Method of controlling process of extracting emulsion rubber from latex

FIELD: chemistry.

SUBSTANCE: rubber is extracted from latex continuously by mixing latex with a coagulant. Consumption of coagulant is varied depending on the given turbidity value of serum (primary serum), which is maintained by the amount of coagulant fed. The given turbidity value of primary serum is adjusted depending on the turbidity of the serum released (secondary serum) towards the minimum consumption of coagulant to obtain minimum turbidity of the released serum.

EFFECT: method of controlling the coagulation process enables to reduce contamination of waste water through loss of partially coagulated latex with minimum consumption of coagulants.

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The invention relates to the field of production of synthetic rubbers and emulsion polymerization, the most important stage - the selection of rubber from latex using coagulants.

Emulsion rubbers with this stage on an industrial scale appeared in the world in the 30-ies of the last century (Suitby. Synthetic rubber. HP: Goskomizdat, 1957).

In the world today there are several dozen factories producing emulsion rubbers (VII, Uwian. Rubbers Russia and materials for their production. Reference, Voronezh, 2001; The Synthetic rubber Manual. / Elastomer Product Information Sapporting Rubber Industry. IISRP. 2005, p.48, 62, 75).

In connection with the aggravation of the environmental situation in the world questioned the feasibility of the operation of a number of existing facilities emulsion rubbers due to the large amount of pollution. In the production of emulsion rubbers main waste obtained at the stage of their selection. So, for every tonne produced styrene butadiene rubber produced ~20 m3water contaminated with inorganic salts, emulsifiers, dispersants, coagulants, negociaciones latex and crumb rubber. Getting into the waste water, the waste interfere with the operation of wastewater treatment plants and lead to contamination of valuable freshwater (in our country it is the Volga river, the Yenisei, And this, White, Voronezh reservoir), with uncertain long-term consequences.

The selection of emulsion rubber of the latex is carried out under continuous mixing of the latex with a coagulant (coagulants) in the coagulator with the formation of the slurry (a suspension of crumb rubber in the serum concentration of crumb 5-10%) when the selected modes: temperature, speed of agitation of the pulp, the ratio of latex and return of serum, pH of the pulp. Established over fifty years of patterns for selection of rubbers and applied technological equipment versed in the following works:

1. Maurauders al. / Development conditions coagulation of the latex containing nical and Soaps of carboxylic acid chloride recycle serum. // Rubber & rubber, 1961, No. 4, 16-22.

2. Ability. The basic technology of synthesis of rubber. M, Chemistry, 1964, s-399.

3. Rea al. / Butadiene-styrene and butadiene-alpha-methylstyrene rubber emulsion polymerization. // In the book. Synthetic rubber. L., Chemistry, 1983, s-215.

4. Iversoon al. / Development of equipment and technologies for extraction of butadiene-alpha-methylstyrene rubber from latex. // M: Tsniiteneftehim, 1997, 67 S. In the specified survey recorded the results of many years of experience in plant selection JSC "Voronezhsintezkauchuk" and the scheme of coagulation, RA is Otava until improvements developed by the authors of the present invention.

At the stage of selection, you will have to solve the following technological, economic and environmental objectives:

1) to use the minimum number of efficient and environmentally friendly coagulant ensuring completeness of coagulation;

2) to obtain a slurry of rubber with a uniform size crumbs, optimal for used equipment;

3) apply the minimum amount of water;

4) to have in the pulp minimal number of small sticky crumbs;

5) to prevent or minimize contact with discharged serum negociaciones latex using the minimum amount of coagulant to prevent the deterioration of drying rubber, piling equipment, negative impact on the performance of treatment plants and the reduction of economic performance.

On items 1)-4) tasks to a certain extent solved in the following ways :

- Offered little effective coagulant sodium chloride with the consumption of 180-350 kg per ton of rubber to replace with efficient and environmentally friendly coagulants: for example, widely tested in the production of rubbers biodegradable protein coagulants with the consumption of 4-7 kg per tonne of rubber (A.S. 1065424, C08C 1/15, publ. 07.01.1984; A.S. 1131883, C08C 1/15, publ. 30.12.1984; VII and other Use of proteins upon receipt of the elastomers. Zeiten ftehim, M., 1985, 53 S.).

- Mastered the use of dietary non-biodegradable polyamino coagulant VPK-402 (polydimethyldiallylammonium-chloride) with a flow rate of 2-4 kg of coagulant per ton of rubber (U.S. Pat. RF 2067591, C08F 236/10, C08C 1/15, C08F 6/14).

- Developed on an industrial scale application of salts of divalent metals (magnesium chloride and calcium chloride) with a flow rate of 15-20 kg of coagulant per ton of rubber of a given composition (U.S. Pat. Of the Russian Federation No. 2351610, C08C 1/14, 1/15, C08F 6/22, publ. 10.04.2009, BI. No. 10), thereby reducing pollution and waste chlorides with warranty does not occur distant negative consequences. The great achievement of this technology was to increase the zone of maturation of the pulp in the scheme of coagulation and reducing the consumption of valuable fresh water for 12 m3for every tonne produced of rubber. Recent advances apply to any low-salt and salt-free coagulation with the use of a wide range of coagulants.

- The need to obtain a slurry of rubber with a highly uniform crumb optimum size is dictated by the performance of the drying unit and is carried out with a visual way to control the regulation of the flow ratio of latex and return of serum, temperature and pH of coagulation, the design of the mixing device, the intensity of mixing of the pulp.

To solve tadacipo reduction in the formation of a number of small chips in the pulp, adversely affect the drying of rubber, slaughter equipment, and reducing losses of rubber in the form of small chips was asked a series of ways of regulation of the coagulation process using sodium chloride and sulfuric acid, is given in the reviews (Vajroli, Ameriven, Vinapco. The management of processes of production of synthetic rubbers, Thematic review, Tsniiteneftehim, M., 1986, 38 S.; Ameriven, Vinapco, Industry SK, 1985, No. 2, 9-12).

So, there is a method of regulation of the process of coagulation of the latex of synthetic rubber, in order to reduce losses polymer adjust the rotation speed of the stirrer in inverse proportion to the changes in the concentration of polymer particles in reciprocal serum (A.S. USSR №895989, C08C 1/14, G05D 27/00, Appl. 23.05.80, publ. 07.01.82, BI No. 1).

There is also known a method of regulating the process of coagulation of synthetic rubber, in order to improve the stability of the strength of the rubber and reduce losses polymer adjust the temperature in the apparatus coagulation depending on the concentration of polymer particles in the serum (A.S. USSR №852877, C08C 1/14, G05D 27/00, Appl. 21.11.79, publ. 07.08.81, BI No. 29).

However, the above known methods of regulation are speculative and their implementation in practice, as an instrumental control, did not happen for the following reasons the m:

1. Return the serum does not reflect the true content of small crumbs are formed during coagulation, because the serum, the last sieve lineatriton machine, be sure tank - clarifier (the authors of the above method the tank # 8), designed to ensure operation of the pump, which supplies return the serum in the coagulator. Crumb rubber from the clarifier flows in three directions: surfaced periodically removed by net for separate processing, the second part is fond of flow of return of serum, the third part gets discharged in the serum.

2. Concentrations of small chips in the serum depends simultaneously on many factors:

the flow ratio of latex and return of serum,

- mixing intensity in the coagulator and doserates,

the temperature and pH of coagulation,

- design of agitators,

- the content of the dispersant in the latex (lakanal, dispersant NF),

- filter capacity of the tape rubber (in the case of technologies with tentatively machines).

The solution of problem (5) in the elimination or significant reduction of rubber and pollution wastewater them as negociaciones latex using the minimum amount of coagulant is complicated for the following reasons:

A) it is Impossible to significantly increase the supply of coagulant coagulation, as it leads the children to the increase of pollution of wastewater coagulant and in some cases to increase the number of small crumb rubber and, as a consequence, the negative economic and environmental consequences.

B) In case of insufficient supply of coagulant appear loss of rubber in the form of a latex (incomplete coagulation), leading to pollution and waste latex, fouling of equipment sticky polymer economic losses.

C) Floating supply latex and serum due to the condition of the equipment, working in difficult conditions; fluctuations in the speed of drying of the rubber (which requires frequent adjustment of the volume flows of latex and coagulant). Simultaneous operation of up to seven production lines highlight rubbers (usually of different brands at the same time) complicates the work of staff and timely decisions on the adjustment process.

G) the Originality of the parties latex resistance to coagulate due to the unusual depth of polymerization of the monomers.

D) a Complex dependence of the efficiency of coagulants from a number of highly basic amines, Quaternary salts of amines, which, as coagulants, working in a narrow interval of consumption, above and below which there is no complete coagulation.

E) Lack of operational management with continuous instrumental monitoring of complete coagulation of the latex is not possible to reliably eliminate pollution and waste latex and R is to guluronate optimal supply of coagulant.

For scientific investigations of the kinetics of coagulation of the latex in the initial stages of coagulation process is highly diluted latex is widely used values method (Rahaman. Coagulation of synthetic latexes. Voronezh, Publishing house of Voronezh state University, 1967, s-107; Rahaman. Essays colloid chemistry of synthetic latexes. Voronezh, Voronezh state University, 1980, p.119-137; Workshop on colloidal chemistry and electron microscopy. Ed. OSI, Rampant, M., Chemistry, 1974, p.26).

You can control the completeness of coagulation by periodic sampling apparatchik pulp rubber during its passage through the cascade manually by filtration of the samples and measurement of the turbidity of the filtered serum on the turbidity meter. The duration of this method of analysis will be more than an hour, so the results apparatchik very late decision on the regulation of coagulation parameters. Given the large production capacity, working simultaneously around the clock to seven production lines selection, this method is difficult to implement, it will distract the operators and laboratory staff to perform a large amount of extra work, but will not allow you to quickly and securely manage the allocation process rubbers in order to reduce losses of rubber in the form of negociaciones latex with minimal expense to the of Galanta.

Known methods closest to the proposed technical essence is a way of dealing with the process of coagulation of the latex of synthetic rubber, in order to reduce losses of the polymer in the form of crumbs with serum adjust the flow rate of the sodium chloride solution depending on the concentration of polymer particles in reciprocal serum (A.S. USSR №698986, C08C 1/14, G05D 21/00, Appl. 31.03.78, publ. 25.11.79, BI No. 43).

Under the concentration of polymer particles in reciprocal serum authors known way mean a fine crumb and propose to use for the regulation of the coagulation process pattern, "... that the rate of flow of sodium chloride depends on the magnitude of the resulting polymer crumb. For large values of consumption of sodium chloride are formed fine particles" (p. 1, paragraph 1 below).

In the known solution is proposed to regulate the flow of sodium chloride, maintaining the concentration of small crumbs at a given level, and by increasing the concentration of polymer particles in reciprocal serum (indicating a decrease in size formed by coagulation of the polymer particles) corrective signal to the controller 13 decreases, and Vice versa" (page 4, line 11 above).

There is a method of regulation has a number of disadvantages, which do not allow its use is in industry, in order to keep the flow of the coagulant at a minimum, the ingress negociaciones latex drains:

1) According to the generated number of small crumb rubber and the remaining negociaciones latex in reciprocal serum from the number of submitted coagulant of sodium chloride is completely the opposite. When the number of small crumbs are necessary to reduce the consumption of sodium chloride, however, reduced consumption of sodium chloride leads to an increase in the number negociaciones latex.

2) In a production environment when selecting rubber from latex formation of small crumbs is an essential property, that depend simultaneously on a number of factors - latex composition, temperature and pH of coagulation, the nature and concentration of coagulants, the flow ratio of latex and return of serum, design samples, dotivala and used mixers, speed mixing pulp quality drying machine.

Therefore, it is impossible to control the concentration of fine crumb rubber only one reception - adjustment of the flow rate of the coagulant (sodium chloride solution).

3) try to apply the full range of measures to reduce its inception in the coagulation process and collect in the sump serum slipped out fine crumbs using the special nets, and only part of the crumb fond return flow of serum.

4) there is a method bound to the outdated scheme of coagulation created in the 30-ies of the last century in the first production of emulsion rubbers using tentatively machines. By moving the sieve lineatriton machine (length - 37.5 m; width - 2.4 m; the hole diameter is 0.45 mm; 1 cm2- 380 holes) is fed continuously to the flow of pulp rubber size crumbs 1-2 mm groundmass and some chips with a size less than the diameter of the hole sieve. On the sieve is formed strip of rubber in the form of a dense membrane, through which the filtered serum, then acidified wash water. Thus, the number of small crumbs held in returnable serum will be determined not only by the diameter of the holes of the sieve, but the filtering capacity of the tape, which may not be permanent. The transition from NaCl to other modern coagulants in this scheme turned out to be today possible.

5) the extraction Technology of rubber on tentatively machines require the submission of an excess of sodium chloride up to 250 kg per ton of rubber instead of 180-200 kg/t to a modern cascade technology (Fig.1), to avoid getting negociaciones latex on lineatriton machine due to the rapid overgrowth of sieves sticky rubber.

Known sposobnosti be applied to solve control weight coagulation with minimal consumption of coagulant.

For the above reasons, the completeness of the coagulation today in the industry for any type of machinery used to continue to carry out subjective visual way. Therefore, the performance management process of coagulation is determined mainly by the experience and skill of the operator.

The technical task of the invention is to improve the environmental, economic parameters of the industrial process of separating the emulsion rubber from latex, improving performance and safe operation of equipment by eliminating losses rubber in the form of negociaciones latex and reduce pollution wastewater excess amount of coagulant through the use of continuous automatic monitoring of the completeness of coagulation and controlling the flow of coagulant.

The problem is solved as follows.

The process control method of allocation emulsion rubber from latex with continuous mixing of the latex with a coagulant to form a slurry of rubber by changing the flow rate of the coagulant, wherein the continuously cleaned constantly allocated a portion of the pulp rubber (or pulp) from crumb rubber automatically and continuously measuring the turbidity obtained constantly updated purified from crumbs primary is on serum and adjust the flow rate of the coagulant depending on a given value of the turbidity of the primary serum, and given the magnitude of the turbidity of the primary serum adjust depending on turbidity cleared crumb discharged serum towards the minimum flow of the coagulant to obtain the minimum value of turbidity discharged serum.

Proposed method of control the process of separation of rubber from latex has the following differences and advantages of the method according to the prototype:

1. By an action (or set of actions), order of execution and mode of the inventive method provides for the cleaning of pulp, serums from crumb rubber, measuring the turbidity of the purified primary serum (concentration of colloidal particles, not crumbs) turbidimeter, the adjustment of consumption of coagulant depending on a given value of the turbidity of the primary serum, measured turbidity discharged serum and adjusting a given value of the turbidity of the primary serum, depending on the turbidity discharged serum.

2. On the basis of terms act - the inventive method is based on measurements of turbidity (the concentration of the colloidal latex particles) in the treated from crumb rubber-serums - primary serum and discharged serum.

3. On the basis of the substance used - the inventive method additionally works with streams free from crumb rubber primary and discharged serums, any type of coagulant

4. On the basis of the used devices, the inventive method involves:

- applying device for purifying serums from crumb rubber based, for example, decantation, or a combination of decantation and fine sieve;

- the use of automatic flow regulating motomeru.

The proposed method is efficient and versatile to use any type of coagulant and any type of equipment for separating the incoming drying crumb rubber from serum, helps to improve the environment and economy of the process due to the reduction or complete elimination of pollution of waste water loss of rubber in the form of nesquehoning latex and excess coagulant.

This increases the performance and safe operation of the equipment by reducing deposits of coagulum in the flows between devices on the walls of vessels and pipelines, reduced risk of injury and negative impacts on health of workers by reducing their contact with the equipment and harmful volatile chemicals.

Accessibility equipment for measuring turbidity and purification of serum allowed widely and successfully to test the proposed method in a production environment.

The solution of a technical problem has become possible due to four factors:

1. Application to measure the Oia turbidity of the serum control the flow of process analyzers turbidity continuous action.

2. Create a simple device that allows you to continuously obtain a serum-free crumb rubber.

3. Correctly selected the location of the sensors motomeru.

4. The turbidity measurement of serums, as a rule, in two points of the line coagulation.

For the stable and secure operation of the cascade selection rubbers, reduce economic losses and negative impacts on the environment and health of the staff is more preferable to perform continuous automatic control of complete coagulation of the latex with automatic flow control of coagulant for a given turbidity, but there is another option - automatic, continuous measurement of turbidity primary serum and subsequent manual regulation of the flow of the coagulant with the output value of the primary turbidity of the serum on the specified level.

As an industrial motomeru us were tested:

- Automatic analyzer turbidity COSMOS 25 firms Zullig (Catalogue products LLC Technogenetic". Measurement of flow rate and composition of wastewater, control of gas emissions, p.14). Mutemeri this type are more preferred and proven in field tests.

Industrial analyzer turbidity company HACH LANGE brand SOLITAX.

Industrial NIR turbidimeter Mettler Toledo 8000 series (Process Analytics. Industrial analytical system is ettler Toledo. Directory of industrial analytical equipment 2006).

The principle of operation of the above motomeru in the case of latexes is to determine the concentration of colloidal particles of rubber size 10-6-10-5cm in water using the scattering effect of the light beam passing through the dispersion system.

Measurement of the turbidity sensor serum is carried out continuously in the field of near infrared radiation at a wavelength of 860±30 nm, the results are converted to a photocurrent is processed and continuously displayed on the display unit, installed in any convenient and safe for maintenance. The results can be registered also in the form of a chart on the recorder on Board instrumentation, or on the monitor of the host PC. Industrial mutemeri used for continuous monitoring of wastewater quality in different industries: food (milk, beer and beverages), hydrometallurgical industry and in biotechnology.

Universal process control method selection emulsion rubber from latex by continuous automatic measurement of turbidity cleared crumbs serum and maintain a minimum flow of coagulant with minimal loss of negociaciones latex using protoc the s industrial motomeru not known (mutemeri in the production of IC at the stage of selection of rubbers are used by us for the first time).

We found that for applications running industrial motomeru continuous action to control the completeness of coagulation requires continuous receiving initial serum from the zone of coagulation, released from crumb rubber. In the best case this is achieved by continuously divert a portion of the pulp rubber from the zone of coagulation (after the first doserates) sufficient for the subsequent measurement of turbidity (in the analytical volume). Given a part of the pulp is fed into a special cleaner that allows you to continuously separate the crumb rubber from serum. By construction, the purifier is a metal box with dividers, repeatedly changing the direction of movement of the pulp system (labyrinths). In the operation of the cleaner at its output appears serum (primary serum), released from crumb rubber.

In this initial serum is placed sensor of the first control turbidimeter.

The role of cleaner serum from crumb rubber can perform hubs, vibrating screens and other specially trained for this device in any combination.

Installation of the sensor in the serum obtained from the pulp prior to the first doserates, proved impossible because of the difficulty of purification of serum from sticky crumb rubber. It is also possible to install the first steering sensor in serum crack and the surrounding through the water seal of the latest hub. Thus there is a slight delay of the control action, but simplifies the design of additional purifier serum from crumb rubber.

Measurement of turbidity on reset the serum, past the maximum time of ripening, to be as close as possible to the place of discharge of serum in the sump of serum or sewage system. Usually such places are hydraulic lock of the last hub or water seal tank serum.

Preferably turbidity discharged serum to measure the second turbidimeter automatically and continuously with the output on the computer of the operator. The sensor is placed in the turbidimeter net cone, located in the trap of settling. Net cone clears the measured part of the discharged serum from crumb rubber. But you can place a second controlling NIR turbidimeter, for example, carrier apparatchiks or about line selection in the shop and manually measure the turbidity of periodically sampling the reset serum of net cone.

The turbidity measurement discharged serum allows you to:

1) to control the amount of rubber that falls into the waste water in the form of negociaciones latex;

2) know what is the minimum level of turbidity values can be achieved on-line selection of a particular party coagulation of the latex when the optimal podcasta, modes of coagulation and maximum performance dryers;

3) to establish the optimum set value of turbidity on the first control turbidimeter, in order to obtain the minimum value of turbidity (negociaciones latex) discharged in the serum.

Due to the fact that between the place of measuring the turbidity of the first (primary serum) and second (discharged serum) sensors motomeru, as a rule, are doznavatel, hubs, sump, which is additional coagulation, there is no need to ask on the first sensor turbidimeter turbidity at a very low level, as this will cause excessive coagulant. This approach allows you to keep removed in the absence of serum or minimum number negociaciones latex with a minimum consumption of coagulant.

Depending on the composition of the used equipment, the flow of the pulp rubber and serums specific line selection rubber number of motomeru, their location and functionality may vary, the primary and discharged serum can mean the same thread. But in all cases is the main thing - using a control turbidimeter, automatically and continuously monitor the turbidity of the purified from crumb rubber serum and correcting the flow rate of the coagulant of a given value of hmotnost is on the turbidimeter with obtaining the lack or minimal amount negociaciones latex discharged in the serum with a minimum quantity of coagulant.

The authors present invention empirically established:

1. The value of turbidity (M) in units of FNU is associated with the content of the rubber (CCF) in serum in dimension mg/l dependence of CCF=(4-4 .5)·M when the accepted standard recipe for producing latex and the calibration curve by diluting water source additional stabilizirovannogo dispenser latex;

2. A given value of the primary turbidity of the serum depends on the location of the sensor control turbidimeter, a typical interval 10-100 FNU (preferably not more than 50 FNU) on the first sensor turbidimeter. Given the magnitude of the turbidity of the primary serum above 100 FNU leads to large losses of rubber in the form of nesquehoning latex, because not enough time on his docomplete until the reset of the serum into the sewer. Due to the presence of dotivala provided technological scheme, turbidity discharged serum, measured by the second sensor, as a rule, considerably less than in the first turbidimeter and should not exceed 5 FNU. These figures can be different, if the components of the polymerization recipe (typically, emulsifiers, dispersing agents) lead to higher background turbidity of the serum, such as the use of large quantities of dispersant NF.

With a large number of technological lines for economy which means the second NIR turbidimeter (or portable is the portable version of the analyzer) can be used in a carrier for measuring the turbidity of the samples purified discharged serum, select manually.

The inventive method of controlling the allocation process rubber from latex applies to all brands of emulsion rubber (oil-free and oil-filled styrene - (alpha-methyl)styrene, polybutadiene and butadiene-nitrile rubber), as non-functional, and contains functional groups, and involves the use of any inorganic and organic coagulants or their combinations, as well as physical methods of coagulation.

Fig.1 shows the principal classical technological scheme of the line coagulation of the latex with the use of sodium chloride employed in the industry for over 20 years. In this diagram in example 1, the results of the tests attempt to apply industrial flow NIR turbidimeter continuous operation (automatic analyzer turbidity COSMOS 25 firms Zullig) to control the coagulation process by placing the sensor in the return line of the serum apparatus 8 in accordance with the General recommendations of how the prototype (A.S. 698986).

In example 2 (scheme coagulation Fig.1) the results of the visual control of the coagulation process, which is used throughout the world since the organization of the production of emulsion rubbers and present.

Figure 2 presents the fundamental universal scheme of coagulation of latex painted. who and with the proposed method of automatic control of the process of separation of rubber from latex (examples 3-6). Universal line circuit coagulation (figure 2) has the following important differences from the well-known classical scheme (Fig.1) and schema coagulation with lineatriton machine:

1. The scheme is equipped with an automatic control and management of the turbidity of the serum with the use of industrial flow motomeru.

Figure 2 shows the location of the first turbidimeter (pos.17 or POS) and the second turbidimeter (POS or operator). The second NIR turbidimeter can be placed in POS, if the first NIR turbidimeter is located in pos.17.

2. The reduced number of vehicles (excluded hub 17).

3. Increased coagulation time due to changes in functions of the devices 18 and 19, because the devices 18 and 19 (instead of the functions of the washing machine and hub) converted into additional doznavatel, but 19 also serves as a hub.

4. On the coagulator 6 implemented universal harness threads, allowing to supply sulfuric acid or return the product (as is customary in the diagram of Fig.1, either in latex or simultaneously in two points, which expanded the range of applied coagulants.

5. Applied advanced design mixer for averaging return of serum and concentrated solution of coagulant.

6. An improved scheme allows to optimize the consumption of coagulant at escarpa the surrounding coagulation of the latex and to reduce the consumption of softened water for 12 m 3for every tonne produced of rubber.

In the improved scheme (Fig.2) latex on line 1 enters the coagulator 6, line 11 enters the coagulant, line 14 - returnable serum, 25 (9, 14) is sulfuric acid (phosphoric, acetic, hydrochloric or any combination thereof). Apparatus 7, 18 and 19 perform the role of dotivala. The device 19 performs a dual role: doserates and hub (separator crumbs from serum). Of flow 27 after the first doserates through a special device 15 is continuously divert a portion of the pulp rubber in running the cleaner 16 (preferably a system of labyrinths with the application of the principle of decanting). In the purifier multiple branch crumbs from serum into clean part of the primary serum is placed first sensor industrial turbidimeter 17, which gives an automatic signal to the controller 10 further preferably automatic or manual control consumption of coagulant valve 12.

This is the best accommodation option sensor first turbidimeter, as between the first turbidimeter and the place of discharge of serum into the sewer is more dotivala, increasing the time and, as a consequence, the completeness of coagulation. This allows you to keep a specified amount of turbidity primary serum is not at the lowest level and thus save expense to the of Iolanta by increasing the time of coagulation and get removed in the absence of serum or minimum number negociaciones latex.

You can install the sensor first turbidimeter 20 in the trap 21 of the hub 19 for automatic, continuous measurement of turbidity primary serum and through the controller 22 to control the valve 12 feed coagulant. In this case, for purification from crumbs continuously flowing through the water seal 21 serum in last place simplified cleaning device including a cone of metal mesh having a mesh size of 0.1 mm, and the turbidity is measured inside the cone.

In hydraulic lock 23 of the collection of serum 8 coming from the hub 19 may be installed sensor of the second turbidimeter, which captures the magnitude of turbidity discharged serum in household and factory sanitation (HSC) or on site additional wastewater treatment. The value of turbidity discharged serum measured in the trap 23 is lower (preferably not more than 5 FNU) and allows you to adjust the preset value of turbidity on the first turbidimeter through the regulator 31 is automatically or manually.

The second NIR turbidimeter can be installed in a room attendants (attractive portable is the portable version of the analyzer, turbidity) for periodic measurement of turbidity discharged serum and adjustments specified turbidity on the first turbidimeter.

When using two motomeru first one is by managing and must always work in automatic mode.

If the Trustee NIR turbidimeter is pos.17, the second controlling NIR turbidimeter can be located in POS, and serum flowing through the water seal 21, is discharged.

In some cases, the first managing NIR turbidimeter placed in purified serum after separation of the entire crumb rubber (POS, water seal 21), can only work for a given value of the turbidity without adjusting the magnitude of turbidity discharged serum. In this case, you would set the lowest value of the turbidity of the primary serum. This situation can be, for example, when one tank 8 are serums with multiple lines selection from different brands of rubber or when the serum, bypassing the sump 8, immediately reset to HSC (primary and discharged serum become identical).

Describes the typical options motomeru are the most convenient, technically feasible and workable. It is also possible placement of sensors motomeru and in other places of the technological line of the selection, however, this will complicate the process of managing the fullness of coagulation.

The management process of coagulation of the latex by the proposed method allows for a minimum amount of coagulant to exclude or minimize the discharge of negociaciones latex with serum.

Example 1 (the prototype).

Classic promyshlennaia (Fig.1)

The apparatus of the cascade (coagulator 6, gotravel 7 and the hub 17) in line 3 are filled recoil serum is heated to a temperature of 50°C, and sodium chloride on line 2 to its concentration in the serum to 5%, and line 4 is fed sulfuric acid to a pH in the devices 6 and 7 in the range of 4-5 units Further includes applying latex rubber SKS-30 ark on line 1 in the amount of 15 m3in hour 3 tons of rubber per hour). Consumption of sodium chloride exhibited at the rate of 200 kg absolute product per ton of rubber, according to the factory schedule. The resulting slurry of rubber from doserates 7 to flow 27 enters the hub 17, where separated crumb through the flush tank 18 flows into the hub 19 and after separation from the flushing water is directed to the extraction and drying. Serum from the hub 17 through the water seal 22 enters the sump 8. This sump is concentrated crumb rubber, jumping out of the hub 19, and through a hatch apparatus 8 periodically at the discretion of the official in the emerged part of the crumb is selected net for separate processing. From the lower part of the device 8 serum (returnable serum), carrying away part of the crumbs from the apparatus, the pump is pumped into the bottom of the coagulator 6. Excess serum from the apparatus 8 through the hydraulic seal 23 is reset to HSC.

To validate the method of regulation of the prototype sensor turbidimeter Cosmos 25 (protot is PE is not specified type of device for measuring the concentration of crumb rubber in reciprocal serum) using quick shutter was placed in line 3 return of the serum after the apparatus 8. After turning on the turbidimeter after 10 min of work has been the occasional clipping device. After increasing the flow of coagulant of sodium chloride up to 400 kg per tonne of rubber, the turbidity value has not decreased and showed the occasional clipping device (turbidity above 9999 FNU). When removing the sensor turbidimeter from the return line of the serum, it was found that measuring sapphire Windows (6 pieces with a diameter of 2 mm) on the sensor were completely plastered with sticky crumb rubber.

To test the operation of the turbidimeter were hand-selected samples return of serum in the above location and purified from crumb rubber filtration through a metal grid with a hole diameter of 0.1 mm is Placed in a purified from crumb rubber recoil serum sensor turbidimeter showed the value of turbidity equal to 150 FNU and 10 FNU at a flow rate of sodium chloride 200 kg and 400 kg per ton of the selected rubber, respectively. Thus, to measure the amount of turbidity return of serum by the turbidimeter can only manually after-low-tech operations of sampling and purification of serum from crumb rubber. Apply industrial flow mutemeri to determine the concentration of crumb rubber (in the prototype does not specify the type of monitor device for determining the concentration of crumb) was impossible.

Example 2 (control)

Classic industrial is Hema (Fig.1) with visual control of the coagulation process (working in industry).

The apparatus of the cascade (coagulator 6 and gotravel 7) in line 3 are filled with serum, heated to a temperature of 50°C, and sodium chloride on line 2 to its concentration in the serum 5%, in line 4 is fed sulfuric acid to a pH in the devices 6 and 7 in the range of 4-5%

Further included the supply of latex rubber SKS-30 ark on line 1 in the amount of 15 m3in hour 3 tons of rubber per hour). Consumption of sodium chloride exhibited at the rate of 200 kg absolute product per tonne of rubber in accordance with the company's regulations. The resulting slurry of rubber from doserates 7 to flow 27 enters the hub 17, where through the washing tank 18 babe enters the hub 19, which is separated from the wash water and then fed to the extraction and drying.

Management fullness coagulation according to the classical scheme is that the operator systematically observing visually the completeness of coagulation, climbing the stairs to the devices 6 and 7, and depending on subjective observations completeness coagulation (transparency serum) in units 6, 7, flows 26 and 27 and the hub 17 takes the decision whether the addition or subtraction of the amount of coagulant of sodium chloride, going to the line selection while adhering to the prescribed expenditure norms coagulant in accordance with the technological regulations, close to 200 kg/ton of rubber, without the sun the coy reference to a specific party latex. If this is not given the attention turbidity discharged serum.

For an objective assessment of the effectiveness of visual fullness of coagulation by the authors of the present invention from the overflow 27 every two hours samples were taken of the pulp rubber. In the laboratory the rubber from the pulp was separated from the serum by filtration through a metal mesh hole size of 0.1 mm In the obtained serum was added with additional special coagulant, and the serum was boiled to a full clarification within two hours. Serum was cooled and released by boiling the rubber was collected on pre-weighed filter paper, dried and weighed.

It turned out that in the serum of the pulp flow 27 was rubber in the form of negociaciones latex in an amount of from 50 to 800 mg/l (results of the 15 selections), and discharged in the serum of 30-200 mg/L.

Thus, a visual way to control the fullness of coagulation on the classical technology of isolating rubbers leads to large fluctuations in loss of rubber in the form of a latex.

Control of the coagulation process by manual sampling of serum, docomplete latex in the laboratory and determining the loss of rubber for a long time, time-consuming, the information obtained will be very late, so in practice.

In addition, visual way driven by the I process of coagulation, in addition to creating economic and environmental problems, is potentially dangerous to the health personnel because of their contact through the hatches of the apparatus and flows between pairs of harmful chemicals (styrene, a nitrile of acrylic acid, sulphuric acid). There is a high probability of injury (especially night shifts) when lifting apparatus for high stairs.

Example 3.

Managing the allocation process rubber SKS-30 ark, an improved scheme (2)completeness of the coagulation method, automatic, continuous measurement of turbidity primary (pos.17) and discharged (POS) serums and automatically adjusting feed coagulant.

The production of butadiene-styrene rubber SKS-30 ark was carried out on an improved industrial process diagram, shown in figure 2.

For this purpose, the apparatus of the cascade (6, 7, 18, 19) was filled with water in line 14, then turn on the flow of acid through line 25 and 9 to achieve a serum pH of 4-4 .5 and the supply of coagulant magnesium chloride (bischofite) in the apparatus 6 through line 11 to its concentration in the specified unit of 0.25%. The obtained serum was heated to a temperature of 50°C and line 1 was extended to supply latex styrene butadiene rubber SKS-ARC in the amount of 15 m3per hour (with line capacity allocation 3 tons of rubber per hour).

Of flow 27 through JV the social unit 15 continuously took part pulp rubber in running the cleaner 16 obtaining at the output of the primary serum, purified from crumb rubber.

In the overflow sump 23 8 put the cone of a metal grid with hole diameter of 0.1 mm to clear the secondary (discharged) serum from crumbs.

In purified primary serum was placed sensor 17 industrial turbidimeter Cosmos-25, giving an automatic signal to the controller 10 with the subsequent control flow of coagulant valve 12.

In cleared crumb discharged serum inside a metal cone was placed sensor 30 second turbidimeter, continuously measure the amount of turbidity of the serum coming in HSC.

On the first turbidimeter first installed the set value of turbidity interval 25-35 FNU and NIR turbidimeter automatically supported the turbidity of the purified primary serum in this range, acting on the valve 12 consumption of bischofite. The sensor of the second turbidimeter showed the value of turbidity discharged serum in the range of 10-15 FNU. On the evidence of the second turbidimeter was corrected value specified turbidity on the first turbidimeter in the range of 10-16 FNU. When such a given value of the turbidity on the first turbidimeter second NIR turbidimeter consistently showed turbidity discharged serum in the range of 2-5 FNU, indicating almost complete coagulation of the latex.

This mode of coagulation worked without failure around the clock during time trials - 25 su is OK. During this time, they have repeatedly changed the quality of different batches of latex, the amount of feed of latex, but NIR turbidimeter quickly deduced the process of coagulation by a specified amount of turbidity, automatically affecting the flow of bischofite, the consumption of which was in the range of 15-21 kg/ton of rubber.

Control of the coagulation process by the above proposed method using automatic turbidity primary and discharged serums sensors turbidimeter has clear advantages:

- efficiency process control;

- dramatically reduces the loss of rubber in the form of negociaciones latex;

- set the optimal consumption of coagulant (without fees);

- there is an opportunity for the operator to focus on getting the maximum performance by controlling other process parameters that cannot be controlled tool. These settings include obtaining pulp rubber with uniform and optimal size of a crumb (10-20 mm), with a minimum number of small crumbs. Zastabilizirovat given the completeness of the coagulation of the proposed method, the operator using the change of the stirring speed in the coagulator, selection of flow ratio of latex and return of serum quickly find the optimal parameters of coagulation for each party latex painted. is and. As a result improves the economy and ecology of the allocation process of the rubber. Reduces the risk of negative impact of harmful substances on the staff.

Example 4.

Managing the allocation process rubber SKS-30 ARKN manufactured on an advanced scheme (2) continuous measurement of turbidity primary (POS) and discharged (.23) serums and adjusting the flow rate of the coagulant.

The production of butadiene-styrene rubber SKS-30 ARKN with organic amine coagulant VPK-402 was performed on an improved industrial process diagram, shown in figure 2.

In hydraulic lock 21 of the hub 19 was placed purifier primary serum in the form of a cone of metal mesh hole diameter of 0.1 mm

In the overflow sump 23 8 put the cone of metal mesh hole diameter of 0.1 mm for cleaning parts discharged serum from crumbs.

In purified primary serum was placed sensor 20 industrial turbidimeter Cosmos-25, giving an automatic signal to the controller 10 with the subsequent control flow of coagulant valve 12.

In cleared crumb discharged serum inside a metal cone was placed sensor 30 second turbidimeter, continuously measure the amount of turbidity of the serum coming in HSC.

Start-up and operation of industrial cascade selection of westlakes in accordance with example 3 of the description.

The coagulant solution was fed to the coagulator 6 through line 11, sulfuric acid with a concentration of 1.5% was desirables on line 25, 14 to maintain the pH in the devices 6 and 7.

Control of the coagulation process was implemented automatic, continuous measurement of turbidity primary serum sensor turbidimeter in accordance with example 3 of the description. Given the magnitude of the turbidity of the primary serum were set equal to 80-100 FNU.

The sensor of the second turbidimeter showed the value of turbidity discharged serum in the range of 30-40 FNU. Based on the sensor readings of the second turbidimeter was corrected value specified turbidity on the first turbidimeter range from 5 to 10 FNU. After 50 minutes of work lines highlight the value of turbidity discharged serum was recorded by the sensor of the second turbidimeter in the range of 2-3 FNU.

Proposed method of control regardless of the quality of the latex allows you to keep the weight of coagulation close to comprehensive with a minimum consumption of coagulant.

Example 5.

Managing the allocation process rubber SKS-30 apkm-15 on the enhanced scheme (Fig.2) with the completeness of the coagulation method of automatically measuring the turbidity of the primary serum with manual turbidity measurement discharged serum.

In hydraulic lock 21 of the hub 19 put the purifier part of the primary product in the form of a cone of metal behold the key hole diameter of 0.1 mm

In purified primary serum was placed sensor 20 industrial turbidimeter Cosmos-25, giving an automatic signal to the controller 10 with the subsequent control flow of coagulant valve 12.

The second NIR turbidimeter sensor is installed in the operator's apparatchiks for periodic monitoring of turbidity discharged serum and adjustments specified turbidity in the primary serum on the first control turbidimeter.

Start-up and operation of industrial cascade selection was carried out in accordance with example 4 of the description.

On line 1 desirables oil-latex emulsion.

The coagulant solution was fed to the coagulator 6 through line 11, sulfuric acid was desirables on line 25, 14 to maintain the pH in the devices 6 and 7.

Control of the coagulation process was implemented automatic, continuous measurement of turbidity primary serum sensor turbidimeter in accordance with example 4 of the description. Given the magnitude of the turbidity of the primary serum was set equal to 8-10 FNU.

Every two hours manually selected sample purified discharged serum from trap 23 of the sump 8 and was measured in the value of the turbidity sensor of the second turbidimeter that is installed in the carrier. The value of turbidity discharged serum was in the range of 0-2. Consumption of coagulant VPK-402 was 2.2-2.4 kg/ton of rubber.

The apparatus of the IR manually adjusted preset value of turbidity on the first turbidimeter in the range of 10-15 FNU. After an hour of work line selection turbidity selected discharged serum was established in the range of 2-5 FNU, consumption VPK-402 was 1.8 kg/ton of rubber.

Proposed method of control regardless of the quality of the latex allows you to keep the weight of coagulation close to comprehensive with a minimum consumption of coagulant.

Example 6.

Managing the allocation of butadiene-nitrile rubber NITRILASE on the enhanced scheme (Fig.2) with the completeness of the coagulation method of automatically measuring the turbidity of the primary serum with manual turbidity measurement discharged serum.

Management was implemented with the release of butadiene-nitrile rubber NITRILES with coagulant bischofite according to the procedure of example 5 of the description. Given the magnitude of the turbidity of the primary serum was set equal to 10-15 FNU.

Every three hours manually selected sample purified discharged serum from trap 23 of the sump 8 and was measured in the value of the turbidity sensor of the second turbidimeter that is installed in the carrier. The value of turbidity discharged serum was in the range of 3-6 FNU. Consumption of coagulant bischofite was 18.1 kg/ton of rubber.

The operator has manually adjusted the specified amount of turbidity on the first turbidimeter in the range of 5-8 FNU. After an hour of work line selection turbidity selected relieves discomfort from overheating the CSOs serum was established in the interval 0-1 FNU, consumption of bischofite was 19.2 kg/ton of rubber.

Proposed method of control regardless of the quality of the latex allows you to keep the weight of coagulation close to comprehensive with a minimum consumption of coagulant.

As can be seen from the results of examples 1-6, the claimed process control method selection emulsion rubber from latex by continuous automatic measurement of the turbidity of treated from crumb rubber serums and adjust the flow of coagulant depending on the value of the specified primary turbidity of the serum in the control turbidity discharged serum helps to solve the technical problem of improving the environment, economy and security of the allocation process of emulsion rubber from latex.

It is important that the inventive method of control of the coagulation process is the most rapid and versatile for the production of emulsion rubbers all brands using any coagulants and facilitates the work of the maintenance staff. Proposed method of control the process of separation of rubber from latex has been applied in industrial tests.

The process control method of allocation emulsion rubber from latex with continuous mixing of the latex with a coagulant to form a slurry of rubber by changing the flow rate of the coagulant, wherein the continuously about imaut constantly allocated a portion of the pulp rubber (or pulp) from crumb rubber automatically and continuously measuring the turbidity obtained constantly updated purified from crumbs primary serum and correct consumption of coagulant depending on a given value of the turbidity of the primary serum, and a specified amount of turbidity primary serum adjust depending on turbidity cleared crumb discharged serum towards the minimum flow of the coagulant to obtain the minimum value of turbidity discharged serum.



 

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FIELD: chemistry.

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FIELD: chemistry.

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FIELD: chemistry.

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2 cl, 3 tbl, 2 ex

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FIELD: chemistry.

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FIELD: polymers, chemical technology.

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9 cl, 1 tbl, 1 dwg, 6 ex

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The invention relates to the production of emulsion rubbers in powdered form and can be used in the synthetic rubber industry

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The invention relates to the production of synthetic rubbers and emulsion polymerization

FIELD: medicine.

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4 tbl, 12 ex

FIELD: polymer materials.

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