Chemical method of pulp cooking

FIELD: chemistry.

SUBSTANCE: caustic soda is substituted with cheap lime and complexing, flocculation and acid-base neutralisation of aluminium sulphate are additionally used, the useful ingredients contained in black liquor are reused, output close to the yield of pulp is achieved, high-quality pulp is produced, cyclical utilisation of black liquor is carried out, and the problem of its pollution is solved.

EFFECT: highly effective pulp production.

10 cl

 



 

Same patents:

FIELD: process engineering.

SUBSTANCE: proposed process comprises the steps that follow. Thin 6 mm deep (maximum) chips are fed into bin. White (boiling) lye is added thereto or in chits transfer tube extending from said bin to continuous boiling digester top inlet. Medium-pressure steam or other heated fluid is forced to digester top area to up the boiling temperature to at least 130°C. Chips are boiled in digester downstream without extraction from or addition to digester boiling area of lye. Flushing fluid is forced to digester bottom area. Flushing fluid is discharged from digester bottom area through the sieve. Digested thin chips are discharged from boiler bottom area.

EFFECT: perfected method.

17 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: method of processing a cellulose mass by the Kraft-process with preliminary hydrolysis (PHKP) includes the addition of wood chips or a similar material into a reaction vessel, carrying out preliminary hydrolysis and neutralisation of the mixture by the first quantity of white liquor with the further addition of another solution, such as an alkaline filtrate of cold-alkaline extraction, if necessary, enriched with white liquor. Neutralisation liquids are replaced with digestion liquor, containing hot black liquor and the alkaline filtrate, if necessary, enriched with the white liquor. The concentration of effective alkali in the digestion liquor can be relatively high.

EFFECT: effective and cost-effective production of soluble cellulose with the high content of alpha-cellulose by the prevention of re-precipitation of hemicelluloses.

43 cl, 18 dwg, 1 tbl, 10 ex

FIELD: chemistry.

SUBSTANCE: invention relates to an integrated method of producing cellulose and at least one reusable low-molecular weight material. The method comprises preparing starting material containing lignocellulose and pulping using an alkaline treatment medium; from the pulped material, separating a cellulose-rich fraction and a cellulose-depleted fraction; subjecting the cellulose-depleted fraction to treatment using a method selected from a group comprising depolymerisation, hydrocracking, decarboxylation and a combination thereof; obtaining at least one reusable (secondary) low-molecular weight material selected from a group including, for example, hydrogen, aliphatic, cycloaliphatic, aromatic hydrocarbons and mixtures thereof, aromatic alcohols, aromatic aldehydes and mixtures thereof.

EFFECT: invention enables optimum integration of production of said end products, including additional reusable materials when producing cellulose.

31 cl, 6 ex, 3 dwg

FIELD: chemistry.

SUBSTANCE: method comprises mixing lignocellulose material with an aqueous dioxane solution which is obtained by mixing concentrated nitric acid and 1,4-dioxane in ratio of 1:4 (by volume), heating the reaction mixture on a boiling water bath for 15 minutes, adding 2 M sodium hydroxide solution, adjusting the volume of the reaction mixture with distilled water and filtering, measuring optical density of the filtrate at 440 nm and determining content of lignin in the cellulose semiproduct based on the value of optical density.

EFFECT: simpler and faster analysis.

2 tbl, 24 ex

FIELD: chemistry.

SUBSTANCE: method for pulp processing using cold caustic extraction includes: delignifying organic materials in a digester and treating the resulting brown pulp to obtain semi-purified pulp for use in producing soluble pulp; extracting the semi-purified pulp with a caustic solution during a cold caustic extraction process; washing the purified pulp and collecting the obtained spent wash liquid by separating the hemicellulose-containing solution from the purified pulp; combining the spent wash liquid and the hemicellulose-containing solution to obtain an alkaline filtrate; concentrating the alkaline filtrate and using at least a portion of the concentrated alkaline filtrate in said digester to obtain a soluble pulp.

EFFECT: high content of alpha cellulose in soluble cellulose and high efficiency of using the filtrate.

50 cl, 5 dwg, 1 tbl, 4 ex

FIELD: textiles, paper.

SUBSTANCE: method comprises processing of wood chips in two stages with aqueous alkaline media prepared by mixing black and white liquors and containing 15-30 g/dm3 of active alkali in units of Na2O for the first stage and 55-70 g/dm3 for the second stage. Processing at the first stage is carried out with the temperature rise to 125-155°C for 30 minutes and exposure for impregnation, hydrolysis and pulping at the final temperature for 60 minutes. The output of the waste media at this stage is carried out by its displacement with the aqueous medium for the second stage. The second stage is carried out with the temperature rise to 140°C for 40 minutes, exposure for impregnation and pulping at this temperature for 40 minutes, the temperature rise to 170°C for 40 minutes, exposure for pulping at 170°C for 90 min.

EFFECT: possibility is provided to obtain from larch wood the pulp for chemical processing or sanitary and hygienic purposes with values acceptable for these purposes for Kappa pulp, viscosity and content of α-cellulose, increase in pulp yield, increase in utilisation rate of heat and chemicals of waste alkaline media.

4 cl, 1 tbl

FIELD: textiles, paper.

SUBSTANCE: method of treatment of plant cellulose-containing materials includes the use of the device consisting of a housing, bottom and lid forming its working cavity, equipped with a means of its temperature-controlled heating, external means of recirculation of the liquid phase. The device comprises a working cavity which is divided into zones formed by the elements placed in the cavity, each of which consists of a cylindrical part and a perforated bottom with a plated filter screen located on it. Loading of the material in the device is carried out by its preliminary loading in the elements and their subsequent installation into the cavity. The elements are loaded with materials differing in characteristics. Replacement of one liquid phase in the device is carried out by displacement by the other liquid phase. Removal of products of each material treatment is carried out separately.

EFFECT: ability simultaneous treatment of several different samples of materials in the same modes and alignment of the characteristics of these samples.

1 cl, 3 dwg, 1 ex

FIELD: textiles, paper.

SUBSTANCE: method is carried out by successive soaking of cellulose raw material in alkaline solution thermo-mechanical chemical processing, extraction, washing, bleaching, extraction, washing, extraction and drying, and herbaceous plants are taken as the cellulose raw material. Before drying the cellulose raw material is loosened to individual fibres, transported on screws in which the diffusion alignment is carried out on moisture by volume, followed by drying in a microwave unit.

EFFECT: invention enables to reduce energy costs and to obtain cellulose which is uniform on quality characteristics.

10 cl, 3 ex, 1 tbl

FIELD: textiles, paper.

SUBSTANCE: method and device generally relate to feeding of white liquor and NaOH to increase the pH of the cooking liquor on the extraction sieve or near it, which inhibits adhesion of lignin to the extraction sieve.

EFFECT: invention enables to prevent clogging of the extraction sieve.

20 cl, 2 dwg

FIELD: textile, paper.

SUBSTANCE: method for production of sulfate cellulose from larch wood includes two stages of wood chips extraction using water at the first stage as the extractant and at the second stage - black lye, and subsequent boiling in a boiler of periodic action.

EFFECT: higher mechanical properties of cellulose and reduced value of Kappa number - when producing viscose cellulose.

3 cl, 1 dwg, 2 tbl

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.

2 tbl

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

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