified stage bleaching with vysokokonkurentnoj oxygen delignification (Om) it is possible to illustrate by comparing the values of viscosity and permanganate numbers received on the southern coniferous species, in similar processes with identical conditions. Thus, the use of the Kraft process in its standard form with standard bleaching when vysokokonkurentnoj oxygen delignification allows to obtain a pulp, permanganate number of which lies approximately in the range from 12 to 14, and a viscosity of approximately 15. Similar permanganate number is too large to follow demotivational by bleaching, the resulting mass will be permanganate number less than about 9, whereas the viscosity of the mass will exceed 12-14. This permanganate number allows you to use lots of at the stage of the ozone bleaching according to this invention.

In accordance with the invention the next step represents the ozone delignification and bleaching of oxygen delignification unbleached pulp. Such ozonization is carried out in an ozone reactor, described in detail below in shown in Fig.2, 3 and 4. Before you begin processing the mass of ozone, it is necessary to condition in order to ensure the most effective selective delignification of the pulp and to minimize chemical exposure to ozone for pulp. Incoming mass 36 is directed into the mixing tank 40, where it is diluted to a low consistency. To nizkochastotnoi the mass of added acid 42, for example sulfuric acid, formic acid, acetic acid and so on, to reduce the pH of the mass in the mixing tank 40 to approximately 1-4 and preferably 2-3. Adjustment of pH is carried out for the reason that known as the relative efficiency of the ozone mass bleaching depends on the pH of the mixture. More is giving a pH of more than 4-5 will lead to a decrease in viscosity and increase in the consumption of ozone.

The acidified mass process helatoobrazouatelem 44 for the formation of complexes of any of the metals or their salts that may be present in the mass. Such helatoobrazovatel used to make metals less reactive or harmful to the ozone reactor, so that they do not lead to the disintegration of ozone and consequently to a deterioration in the removal of lignin and reduce the viscosity of the pulp.

By themselves, the chelating agents are known, it is, for example, polycarboxylate and its derivatives, for example, di-, tri-, and tetracarboxylate, amides, etc. To the number of preferred chelating agents for reasons of price and efficiency are DTRA, EDTA and oxalic acid. A number of chelating agents is approximately in the range from 0.1 to 0.2 wt. the weight of absolutely dry mass, although at high concentrations of metal ions may require an additional amount.

To monitor the efficiency of the process of the ozone bleaching is used a number of interrelated parameters, including pH and the amount of metal salts in the mass. Another very important aspect is the consistency of the pulp during ozone bleaching. In exposed bleaching mass should content the window should be sufficiently saturated with water. The presence of water in the fibers provides the transfer of ozone from the gaseous ozone atmosphere to the surface treatment of fibers, and more importantly, the aqueous phase provides the transfer of ozone to less than the available internal area of the individual fibers, thereby ensuring a more complete removal of lignin from the fibers.

On the other hand, the consistency should not be so small that the ozone will begin to dissolve and will begin its chemical decomposition instead of mass bleaching.

It was found that the preferred range of consistency, particularly for southern softwood USA, is in the range from 25 to 50% of the optimal results are obtained in the range from 35 to 45% To achieve the preferred results under such limits indicates the relative amount of delignification, a relatively small degree of degradation of cellulose and a noticeable increase in whiteness of the treated mass.

Also important controlling factor is the reaction temperature, which is ozone treatment. The ozone stage can effectively hold up to some critical temperature at which the reaction causes excessive degradation of the cellulose. The critical temperature in BPO way, the maximum temperature fibers, which should be reaction should not exceed the temperature at which there is excessive degradation of the cellulose, for southern softwood USA a maximum of 120-150oF (48,9-65,6oC).

Used during bleaching gaseous ozone can be used in the form of a mixture of ozone, oxygen and/or inert gas, or to use a mixture of ozone with air. The amount of ozone that can be included in the gas is limited by the stability of ozone in the mixture. For use in this invention are suitable ozone-gas mixture containing about 1-8 wt. ozone in the mixture of ozone, oxygen, or about 1-4 wt. ozone in the mixture of ozone with air. In relatively small reactors and shorter reaction times can be used high ozone concentration in the mixture for processing equivalent quantities of mass, which reduces the capital cost of the equipment. However, ozone-gas mixture with a content of less ozone is not so expensive to produce and reduce operating costs.

Another controlling factor is the relative weight of ozone used for the bleaching for the / establishment, which should be removed during ozone bleaching when the balance on the relative amount of degradation of the cellulose, valid during ozone bleaching. In accordance with a preferred method according to this invention is used, the amount of ozone, which reacts with approximately 50-70% of the lignin present in the mass. At the stage of the ozone bleaching does not remove lignin in the mass, as evidenced by the permanganate number equal to 3-4 after this step, since the absence of lignin in the reaction zone can lead to excessive reactions of ozone with cellulose, which will greatly reduce the degree of polymerization of cellulose. In accordance with a preferred method according to this invention, the added amount of ozone in the calculation by weight of dry matter is approximately from 0.2 to 1% to reach the level of lignin in 3-4 permanganate number. You might want a large quantity, if the system will contain significant amounts of dissolved solids.

The reaction time required for the ozone bleaching, is determined by the desired rate of completion of the reaction of ozone bleaching, indicating a complete or almost complete absorption of the used ozone. This time varies depending on the concentration of ozone in the ozone-gas mixture, and a relatively Bo is that it is desirable to remove.

It is desirable that this time was less than two minutes, however, the procedure may be longer depending on other parameters of the reaction.

An important feature of this invention is the uniform bleaching of the pulp. Partly this feature is achieved by grinding the mass of a single particle flakes with a sufficiently small diameter and a sufficiently low density so that the ozone-gas mixture is fully penetrated almost all fiber cereal, i.e., flakes of fiber agglomerates. During grinding it is impossible to completely separate the mass into individual fibers. As a rule, obtained by grinding the particles have a relatively compact core surrounded by a multitude of projecting fibers. In this invention the particle size is determined by the smallest diameter relatively rough core. The particles mentioned mass with increased consistency is ground to such a size that facilitates uniform contact with ozone in the absence of substantial destruction of the cellulose components of the mass.

The uniformity of bleaching largely depends on some other parameters of the process, however, it was found that if the particle size of the Ogre is abode a significant number of particles, the evidence of which is a small number of dark unbleached flakes. If the particle size exceeds 5 mm, the bleaching is heterogeneous, a testimony to the great number of dark potbelly centers. This explains the importance of such grinding, when the size of the main lobe of the flakes have an average of 5 mm for uniform treatment with ozone.

Another important process parameter is related to the fact that during the ozone bleaching particles should act ozone whitening mixture at such mixing, which provides access of the ozone-gas mixture to all surfaces of the flakes along with the same access of the ozone-gas mixture to all cereals. Mixing in the ozone-gas mixture allows to obtain better results for homogeneity in comparison with the results obtained in static layer, when some of the flakes are isolated from gaseous ozone, other cereals and therefore can be bleached to a lesser extent.

Due to the movement of the flakes is achieved a more uniform processing of the ozone-gas mixture. The result of the mass is removed the desired amount of lignin, in this case there is excessive is a processing in accordance with this invention through the use of particles with controlled size, and due to their turbulent movement during ozone treatment provides the finished weight of such variations in white, the permanganate number and viscosity that does not exceed 5% For comparison, note that for heterogeneous processing, typical for reactors with static layer (i.e., in the reactor, where, during the ozone treatment, the particles do not mix), some areas of the layer excessively bleached, while others are almost not react because of the heterogeneity of the flow of gaseous ozone in the reactor with a static layer.

In the case of treatment with ozone vysokokonkurentnoj masses it is necessary to pay special attention to the crushing of the fibers of the mass and for proper contact between the individual fibers and the flow of gas, otherwise it will inevitably happen heterogeneous ozone bleaching of fibers. In this invention such heterogeneous processing indicated by the letter "Z". Using the modified technology of ozone treatment according to this invention, when the fibers are crushed to a size of approximately 5 mm or less and take the correct and uniform contact with gaseous ozone flow, denoted Zm.

The white mass at the outlet of the ozone reactor sostav the AET 55% Permanganate number of mass as coniferous, and hardwood, is in the range from 3 to 4 (preferably 3,5), which is fully satisfactory for mass at this stage of the invention.

In Fig. 2, 3 and 4 shows the device that is most adapted to ozone treatment according to this invention. As mentioned above, the washed mass 36 is routed to the mixer 40, where it is treated with acid 42 and helatoobrazouatelem 44. Acidified and melirovanie Malcontenta mass 46 is served in spustitelny installation 48, where it removes the excess liquid 50, it can be a double roll press, where the consistency of the pulp is increased to a specified level. At least part of the excess fluid 50 can be recycled to the mixer 40, and the rest be sent to the blow tank 32. Next, the resulting vysokochastotnaya weight 52 passes through the screw feeder 54, fulfilling the role of gas seals for gaseous ozone, and grinding through the installation 56, such as a leavening agent, where the mass is crushed up flakes 60 predefined size, which should not exceed 5 mm, as mentioned above. The crushed particles are introduced later in the camera dynamic reaction with ozone 58 by means of the conveyor 62, privatistic mass 60 with the to the entire surface of the particles was opened by the action of the ozone-gas mixture 66 during movement. It is evident from Fig. 2 shows that after treatment flakes 60 freely fall into the solvent reservoir 68.

In Fig. 3 presents a view of the ozone reactor 58 in section, where you can see the location of the particle mass 60 when moving through the reactor conveyor 62. In Fig.4 shows the preferred conveyor section and to move the crushed particles through the reaction chamber 58 is used blade design.

In Fig.2 shows that processed by ozone mass moves in one direction with the ozone-gas mixture. Alternatively, the portion of the mass which must otmelivatsja more may initially communicate with incoming ozone mixture containing the maximum amount of ozone by passing ozonoterapia gas in countercurrent flow with a mass of 60. Arriving in reactor mass has the highest content of lignin and initially in contact with the outgoing and almost spent the flow of the ozone-gas mixture, which allows almost entirely to absorb ozone. This method is very effective for the selection of ozone from the mixture of ozone with oxygen or ozone to the air.

From the reservoir 68 of spent gaseous ozone 70 is sent to a pre-processing stage 76 with a carrier gas, where it is added to the carrier gas 78 in the form of oxygen or air. The resulting mixture 80 is supplied to the ozone generator 82, where and generated such an amount of ozone, which is required to obtain the desired concentration. Next, you'll need a mixture of ozone with air 66 is sent to the ozone reactor 58 for delignification and bleaching of pulp.

At the completion of phase ozone bleaching all essentially delignification weight 74 again washed in the washing installation 84, as shown in Fig.2, and at least part of the recycled water 86 to recycle the wash installation 34, thereby significantly improving environmental protection, because it eliminates the presence of sewage.

After ozone bleached nizkochastotnaya weight 74 contains a reduced amount of lignin and therefore has a lower permanganate number and subjected to mass. For example, the mass of conifers in the southern USA, processed according to standard Kraft method, first delignified method modified vysokokonkurentnoj oxygen delignification (Om), and then click next delignified ozone, preferably using a modified homogeneous ozone treatment (Zm), permanganate number is 3-4, and a viscosity of approximately 10. The mass of conifers in the southern USA, subjected to cooking in the Kraft process with addition of anthraquinone and then modified vysokokonkurentnoj oxygen bleaching (Omand modified the ozone treatment (Zm), usually has a permanganate number of about 2 and a viscosity of more than 12.

The resulting mass 74 noticeably whiter than the original mass. For example, the mass of the southern conifers after cooking has a whiteness of from about 15 to 25% after oxygen bleaching white is from approximately 25 to 45%, and after ozone bleaching white is approximately from 50 to 70%

Alkaline treatment

Then the washed mass of 88 combined with a sufficient quantity of alkaline material 90 in the reaction tank 92 for the implementation of the alkaline is mperature, consistent with the available quantity of alkaline material to be dissolved in the tank 92 of a significant proportion of the lignin remaining in the pulp. The process be also improves the whiteness of the mass, usually 2 points on a scale of white CE. Next, the treated mass 94 sent to wash installation 96, where mass was washed aqueous-alkaline solution in order to remove virtually all dissolved lignin and as a result get a lot, practically do not contain lignin. This step is well known to specialists, and probably there is no need for any additional comments. Illustration of the preferred options be this phase can be found in the examples. At least part of the regenerated alkaline solution is recycled in the washing installation 84. The fact that at this stage there are no waste water, contributes to a significant improvement of environmental protection.

In some cases, and particularly when it is necessary to achieve the greatest white, stage alkaline processing can be enhanced by introducing into it the oxygen treatment (Eabout). Any comments on this phase, also well known in the art, is not required.

Additional stages of bleaching.

WESM is. the advanced button to raise the white to a more preferred range from approximately 70 to 95% by weight is subjected to bleaching and clarifying that primarily provides the conversion of the chromophore groups of the lignin in a colorless state.

After melacini and pulp washing you can spend and clarifying the bleaching salacinol and treated with ozone mass for this purpose can be used a variety of materials. In Fig.2 shows that the washed mass 100 is connected with the selected bleach 102 in otbelivanie the reservoir 104. Preferred bleach is chlorine dioxide or peroxide. After bleaching the mass 106 is washed with water 114 in the wash installation 108, and effluent or recycle 110 or thrown 112. In the case of recycling at least part of the water flow 110 is sent to the wash installation 96. Received bleached mass 116 can be collected and used for various purposes.

One of the main materials, widely used in the past and which is highly efficient and at the present time, is chlorine dioxide (d) (see Fig. 1). In accordance with this invention by use of an appropriate quantity of chlorine dioxide can be obtained is speaking on stage treatment with chlorine dioxide, relatively small, and clarifying the bleaching can be carried out in the presence of only 0.25 to 1% chlorine dioxide based on the weight of absolutely dry mass.

Preferably, the chlorine dioxide used in the clarification process, there was no chlorine gas. Less desirable, when using a chlorine dioxide containing a small amount of gaseous chlorine, which however does not lead to increased discharges of hazardous substances for the reason that in the mass, coming to this stage after ozone bleaching, there is a relatively small amount of lignin. Effluent coming from the last stage of the bleaching of the present invention, when using chlorine dioxide, is extremely small, and it can be safely discharged, as shown in Fig.2.

If the discharge of wastewater from the last stage bleaching with chlorine dioxide unacceptable, then this stream can be further cleaned by treatment in the process of membrane filtration such as reverse osmosis. When such technology is pure filtrate, which can be recycled back to the previous stages of bleaching for future use. This reduces the need for clean water. In addition to the ptx2">

You might encounter a case when you need to get a lot with extremely high whiteness, for example 92-95 SOWING, then you can apply several additional stages of bleaching. Most often the choice of stops for extra bucking and treatment with chlorine dioxide, i.e. as a result of the bleaching sequence OmZmEDED.

Instead for the final bleaching apply chlorine dioxide by bleaching and clarifying apply hydrogen peroxide, which is also shown in Fig.1. In this case, we have a cycle of bleaching in the complete absence of chlorine (for example, a sequence of type OmZmER), whereas during the bleaching process does not form chlorinated materials, and leachate can be recycled, without resorting to complex filter apparatus. However, when using peroxide as a bleach, it is necessary to reduce the permanganate number of the mass from both coniferous and deciduous species to the level of approximately 6 to stage ozonation, so that after the stage peroxide bleaching in the quality of the final product to get a lot of acceptable white, for example, more than 80% since the peroxide is not as effective as DVI chlorine, peroxide can give satisfactory results.

Specific types of peroxide clarifiers and their application at this stage is well known, and therefore the specialist will not be difficult to find the necessary concentration, the type and the usage of peroxide. The most preferred hydrogen peroxide.

White washed and additionally lighter weight ranges from 70 to 95%, preferably from 80 to 95% of their physical properties like mass close to the mass obtained by standard processes DD or OS/DD.

Recycling wastewater

In any production process from cellulose by weight of one of the major factors affecting the economic efficiency or the total cost of the process is the neutralization of the filtrate. There is also the problem of access to an appropriate source of water and the problem of wastewater treatment prior to discharge.

To reduce the demand for water in this process, it is desirable to send to recycling as much waste water. Such a practice cannot be used in processes that use chlorine or chlorine dioxide, as in the wastewater produced during these processes, large quantities kept talking to the formation of chlorides, which, in turn, lead to corrosion of equipment or the use of expensive materials. In addition, such water must be serious processing until the reset, which requires additional costs associated with equipment and chemicals.

In Fig. 5 shows that the use of standard process DED way or OS/DD leads to serious difficulties in the discharge of wastewater received at the washing steps, due to the presence of large levels of chlorinated compounds. We have already mentioned that these flows cannot be recycled, it should be treated before discharge into the environment. Recycling waste water can be applied, wanting to reduce the amount of water used. But then, the equipment may suffer from accelerated corrosion caused by the high level of chlorine in recycled effluent.

In contrast, in the use process OFmZmED according to this invention produces the minimum amount of chlorinated material in the wash water, and this water can be safely discharged without violating basic environmental standards. Alternatively, the waste water can be treated Abram bleaching, as shown in the drawing, there is no increase in chloride concentration. On stage pulp washing, essentially do not contain lignin, separate the mass from the resulting wash water and direct at least part of these wash water in the washing step essentially delignification mass. This washing step is essentially delignification weight referred to the weight of the wash water from the pulp washing, essentially do not contain lignin, separate the mass from the resulting wash water and direct at least part of these wash water in the washing step partially delignification mass.

In the washing step partially delignification weight referred to the weight of the wash water from the washing essentially delignification mass, separating the mass from the resulting wash water and direct at least part of these wash water in the washing step of the masses.

In addition, the washing step weight referred to the weight of the wash water from the washing partially delignification mass, separating the mass from the resulting wash water is collected referred to the wash water and concentrate it to calcination in the HRSG. If it is desirable to conduct the study is about the use stage Eaboutachieving a higher degree of whiteness, although the use of sodium hydroxide and oxygen leads to an increase in costs. In addition, well-known industrial technology for production of chlorine dioxide, which minimized the levels of residual chlorine (for example, the process R8 process R3). Such chemicals with a reduced level of chlorine, it is preferable to apply at stage D, to reduce the level of chlorides in wastewater.

To get additional significant advantages over the known technical solutions can instead process ABOUTmZmED to use amZmER, this reduces the amount of chlorinated compounds. In the waste water can be recycled without the problems associated with increasing the concentration of chlorides in wastewater flows.

Thus, the method according to this invention has significant advantages in terms of reducing the volume of wastewater, COD, D and chlorinated organic compounds, as well as in the sense of color. Because in the wastewater coming from the washing steps, there is significantly less chloride in comparison with known processes where chlorine is used, trabocchi before discharge into the atmosphere.

For a more complete understanding of the principles of the present invention consider the following examples are presented solely for illustrative and not restrictive purposes. If there are no other indications that everywhere in the examples, the percentage of chemicals is calculated by weight absolute fiber (D). In addition, the specialist should be clear that the exact achieving a given level of whiteness is difficult as the deviation of whiteness within plus or minus 2% of the set value is valid. In all examples, where there is a stage D, with the exception of example 11, was used a solution of chlorine dioxide with respect dioxide to gaseous chlorine 6:1.

Example 1 (comparative). Chips incense pine was subjected to periodic boiling in the conditions specified in the table.I, to obtain the mass of a typical Kraft process. The resulting mass had a permanganate number 22,6 when the viscosity 27,1 SP. Then mass was subjected to standard processing oxygen (tables II and V), followed by bleaching to the final specified white 83 GEB using standard sequence OS/DD (PL.III) and the sequence of bleaching OZmED (PL.IV and V). Stage ozone bleaching was carried out with consistency the conditions of bleaching OZmED turns out to mass, having acceptable strength properties in comparison with the mass processed by the OS/DD white 83% In these conditions the mass of OZmED has a limiting viscosity of 9.7 CP. Strength properties were measured on the mass of OZmED, when the final admission to stage D was 2.5% of the Desired whiteness is achieved only when excessive loading of chlorine dioxide. From the reaction mass OZmE to the processing of chlorine dioxide can be seen that most white can only be achieved by increasing the feed rate of ozone, leading to significant loss of toughness and strength.

Example 2. In a laboratory digester plant periodic operation according to the method of Kraft with addition of anthraquinone got unbleached pulp from chips frankincense pine, see table.VIII. The permanganate number of the received unbleached pulp was equal to 18.3, viscosity 20,6 SP. During cooking, the Kraft process with addition of anthraquinone was obtained weight with significantly less lignin than the mass of example 1, the evidence of which is the permanganate number, when this was not observed deterioration in the strength of the masses, the evidence of which is its viscosity.

Then unbleached mass was subjected to bleaching with the use of a standard posledovatel is 83% SOWING. Through the use of the Kraft process with addition of anthraquinone was obtained the desired compound with little permanganate number and the desired viscosity properties required for the ozone bleaching. Stage ozone bleaching was carried out with consistency in 35% when applying ozone to 0.35% on the last D stage to achieve the desired whiteness was applied at 1.6% ClO2.

As can be seen from the following table.IX and X, there is an improvement of the optical properties measured by the bleaching reaction, at the last stage of treatment with chlorine dioxide, while the strength properties remain satisfactory in comparison with the values obtained by the method of OS/DD.

Example 3 (comparative). Unbleached mass, obtained by the Kraft process and having a permanganate number of about 24, was subjected to pressing to the consistency of approximately 30-39 wt. to obtain vysokochastotnogo Mat. This Mat adorning 10% solution of sodium hydroxide in a quantity sufficient to obtain about 2.5 wt. of sodium hydroxide based on the weight of dry matter. For dilution was added water in an amount sufficient to obtain a consistency of approximately 27% More Mat from vysokochistom the duration of 30 min, oxygen pressure of 80 pounds per square inch.

Example 4. Unbleached pulp of example 3 was introduced in obrabotany tank with sufficient 10% NaOH solution for the implementation of 30% NaOH additive when calculating the mass of dry matter. To achieve obrabotochka reservoir consistency brownstock pulp to approximately 3 wt. there was added a sufficient amount of water. Mass and aqueous sodium hydroxide solution are thoroughly mixed at room temperature using a tape-screw mixer for approximately 15 minutes Treated unbleached weight then opressively to the consistency of approximately 27 wt. After pressing, the amount of sodium hydroxide in the fiber was equal to approximately 2.5% as in example 3. Next treated unbleached mass was delignification as described in example 3 the procedure of oxygen delignification. Comparative data are presented in table.XI.

A comparison of the data obtained in examples 3 and 4, one can notice that the application of the preferred method according to this invention using nizkochastotnoi alkaline additives, followed by vysokochastotnaya oxygen quenching is m by known methods, this was not observed any significant changes in strength properties.

Because the mass obtained by this process has a lower permanganate number, the subsequent bleaching stages may be adjusted under a lot with less lignin and more white. Therefore, for different stages of bleaching in this case requires less bleach or less time whitening in comparison with the mass, has not been processed according to this invention.

Example 5. The mass obtained from pine to process ABOUTmfrom example 4 of the present invention, compared with the mass obtained by the standard method (O), (i.e. in the absence of phase nizkochastotnoi alkaline processing). The average dosage of caustic soda for vysokokonkurentnoj oxygen delignification of unbleached pulp was 45 pounds per ton of dry matter (lb-t) or 2.3% At this level, the average reduction of the permanganate number after reactor oxygen delignification was 10 units. At the same level caustic fed to the mass in accordance with the preferred stage of processing, the average reduction of the permanganate number during delignification was 13 units, i.e., there is an improvement of 30% in comparison with typical Osti mass. Average permanganate number and the viscosity of the sample mass is 12,1 14,4 CP, respectively. According to the preferred method of treatment according to this invention, the average permanganate number with the same viscosity (14,0 SP) was 8.3.

Delignification selectivity can also be expressed through the change of viscosity as a function of changes permanganate number between unbleached mass and processed accordingly. When changing permanganate number begins to exceed 10 units, is a very rapid drop in oxygen delignification selectivity. The decrease in selectivity is observed with the rapid increase of viscosity changes for a given change permanganate number. For example, when a change permanganate number is 12 units, you can expect a corresponding change in viscosity will be from 12 to 13 SP. In contrast, when the same change permanganate number (12), obtained on delignification mass processed according to this invention, the viscosity was approximately 6 SP. The change in viscosity with change in permanganate number is almost constant until the change reaches 16-17 units Example 6. At a working installation of 600 tons/day for the production of thin paper from false pines made a lot, using a modified process oxygen delignification (Om) when the conditions specified in the table.II in combination with a uniform alkaline treatment as described in examples 4 and 5, and under the conditions shown in table XIII below. The mass properties obtained during the oxygen treatment under the new method, required additions to the bleaching process using ozone, as described in the preferred embodiment of the invention. After the oxygen stage permanganate number mass was equal to 7.9 (model after the oxygen stage permanganate number is approximately 12). Viscosity delignification mass was approximately 15 JV, while it was not observed significant decrease after delignification conducted according to methods modified oxygen process. Next, the mass was subjected to further bleaching using ozone, using one of the variants of implementation to get a lot with the required ultimate strength and optical properties.

The bleaching of pulp by the method WITH/DD was completed in the laboratory, as shown in t the information, is depicted in Fig.2. Working conditions experienced reactor are presented in table.XV.

Then bleached in a pilot plant mass was treated with bucking and chlorine dioxide in laboratory conditions described in table.V, the result is ready the bleached pulp with a given white. Download on D last stage was only 1.0% ClO2.

In table.XVI and XVII presents the data for comparison of the strength and optical properties of mass separated using ozone and pulp, processed by standard methods OS/DD.

Example 7. To bring additional example of the usefulness and applicability of the process according to this invention, by using ozone pilot plant described above in example 6 was carried out bleaching of fibers from deciduous southern rock, consisting mainly of eucalyptus and oak. The mass obtained at a working installation of 600 TRD, after a stage of a typical oxygen treatment was treated with ozone in the experimental reactor.

The permanganate number of the pulp after oxygen stage was equal to 5.7, viscosity 14,1.

The part of the mass with the oxygen stage was bleached on the sample sequence WITH/DD in the laboratory to obtain Sravnitelnoe presented in table.XIX. The mass obtained with the experimental setup after the stage Zmwas finally subjected to bleaching by standard stages E and D to the desired whiteness, the conditions for these stages are presented in table. XX. Download ClO2phase D was only 0.35% of dry matter. Strength and bleaching properties are compared in table.XXI and XXII.

Example 8. Comparative tests, the same tests as example 5 were carried out with a mixed mass of hardwood, which consisted mainly eucalyptus and oak. In this case, it was also discovered that achieved significantly greater reduction of the permanganate number in the reactor oxygen delignification using a modified basic oxygen process (Omin comparison with standard oxygen treatment (About). The average dosage of caustic soda for hardwood was 27 pounds/tons, or 1.4% reduction of the permanganate number on stage oxygen treatment was 5 units. When using caustic at the same level in the modified process oxygen treatment was observed an average reduction of permanganate number 7.3 units, i.e., there is an increase of almost 50%

This same advantage delignification selectivity can be shown on the but this invention was obtained permanganate number 6 with a viscosity of 17.7. In addition, it was found that permanganate number with the same viscosity of the mass, the raw material (16 SP), was 5.8.

Delignification selectivity can also be expressed through the change of viscosity as a function of changes permanganate number of the unbleached pulp and the pulp passing through a modified oxygen treatment. When comparing the weight after sample processing mass obtained according to this invention, a significant reduction delignification selectivity at elevated degree of delignification. When changing permanganate number 4 units average change in viscosity was 4 SP from mass produced by standard process. In contrast, a change permanganate number from the mass measured on a modified oxygen method with the same change in viscosity was 7 units. Thus, the selectivity of the modified method was 1.8 units permanganate number of the CP, the selectivity of the model process 1 unit, permanganate number - CP, i.e., the increase is 80% of the Results are presented in table.XXIII.

Example 9. In the pilot plant was conducted a series of experiments on the mass, p is(About). Experiments should illustrate the effect of pH during ozone bleaching on the southern deciduous. The operating conditions of the reactor was maintained constant, they are listed in the table.XXIV, the only variable was only pH on ozone stage.

From table. XXV you can see how great the influence of pH during ozone bleaching, and low values of pH improve the selectivity of the bleaching process.

Example 10. It is of interest to cite a number of properties that illustrate the positive influence of the process OZmED in the production of fully bleached pulp. Were collected typical operating data and measurements of wastewater from different business units, which used methods of bleaching DD and OS/DD mass of pine. All these values were compared with values related to wastewater, obtained by the method of OZmED using mass ABOUTmED and wastewater obtained in example 1. Data model methodology DD see table. XXVI, data model methodology OS/DD see table.II and III, the data by the method of OZmED, see table.IV and V

Note that in the method DD wastewater represent a combination of sewage with steps C, E1D1, K2and D2. In the method OS/DD Stoc only wastewater from the stage D. As seen from the above table. XXVII, the method of the ozone bleaching can significantly reduce the impact of wastewater from the stage of bleaching on the environment. To determine the color used EPA method 110.2. From the obtained data it can be seen that the invention allows to obtain a wastewater containing dye is not more than 2 pounds per ton, the value of D5do not exceed 2 pounds per ton and the amount of organic chloride in the amount of not more than 2, and preferably less than about 0.8.

Example 11. A lot of pine, obtained by the Kraft process, was subjected to bleaching with three modifications of the basic method OZED. In the first case (ZmED) mass otvalivalas in accordance with the data table.IV and V with a typical processing oxygen modified by treatment with ozone, bucking and treatment with chlorine dioxide according to the sequence R-3 with respect to ClO2/Cl26,1. In the second case we have used the modified oxygen process (Om), and at the last stage was applied to the chromium dioxide by R-3. In the third case was also used a modified oxygen process (Om), while the last stage was used a solution of chlorine dioxide in the ratio of 95: 1 to R-8. From Tabom). We also see a positive effect in obalochnogo solution of R-8.

Example 12. In the Kraft process and the Kraft process with addition of anthraquinone from the frankincense pine got the pulp mass in accordance with the conditions shown in table.I and VIII above. The mass was subjected to standard and modified oxygen delignification according to the conditions of examples 4 and 5 in order to show the effect of the combination of these processes (for extended delignification with minimal impact on the strength of the masses) during ozone bleaching. From table. XXIX shows that these processes give an additive effect. It is possible to achieve very small permanganate numbers when the action method ABOUTmZmE at small effect on the final viscosity. Conversely, you can significantly reduce the amount of ozone required to achieve specified in the method ABOUTmZmE permanganate of 3.5 for the previously described processes of bleaching. In addition, due to the additive effect is weight, which can be completely bleached by the method of OmZmER, where the peroxide stage requires a very small permanganate number.

Example 13. A lot of conifers, such as frankincense pine, bleached to a predetermined DD, presented in table. II and III and applying the methodology OZmED, are presented in table.IV and V. in order To check the ability to remove contamination using this method compared to bleaching by the method DD and OS/DD to the original unbleached weight added ground polluting material based on wood with 0.75 wt. All three methods properties for removing contaminants were equivalent when measuring effective black square, bark and wood chips.

Example 14. This example illustrates the applicability of the process according to this invention during ozone bleaching. Bleached mass can be obtained with different values of whiteness through appropriate combinations of ozone and chlorine dioxide while minimizing environmental pollution and reduce operating costs. From the above table. XXX can be seen that various combinations of ozone and chlorine dioxide can be obtained products, the whiteness of which exceeds 65% GEB, when it saved the required strength properties.

Although from the above it is seen that the invention provides for the achievement of objectives, but the specialist obvious possibility of various modifications and variants.

1. The method of obtaining from the ssy, oxygen delignification of the pulp to remove a substantial portion of the lignin, the combination of the stages of chemical digestion and oxygen delignification chosen such as to obtain intermediate pulp mass, containing a specified number of lignin and having a given viscosity, and ozone delignification intermediate mass, characterized in that the ozone delignification is carried out at regulation consistency and pH of the intermediate mass to certain values, crushed intermediate mass to separate particles of sufficiently small diameter and a sufficiently low density to facilitate essentially complete penetration of ozone in the majority of the particles and bleach particles with ozone in an amount sufficient to remove a substantial part, but not all of lignin through close contact and mixing of individual particles with ozone for a time and temperature sufficient to provide essentially uniform delignification and bleaching of the majority of the particles for the formation of bleached pulp, with a certain amount of lignin in the intermediate mass is such that after ozone delignification of the bleached pulp was achieved certain white, while opravou delignification and obtain a bleached pulp of a certain strength.

2. The method according to p. 1, characterized in that the particle size mass less than approximately 5 mm

3. The method according to p. 1 or 2, characterized in that it contains the chemical extraction of lignocellulosic material by the Kraft process, Kraft process with addition of anthraquinone or extended delignification.

4. The method according to p. 1, characterized in that on stage oxygen delignification form a mass with the consistency from low to medium, treated with an aqueous solution of alkaline material mass with the consistency of minor to average over a certain period of time and at a certain temperature depending on the amount of alkaline material to essentially uniform distribution of alkaline material throughout the mass, increase the consistency of the pulp to high and put the received vysokokompetentnoe mass vysokokonkurentnoj oxygen delignification to produce an intermediate pulp.

5. The method according to p. 1, wherein receiving the pulp mass, a degree of whiteness which is at least 50% of a certain viscosity at a specific strength greater than 10 centipoise, and a specified number of lignin from intermediate mass indicates permanganate number, cellulosic material is pine wood, some white is at least equal to 50% of a certain viscosity at a specific strength greater than 10 centipoise, at a specified quantity of lignin in the intermediate mass indicates permanganate number equal to approximately 7 to 10, and set the viscosity exceeds 13 SDR.

7. The method according to p. 1, characterized in that the lignocellulosic material is hardwood timber, some white more than 55% of a certain viscosity at a specific strength greater than 10 centipoise, at a specified quantity of lignin in the intermediate mass indicates permanganate number equal to approximately 5 to 8, and set the viscosity exceeds 13 SDR.

8. The method according to PP.5, 6 or 7, characterized in that the amount of lignin contained in the mass after oxygen delignification, is determined by the permanganate number of bleached pulp, approximately 3 to 4.

9. The method according to p. 1, characterized in that it further comprises the bleaching of pulp after ozone delignification using a clarifier to increase the whiteness of the bleached pulp.

10. The method according to p. 9, characterized in that it further comprises a stage on which connect the bleached pulp with a sufficient quantity of alkaline material in an aqueous-alkaline rasia significant part of lignin, remaining in bleached mass, and then removing a portion of the caustic solution in order to remove therefrom essentially all the dissolved lignin and get leached mass prior to bleaching the clarifier.

11. The method according to p. 9, wherein the clarifier is chlorine dioxide or hydrogen peroxide.

12. The method of delignification and bleaching of lignocellulosic material to pulp, with some white and a specific strength, which indicates a certain viscosity, characterized in that the boil lignocellulosic material to obtain a weight having a first permanganate number and the first value of the viscosity, delignification oxygen resulting mass to obtain partially delignification mass having a second permanganate number less than the mentioned first permanganate number and sufficient for further delignification ozone partially delignification mass while maintaining the viscosity at a level at which there are significant chemical damage to the pulp components mentioned partially delignification mass due to oxygen delignification, expose partially delignification weight of ozone is on with the amount of ozone, supplied to the above-mentioned partially delignification mass to obtain delignification mass having a third permanganate number, much less mentioned second permanganate number mentioned partially delignification masses and values of white, exceeding the value of the white of the partly delignification mass while maintaining the viscosity at a certain level, preventing the destruction of the cellulose components of the mass in order to avoid a significant reduction in its strength.

13. The method according to p. 12, characterized in that the partially delignification mass contains such a quantity of lignin, which after ozone delignification allows a certain white, and has such a viscosity that is high enough to compensate for the drop in viscosity during the ozone delignification, to achieve a certain strength delignification mass.

14. The method according to p. 12, characterized in that it further comprises a stage on which connect delignification mass with a sufficient quantity of alkaline material in an aqueous-alkaline solution at a certain temperature, combined with a number of connected alkaline material, d water-alkaline solution with the to remove virtually all dissolved lignin and get a lot of, almost do not contain lignin.

15. The method according to p. 14, characterized in that it further comprises the step of bleaching containing no lignin mass to the point of whiteness, which is significantly higher than the value of white at delignification mass.

16. The method according to p. 12, characterized in that the viscosity mentioned partially delignification mass support more than about 13 centipoise.

17. The method according to p. 16, characterized in that the viscosity decreases mentioned partially delignification mass is maintained at 30% or less from the first value.

18. The method according to p. 12, characterized in that the said lignocellulosic material is a deciduous wood.

19. The method according to p. 18, characterized in that the said first permanganate number is in the range of 10 14.

20. The method according to p. 18, characterized in that the said first value of the viscosity is in the range of 21 SDR 26.

21. The method according to p. 18, characterized in that the said second permanganate number is in the range 5 to 8.

22. The method according to p. 21, characterized in that the said third material is pine wood.

24. The method according to p. 23, characterized in that the said first permanganate number is within 20 24.

25. The method according to p. 23, characterized in that the said second permanganate number is within 7 to 10.

26. The method according to p. 12, characterized in that the oxygen delignification processing is performed on the mass medium consistency.

27. The method according to p. 12, characterized in that the phase partial delignification further includes the steps, in which process the mass of a certain quantity of alkaline material in an aqueous-alkaline solution for a certain time and at a certain temperature, combined with a quantity of alkaline material in order to realize a uniform distribution of alkaline material throughout the mass, increase the consistency of the mass upon completion of the processing step, is subjected to mass with increased consistency vysokokonkurentnoj oxygen delignification to obtain partially delignification mass.

28. The method according to p. 12, characterized in that the viscosity of the specified delignification mass support more than about 10 centipoise.

29. The method according to p. 28, characterized in that the viscosity decreases casanovaroy mass.

30. The method according to p. 12, characterized in that an additional stage of delignification further provides the steps, which increase the consistency of partially specified delignification mass, crushed specified weight increased consistency to particles of a certain size, provide uniform contact specified crushed mass with the specified sufficient amount of ozone by passing the mass through this process.

31. The method according to p. 30, characterized in that the particles mentioned mass with increased consistency is ground to such a size that facilitates uniform contact with ozone in the absence of substantial destruction of the cellulose components of the mass.

32. The method according to p. 31, characterized in that the mass is crushed to a size of approximately 5 mm and move through the process in such a way as to avoid uneven supply of ozone to the mass.

33. The method according to p. 32, characterized in that the ground mass is advancing in the same direction with ozone.

34. The method according to p. 32, characterized in that the ground mass promote prototechno ozone.

35. The method according to p. 15, characterized in that the mass, containing no lignin, bleached with chlorine dioxide.

37. The method according to p. 35 or 36, characterized in that the step of bleaching the white mass, containing no lignin, rises at least approximately 70%

38. The method according to p. 35 or 36, characterized in that the step of bleaching the white mass, containing no lignin, rises at least approximately 80

39. The method according to p. 35 or 36, characterized in that the step of bleaching the white mass, containing no lignin, rises at least approximately 90%

40. The method of delignification and bleaching of lignocellulosic material, wherein the partially delignified lignocellulosic material to obtain a pulp having a permanganate number of about 10 or less and a viscosity of more than about 13 centipoise, and then delignification a lot some a sufficient amount of ozone for a time sufficient to obtain almost delignification mass having a permanganate number of about 5 or less, viscosity of about 10 centipoise and a whiteness of at least about 50%

41. The method according to p. 40, characterized in that the lignocellulosic material is pine wood and partially delignified to mass with PE who CLASS="ptx2">

42. The method according to p. 41, characterized in that the mass of the softwood has a permanganate number of about 3 to 4, the viscosity is more than 10 centipoise and a whiteness of at least 50% after the specified additional ozone delignification.

43. The method according to p. 40, characterized in that the lignocellulosic material is deciduous wood and partially delignified to mass, having a permanganate number of about 5 to 8 and a viscosity of more than 13 SDR to additional ozone delignification.

44. The method according to p. 43, characterized in that the weight of the hardwood has a permanganate number of about 3 to 4, the viscosity is greater than 10 centipoise and white more than 55% after ozone delignification.

45. The method according to p. 40, characterized in that it further contains the steps that connect mainly delignification mass with some effective quantity of alkaline material in an aqueous-alkaline solution for a certain time and at a certain temperature, combined with a quantity of alkaline material to dissolve a substantial portion of the lignin remaining in the mass, extract the aqueous-alkaline solution to remove virtually all dissolved loginpanel phase extraction white mass increased by approximately 2 points on a scale of white GE.

47. The method according to p. 45, characterized in that it further includes a step in which bleach mass, containing no lignin, using chlorine dioxide or hydrogen peroxide to increase the whiteness of at least approximately 70%

48. The method according to p. 47, characterized in that the whiteness increases at least approximately 80%

49. The method according to p. 47, characterized in that the whiteness increases at least approximately 90%

50. The method according to p. 45, characterized in that the lignocellulosic material is partially delignified with oxygen delignification processing.

51. The method according to p. 50, characterized in that the oxygen delignification treatment is carried out at the mass of medium consistency.

52. The method according to p. 45, characterized in that the lignocellulosic material is partially delignification on stages, in which form the mass of the comparative low consistency of approximately less than 10 weight. process nizkobonitetnyh the mass of a certain quantity of alkaline material in an aqueous-alkaline solution for a certain time at a certain temperature, combined with a quantity of alkaline material for uniform distribution of the alkaline material throughout the mass, Urgut mass increased consistency, containing alkaline material, vysokokonkurentnoj oxygen delignification to obtain partially delignification mass having a permanganate number of about 9 or less and a viscosity of about 13 centipoise or more.

53. The method of delignification and bleaching of lignocellulosic material, characterized in that it contains the steps that partially delignified lignocellulosic material to obtain a pulp, reduce the consistency of the pulp to less than 10 weight. process nizkobonitetnyh the mass of a certain quantity of alkaline material in an aqueous-alkaline solution for a certain time at a certain temperature, associated with the quantity of alkaline material for the essentially uniform distribution of alkaline material throughout the mass, increase the consistency of the mass of at least 20 weight. upon completion of the processing step, is subjected to a lot increased consistency, containing alkaline material, vysokokonkurentnoj oxygen delignification to obtain partially delignification mass with permanganate number, approximately equal to 9 or less and a viscosity of more than 13 SDR, then delignification mentioned Justicia mainly delignification mass, having a permanganate number of about 5 or less, a viscosity of more than 10 centipoise and white, at least equal to approximately 50% connect virtually delignification mass with some sufficient amount of alkaline material in an aqueous-alkaline solution for a certain time at a certain temperature, combined with a quantity of alkaline material to dissolve a substantial portion of the lignin remaining in the mass, extract the aqueous-alkaline solution in order to remove essentially all the dissolved lignin and get a lot of, containing no lignin, and bleach containing no lignin mass to increase its whiteness at least approximately 70%

54. The method according to p. 53, characterized in that the whiteness increases at least approximately 80%

55. The method according to p. 53, characterized in that the whiteness increases at least approximately 90%

56. The method according to p. 53, characterized in that the lignocellulosic material is pine wood and delignified to permanganate number, approximately 8 to 9 and a viscosity of more than 14 SDR to additional ozone delignification.

57. The method according to p. 56, characterized in that Thu is Eliso at least approximately 54% upon completion of said additional ozone delignification.

58. The method according to p. 53, characterized in that the lignocellulosic material is a deciduous wood, and partly delignification to permanganate number in the range of about 6 to 7 and a viscosity of more than 15 centipoise to conduct the above-mentioned step additional ozone delignification.

59. The method according to p. 58, characterized in that the weight of the hardwood has a permanganate number in the range of about 3 to 4, the viscosity is more than 10 centipoise and a whiteness of at least about 63% upon completion of specified additional ozone delignification.

60. The method according to p. 53, characterized in that the partially delignifying lignocellulosic material obtained using the Kraft process, Kraft process with addition of anthraquinone or extended delignification of lignocellulosic material.

61. The method according to p. 53, characterized in that they reduce the permanganate number mass increased consistency of at least about 60% during oxygen delignification, without causing significant damage to the cellulose components of the mass.

62. The method according to p. 53, characterized in that the mass is subjected vysokokonkurentnoj oxygen delignification without significant changes to the viscosity of the mass during stage oxygen delignification at least 25%

64. The method according to p. 53, characterized in that the consistency of the mass, the treated aqueous-alkaline solution to stage oxygen delignification, is in the range of approximately 1 to 4.5%

65. The method according to p. 53, characterized in that the consistency of the mass increase in the range of about 25 to 35 weight. to stage oxygen delignification.

66. The method according to p. 53, characterized in that the quantity of alkaline material, distributed throughout nizkochastotnoi mass to the stage oxygen delignification, lies in the range of about 15 to 30 weight. when calculating the weight of dry matter weight.

67. The method according to p. 66, characterized in that the aqueous-alkaline solution has a concentration of alkaline material lying in the range of about 20 to 120 g/l, so that the concentration of alkaline material in nizkochastotnoi mass was in the range of approximately 6.5 to 13 g/L.

68. The method according to p. 53, characterized in that the phase of the alkali treatment is conducted for 1 to 15 minutes at a temperature of 90 150oF (32,3 - 65,6oC).

69. The method according to p. 53, characterized in that the initially formed mass is unbleached weight, and at least part of the liquid obtained from the alkaline solution at the stage of increasing con is notelling material, characterized in that it contains stages, which are unbleached pulp with permanganate number approximately 10 24 due to the implementation of the Kraft process, Kraft process with addition of anthraquinone or extended delignification of lignocellulosic material, reduce the consistency of the said mass about 1 to 45 weight. process the reduced mass of the consistence of a certain quantity of alkaline material in an aqueous-alkaline solution, where the concentration of the alkaline material is in the range of about 20 to 120 g/l during time 1 15 min and at a temperature of approximately 90 150oF (32,3 65,6o(C) so that during this phase, the concentration of alkaline material in the mass of reduced consistency was in the range of 6.5 to 13 g/l for the implementation of essentially uniform location alkaline material throughout the mass, increase the consistency of the treated alkaline pulp to approximately 25 to 35 weight. put the weight increased consistency vysokokonkurentnoj oxygen delignification without changing the viscosity of the mass to obtain a partially delignification mass with permanganate number of about 10 or less and a viscosity of 13 centipoise or less and a viscosity of 13 centipoise or more, with respect at least approximately 25% more delignification mentioned oxygen-delignification mass with an effective amount of ozone for a time, sufficient to obtain essentially delignification mass with permanganate number of about 5 or less, viscosity of about 10 centipoise or more and a whiteness of at least about 50% connect virtually delignification mass with a sufficient quantity of alkaline material in an aqueous-alkaline solution at a certain time and at a certain temperature, combined with the amount of alkaline material to dissolve a substantial portion of the lignin remaining in the mass, extract the aqueous-alkaline solution in order to remove therefrom practically dissolved lignin and get a lot of, containing no lignin, and bleach is essentially not containing lignin mass by increasing the whiteness of at least approximately 70%

71. The method according to p. 70, characterized in that the whiteness increases at least approximately 80%

72. The method according to p. 70, characterized in that the whiteness increases at least approximately 90%

73. The method according to p. 70, wherein during stage oxygen delignification permanganate number mass increased consistency is reduced by at least 60% without significant destruction of the cellulosic components of this mass.

75. The method according to p. 74, characterized in that the peroxide is a peroxide.

76. The method according to p. 70, characterized in that it further comprises a stage on which the said mass before the start of the ozone delignification add helatoobrazovatel in order to make the metal ions almost directionspanel to ozone.

77. The method according to p. 76, characterized in that helatoobrazovatel is DTRA, EDTA or oxalic acid.

78. The method according to p. 70, characterized in that it further comprises a stage on which regulate the pH of the mass is in the range of about 1 to 4 due to additives to mass a sufficient amount of acidic material to the stage of the ozone delignification.

79. The method according to p. 70, characterized in that it further comprises a stage on which enhance the consistency of the mass to approximately 25 to 50 weight. until the ozone delignification.

80. The method according to p. 79, characterized in that the consistency of the mass increase to approximately 35 to 45 weight. until the ozone delignification.

81. The method according to p. 70, characterized in that the pulverized mentioned mass up to a diameter less than approximately 5 mm after oxygen delignification and to soeu support at a temperature of less than approximately 120oF (48,9oC).

83. The method according to p. 70, characterized in that the ozone is supplied in a mixture containing ozone and oxygen.

84. The method according to p. 83, characterized in that the concentration of ozone in the mixture is in the range of about 1 to 8 weight.

85. The method according to p. 70, characterized in that the ozone is supplied in a mixture of ozone with air.

86. The method according to p. 85, characterized in that the ozone concentration is in the range of about 1 to 4 weight.

87. The method according to p. 70, characterized in that the partially delignification a lot on the stage of the ozone delignification move in such a way that essentially the entire mass experiences the action of ozone.

88. The method according to p. 87, characterized in that ozone is served in the counter-current floating mass.

89. The method according to p. 87, characterized in that ozone is served in the same direction with the movable mass.

90. How delignification and bleaching of lignocellulosic material, characterized in that it contains the steps that partially delignified lignocellulosic material due vyvarki to obtain pulp and delignification mentioned a lot of oxygen to obtain a partially delignification mass of permanganate num is the said mass with the to make the inside metal ions is not inherently capable of reaction with ozone, regulate the pH of the said pulp in the range of about 1 to 4 by adding a sufficient amount of acid material, increases the consistency of the mentioned mass of approximately 25 to 50% crushed mentioned mass with increased consistency to a particle diameter of less than approximately 5 mm, optionally delignification mentioned mass with increased consistency through a sufficient amount of ozone for a sufficient time, moving the ground mass in such a way that the whole mass experiences the action of ozone to obtain essentially delignification mass having a permanganate number of about 5 or less, the viscosity is more than 10 centipoise and white GE at least about 50% connect virtually delignification mass with a sufficient quantity of alkaline material in an aqueous-alkaline solution for a certain time and at a certain temperature, combined with the available quantity of alkaline material to dissolve a substantial portion of the lignin remaining in the mass, extract the aqueous-alkaline solution in order to remove almost all of the ROI lignin mass using chlorine dioxide to increase its whiteness at least approximately 70%

91. The method according to p. 90, characterized in that the whiteness of the weight increase of at least approximately 80%

92. The method according to p. 90, characterized in that the whiteness of the weight increase of at least approximately 90%

93. The method according to p. 90, characterized in that boiling is the Kraft process, and on the stage oxygen delignification permanganate mass number decreases by at least about 60% without substantial destruction of the cellulose component mass or without a significant change in its viscosity.

94. The method according to p. 93, characterized in that the boiling carry out the Kraft process with addition of anthraquinone.

95. The method according to p. 94, characterized in that on stage oxygen delignification permanganate mass number decreases by at least about 60% without substantial destruction of the cellulose component mass or without a significant change in its viscosity.

96. The method according to p. 90, characterized in that the boiling connects cooked by the Kraft process with addition of anthraquinone and extended delignification and oxygen delignification permanganate mass number decreases by at least about 60% without significant re, characterized in that at the stage of the ozone delignification mass is moved so that its temperature is maintained less than 120oF (48,9oC).

98. The method according to p. 90, characterized in that helatoobrazovatel and acid is added to the said mass in the mixing tank.

99. The method according to p. 98, characterized in that at least part of the liquid separated from the mass at the stage of improving consistency, recycle to the mixing tank.

100. The method according to p. 98, characterized in that the paste is stirred in one direction with ozone.

101. The method according to p. 98, characterized in that the paste is stirred in a counter ozone.

102. How delignification and bleaching of lignocellulosic material, characterized in that it contains the steps that partially delignified lignocellulosic material due to its cooking to obtain pulp and delignification oxygen-mentioned material for partially delignification mass having a permanganate number, approximately equal to 10 or less and a viscosity of more than 13 SDR add helatoobrazovatel to the said mass to make existing metal ions are not capable of reaction with oz the first material, increase the consistency mentioned mass approximately 25 to 50% crushed mentioned mass increased consistency up to a diameter less than approximately 5 mm, optionally delignification mentioned mass increased consistency with a sufficient amount of ozone for a sufficient time to obtain essentially delignification mass having a permanganate number of about 5 or less, a viscosity of more than 10 centipoise and a whiteness of at least about 50% connect virtually delignification mass with a sufficient quantity of alkaline material in an aqueous-alkaline solution at a certain time and at a certain temperature, combined with the amount of alkaline material to dissolve a substantial portion of the lignin remaining in the mass, extract the aqueous-alkaline solution in order to remove essentially all the dissolved lignin and get a lot of, containing no lignin, and bleach a lot, practically do not contain lignin, using peroxide to increase its whiteness at least approximately 70%

103. The method according to p. 102, characterized in that the whiteness increases at least approximately 80%

104. The method according to p. 102, characterized in that Belial carried out using the Kraft process, and on the stage oxygen delignification permanganate number is reduced at least about 60%, without significant damage to the cellulose component mass or without a significant change in its viscosity.

106. The method according to p. 102, characterized in that the cooking material is carried out using the Kraft process with addition of anthraquinone.

107. The method according to p. 106, characterized in that on stage oxygen delignification permanganate number weight reduce at least about 60%, without significant damage to the cellulose component mass or without a significant change in its viscosity.

108. The method according to p. 102, characterized in that the boiling perform a combination of the Kraft process with addition of anthraquinone and extended delignification and oxygen delignification permanganate number weight reduce at least about 60%, without significant damage to the cellulose component mass or without a significant change in its viscosity.

109. The method according to p. 90 or 102, wherein the phase ozone delignification permanganate mass number is reduced by at least 50%

110. The method according to p. 90 or 102, characterized in that e is ZNU mass increase at least up to 83%

112. The method of delignification and bleaching of lignocellulosic material, characterized in that it contains the steps that partially delignified lignocellulosic material through cooking to obtain the mass, washed with specified weight and delignification specified weight with oxygen to produce a partially delignification mass having a permanganate number of about 10 or less and a viscosity of more than 13 SDR, washed partially delignification mass, additionally delignification mentioned partially delignification mass with a sufficient amount of ozone for a time sufficient to obtain essentially delignification mass having a permanganate number of about 5 or less, the viscosity is more than 10 centipoise and a whiteness of at least about 50% washed almost delignification mass, connect virtually delignification mass with a sufficient quantity of alkaline material in an aqueous-alkaline solution for a certain time and at a certain temperature, combined with the amount of alkaline material to dissolve a substantial portion of the lignin remaining in the mass, extract the aqueous-alkaline solution, so that beats the piss, containing no lignin, bleach this mass by chlorine dioxide or hydrogen peroxide in order to increase the whiteness of the mass of at least approximately 70% bleached and washed a lot.

113. The method according to p. 112, characterized in that the whiteness increases at least approximately 80%

114. The method according to p. 112, characterized in that the whiteness increases at least approximately 90%

115. The method according to p. 112, characterized in that the step of washing the bleached pulp rinse referred to the weight of pure water and separate the mass of wastewater produced.

116. The method according to p. 112, characterized in that at the stage of bleaching uses chlorine dioxide, and waste water after bleaching is reset.

117. The method according to p. 112, characterized in that at the stage of bleaching uses chlorine dioxide, and waste water after bleaching are processed by reverse osmosis to obtain the processed filtrate, at least part of which is directed to the stage pulp washing, containing no lignin.

118. The method according to p. 112, characterized in that at the stage of bleaching using peroxide and at least a portion of the bleached pulp recycle on stage pulp washing, practicalaction do not contain lignin, the mass is washed with water from washing the bleached pulp, separating the mass from the resulting wash water and direct at least part of these wash water in the washing step almost delignification mass.

120. The method according to p. 119, characterized in that the washing step is almost delignification weight referred to the weight of the wash water from the pulp washing, essentially, do not contain lignin, separate the mass from the resulting wash water and direct at least part of these wash water in the washing step partially delignification mass.

121. The method according to p. 120, wherein the washing step is partially delignification weight referred to the weight of the wash water from the washing essentially delignification mass, separating the mass from the resulting wash water and direct at least part of these wash water in the washing step of the masses.

122. The method according to p. 121, characterized in that the washing step weight referred to the weight of the wash water from the washing partially delignification mass, separating the mass from the resulting wash water is collected referred to the wash water and concentrate it to calcination in the recovery boiler.

124. The method according to p. 116, characterized in that the discharged waste water have the dye is not more than 2 pounds per ton and the total amount of organic chlorides not more than about 2.

 

Same patents:

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The invention relates to the field of pulp and paper production and is intended for use in the production of bleached pulp

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The invention relates to the field of chemical processes of cooking and, in particular, to method pulping (for example, for the manufacture of paper products), in which the fibrous material is cooked at elevated temperature and pressure in the presence of chemical reagents, and then treated in a digester to separate the fibers from the binders present in the material, and for bleaching cellulose pulp

FIELD: textiles, paper.

SUBSTANCE: invention is related to pulp and paper industry. Method for processing of lignocellulose material includes stage of impregnation, at which lignocellulose material is soaked in impregnation solution; the first stage of recycle, at which impregnation solution is drained, filtered, concentrated and returned to the stage of impregnation; stage of catalytic reaction, at which soaked lignocellulose material is mixed on chamber of catalytic reaction and heated up to the temperature over point of impregnation solution evaporation, thus, evaporated impregnation solution and lignin are produced. Besides method includes the second stage of recycle, at which evaporated impregnation solution is condensed and returned to stage of saturation; stage of boiling, at which lignin is energetically mixed in cooking boiler in presence of black iron and alkaline solution for production of cellulose pulp and black lye of full concentration; stage of processing, at which cellulose pulp is drained, washed and dried, thus, dried cellulose pulp and dissolved black lye are produced. Method includes the third stage of recycle, at which dissolved black lye is returned to the stage of boiling; stage of separation, at which black lye of full concentration is cooled and energetically mixed in presence of acid solution, thus, sweet lye is produced, as well as deposited lignin of natural origin; stage of filtering, at which sweet lye is filtered in order to extract lignin of natural origin, and stage of fermentation, at which sweet lye is added to bacteria in fermentation apparatus, thus, unicellular protein is produced as product of fermentation. Invention is related to device for processing of lignocellulose material, and also unicellular protein and lignin, which are produced by above-mentioned method.

EFFECT: possibility is provided to process various types of vegetable material with no necessity in re-equipping or variation of technological equipment, prevention of environmental pollution and reduction of power inputs.

12 cl, 6 dwg, 4 tbl

FIELD: textile, paper.

SUBSTANCE: in accordance with preferable versions of this invention realisation, method and device are provided for continuous production of cellulose mass from suspension produced from ground hard wood, by means of its treatment at the first stage of boiling under conditions sufficient to reduce content of syringice acid (s-ligning) in hard wood compared to content of guaiac ligning in it (g-ligning), and subsequent treatment of suspension of ground hard wood at the second stage of boiling under conditions sufficient to reduce content of g-lignin that remain in it after the first stage of boiling.

EFFECT: reduced amount of cellulose mass wastes with specified Kapp number.

18 cl, 2 dwg, 1 ex

FIELD: textile, paper.

SUBSTANCE: method includes two stages of rice straw boiling. The first boiling stage is carried out in the alkaline medium with subsequent separation of cellulose-containing product, the second stage of boiling is carried out in the acid medium by mixture of peracetic acid (PAA), acetic acid and hydrogen peroxide in presence of a stabiliser, such as a mixture of organic phosphonates. At the same time the second stage of boiling is carried out in presence of ozone with a flow rate of 2-4 g/hr.

EFFECT: reduced flow of composition based on PAA, higher yield of finished product, reduced content of lignin and increased whiteness indices.

2 cl, 1 tbl

FIELD: machine building.

SUBSTANCE: device for continuous bleaching cellulose containing semi-finished products consists of vertical hollow container of "pipe-in-pipe" type, of receiving unit, of bleaching unit, of flush unit and of unloading unit. The receiving unit is made in form of a loading element, a cutting-off or rotary gate and a pneumatic chamber with a branch connected with a pulsator. The pneumatic chamber is connected with the bleaching unit. The bleaching unit is made in form of a rotating internal pipe with orifices in its lower part. Also, a mixing device is secured along whole length of external surface of the internal pipe. The mixing device corresponds to a screw-type of a spiral-type band, or a rod, or blades. The flush unit is made as an external pipe with a bottom. The pipe is stationary fixed on a foundation. In the middle part of the pipe there is made a branch, while in a lower part there are made a process hatch and a branch. The unloading unit corresponds to a coaxial hollow cylinder attached to the external pipe; the cylinder has two bottoms. An internal bottom has orifices and is connected with an off-take chute. A branch withdrawing spent fluid is attached to an external bottom. Inside the coaxial hollow cylinder there is installed a device for target product wringing and unloading. This device is equipped with at least one scraper (s) in form of a rod(s) rigidly attached with its one end to the internal pipe. On another end the rod has a blade(s) with controlled angle of incline.

EFFECT: increased operational reliability of device.

4 cl, 2 dwg

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