Method to produce cellulose

FIELD: textile, paper.

SUBSTANCE: method is carried out by means of subsequent soaking of cellulose-containing herbal raw materials in alkaline solution, thermomechanical treatment, squeezing, washing, bleaching, squeezing, washing, squeezing and drying, besides, squeezing and washing are done in pulsating centrifuge.

EFFECT: higher yield of cellulose, reduced norms of consumption of initial reagents and water and reduced power inputs.

1 tbl, 3 ex

 

The invention relates to pulp industry, namely the production of cellulose from cellulose-containing vegetable material, and can be used for pulp production, designed to generatenode, in the paper industry, etc.

A method of obtaining cellulose by loosening plant materials, alkaline cooking using NaOH, surface-active substances (surfactants), T=120-130°C for 1 hour, rinsing 1-5 fold amount of clarified water hydrocyclone cleaning the clarified water, grinding, fine hydrocyclone cleaning the clarified water, 2-fold bleaching NaOCl at pH=9-11,5, T=35-40°C for 1 hour, 2 times washing softened water, kislovka solution of H2SO4at 15-40°C for 1 hour, rinsing, softened water, wringing, drying air (Constant technological regulation No. 4-2 "Production of esters and ethers of cellulose", approved on 18 January 1995, Gene. Director Engels JSC "Khimvolokno").

A method of obtaining cellulose, including mechanical treatment of cellulose-containing material by its simultaneous loosening and cleaning, boiling in an alkaline solution at a temperature of 130-140°C under a pressure of 3-4 atmospheres within 180-210 min, rinsing, bleaching in acid solution with sodium hypochlorite, centrifuge, loosening and drying (EN 2078163, CL D04H 1/02, op is BL).

The disadvantages of the above methods are: the process of alkaline cooking in harsh conditions and at temperature T=120-140°C, pressure P=2-4 ATM, bleaching carcinogenic sodium hypochlorite.

A method of obtaining cellulose by simultaneous loosening and clearing a cellulose-containing material, grinding, steeping in a solution of NaOH and cleaning, alkaline cooking for 1.5-3 hours at a water ratio of 1:(5-20), additionally containing surfactants, washing, bleaching in a solution of N2About2, rinsing, wringing and drying (Patent RF №2304647).

The disadvantages of this method is the impossibility of obtaining cellulose from cellulose-containing raw material with a high degree of zakostrennost and high content of lignin.

The closest in technical essence and the achieved effect is a method of obtaining cellulose by successive simultaneous loosening and clearing a cellulose-containing material, washing and cutting, locks, termomekhanicheskoi processing, washing, bleaching, washing, pressing and drying. In the embodiment of the method after termomekhanicheskoi processing material left for ripening in alkaline solution (Patent RF 2343241, D21 5/00).

However, when receiving pulp in a known manner, the process of washing of pulp is performed with the way you the of essenia, which takes a long time with a significant loss of fine fibers (less than 1 mm), the resulting termomekhanicheskoi processing, and also requires the use of large amounts of wash water.

The basis of the offer of the invention is the creation of efficient, cost-effective method of obtaining cellulose by use of at the stage of washing forced filtering method. Used for this purpose is the separation of the liquid and solid phases in a centrifugal field pulse centrifuge, resulting in accelerating the process of displacement of waste chemicals and excluded technological losses of fine fibers, and reduced dosing ratios of the raw materials and water.

The problem is solved so that, in the method of producing pulp by successive steeping cellulose-containing raw material in an alkaline solution, termomekhanicheskoi processing, washing, bleaching, washing, pressing and drying, before leaching lead the pomace and the pomace and leaching lead into the pulsing centrifuge, and as a cellulose-containing material take herbaceous plants.

As a cellulose-containing material used herbaceous plants, such as: flax, -intermediate, -Curley-Zieleniec, hemp, rape, cane, sunflower, bowl the tooth, clover, alfalfa, castor, Jerusalem artichoke, goat's Rue, Sosnowski's Hogweed, corn and the like, of various degrees of maturity, with a high content of fires, lignin, longer curing in warehouses and fields.

In the proposed method are pre-locked to a cellulose-containing raw material of herbaceous plants in the cooking liquid, which are circulating water with NaOH content - 10-60 g/l surfactant is 0.2 - 0.8 g/l, for 15-60 minutes at a temperature of 90-100°C. hydronic equal 1:(10÷20).

Soaked in the cooking solution of the cellulose raw material is fed through the receiving hopper - hopper in a preheated temperature of 80-100°C twin screw apparatus of the AL-200, on the shafts of which are placed alternating injection screw and Cam grinding nozzles that are offset one with respect to another with the formation of the screw channel (A.S. USSR №884715, 1981).

After termomekhanicheskoi activation recycled pulp is pumped by massanassa in the pulsating centrifuge brand P-80 for removing fiber substances, soluble in water and absorbed in the process of cooking the fiber.

Throbbing centrifuge consists of placed in the perforated casing of the rotor, consisting of the inner and outer drums in the form of a metal slotted sieves; conical funnel; loading branch pipe for supplying suspense and two washing nozzles with nozzles for supplying hot and cold water; the collector is divided into sections, for removal of supernatant and sludge (Passport P-80 Ferrum No. D11 company Bowas-Induplan Chemie GmbH).

The principle of operation of the centrifuge consists of the following: alkaline slurry of pulp is continuously fed through the feeding pipe in a narrow part of the tapered funnel, moves its inner surface, gradually gaining speed equal to the speed of rotation of the rotor. Then the suspension is dropped on the surface of the inner drum, which pushes the spent liquor and is output from the collector of the centrifuge. Pressed the pulp due to the pulsation of the centrifuge is fed into the outer drum for washing. Washing is carried out by spraying a mass of water with a temperature of 70-90°C injection through the nozzle washing nozzle. The filtered solution is output from the collector. Then as you progress in the outer drum centrifuge initially filtered mass is irrigated with water with a temperature of 30-40°C, which is injected through the second nozzle washing nozzle. Washed the pulp discharged through the discharge channel centrifuges and transported to the bleaching in the bleaching tower.

The bleaching of pulp is performed with hydrogen peroxide solution with a concentration of 5-10 g/l at a temperature of 85-95°C for 90 minutes. Hydraulic module- 1:(10÷20).

Leaching from otaling the solution is carried out just the same as a rinse after alkaline termomekhanicheskoi activation.

Pulp, pressed to a moisture content of 30-40%, pneumatic serves for drying.

Drying cellulose conduct flue gases at a temperature of 140-160°C vibrosource.

The dried pulp is served in the press and then on the package.

To prove the conformity of the way the criterion of "industrial applicability" presented concrete examples of implementation of the method.

Example 1.

1000 kg unpacked and loosened chaff rape a size of 2-3 cm and 10 m3cooking solution with a concentration of NaOH 30 g/l recycled water and 0.2 g/l cintanya ALM-10 served in the reactor-the drive locked. The reaction mass in the reactor device is heated to 100°C and kept at this temperature for 30 minutes. Operating temperature support through the heated cooking solution tube heat exchangers. Soaked in the cooking solution raw material of the reactor-drive goes through the receiving funnel - spout in the twin screw apparatus of the AL-200 (capacity 2.0 tons/hour), preheated to a temperature of 100°C, and hold termomekhanicheskoe processing within 30 minutes with keeping the temperature parameter.

At the end termomekhanicheskoi processing recycled pulp massanassa pumped into the pulsating centrifuge, in which the original is Ino carry out the extraction of the spent alkaline solution. Pressed pulp mass to a moisture content of 32% washed by the flow through the flushing nozzles 5 m3water with a temperature of 70-90°C and 5 m3water with a temperature of 30-40°C.

Next, the pulp is mixed with an aqueous solution of hydrogen peroxide concentration 5 g/l and a screw conveyor is served in the bleaching tower. The mass is heated with live steam to a temperature of 90-95°C and carry out the bleaching for 1.5 hours.

Leaching from the bleaching solution carried out as a rinse after alkaline termomekhanicheskoi activation pulse centrifuge.

Pulp, pressed to a moisture content of 32%, pneumatic serves for drying.

Drying is carried out by feeding the pulp into vibracoustic. Flue gas temperature is 140-160°C.

The dried pulp is served in a horizontal press and then on the package.

Get the pulp with a yield of 48%.

Example 2-3 behave analogously to example 1, by changing the process conditions. Data examples are presented in the table.

As can be seen from the table, the claimed method is cost effective, as it allows to increase the output of pulp at 10% due to catch the very fine fibers, to reduce the rates of consumption of the raw materials and water, reduce energy costs by drying the product with a lower content of residual water in it.

The method according to the teachings of the pulp by successive steeping cellulose-containing raw material in an alkaline solution, termomekhanicheskoi processing, washing, bleaching, washing, pressing and drying, characterized in that before leaching lead the pomace and the pomace and leaching lead into the pulsing centrifuge, and as a cellulose-containing material take herbaceous plants.



 

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1 tbl, 7 ex

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2 cl, 17 ex, 16 tbl

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1 tbl, 9 ex

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