A method of obtaining a bleached kraft pulp
(57) Abstract:The inventive water vapor and odorous substances are separated from the hot black liquor by cooling the latter in the evaporation cyclone, mixed with the pulp slurry and oxidant at the stage oxygen-alkali delignification of unbleached pulp or oxygen-alkali delignification with the addition of hydrogen peroxide or oxidizing be chlorinated pulp. Implementation of the proposed method allows to reduce the consumption of steam as the neutralization pornopanda substances, and to reduce its consumption in the bleaching of pulp. When this is achieved a high degree of neutralization of odorous substances by oxidation to non-toxic and non-volatile oxygen derivatives of sulfur. table 2. The invention relates to the production of bleached fibrous semi-finished and can be used to obtain bleached Kraft pulp for various purposes in the cooking apparatus of periodic action.A method of obtaining cellulose, including boiling the pulp in the apparatus of periodic action, filler mass in the blow tank, washing, and bleaching the cellulite, tighten the high temperature and pressure (160-170aboutWith and 0.6-0.6 MPa). In the process of blowing intense boiling of the liquid in the blow tank, accompanied by release of water vapor and toxic substances (mercaptan dimethyl sulfide, dimethyl disulfide and others) in the atmosphere even when using install heat recovery type "Rosenblad". In addition, during the blowing occurs mechano-chemical degradation of cellulose, and when forced outages digester with the obtained pulp by weight deteriorate its mechanical properties due to the slow decrease of the temperature.Closest to the technical nature of the invention is a method for bleached Kraft pulp in the cooking apparatus of periodic action, including the cooking of cellulose, the displacement of the hot black liquor, unloading cooled mass with steam, air or pump and the bleaching of pulp .The known method has two significant weaknesses. First, for cooling extruded from the digester black liquor use spiral and tubular heat exchangers closed, pressure of 0.5-0.7 MPa. It is required to reduce the temperature of the black liquor 150-170 up to 80-90aboutWith that uslojnyaet the deposits. In the heat exchanger is inevitable contamination of the inner surfaces of the deposits of mineral salts and organic substances, which requires periodic cleaning. Secondly, formed during cooking odorous and toxic compounds with extruded and cooled black liquor coming to evaporation in the process of being transferred into the secondary steam condensate and in the atmosphere. For disposal of contaminated condensates requires a complex and energy-intensive to install their separation by distillation with water vapor, collection, transportation and incineration.The aim of the invention is to increase process efficiency by reducing the consumption of steam for the cooking and bleaching of pulp and residue liquor, prevent emissions of VOC while maintaining quality indicators cellulose, as well as simplification of the system heat recovery hot black liquor.This is achieved by the fact that in contrast to the known method of producing sulphate pulp extruded from the digester, hot black liquor is sent to the evaporation cyclone for its cooling and separation of water vapor from volatile broadnose substances that guide in the installation of oxygen-Selo is Orada or oxidative be chlorinated pulp.The implementation of this method allows to increase by 1.5-2.0% (absolute) solids content black liquor sent to the residue (equivalent to savings of 7-8% of steam consumption per residue), separated from the black liquor up to 92% volatile odorous compounds and almost completely oxidize them to non-toxic and non-volatile oxygen-containing sulfur compounds (sulfite, sodium thiosulfate and others) at the stages of oxygen-alkali delignification of cellulose or oxidative be. The obtained filtrate after oxygen-alkali delignification can be used for washing of unbleached pulp.In addition to the neutralization of odorous compounds proposed method allows the use of heat, water vapor formed during samosatene black liquor, during oxygen-alkali delignification of unbleached pulp or oxidative be chlorinated mass.P R I m e R 1. Boiling cord pulp with preliminary water hydrolysis of wood chips made from pine wood, is carried out in a laboratory autoclave with a volume of 5 l equipped with electric heating and forced circulation system according to the following mode. The hydrolytic water ratio and su is aboutWith 80 minutes After extraction of the hydrolysate in the autoclave download white and black liquor to the desired water ratio and spend sulphate cooking: the consumption of alkali - 18,5% (unit Na2O), impregnation when 130aboutC - 30 min, temperature rise from 130 to 170aboutS - 60 min, Parking at 170aboutC - 90 minIn order to simulate the process by a known method using three cooking autoclave. In the first autoclave are boiling, after which the hot black liquor to a temperature of 170aboutTo displace warm black liquor temperature 70about(Autoclave N 2) in the autoclave N 3 using nitrogen gas as long as the temperature in the autoclave 1 pulp mass does not reach the 90aboutC. Then the hot black liquor temperature 155aboutServed with from the autoclave N 3 in evaporative cyclone. Pair samosatene black liquor from the cyclone is directed to the cooling and collecting in a container with a volume of 2 liters via direct water cooler. By gas chromatography to determine the content of the most toxic component of odorous gases - methylmercaptan in the condensate and cooled black liquor. The obtained experimental data show that upon evaporation of 1.1 m3water vapor per 1 ton of the Zell is Aptana - the most dangerous of which is formed with a single-component vapor-gas emissions. In the latter case, this would amount to about 91.8% of the total number found in the liquor after cooking.P R I m m e R 2. Boiling cord pulp is carried out in conditions similar to those specified in example 1. Forced out of the autoclave 1 in the autoclave 3 hot black liquor is sent to the evaporation of the cyclone. Formed in the cyclone of water vapor samosatene together with broadnose compounds fed into the reactor with unbleached cord cellulose. Then the reactor is pumped oxygen and carry oxygen-alkali delignification according to the following mode: the concentration of the pulp 8.0%, lye concentration of 2.5%, temperature 70aboutC. Processing the mass is performed under oxygen pressure of 0.15 MPa for 60 minutes, then the reactor pressure is reduced to atmospheric and maintain the pulp mass within 150 minutes a content Analysis of odorous volatiles in the vapor condensate of samosatene black liquor and filtrate after oxygen-alkali delignification carried out by gas chromatography. Data on the degree of neutralization of VOC after stage oxygen-alkali delignification presented in the chlorination with the addition of ClO2;
SCHO2- oxidative bucking;
D - treatment with chlorine dioxide;
G - treatment with sodium hypochlorite;
To treatment with the aqueous solution SO2.P R I m e R 3. Boiling cord pulp is carried out in conditions similar to those described in example 1. Pair samosatene black liquor is served on the stage oxygen-alkali delignification of unbleached cord pulp with the addition of hydrogen peroxide. The consumption of H2ABOUT2is 5 kg per 1 ton of pulp.The results of the analysis and the degree of neutralization of the odorous substances are presented in table.2, column 4.Dabelko cord pulp is carried out by the scheme: X/D - SCHO2- D - G - K.P R I m e R 4. Boiling cord pulp is carried out in conditions similar to those described in example 1. Pair samosatene displaced from the digester black liquor together with broadnose volatile compounds is sent to the reactor before carrying out oxidative be chlorinated pulp. Conditions of oxidative be: concentration of pulp 8% , the concentration of alkali 3.0%, temperature 70aboutC. Processing the mass is performed under oxygen pressure of 0.25 MPa for 60 min, then the pressure in the re Data quality indicators pulp after stage oxygen-alkali delignification (AMD) and oxidative be (SL2) are presented in table. 1.Indicators cord pulp unbleached: 95,0% Kappa; Of 29.5 MPa. The results demonstrate that the addition of volatile components with pairs of samosatene black liquor when bleaching does not lead to deterioration in quality cord pulp.The results of the analysis and the degree of neutralization of the odorous substances are presented in table.2.Dabelko cord pulp is carried out by the scheme: X/D - SCHO2- G - d - D - D - K.Received cord pulp after bleaching with the addition of vapor samosatene black liquor and VOC no significant differences compared with cellulose, bleached without vapor samosatene and all indicators of the quality meets the requirements of GOST 16762-82 "Cellulose sulfate prehydrolysis for cord yarns and high-modulus fibers".Thus, implementation of the proposed method in contrast to well-known not only to avoid the consumption of steam for the disposal of odorous substances, but also to reduce its consumption in the bleaching of pulp. what I mercaptan) by oxidation to non-toxic and non-volatile oxygen derivatives of sulfur. A method of OBTAINING a BLEACHED Kraft PULP, including periodic cooking of cellulose, the displacement of the hot black liquor, cooling it in the evaporation cyclone separating water vapor and odorous substances and the bleaching of pulp, characterized in that, to prevent emissions of odorous substances and increase process efficiency while maintaining quality indicators derived cellulose, water vapor and odorous substances separated from the extruded hot liquor, served on the stage of pulp bleaching and mixed with the pulp slurry and oxidant at the stage oxygen-alkali delignification of unbleached pulp, or oxygen-alkali delignification with the addition of hydrogen peroxide, or oxidative be chlorinated pulp.
FIELD: production of cellulose, namely method and plant for generating heat and electric power in cellulose-producing factory, especially in sulfate-cellulose factory.
SUBSTANCE: according to invention liquor remained from digesting liquor at making wood cellulose is concentrated and burned in recovery boiler at presence of biogenic fuels. During such process heat power of exhaust gases generated at burning is taken off and if it is desirable it is converted to electric power. According to invention bark or similar wood waste materials subjected to drying till moisture content no more than 30% are used as biogenic fuel. Then said waste materials are gasified for producing fuel gas to be supplied into recovery boiler. Plant for performing the method includes apparatuses for drying and gasifying bark; unit for feeding bark incorporated in apparatus for bark gasifying is joined to unit for discharging dried bark incorporated in drying apparatus. Unit for discharging fuel gas is connected with recovery boiler for feeding fuel gas generated from gasified bark into it. In cellulose producing factory separate boiler is generally used for burning bark.
EFFECT: lowered investment cost, simplified design, maintenance and operation of equipment due to elimination of necessity of using separate boiler for burning bark, enhanced efficiency of using power.
27 cl, 2 dwg
SUBSTANCE: method involves collecting concentrated gases possessing an unpleasant smell, containing sulphur compounds, and burning the collected gases to oxidize the sulphur compounds. Concentrated gases with unpleasant smells are burnt in an air index of less than one in the first aggregate for burning using the Claus method in such a way that, at least an essential part of the sulphur compounds are oxidized to elementary sulphur. At least 10 mol. % of the sulphur compounds which have passed through the Claus system are later burnt in the device for burning the second aggregate.
EFFECT: obtaining elementary sulphur, isolated in liquid or solid state, which can be returned to the production cycle or used for other practical purposes, is ensured.
24 cl, 5 dwg
FIELD: machine building.
SUBSTANCE: boiler-utiliser of waste of alkali liquor consists of system of water/steam circulation equipped with super-heaters. Also the said system of circulation is coupled with a steam turbine containing a stage of high pressure and a fire chamber for waste alkali liquor combustion and for production of furnace gases. Furnace gases pass through an upper part of the system of circulation. The system of water/steam circulation in the boiler-utiliser is equipped with an intermediate super-heater for intermediate steam super-heating after the stage of high pressure of the turbine. The intermediate super-heater has the first and the second parts. The first part is positioned in a flow of furnace gases formed in the furnace; the said first part is connected with a channel for steam outlet of the turbine high pressure stage. Also here is disclosed the method of production of energy on a cellulose pant equipped with the boiler-utiliser.
EFFECT: reduced corrosion and increased output of power at energy production in cellulose plant.
19 cl, 1 dwg, 1 tbl
SUBSTANCE: vapour-containing flue gases are fed into a surface heat-exchanger where they are cooled. Further, the vapour-containing flue gases are fed into a mixing heat exchanger at pressure 1-15 bars where adiabatic cooling takes place to saturation temperature, after which the vapour-containing flue gases are fed into an evaporation apparatus for evaporation of alkali-containing solutions. From the evaporation apparatus, the vapour-containing flue gases are once again fed into the surface heat exchanger where they are heated to temperature which is 5-20°C higher than the saturation temperature of water vapour and are released outside through a flue-pipe.
EFFECT: high efficiency of utilising heat of vapour-containing flue gases.
FIELD: textile, paper.
SUBSTANCE: method includes stages of raw materials loading, its compaction, supply of cooking liquor, increase of temperature and pressure up to working parameters, soaking of the boiler content at the specified temperature, blowing of mass into a blow tank and removal of boiling vapours in process of blowing from the blow tank. Boiling vapours are removed during boiling through a three-stage condensation system in a counterflow mode. At the inlet of the first stage the temperature of a cooling agent - a solution of calcium chloride is maintained within the range of 40-50°C. At the inlet of the second stage the temperature is maintained within the limits of 17-27°C. At the inlet of the third stage the temperature is maintained below 0°C. The line of boiling vapours removal is isolated from environment by a mechanical lock in the beginning and by a hydraulic lock in the end. Removal of non-condensed vapours is carried out by means of ejection.
EFFECT: prevention of hazardous emissions into atmosphere and catching precious components from steam and gas mixture.
FIELD: textile, paper.
SUBSTANCE: device to feed one or more chemicals into a process flow of a paper-making plant includes the following: the first channel, having one or more inlet holes and outlet holes; the second channel, having one or more inlet holes and outlet holes, besides, the specified first channel is fixed to the specified second channel and crosses the second channel; a mixing chamber, having one or more inlet holes and outlet holes, besides, the specified second channel is connected to the specified mixing chamber, and outlets of the first channel and outlets of the second channel are connected to the mixing chamber; and an adapter, which is connected to the specified outlet holes of the mixing chamber and is attached to the specified mixing chamber. A method is proposed to feed one or more chemicals into a process flow of a paper-making plant, where the device is applied.
EFFECT: reduced quantity of chemicals and monitoring over chemicals feed into a process flow and final properties of products.
22 cl, 9 dwg
FIELD: textile, paper.
SUBSTANCE: method includes feeding raw materials into a boiling pot and its compaction. Supply of boiling liquid, increased temperature and pressure to working parameters. Soaking the pot content at the specified temperature. Blowing the mass into a blowing reservoir. Removal of boiling vapours and discharge of non-condensed gases by ejection. Removal of boiling vapours during blowing is carried out via a three-stage system of condensation in a counterflow mode. Upstream the three-stage system of condensation, the boiling vapours are mixed with spent alkali in a mixing condenser, and the mixture is heated up to 80-90°C. The heated spent alkali is supplied to a boiling pot arranged at the charging stage for preliminary heating of the process chips.
EFFECT: reduced power inputs due to recuperation of blowing vapours heat in the mixing condenser and using this heat for heating of alkali, which makes it possible to considerably reduce the required surface of condensation in the heat exchanger.
1 dwg, 1 ex
FIELD: cellulose derivatives production.
SUBSTANCE: invention is intended to be employed in paper-and-pulp industry in sulfate or natron cellulose manufacture process. Coniferous or foliferous wood is cooked in alkali solution at elevated temperature and pressure in presence of anthraquinone as delignification catalyst, the latter being product obtained after acylation of phthalic anhydride with benzene, which is added in 0.01-0.1% excess to dry wood, cooking being carried out in a way that 12-16% of active alkali based on the weight of dry wood is consumed.
EFFECT: improved quality of produced material due to reduced degree of delignification and amount of non-cooked raw material, increased yield, and improved physicochemical characteristics.
4 tbl, 3 ex
FIELD: production of fibrous half-finished products at different degree of delignification; wood-pulp and paper industry.
SUBSTANCE: cellulose-containing vegetable material is subjected to boiling at higher sulfidity of boiling solution, up to 100%. Used as sulfide-containing component are alkaline wastes of oil desulfurization processes which contain inorganic compounds, including sodium sulfide at concentration up to 120 g/l in Na2O terms and residual organic compounds in form of sulfur-containing hydrocarbons C5-C6 and phenolates at concentration up to 15 g/l. Boiling is carried out at 130-160°C.
EFFECT: high parameters of delignification process; enhanced economical efficiency; reduction of toxic emissions.
FIELD: paper-and-pulp industry.
SUBSTANCE: invention relates to production of pulps used in binder-based articles. Method of invention comprises repetitive soaking and washing of unbleached pulp in water, which is maintained in alkaline state at elevated temperature to obtain cellulose product characterized by chemical oxygen demand not above 2.0 kg per 10 kg dry cellulose.
EFFECT: improved strength characteristics of products.
14 cl, 1 dwg, 2 ex
FIELD: paper-and-pulp industry.
SUBSTANCE: invention relates to unbleached pulps, which are used in binder-based cellulose products, which are kraft pulp products. Cellulose product is maintained under alkali conditions during washing operation since initial soaking phase to cellulose drying step and exhibits chemical oxygen demand not higher than 2.0 kg per 1000 kg dry cellulose.
EFFECT: increased strength characteristics of product.
11 cl, 1 dwg, 2 ex
FIELD: paper-and-pulp industry.
SUBSTANCE: invention provides cellulose production process that can be used in pulping carried out by alkaline, neutral, and neutral sulfite methods. Cellulose-containing stock is pulped in presence of catalyst, in particular waste produced in production of anthraquinone via catalytic vapor-phase oxidation of anthracene. In this case, anthraquinone production waste is preliminarily exposed for 3-10 min to ultrasonic field and simultaneously treated with white lye at lye-to-anthraquinone production waste (1-4):1.
EFFECT: improved pulping characteristics for cellulose-containing vegetable stock.
2 cl, 1 tbl, 22 ex
FIELD: paper-and-pulp industry.
SUBSTANCE: cellulose-containing material preparation method provided by invention can be used in sulfate and natron cellulose production processes. Cellulose-containing stock is subjected to alkaline treatment at heating and pressure in presence of dispersion containing anthraquinone-containing additive particles and black lye. Dispersion is prepared by jointly grinding anthraquinone-containing additive particles in black lye medium at lye-to-additive ratio (0.71-0.91):1 and process is effected until density of dispersion achieves 1.07-1.20.
EFFECT: enhanced pulping efficiency.
1 tbl, 7 ex
FIELD: paper-and-pulp industry.
SUBSTANCE: preparation of white alkali liquors finding use, for example, in sulfate pulping process, involves exposing oxidized white alkali liquor, which is obtained by oxidation of white alkali liquor with oxygen-containing gas in presence of lime sludge and/or manganese dioxide, to controlled temperature. Controlled temperature provides increase in concentration of UV-detectable (at 285 or 286°C) polysulfide or visible light-detectable (at 416 nm) polysulfide, while weight ratio of UV-detectable polysulfide to gravimetrically measured polysulfide or visible light-detectable polysulfide to gravimetrically measured polysulfide is also raised.
EFFECT: increased percentage of active polysulfide in total polysulfide, which can be used to increase yield of cellulose in sulfate pulping process.
44 cl, 11 tbl, 13 ex
FIELD: woodworking and resin industries.
SUBSTANCE: invention concerns anthraquinone-based wood delignification catalyst, which can be used in vegetable stock cooking process involving alkaline technologies. Method comprises liquid-phase interaction of anthracene with oxidant in organic solvent followed by crystallization of anthracene. The latter operation is conducted for 1 to 10 min in presence of benzoic acid (consumption 0.01-0.3%) in ultrasonic field generated by ultrasonic emitter at acoustic power 0.6 kW and frequency 22 kHz.
EFFECT: increased catalytic activity of anthraquinone and reduced consumption of catalyst.
3 cl, 4 tbl, 4 ex
FIELD: pulp-and-paper industry.
SUBSTANCE: invention relates to manufacture of cellulose from vegetable cellulose-containing raw material and can be used to manufacture cellulose from linen material, designed for chemical processing as well as for manufacturing cotton wool and paper. Cellulose-containing material is simultaneously loosened and cleaned and then subjected to grinding, soaking in NaOH solution, cleaning, and pulping. The latter operation is effected in surfactant-containing alkali solution for 1.5-3 h at water duty 1:(5-20). Material is then washed and bleached in H2O2 solution, rewashed, squeezed, and dried. According to this invention, before the washing step, material is acidified with nitric acid solution and, before drying, ground. According to another embodiment of invention, material is simultaneously loosened, cleaned, pulped, and then washed. Then follow: bleaching in H2O2 solution for 1-2 h at water duty 1:(5-20), rewashing, squeezing, and drying. After bleaching material is acidified and, before drying, ground.
EFFECT: simplified process and improved environmental safety.
6 cl, 2 tbl, 10 ex
FIELD: pulp-and-paper industry.
SUBSTANCE: invention relates to manufacture of cellulose from vegetable cellulose-containing raw material and can be used to manufacture cellulose from linen material, designed for chemical processing as well as for manufacturing cotton wool and paper. Cellulose-containing material is first loosened, then soaked in aqueous solution containing alkali, hydrogen peroxide, and surfactant. After that, material is pulped and simultaneously bleached, then washed with softened water in two steps at water duty 1:(5-20), squeezed to moisture content 60-80%, and dried. According to this invention, before the washing step, material is acidified with nitric acid solution and, before drying, ground.
EFFECT: improved economical efficiency of manufacturing cellulose suitable for chemical processing due to use of out-autoclave low-temperature alkali pulping and improved environmental safety of process.
3 cl, 3 ex
FIELD: pulp and paper industry.
SUBSTANCE: disclosed is bleached craft fiber from conifer species wood cellulose with high content of alpha-cellulose and higher brightness and whiteness.
EFFECT: invention also describes methods for production of craft fibres and products manufactured from it.
19 cl, 12 tbl, 7 ex