WO2008074220A1

WO2008074220A1 - A preparation method of a bamboo pulp

Info

Publication number: WO2008074220A1
Application number: PCT/CN2007/003645
Authority: WO
Inventors: Dewu Song; Shuhua Zheng; Zhenfeng Li; Zhenjun Xue; Meixin Fan; Huanzhi Zhang
Original assignee: Hebei Jigao Chemical Fiber Co., Ltd.
Priority date: 2006-12-18
Filing date: 2007-12-18
Publication date: 2008-06-26

Abstract

A preparation method of a bamboo pulp comprises the steps of preparing material, cooking and bleaching. In the step of preparing material, bamboo material is obliquely cut at the angle of 10-85º into bamboo chip with a chip cross-section spacing distance of 20-40 mm. The method also comprises a step of water cooking between the steps of preparing material and cooking. In the step of water cooking, the temperature is firstly increased to 130-150? and held for 50-70 min, and then to 165-175? and held for 120-180 min. The method also comprises a compressing step using screw extrusion device in the presence of alkali liquor betweenthe steps of preparing material and cooking.

Description

Method for preparing bamboo pulp

Technical field

The present invention relates to a process for the preparation of pulp, and more particularly to a process for the preparation of bamboo pulp for viscose fibers.

Background technique

Chemical fiber, as a raw material for the textile industry, is growing in number, especially today, when energy is scarce. The manufacture of chemical fiber is largely limited by coal and petroleum resources, so it is necessary to return the look of fiber raw materials to cellulose fibers.

Bamboo has a very rich resources and is widely distributed. There are more than 40 species of bamboo and more than 400 varieties. It can be cut into forests after 2 to 3 years of planting. It is a fast-growing and high-yielding plant material. Take the most widely used and good quality Cizhu as an example, its hemicellulose content is 40-50%, lignin content is 20-30%, ash 1-3%, polypentose 16-20%, fiber The average length is 2. 7rara, which is an excellent cellulose raw material.

Because of the tight structure of bamboo, the cell wall is thick and the diameter of the cavity is small, the content of miscellaneous cells is high, and there is a layer of fatty wax on the outside. When cooking, the penetration of chemicals is worse than that of wood. Therefore, in the process of pulping, pre-hydrolyzed sulfate is often used. Add multiple bleaching methods.

Prehydrolysis kraft cooking is a combination of prehydrolysis and kraft cooking of bamboo raw materials. In the pre-hydrolysis stage, part of the hemicellulose in the bamboo raw material reacts with the hydrolysis medium under high temperature and acidic conditions and is transferred into the solution, and the hemicellulose remaining in the raw material is also hydrolyzed to some extent, which improves the alkali cooking time. Transfer to the solubility of the solution. Pre-hydrolysis impairs or destroys the linkage between lignin and carbohydrates in the outer layer of the cell wall or between the carbohydrates, loosening the outer layer of the cell wall, thereby creating favorable conditions for the permeation of the cooking liquor.

Due to the contradiction between the increase of whiteness and the decrease of polymerization degree in the bleaching process, the prior art generally adopts three-stage bleaching or four-stage bleaching to obtain a certain effect.

However, the state of the art is often due to the above-mentioned pretreatment and bleaching processes, and there are many steps, large consumption, and serious pollution. A more representative technical solution can be found in the Chinese patent application CN1308160, "Using Bamboo." Process for producing viscose fiber pulp, the process flow is: preparation→cutting→screening→washing→pre-hydrolysis→washing→cooking-dumping→washing→screening→disintegration-de-sanding→concentration→ Chlorination, washing, alkali refining, washing, bleaching, washing, acid treatment, washing, sand removal, concentration, and papermaking. After cooking, the cellulose content is ≥ 95.5%, pulp hardness (Kappa) The value is 4-10, the average degree of polymerization is DP 600; the bleaching whiteness is 3⁄4 75%, the average degree of polymerization is DP 450, the viscosity is > 7. 5 mPa - s , and the cellulose content of A is 3⁄4 93%. The technical solution has complicated production methods, long process flow, high energy consumption, serious pollution, difficult quality control, large fluctuations in product quality, and difficulty in meeting actual production. The need for development. Moreover, due to the long process, the natural antibacterial property of the bamboo fiber itself is seriously damaged, and thus the produced pulp has poor antibacterial property.

Summary of the invention

Accordingly, it is a primary object of the present invention to provide a method for preparing a bamboo pulp which has a shorter process flow and less environmental pollution due to the beveling of the bamboo material during the preparation process.

In order to achieve the above object, the technical solution adopted by the present invention is:

A method for preparing bamboo pulp, the method comprising preparing, cooking, washing, sand removing, concentrating, and bleaching, wherein the preparation is to first flatten the bamboo into a long strip of bamboo, and then to form a long strip of bamboo. Oblique cutting, so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 10-85 degrees, and a bamboo piece having a section spacing of 20 - 4 Oram is obtained; preferably the chamfered surface and the long strip of bamboo are in the middle The axis is at an angle of 20 - 70 degrees, and a bamboo piece having a slice section spacing of 20 - 30 mm is obtained; more preferably, the oblique section is at an angle of 40 - 60 degrees with the central axis of the long strip of bamboo, and the section spacing of the section is 25 Bamboo pieces.

The bamboo piece according to the present invention is a horseshoe-shaped slice, and the weight of the horseshoe-shaped slice accounts for more than 70% of the total weight of the bamboo piece.

In the present invention, the boiled water is further included between the preparation and the cooking, and the boiled water is: placing the prepared bamboo pieces in the digester, adding water, and making the liquid ratio 1: 3. 0 - 5. 0, Preferably, the liquid ratio is 1: 3. 0-4. 0; first heat up to 13G - 15G ° C for 50 - 70 minutes, then raise the temperature to 165 - 175 ° C, keep warm for 120 - 180 minutes, The boiled bamboo pieces are obtained.

In the present invention, pre-hydrolysis is further included between the preparation and cooking, and the pre-hydrolysis is: placing the prepared bamboo pieces in a digester, adding water or an acidic solution to make the liquid ratio 1: 5 - 8. 0, preferably the liquid ratio is 1: 3. 5-4. 0 and then maintained at a pressure of 0. 65 - 0. 75MPa for 60 - 150 minutes, preferably for 100-150 minutes; The liquid was drained to obtain a pre-hydrolyzed bamboo piece. The acidic aqueous solution is preferably an acidic aqueous solution having a pH of from 4. 5 to 5.

The cooking described in the present invention is an alkaline cooking, comprising: placing a bamboo piece in a digester, and using an alkali amount of NaOH as an absolute dry material amount of 15 to 35%, preferably using the alkali amount as约约。 The NaOH is the absolute dry material amount of 25 - 35%; the liquid ratio is 1: 3. 0 - 5. 0, preferably the liquid ratio is 1: 3. 5-4. 0, the pressure is 0. 65 - 0. The cooking is carried out at 75 MPa for 100 - 150 minutes to obtain a steamed slurry; preferably, the amount of the base used is 20-30 °/» of the dry raw material in terms of 'NaOH.

The cooking according to the present invention may also be a kraft cooking process, comprising: placing the prepared bamboo pieces in a digester, and using the alkali amount to be NaOH, the amount of the dry raw material is 20 - 30%, and the liquid ratio is 1: 3. 0 - 5. 0, preferably the liquid ratio is 1: 3. 5-4. 0; the degree of vulcanization is 15. 0 - 25. 0% and the pressure is 0. 65 - 0. 75MPa under cooking 100 - After 150 minutes, the cooked slurry was obtained. The bleaching of the present invention is to carry out conventional washing and sand removal of the cooked slurry, and then adding an alkali solution to the slurry so that the concentration of the alkali in the slurry is 60 - 20 Og/m ³ , which is preferred. The amount of chlorine in the slurry is not more than 60-150 g/ra ³ ; and the bleaching is carried out at a temperature of 40 - 45 ° C, and the chlorine content is 0. 30 - 0. 50g / Bleaching under conditions of L for 60-180 minutes; said two-stage bleaching means two-stage bleaching after the above-mentioned one-stage bleaching, the second-stage bleaching is at a temperature of 40 - 45 ° C, and the chlorine content is 0. Bleaching for 30 to 120 minutes under conditions of 15 - 0. 30 g/L; preferably the alkali solution is a sodium hydroxide solution.

The bleaching according to the present invention further comprises hypochlorite bleaching, the bleaching agent is used in an amount of 2 - 8% of the dry pulp, and the temperature is 35 - 5 (TC conditions are bleached for 1-3 hours, the hypochlorite The acid salt is calcium hypochlorite or sodium hypochlorite.

In the present invention, after the bleaching, a slurry having a whiteness of ≥ 77% and an α-cellulose content of ≥ 94% is obtained. In the preparation of the present invention, the bamboo material is chamfered in a long strip shape, so that the surface area per unit weight of the original bamboo piece is increased, and at the same time, since the bamboo material is sliced, the bamboo stem is chamfered at a certain angle with the central axis of the bamboo material. The corresponding section of the same tubular fiber bundle on the dry section is enlarged, which facilitates the rapid penetration of the hydrolyzate and the cooking liquor during the pre-hydrolysis and cooking process, improves the pre-hydrolysis and cooking effects, accelerates the dissolution rate of the soluble matter, and cooks. The quality is relatively good, the degree of polymerization is relatively uniform, the primary wall is fully damaged, and the purity of the cellulose is relatively high. It is possible to go to these supplementary links (chlorination or alkali refining), and the produced pulp can fully satisfy the chemical fiber. The use of viscose fiber, the total cooking time of the chemical fiber pulp prepared in the patent CN00135021. 8 is about 11 hours, and in the present invention, the total cooking time is shortened by 4 hours, saving a lot of energy consumption. At the same time, it reduces the destruction of cellulose by the cooking liquor, improves the cooking effect and product quality, and maintains the bamboo fiber as much as possible. The antibacterial properties.

Compared with the prior art, the method of the invention saves the screening and dissolving steps after cooking, greatly shortens the holding time during cooking, eliminates the steps of chlorination and alkali refining, shortens the bleaching time, and makes hypochlorous acid bleaching. Direct bleaching of the salt can achieve good results and greatly reduce the energy consumption of the process. At the same time, due to the shortening of the process, the pollution generated by the bleaching section is reduced. At the same time, the effect of the cooking liquor on the cellulose is reduced. It improves the cooking effect and product quality, and maintains the antibacterial properties of bamboo fiber as much as possible. Therefore, the method of the invention has advanced technology, short process flow, small environmental pollution, stable quality, low production cost, meets the requirements of industrialized large-scale production technology advancement, and accelerates the utilization and development of bamboo resources.

Due to the reduction of the process steps, the washing water used in the relevant steps is omitted in the preparation process, and the water saving effect is obvious, and 50 tons of water can be saved per ton of pulp; the specific cutting treatment shortens the cooking heat preservation time by 4 hours, The tons of pulp can save 1 ton of steam; the chlorination and alkali refining steps are eliminated. Each ton of pulp can save about 20Kg of chlorine, save about 50Kg of alkali, and reduce the cost of tons of pulp by 120 yuan.

Another object of the present invention is to provide a method for preparing bamboo pulp, which is prior to cooking The water is boiled, so that the antibacterial substance in the bamboo pulp can be well maintained, so that the prepared bamboo pulp has good antibacterial properties.

The invention discloses a preparation method of bamboo pulp, which comprises preparing materials, cooking, washing, sanding, concentrating and bleaching, and further comprises boiling water between the preparation and cooking, wherein the boiled is: bamboo material after preparation The tablet is placed in a digester, and water is added to make the liquid ratio 1: 3. 0 - 5. 0, preferably the liquid ratio is 1: 3. 0-4. 0; firstly heated to 130 - 150 ° C Keep the temperature for 50 - 70 minutes, then heat up to 165 - 175 °C, keep warm for 120 - 180 minutes, then drain the liquid to get the boiled bamboo pieces.

The cooking according to the present invention is an alkali cooking, comprising: using an alkali amount of sodium hydroxide in terms of the amount of the dry raw material of 16.0 - 30. 0%, preferably the amount of alkali used is sodium hydroxide Calculate 16-26% of the dry raw material, the liquid ratio is 1: 2. 5 - 6. 0, preferably the liquid ratio is 1: 2. 5 - 3. 5, the temperature is raised by 90 - 240 minutes to 155 - 175 'C , , preferably heated for 150-240 minutes to 155-175 ° C, and kept for 120-180 minutes to obtain a steamed slurry.

The preparation material of the invention firstly flattens the bamboo material into a long strip of bamboo material, and then obliquely cuts the long strip of bamboo material so that the chamfered surface and the central axis of the long strip of bamboo material are at an angle of 10-85 degrees, a bamboo piece having a section spacing of 20 - 40 faces; preferably, the chamfered surface is at an angle of 20 - 70 degrees with the central axis of the long strip of bamboo, and a bamboo piece having a section spacing of 20 - 30 mm is obtained; more preferably a chamfered surface and The central axis of the long strip of bamboo material is at an angle of 40 - 60 degrees, and a bamboo piece having a section spacing of 25 inches is obtained.

The bleaching of the present invention is a period of hypochlorite bleaching or two-stage hypochlorite bleaching; the period of hypochlorite bleaching is 2 - 8% in the bleaching agent and the temperature is 35 - 50 ° C. Conditional bleaching for 1-3 hours, the hypochlorite is calcium hypochlorite or sodium hypochlorite; the two-stage hypochlorite bleaching is after the primary hypochlorite bleaching, and then in the bleaching agent The dosage is 0. 5 - 3%, and the temperature is 30-4 (bleaching for 30-60 minutes under TC conditions).

The boiled residual liquid described in the present invention has a COD of 80000 - 120000 rag/l and a chromaticity of 10,000 - 30,000 times. The cooking residual liquid COD according to the present invention has a COD of 180,000 - 22,000 (kg 八, and a chromaticity of 60,000 - 100,000 times.

In the invention, since the chemical fiber mainly utilizes the cellulose in the bamboo material, the requirements for the pulp are relatively strict, that is, the content of the high cellulose, the ash, the iron, the hemicellulose, the lignin, etc. are low, and Bamboo stems are the main part of pulping applications. In addition to a small proportion of thin-walled tissue, the stems are longitudinally arranged vein-shaped bundles of fibers and thin-walled tissue surrounding the bundle, plus stems. The hard skin outside the rod forms a natural barrier that affects the passage of chemicals into the tissue, thereby affecting the effectiveness of the conventional prehydrolysis process and affecting the functionality of the pulp produced. At the same time, if the impurities of bamboo are not completely dissolved, it will affect the extraction of the residual liquid after cooking, so that more impurities remain in the slurry, resulting in a The aspect pollutes a large number of water sources in the subsequent order, which makes the slurry quality worse.

According to the different temperature stage boiling water of the invention, the first is a low-temperature boiled water, that is, the temperature of 130-150 ° C, the pectin and soluble starch in the raw material are gradually hydrolyzed and dissolved, so that the dense hard skin is fully obtained. The destruction, the antibacterial substance and the cellulose have a combined process, which is not destroyed, and also lays a good foundation for the second stage of high temperature 165-175 °C boiled and the subsequent steps of cooking one by one. The boiled residue has a COD of up to 120,000 ang, and a chroma of up to 30,000 times; the COD of the cooking residue can reach 220,000 mg 八, and the chromaticity can reach 100,000 times. The slurry is subjected to a subsequent cooking step or the like to obtain a bamboo pulp which can be used for producing viscose fibers having excellent antibacterial properties. The stepwise boiling method according to the present invention, that is, the stage treatment under increasing temperature conditions, specifically: first adding water to the digester so that the liquid ratio is 1: 2 - 5 and the temperature is raised to 130 - 15 (TC, keep warm for 50-70 minutes; then further heat up to 165 - 175 °C on this base, keep warm for 120-180 minutes, and drain with water after boiling.

Because the bamboo itself is composed of fiber bundles, lignin, pectin and starch, its lignin content is 20 - 30%, ash is 1-3%, polypentose is 16-21%, and its fiber is slender and hard. There are many thick-walled fibers, narrow cell cavities, dense fibrous tissue, and a hard hard skin on the outside, which makes it difficult to extract impurities by ordinary pre-hydrolysis methods, using stepwise boiling process at different temperatures. The COD of the waste liquid is > 80000 mg / l, and the color is > 10000 times, which is the most likely to remove harmful impurities in the production of cellulose pulp. The cooking residue of the invention has a COD of up to 180,000 - 220000 mg and a color of up to 60,000 - 100,000 times.

Similarly, by adding a boiled method between the preparation and the cooking, although the pretreatment time is increased, the impurities in the raw material are gradually hydrolyzed and dissolved due to boiling, so that the dense hard skin is sufficiently damaged. The purity of vitamins is also relatively high. In order to shorten the cooking time and eliminate the supplementary link (chlorination or alkali refining), the foundation can be saved, and energy saving and pollution reduction can be achieved. In addition, the boiled water of the present invention is heated by stepwise heating, firstly a low-temperature boiled water, that is, 130 - 15 (at a temperature of TC, the pectin and soluble starch in the raw material are gradually hydrolyzed and dissolved, so that the dense hard The quality of the epidermis is fully destroyed, so that the antibacterial substance and cellulose have a combined process, which is not destroyed. At the same time, it is also used for the second stage of high temperature 165-175 °C boiled and then the alkali cooking. Good foundation, the COD of the boiled residue can reach 120,000rag/l, the chroma can reach 30,000 times; the COD of the cooking residue can reach 220,000rag8, and the chroma can reach 100000 times. After the slurry passes through the subsequent process steps, Bamboo pulp having excellent antibacterial properties can be obtained.

The preparation method of the invention may be a conventional preparation method, and the bamboo material may be chamfered in a long strip shape to increase the surface area per unit weight of the raw material bamboo sheet, and at the same time, the bamboo material is sliced at an angle to the central axis of the bamboo material. The method is chamfered to increase the cross section corresponding to the same tubular fiber bundle on the cross section of the bamboo stem, which facilitates the rapid penetration of the hydrolyzate and the cooking liquid during the prehydrolysis and cooking process, and improves the prehydrolysis and cooking. The effect is to accelerate the dissolution rate of the soluble matter.

The bamboo pulp prepared by the method of the present invention has excellent antibacterial properties. Although CN1410626 discloses a pure natural antibacterial bamboo pulp production process, a pretreatment process is added between the preparation and cooking, and the process parameters of the pretreatment process are: liquid ratio = 1: 1. 0-5. 0, temperature rise Conditions: The temperature is raised from normal temperature to 120-140 ° C, the heating time is 45-75 minutes, the exhaust is 5-20 minutes, and the temperature is raised to 120-14 (TC, heat preservation for 4-6 hours. The process is in accordance with the process of the present invention. The similarity is that the two-step boiled water is used, but the boiled process of CN1184374 is to raise the temperature to 120-140 C by the temperature rising process of 45-75 minutes, then exhaust for 5-20 minutes, then heat up. After 120-14 O 'C post-insulation, the present invention first heats up to 130 - 150 'C and then keeps warm, and then continues to heat up to 165 - 175 ° C on the basis of 130 - 150 °C.

The inventors of the present invention found through repeated trials that boiled at a temperature of 130 - 150 ° C, the pectin and soluble starch in the raw material can be gradually hydrolyzed and dissolved, so that the dense hard skin is sufficiently damaged to make the antibacterial substance. There is a process of combining with cellulose, which is not destroyed, and the boiling process of CN1410626 is heated to 120-140 °C, that is, the exhaust gas is cooled, and the boiling effect of the present invention cannot be achieved. The present invention continues to raise the temperature to 165 - 175 °C based on 130 - 151TC, which greatly shortens the time required for the process compared to CN1410626.

A further object of the present invention is to provide a method for preparing a bamboo pulp which is prepared by mashing a bamboo material after preparation for preparing a cooking step, thereby shortening the cooking time, and preparing the bamboo pulp. The quality of cockroaches is high.

The invention relates to a method for preparing bamboo pulp, which comprises preparing materials, cooking, washing, removing, and bleaching, and is characterized in that between preparing materials and cooking, the prepared bamboo pieces are subjected to screw extrusion device. The step of crushing and crushing; the screw extrusion device is preferably a variable diameter extruder; the screw extrusion device is more preferably a variable diameter single screw extruder or a variable diameter double screw extruder.

The preparation material of the invention firstly flattens the bamboo material into a long strip of bamboo material, and then obliquely cuts the long strip of bamboo material so that the oblique cut surface and the central axis of the long strip of bamboo material are at an angle of 10-85 degrees, a bamboo piece having a section cross-section of 20 - 4 Dmm; preferably, the chamfered surface and the central axis of the long strip of bamboo are at an angle of 20 - 70 degrees, and a bamboo piece having a section spacing of 20 - 3 Oram is obtained; more preferably a chamfered surface An angle of 40 to 60 degrees is formed with the central axis of the long strip of bamboo material, and a bamboo piece having a section length of 25 legs is obtained.

The lye according to the present invention is added before the squeezing of the bamboo piece or during the mashing, and the amount of the alkali in the alkali is 5-20% based on the NaOH on the dry raw material.

The cooking according to the present invention is: 5 to 25 % of the amount of the dry raw material in terms of the amount of alkali used, preferably the amount of alkali used is 15-20 °/» of the amount of the dry raw material in terms of NaOH. , liquid ratio is 1: 1-6, 0 ₂ dosage It is 0-5 % of the amount of the dry raw material, and the temperature is 100-170 ° C, preferably the temperature is 1 ² 0-170. The slurry after incubation is maintained for 10 to 180 minutes, preferably for 60 to 180 minutes, more preferably for 90 to 150 minutes.

The bleaching according to the present invention is: after the conventionally washed and sand-removed slurry is subjected to bleaching treatment; the bleaching treatment is two-stage variable bleaching, and the first stage is at pH=9-11. The dry pulp has a chlorine content of 1-3%, a temperature of 35 - 5 (bleaching for 90-180 minutes under TC conditions; a second stage at pH = 2-4, and the relative chlorine content of the dry pulp is 0 2-0. Bleaching time is 10-30 minutes under 5% conditions.

The squeezing and crushing by the screw extrusion device in the present invention means that in the presence of lye, the treated bamboo piece is crushed and crushed by a screw squeezing device, and the residual liquid after squeezing is The slurry is separated, and the residue is extracted and recovered for further treatment. When the bamboo sheet is pre-impregnated with the alkali liquid, the alkali liquid may be mixed and mixed in the process of squeezing the bamboo material, and may be heated by steam, and the amount of the alkali in the alkali liquid is NaOH. Calculate 5-20% of the dry raw materials, the liquid ratio is 1: 1-6. The purpose of alkali pre-impregnation is to: alkali treat the bamboo pieces for a period of time before squeezing, in the process, part of the hemicellulose in the bamboo is reacted with the hydrolysis medium under this condition and transferred to the solution, and the half remains in the bamboo pieces. Cellulose is also hydrolyzed to some extent.

The screw extrusion device is a variable diameter extruder for extracting black liquor in the prior art. In the case of squeezing, the liquid ratio is 1: 1 - 6, and the heat generated during the squeezing process raises the temperature of the plant fiber raw material to 80 ° C - 160 ° C, and the instantaneous pressure generated reaches 7 - 10 MPa. The concentration of the slurry after squeezing is greater than 40%. The lye in the squeezing process may be added during alkaline pre-impregnation prior to squeezing, or may be added during the squeezing process.

The preparation method of the invention may be a conventional preparation method, or a preparation method for slicing a long strip of bamboo material, so that the unit weight surface area of the raw material bamboo piece is increased, and at the same time, since the bamboo material is sliced according to the central axis of the bamboo material The oblique cutting is carried out at a certain angle to increase the corresponding section of the same tubular fiber bundle on the cross section of the bamboo stem. During the prehydrolysis and cooking process, it facilitates the rapid penetration of the hydrolyzate and the cooking liquor, and improves the prehydrolysis and cooking effects. , speed up the dissolution rate of solubles.

According to the method of the present invention, since the squeezing is performed by the screw squeezing device before cooking, a large amount of heat is generated during the squeezing process, a short-term high-pressure treatment is formed in the back pressure zone, the primary cell wall is destroyed, and the bamboo fiber is cut. The impregnation effect is obviously improved, the degree of polymerization is lowered, and the fiber properties are activated. Therefore, the cooking time is greatly shortened, and the conventional cooking method can shorten the time of 1/2-2/3, thereby saving energy and improving efficiency. In the process of squeezing the raw materials, the extrusion process of the screw extrusion device realizes the high-concentration and high-efficiency extraction of the black liquor in the early stage, and the extracted black liquor is recycled, so that the organic matter content entering the production system and other The impurities are greatly reduced. Since the raw material is kneaded before cooking, and the residual liquid no longer enters the digester, the impurities in the raw material are treated in advance, and the washing is carried out after cooking. The amount of water used in the process is reduced. Moreover, in the selection of the cooking method, the oxygen-alkali method is used for cooking, and the use of hydrogen peroxide plays a certain bleaching effect, so that the black liquor has low chroma and COD is reduced. Compared with the traditional method, the black liquor emissions are reduced, and the total amount of COD can be reduced by more than 50%. The shortening of the holding time is compared with the conventional method, as in the method mentioned in the patent CN00135021, the time of heat preservation during cooking is up to 6 hours, and the holding time of the patent is up to 2 hours, so the method of the invention is used. When the pulp is prepared, the steam consumption also decreases as the holding time is shortened.

detailed description

Example 1

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long Nai bamboo are at an angle of 60 degrees, and the section spacing of the section is 20 mra, which is a horseshoe shape piece. This piece accounts for 100% of the total weight of the bamboo piece. The prepared bamboo pieces were placed in a steaming ball, and water was added thereto at a liquid ratio of 1:3.5, and the holding pressure was 0.65 MPa for 150 minutes; then, the hydrolyzate was discharged. Adding the cooking agent to the steaming ball, the alkali amount is 20% by weight of the dry raw material, the degree of sulfurization is 25.0%, the liquid ratio is 1:3.5, the holding pressure is 0.65MPa, the holding time is 150 minutes, and the cooking is obtained. After the slurry.

The steamed slurry is de-sanded in a sand remover, the mortar concentration is 0.7%, the sand removal pressure is 0.30 MPa, and then bleached in the bleaching tank; a bleaching process is used, under the condition of 60 g/m ³ of alkali , the temperature is 45. C, bleaching time 120 minutes, bleaching chlorine content 0.5g / L; bleached slurry treated with hydrochloric acid, and then washed with water to a residual acid amount of 0.15g / L, concentrated, paper-made, to obtain pulp.

The obtained pulp had an α-cellulose content of 95.1%, a moisture content of 11.0%, an ash content of 0.10%, and a whiteness of 80%.

Example 2

First, the bamboo material is flattened into a long strip of bamboo material, and then the long strip-shaped material is chamfered so that the chamfered surface is at an angle of 40 degrees with the central axis of the long strip of bamboo, and the section spacing of the section is 25 mm, which is a horseshoe shape. Sheet, this slice accounts for 90% of the total weight of the bamboo piece. The prepared bamboo pieces were placed in a vertical steamer, water was added, the liquid ratio was 1:4, and the pressure was maintained at 0.75 MPa for 100 minutes; then the hydrolyzate was discharged. The retort was added to the steaming ball, and the amount of the alkali was 30% of the amount of the dry raw material in terms of sodium hydroxide, and the liquid ratio was 1:4. After the pressure was maintained at 0.75 MPa for 100 minutes, the steamed charge was obtained.

The obtained slurry was desilted in a sand remover, the concentration of the mortar was 0., the sand removal pressure was 0.25 MPa, and then bleached in a bleaching tank. A bleaching process was employed, and the alkali was 150 g/m ³ and the temperature was 40. C, bleaching time is 100 minutes, bleaching chlorine content is 0.40 g / L; the bleached slurry is treated with hydrochloric acid, and then washed with water until the residual acid amount is 0.10 g / L, concentrated, and made into a pulp.

The obtained pulp had an a-cellulose content of 94.0%, a moisture content of 9.0%, an ash content of 0.11%, and a whiteness of 79%. Example 3

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of I ⁵ degrees, and the section spacing is 25 mra, which is a horseshoe shape. Sheet, this slice accounts for 90% of the total weight of the bamboo piece. The prepared bamboo pieces were placed in a vertical steamer, and water was added thereto at a liquid ratio of 1:5, and maintained at a pressure of 0.75 MPa for 100 minutes; then, the hydrolyzate was discharged. The retort is added to the steaming ball, and the amount of the alkali is 35% of the amount of the dry raw material, and the liquid ratio is 1:5. After the temperature is maintained at 0. 70 MPa for 120 minutes, the slurry after cooking is obtained. .

The slag is de-sanded in a sand remover, the concentration of the mortar is 0. 8%, the sand removal pressure is 0. 25MPa, and then bleached in the bleaching tank, bleached with a period of sodium hypochlorite, bleached with alkali 80g / m ³ , the temperature is 40. C O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O .

The obtained pulp has an α-cellulose content of 94.3%, a moisture content of 9.0%, an ash content of 0.11%, and a whiteness of 78%.

Example 4

Firstly, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 40 degrees, and the section spacing of the sections is 25 闘, which is a horseshoe shape. Sheet, this slice accounts for 90% of the total weight of the bamboo piece. After the above-described installed in a vertical sheet stock bamboo steamer, water, liquid ratio of 1: 6 at a pressure of 0. ⁷ 5Mpa held at 100 minutes; then discharged hydrolyzate. The cooking agent is added to the steaming ball, and the alkali amount is 15% of the amount of the dry raw material in terms of sodium hydroxide, and the liquid ratio is 1:4. After the pressure is maintained at 0.775 MPa for 140 minutes, the slurry after cooking is obtained. .

8°/。 The slurry was removed in a sand remover, the concentration of the mortar was 0. 8 ° /. The sand removal pressure is 0.25 MPa, and then bleached in a bleaching tank. A hypochlorous acid bleaching process is used to bleach the alkali-containing 100 g/ni ³ at a temperature of 44. C, bleaching time is 60 minutes, the amount of bleaching agent is used; the bleached slurry is treated with hydrochloric acid, and then washed with water until the amount of residual acid is 0. llg / L, concentrated, paper-made, obtained pulp.

The obtained pulp has an α-cellulose content of 94.8%, a moisture content of 9.0%, an ash content of 0.11%, and a whiteness of 80%. .

Example 5

First, the bamboo material is flattened into a long-shaped bamboo material, and then the long strip-shaped bamboo material is chamfered so that the oblique cut surface and the central axis of the long strip-shaped bamboo material are at an angle of 50 degrees, and the section spacing of the sliced section is 40 mm, which is a horseshoe shape piece. This piece accounts for 80% of the total weight of the bamboo piece. Put the prepared bamboo pieces into the steaming ball, add water, the liquid ratio is 1:7, the holding pressure is 0. 70Mpa, hold for 120 minutes; then discharge the hydrolyzate; add the cooking agent to the steaming ball, the amount of alkali is absolutely The dry material weight is 25%, 20. 0%, and the liquid ratio is 1: 3. 0, and the temperature is maintained at 0. 65 MPa for 15 D minutes to obtain a steamed slurry. The obtained material was de-sanded in the sand remover, the mortar concentration was 0.75%, and the sand removal pressure was 0.20 MPa. Then bleaching in the bleaching tank, using a calcium hypochlorite bleaching process, bleaching with 180g/ra ³ reduction, a bleaching temperature of 42 ° C, a bleaching agent dosage of 5%, a bleaching time of 120 minutes; after bleaching The slurry was treated with hydrochloric acid, and then washed with water until the residual acid amount was 0.15 g/L, concentrated, and paper-made to obtain a pulp.

The obtained pulp had an α-cellulose content of 95.7%, a moisture content of 8.0%, an ash content of 0.12%, and a whiteness of 80%.

Example 6

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 70 degrees, and the section spacing of the section is 20 mm, which is a horseshoe shaped piece. This piece accounts for 100% of the total weight of the bamboo piece. The prepared bamboo pieces are placed in a steaming ball, and an acidic aqueous solution having a pH of 5 is added, the liquid ratio is 1:4.0, the holding pressure is 0.72 MPa, and the temperature is maintained for 130 minutes; then the hydrolyzate is discharged; and the cooking agent is added to the steaming ball, wherein The amount of alkali was 30% by weight of the dry raw material, the degree of salinity was 15.0%, the liquid ratio was 1:4, and the temperature was maintained at 0.75 MPa for 130 minutes to obtain a slurry after cooking.

The obtained slurry was de-sanded in a de-miner, the mortar concentration was 0.75%, and the de-sanding pressure was 0.35 MPa. Then bleaching in the bleaching tank, using a two-stage bleaching process, a period of bleaching in the alkali containing 200g / m ³ , a bleaching temperature of 45 ° C, bleaching chlorine content of 0.30g / L, bleaching time of 60 minutes; a bleaching start two Section bleaching, bleaching temperature is 45'C, bleaching chlorine content is 0.2g/L, bleaching time is 100 minutes; bleached slurry is treated with hydrochloric acid, then washed with water to a residual acid content of 0.15g / L, concentrated, #, Made, got pulp.

The obtained pulp had an α-cellulose content of 94.73⁄4, a moisture content of 9.0%, an ash content of 0.10%, and a whiteness of 77%.

Example 7

Firstly, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 85 degrees, and the section spacing of the section is 25 mm, which is a horseshoe shaped piece. This piece accounts for 70% of the total weight of the bamboo piece. The bamboo piece is placed in a vertical steamer, and acidic water having a pH of 4.5 is added, and the liquid ratio is 1:8, and the temperature is maintained at 0.7 OMpa for 60 minutes; then the hydrolyzate is discharged; and the cooking agent is added to the steaming ball, wherein The amount of alkali is 20% by weight based on sodium hydroxide, the liquid ratio is 1:5, the degree of sulfurization is 25%, and the temperature is maintained at 0.68 MPa for 100 minutes to obtain a slurry after cooking.

The obtained slurry was de-sanded in a sand remover with a mortar concentration of 0.75% and a sand removal pressure of 0.30 MPa. Then bleaching in the bleaching tank, using a two-stage bleaching process, a bleaching base containing 150g/ra ³ , a bleaching temperature of 40 ° C, a bleaching chlorine content of 0.40 g / L, a bleaching time of 60 minutes; After the second stage of bleaching, the bleaching temperature is 40 Ό, the bleaching chlorine content is 0.3 g/L, and the bleaching time is 120 minutes; the bleached slurry is treated with hydrochloric acid, and then washed with water until the residual acid amount is 0.15 g/L, and concentrated. Make a copy, get the pulp.

In the obtained pulp, the α-cellulose content was 95.2%, the moisture content was 8.0%, and the ash content was 0.10%. Whiteness is 82%.

Example 8

Firstly, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 10 degrees, and the section spacing of the section is 30 mm, which is a horseshoe shaped piece. This piece accounts for 85% of the total weight of the bamboo piece. The prepared bamboo pieces are placed in a vertical steamer, and acidic water having a pH of 5.5 is added. The liquid ratio is 1:6, the holding pressure is 0.70 MPa, and the holding time is 80 minutes; then the hydrolyzate is discharged; the cooking is added to the steaming ball. The medicament, wherein the amount of alkali is 25% by weight of the dry raw material by sodium hydroxide, the liquid ratio is 1:3.8, the heat preservation pressure is 0.70 MPa, the temperature is kept for 120 minutes, and the cooking is finished, and the slurry is obtained.

The obtained slurry was de-sanded in a desander, and the concentration of the mortar was 0.75%, and the pressure was 0.30 MPa. Then bleaching in the bleaching tank, using a two-stage bleaching process, a bleaching base containing 120g/m ³ , a bleaching temperature of 42 ° C, a bleaching chlorine content of 0.40 g / L, a bleaching time of 180 minutes; a bleaching start of two Section bleaching, bleaching temperature is 42 ° C, bleaching liquid chlorine content is 0.25 g / L, bleaching time is 100 minutes; bleached slurry is treated with hydrochloric acid, then washed with water to a residual acid amount of 0.15g / L, concentrated, Make a copy, get the pulp.

The resultant pulp, alpha] cellulose content of 95.1%, a moisture content of 7.0%, ash 0.10%, a whiteness of 79.9% ₀

Example 9

Preparation: Firstly, the bamboo is cut into small pieces of about 15 - 25 according to the general preparation method, and then further filtered and simply washed into the digester.

Boiled: Put the prepared bamboo pieces into the steamer, add water to the steamer, make the liquid ratio 1:3, and raise the temperature to 130 ° C for 60 minutes, then further on the basis of the holding temperature. Warm up to 175 'C, keep warm for 120 minutes, and drain with water after boiling. The boiled residue has a COD of 80000 mg/l and a color of 10,000 times.

Cooking: Put the boiled bamboo slices into the steamer and add the cooking agent, wherein the alkali amount is 21% of the dried bamboo in NaOH, the liquid ratio is 1:5; the temperature is raised for 150 minutes to 165 °C. When it is kept for 180 minutes. The cooking residue has a COD of 200,000 mg/l and a color of 80,000 times.

Washing, sand removal, concentration: The cooked slurry is washed with a washer, the unremoved physical impurities are removed by a sand remover, and the concentration of the slurry is adjusted to 3-3.5% with a thickener.

Bleaching: bleaching with a period of sodium hypochlorite, one-stage bleaching: bleaching temperature 40 ° C, bleaching agent dosage 2 ° / dry pulp. , bleaching time 180 minutes; two-stage bleaching: bleaching temperature 40 ° C, bleaching agent amount of 3% dry pulp, bleaching time 60 minutes.

Papermaking: The bleached pulp is copied on a pulper, pressed and dried in sequence, and finally cut and metered as required. π Example 10

Preparation: Firstly, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 60 degrees, and the section spacing of the sections is 20, Horseshoe-shaped sheet, which accounts for 75% of the total weight of bamboo.

Boiled: Put the prepared bamboo pieces into the steamer, add water to the steamer, make the liquid ratio 1:4, heat up to 140 Ό, keep warm for 70 minutes, and then further heat up to the above temperature. At 165 °C, keep it for 150 minutes, and drain with water after boiling. The COD of the boiled residue is l OOOOOmg eight and the chroma is 20000 times.

Cooking: Put the boiled bamboo pieces into the steamer and add the cooking agent, wherein the alkali amount is NaOH as 26% of the dried bamboo material; the liquid ratio is 1: 2. 5; the heating time is 195 minutes, the holding temperature 175, holding time 120 minutes. The cooking residue has a C0D of 220000 rag/l and a color of 100,000 times.

Washing, sand removal, concentration: The cooked slurry is washed with a washer, the unremoved physical impurities are removed by a sand remover, and the concentration of the slurry is adjusted to 3 - 3.5% with a thickener.

Bleaching: A period of hypochlorite bleaching or two-stage hypochlorite bleaching, one-stage bleaching: Bleaching temperature 50. C, the amount of bleach is 5% of the dry pulp, the bleaching time is 90 minutes; the second bleaching: the bleaching temperature is 30 °C, the bleaching agent is 1.5% of the dry pulp, and the bleaching time is 30 minutes.

Sand removal, concentration, and papermaking: The bleached slurry is further de-sanded and concentrated, then copied on a paper machine, pressed and dried in sequence, and finally cut and metered as required.

Example 11

Preparation: Firstly, the bamboo is cut into small pieces of about 20 - 30 legs according to the general preparation method, and then further filtered and simply washed into the digester.

Boiled: Add water to the digester to make the liquid ratio 1:5, and raise the temperature to 150 ° C, keep it for 50 minutes, then further increase the temperature to 170 ° C based on the holding temperature, keep it for 180 minutes, boil After the end, the pressure is drained. The boiled residue has a COD of 120,000 mg and a color of 30,000 times.

Cooking: Add the cooking agent to the digester, wherein the reduction is 16 % of the dried bamboo with NaOH; the liquid ratio is 1: 3. 5; the temperature is raised for 240 minutes to 155. At C, keep it for 150 minutes. The cooking residue has a COD of 180,000 mg/l and a color of 60,000 times.

Bleaching: bleaching with two stages of sodium hypochlorite, first at a temperature of 45 ° C, bleaching agent for 8% of the dry pulp, for a period of 60 minutes; then at a bleaching temperature of 35 ° C, the amount of bleach is a dry pulp 0. 5% bleaching time 50 minutes.

Sand removal, concentration, papermaking: further bleaching and concentrating the bleached slurry, then in the pulper On the paper, the paper is pressed and dried in sequence, and finally cut and metered according to the requirements.

Example 12

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 30 degrees, and the section spacing of the section is 25 mm, which is a horseshoe shaped piece. This piece accounts for 100% of the total weight of the bamboo piece.

The prepared bamboo pieces were placed in a steaming ball, and water was added to the steaming balls at a liquid ratio of 1:4, and the temperature was raised to 140 ° C for 55 minutes, and then the temperature was further raised to 165. C, keep warm for 160 minutes, and drain with water after boiling. The boiled residue has a COD of l OOOOOmg/l and a color of 20,000 times. Adding a cooking agent to the steaming ball, wherein the amount of alkali is 25% of the amount of the dry raw material, the degree of sulfurization is 25.0%, the liquid ratio is 1:3.5, and the temperature is raised to 100 minutes to 168' C, the holding time is 150 minutes, and the cooking is finished, and the slurry is obtained. The COD of the cooking residue was 180,000 mg eight and the color was 60,000 times.

The slag is de-sanded in a sand remover, the concentration of the mortar is 0. 7%, the pressure is 0. 30MPa, and then bleached in the bleaching tank; using a bleaching process, under the condition of 60g/m ³ of alkali 15克/L, Concentrate, 造造, 浆浆, The temperature is 50, the bleaching time is 60 minutes, the amount of the bleaching agent is 8% of the absolute dry pulp; the bleached slurry is treated with hydrochloric acid, and then washed with water until the amount of residual acid is 0. 15g / L, concentrated, paper, pulp Hey.

Example 13

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 40 degrees, and the section spacing of the sections is 25, which is a horseshoe shape. Sheet, this slice accounts for 90% of the total weight of the bamboo piece. Put the bamboo piece into the vertical steamer, add water to the steamer, make the liquid ratio 1:3, first raise the temperature to 13 (TC keep warm for 60 minutes, then further increase the temperature to 175 °C, keep warm for 120 minutes) After boiled, the COD of the boiled residue is 80000mg 八, and the color is 10000 times. Then, the cooking is carried out, and the cooking vat is added to the vertical steamer, wherein the amount of alkali is NaOH. 30% of dry bamboo; liquid ratio 1: 2. 5; heating time 195 minutes, holding temperature 175 ° C, holding time 120 minutes. The COD of the cooking residue is 220,000 mg / l, the color is 100,000 times.

The slag is de-sanded in the sand remover, the concentration of the mortar is 0.8%, the sand removal pressure is 0. 25MPa, and then bleached in the bleaching tank, using a period of hypochlorous acid 4 bow bleaching process, bleaching alkali containing 150g / m ^3, a temperature of 40'C, the bleaching time 120 minutes, the amount of bleach to 5% bone dry amount of pulp; bleached pulp treated with hydrochloric acid, and then washed with water until the residual acid in an amount of 0. 10g / L, Concentrate, copy, and get pulp.

Example 14

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 50 degrees, and the section spacing of the sections is 40 mm, which is a horseshoe shaped piece. This piece accounts for 85% of the total weight of the bamboo piece. The bamboo pieces were placed in a steaming ball, the liquid ratio was 1:4, the temperature was raised to 150 ° C, the temperature was kept for 50 minutes, and then the temperature was further raised to 17 G based on the holding temperature. C, insulation 180 Minutes, with water after draining. The boiled residue had a COD of 120,000 mg/l and a color of 30,000 times. The cooking agent is added to the steaming ball, wherein the alkali amount is 30% by weight of the dry raw material, the degree of sulfurization is 20.0%, the liquid ratio is 1:3.8, the temperature is raised for 120 minutes to 160'C for 140 minutes, and the cooked pulp is obtained. material. The cooking residue has a COD of 200,000 mg/l and a color of 80,000 times.

The obtained slurry was de-sanded in a sand remover with a mortar concentration of 0.75% and a sand removal pressure of 0.20 MPa. Then bleaching in the bleaching tank, using a hypochlorite bleaching process, bleaching alkali containing 120g/m ³ , a bleaching temperature of 42 Ό, bleaching agent is 2% of the dry pulp, bleaching time is 180 The bleached slurry was treated with hydrochloric acid, and then washed with water until the residual acid amount was 0.15 g/L, concentrated, and made into a pulp.

Example 15

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 70 degrees, and the section spacing of the section is 20 mm, which is a horseshoe shaped piece. This piece accounts for 95% of the total weight of the bamboo piece. The prepared bamboo pieces were placed in a steaming ball, and water was added thereto so that the liquid ratio was 1:5 and the temperature was raised to 140. C, keep warm for 70 minutes, and then further increase the temperature to 165 °C, keep warm for 150 minutes, and drain with water after boiling. The boiled residue has a COD of 1000 mg/l and a color of 20,000 times. Adding a mixed solution of NaOH and Na ₂ S to the steaming ball, the alkali amount is 35% by weight of the dry raw material, the degree of sulfurization is 15.0%, the liquid ratio is 1:3.8, the temperature is raised from 90 minutes to 170 ° C, and the temperature is maintained for 130 minutes. , after the cooking is finished, the slurry is obtained. The COD of the cooking residue was 220,000 mg octagon and the color was 100,000 times.

The obtained slurry was de-sanded in a sand remover with a mortar concentration of 0.75% and a sand removal pressure of 0.35 MPa. Then bleaching in the bleaching tank, using a two-stage calcium hypochlorite bleaching process, a bleaching in the alkali containing 60g / m ³ , a bleaching temperature of 45 ° C, the amount of bleaching agent is 3% of the dry pulp, bleaching time is 30 minutes; a second bleaching after bleaching, bleaching temperature is 45 °C, the amount of bleach is 0.5% of the dry pulp, the bleaching time is 40 minutes; the bleached slurry is treated with hydrochloric acid, then washed to the residue The acid amount was 0.15 g/L, concentrated, and made into a pulp.

Example 16

The bamboo pieces prepared according to the conventional method are placed in a vertical steamer, water is added to the cooking pot so that the liquid ratio is 1:3, and the temperature is raised to 15 (TC, kept for 50 minutes, and then further heated to the above. 170 Ό, incubated for 180 minutes, with boiling water after boiling. The COD of the boiled residue is 120,000mg 八, and the color is 30,000 times. Add retorting agent to the cooking pot, where the amount of alkali is NaOH. 24% of dry bamboo, liquid ratio 1:3.5; heating time 150 minutes, holding temperature 165 ° C, holding time 180 minutes. The COD of the cooking residue is 200000mg / l, the color is 80,000 times.

The obtained slurry was de-sanded in a sand remover with a mortar concentration of 0.75% and a sand removal pressure of 0.30 MPa. Then bleaching in the bleaching tank, using a two-stage sodium hypochlorite bleaching process, a bleaching base containing 150 g/m ³ , the bleaching temperature is 5 ITC, the bleaching agent is used in an amount of 4% of the dry pulp, and the bleaching time is 120 minutes; After a period of bleaching, two stages of bleaching are started, the bleaching temperature is 40 ° C, the bleaching agent is 1% of the dry pulp, and the bleaching time is 40 minutes; the bleached slurry is treated with hydrochloric acid, and then washed to a residual acid amount of 0. 15g/L, concentrated, made, and obtained pulp.

Example 17

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 10 degrees, and the section spacing of the sections is 36, which is a horseshoe shape. Sheet, this slice accounts for 100% of the total weight of the bamboo piece. The prepared bamboo pieces are placed in a vertical steamer, water is added thereto to make the liquid ratio 1:4, and the temperature is raised to 13 (TC, kept for 60 minutes, and then further heated to 175 ° based on the holding temperature. C, keep warm for 120 minutes, and drain with water after boiling. The COD of the boiled residue is 80000mg/l and the color is 10000 times. The boiled bamboo pieces are cooked in the vertical steamer and added to the cooking. The medicament, wherein the reduction is 18% of the dried bamboo material by NaOH, the liquid ratio is 1:3, the temperature is raised from 240 minutes to 155 ° C, and the holding time is 150 minutes. The COD of the cooking residue is 180,000 mg / l, color It is 60,000 times.

The blasting pressure is 0. 30Mpa. The sand removal pressure is 0. 30Mpa. Then bleached in the bleaching tank, using a two-stage calcium hypochlorite bleaching process, a bleaching base containing 120g/m ³ , a bleaching temperature of 35 'C, a bleaching agent content of 7% of the dry pulp, and a bleaching time of 80 minutes. After a period of bleaching, the second stage of bleaching is started, the bleaching temperature is 40 ° C, the amount of bleaching agent is 2.0%, the bleaching time is 60 minutes; the bleached slurry is treated with hydrochloric acid, and then washed with water until the residual acid amount is 0. 15g / L, concentrated, made, and obtained pulp.

Comparative Example 18

This comparative example compares the bamboo pulp of the general bamboo pulp, CN1088129 and CN1184374, and the pulp obtained from the examples of the present invention, and is listed in Table 1 (see next page).

The antibacterial test in this comparative example used the AATCC100-1998 standard.

It can be seen that the preparation method of chamfering the bamboo material can improve the antibacterial property of the pulp. The step-heating boiled method can completely remove the lignin and other impurities in the raw material, and the antibacterial substance and the cellulose have a combined process, which is not destroyed, so that the obtained bamboo pulp has more Excellent antibacterial properties.

Example 19

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 10 degrees, and the section spacing of the section is 40 mm, which is a horseshoe shaped piece. This piece accounts for 90% of the total weight of the bamboo piece.

The prepared bamboo material is pre-impregnated by thoroughly mixing with the alkali liquid in the digester, wherein the alkali amount is 5% by weight of the NaOH, and the liquid ratio is 1:6, and the pre-impregnation time is lh. , the temperature is 70 °C; then the use of the prior art in the extraction of black liquor for the double helix variable diameter extruder for the aforementioned bamboo raw materials for squeezing, black The liquid is extruded for recycling. The mashed slurry is cooked: cooking by oxygenation. The amount of alkali added to the steaming ball is 25% of the absolute dry pulp in terms of NaOH, the liquid ratio is 1:3, the amount of H ₂ 0 ₂ is 2% of the dry raw material, the cooking temperature is raised to 140 ° C, and the temperature is kept at 60 tnin. Then, the sand removal is carried out in a desander. The technical conditions are: in addition to mortar concentration: 0.7±0.1%, sand removal Zhuangli>0.28MPa; after sand removal, concentrated by a thickener, the pulp concentration is 3.5%. Finally, two pieces of variable bleaching were carried out under the following conditions: the first stage pH=9, the relative dry pulp used was 1% chlorine, the temperature was 35 ° C, the time was 180 minutes: the second stage pH=3, relatively dry The amount of chlorine used in the slurry was 0.2 ° /. , time 30 minutes.

The quality of the prepared chemical fiber pulp is in full compliance with the requirements of the first grade in FZ/T51002-1998.

Example 20

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 40 degrees, and the section spacing of the sections is 30, which is a horseshoe shape. Sheet, this slice accounts for 100% of the total weight of the bamboo piece.

The prepared bamboo piece is pre-impregnated with the lye in the digester, and the amount of the alkali solution is reduced to 20% of the dry raw material by NaOH, and the liquid ratio is 1:3, pre-impregnation time. 3h, the temperature is 80 °C; the bamboo raw material of the double-helical reducer extruder for extracting black liquor in the prior art is used for squeezing, and the black liquor is extruded for recycling. The mashed slurry is cooked: cooking by oxygenation. The amount of alkali added to the steaming ball is 10% of the absolute dry pulp in terms of NaOH, the liquid ratio is 1:4, the amount of H ₂ 0 ₂ is 5% of the amount of the dry raw material, and the temperature is raised to 100 ° C during cooking. Keep warm for 150min. Then, in addition to sand removal, the technical conditions are: in addition to mortar concentration: 0.7 ± 0.1%, sand removal pressure >0.28MPa; after sand removal, concentrated by a thickener, the pulp concentration is 3.5%. Finally, two variable bleaching conditions are carried out under the following conditions: the first stage pH=ll, the relative dry pulp is 1% chlorine, the temperature is 4 (TC, time 100 minutes: the second stage pH=3, relatively dry The amount of chlorine used in the slurry was 0.4% for 15 minutes.

Example 21

The bamboo material is conventionally prepared and placed in a digester and thoroughly mixed with the alkali liquid for pre-impregnation. The alkali amount in the alkali liquid is 8% of the dry raw material in terms of NaOH, and the liquid ratio is 1: 1, pre-impregnation time. 2h, temperature 60 °C; The bamboo material used in the double-helical reducer extruder for extracting black liquor in the prior art is used for squeezing, and the black liquor is extruded for recycling. The mashed slurry is cooked: cooking by oxygenation. The amount of alkali added to the steaming ball was 20% of the absolute dry pulp in terms of NaOH, and the liquid ratio was 1:6, and the cooking temperature was raised to 170. C, keep warm 10m in. Then, the sand removal is carried out in a desander. The technical conditions are: in addition to the mortar concentration: 0.7 ± 0.1%, the sand removal pressure is > 0.28 MPa; after sand removal, it is concentrated by a thickener, and the slurry concentration is 3.5 °/. . Finally, two variable bleachings were carried out under the following conditions: The first stage pH=10, the relative dry pulp used was 1% chlorine and the temperature was 45. C, time 180 minutes: The second stage pH=2, the relative chlorine content of the dry pulp is 0.5%, and the time is 10 minutes. The quality of the prepared chemical fiber pulp is in full compliance with the requirements of the first grade in FZ/T51002-1998.

Example 22

First, the bamboo material is flattened into a long strip of bamboo, and then the long strip of bamboo is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 70 degrees, and the section spacing of the sections is 30, which is a horseshoe shape. Sheet, this slice accounts for 75% of the total weight of the bamboo piece.

The bamboo material is pre-impregnated by thoroughly mixing with the alkali liquid in the digester, wherein the alkali amount is 15% of the dry raw material in terms of NaOH, the liquid ratio is 1:3, the pre-impregnation time is 3 hours, and the temperature is 60°. C; The bamboo raw material of the single-helical variable-diameter extruder for extracting black liquor in the prior art is used for squeezing, and the black liquor is extruded for recycling. The mashed slurry is cooked: cooking by oxygenation. The amount of alkali added to the steaming ball is 5% by weight of NaOH, the liquid ratio is 1:3, and the amount of 3⁄40 ₂ is 5% of the dry slurry, and the cooking temperature is raised to 160 ° C, and the temperature is maintained for 110 minutes. Then the sand removal is carried out in the desander, the technical conditions are: in addition to mortar concentration: 0.7 ± 0.1%, sand removal pressure >0.28MPa; after sand removal, concentrated by a thickener, the pulp concentration is 3.5%. Finally, two-stage variable bleaching is carried out under the following conditions: the first stage pH=9, the relative dry pulp is 1% chlorine, the temperature is 50C, the time is 150 minutes: the second stage pH=4, relative to the dry pulp The amount of chlorine used was 0.3% for 30 minutes.

Example 23

The bamboo material is conventionally prepared and placed in a digester and thoroughly mixed with the alkali liquid for pre-impregnation. The alkali amount in the alkali liquid is 10% of the dry raw material in terms of NaOH, and the liquid ratio is 1:1. 2h, the temperature is 60 ° C; the bamboo raw material of the double helix variable diameter extruder for extracting black liquor in the prior art is used for squeezing, and the black liquor is extruded for recycling. The mashed slurry is cooked: it is steamed by an oxygen-base method. The amount of alkali added to the steaming ball is 18% of the absolute dry pulp in terms of NaOH, the liquid ratio is 1:6, the cooking temperature is raised to 120 ° C, and the temperature is maintained for 90 minutes. Then, the sand removal is carried out in a desander. The technical conditions are: in addition to the mortar concentration: 0.7 ± 0.1%, the sand removal pressure is > 0.28 MPa; after sand removal, it is concentrated by a thickener, and the slurry concentration is 3.5%. Finally, two variable bleaching conditions are carried out under the following conditions: The first stage pfWO, the relative dry pulp has a chlorine content of 1%, the temperature is 45 ° C, and the time is 180 minutes: the second stage ρ Η = 2, relative to the dry pulp Use 0.5% chlorine for 10 minutes.

Example 24

Firstly, the bamboo material is flattened into a long-shaped bamboo material, and then the long strip-shaped bamboo material is chamfered so that the oblique cut surface and the central axis of the long strip-shaped bamboo material are at an angle of 85 degrees, and the section spacing of the sliced section is 30, which is a horseshoe shape. Sheet, this slice accounts for 85% of the total weight of the bamboo piece.

The bamboo material is pre-impregnated by thoroughly mixing with the alkali liquid in the digester, wherein the alkali amount is 15% of the dry raw material in terms of NaOH, the liquid ratio is 1:4, the pre-impregnation time is 3 hours, and the temperature is 60°. C; the above-mentioned bamboo raw material for the single-screw reducer extruder for extracting black liquor in the prior art is used for squeezing, and the black liquor is extruded into 45 rows are recycled and reused. The mashed slurry is cooked: cooking by oxygenation. The amount of alkali added to the steaming ball is 8% of the absolute dry pulp in terms of NaOH, the liquid ratio is 1:3, the amount of 0 ₂ is 5% of the absolute dry slurry, the cooking temperature is raised to 130 ° C, and the temperature is maintained for 180 min. Then the sand removal is carried out in the desander, the technical conditions are: in addition to mortar concentration: 0.7 ± 0.1%, sand removal pressure >0.28MPa; after sand removal, concentrated by a thickener, the pulp concentration is 3.5%. Finally, two pieces of variable bleaching were carried out under the following conditions: the first stage pH=9, the relative chlorine content of the dry pulp was 1%, the temperature was 50'C, the time was 150 minutes: the second stage pH=4, relatively dry The amount of chlorine used in the slurry was 0.3% for 30 minutes.

Bamboo generally embodiment of the invention

Slurry bamboo pulp CN1088129 CN1184374

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 粕粕

Gold

Very

-*,

Portuguese

77 82 80 76 79 80 85 90 95 87 87 88 95 90 92 Ball 60 % 70 % 75 %

% % % % % % % % % % % % % % % less

Rate Table 1 (Note: The antibacterial test uses the AATCC100 - 1998 standard)

Claims

Claim

A method for preparing a bamboo pulp, the method comprising: preparing, cooking, washing, sanding, concentrating, and bleaching, wherein the preparation is to first flatten the bamboo into a long strip of bamboo, Then, the long strip of bamboo material is chamfered so that the chamfered surface and the central axis of the long strip of bamboo are at an angle of 10-85 degrees, and a bamboo piece having a section spacing of 20 - 40 切片 is obtained; preferably the chamfered surface and the The central axis of the long strip of bamboo is at an angle of 20 - 70 degrees, and a bamboo piece having a section spacing of 20 to 30 mm is obtained; more preferably, the chamfered surface is at an angle of 40 - 60 degrees with the central axis of the long strip of bamboo, Sliced bamboo pieces with a section spacing of 25 η.

The preparation method according to claim 1, wherein the bamboo piece is a horseshoe-shaped slice, and the weight of the horseshoe-shaped slice accounts for 70% or more of the total weight of the bamboo piece.

3. The preparation method according to claim 1, wherein the preparation and cooking further comprises boiling, and the boiling is: placing the prepared bamboo pieces in a digester, adding water. , the liquid ratio is 1: 3. 0 - 5. 0, preferably the liquid ratio is 1: 3. 0-4. 0; first warmed to 130 - 150 ° C for 50 - 70 minutes, then raised to 165 - 175 °C, keep warm for 120 - 180 minutes, get boiled bamboo slices.

The preparation method according to claim 1, wherein the pre-hydrolysis is further included between the preparation and the cooking, and the pre-hydrolysis is: placing the prepared bamboo pieces in a digester, adding water Or an acidic solution to maintain a liquid ratio of 1: 3. 5 - 8. 0, preferably a liquid ratio of 1: 3. 5-4. 0 and then maintained at a pressure of 0. 65 - 0. 75MPa under the condition of 60 - 5的水溶液。 The aqueous solution is preferably an aqueous solution having a pH of 4. 5-5.

The preparation method according to any one of claims 1 to 4, wherein the cooking is an alkaline cooking, comprising: placing a bamboo piece in a digester, wherein the amount of alkali is NaOH The amount of the dry raw material is 15 - 35%, and the reduction is preferably 25 - 35% of the absolute dry material by NaOH; the liquid ratio is 1: 3. 0 - 5. 0, preferably the liquid ratio 1: 3. 5-4. 0, the pressure is 0. 65 - 0. 75MPa under the conditions of cooking for 100 - 150 minutes, to obtain a steamed slurry; preferably the amount of alkali used is NaOH The dry material amount is 20-30%.

The preparation method according to claim 1 or 3 or 4, wherein the cooking is kraft cooking, comprising: placing the prepared bamboo pieces in a digester, and using the amount of alkali 5%。 The NaOH is 15: 30%, the liquid ratio is 1: 3. 0 - 5. 0, preferably the liquid ratio is 1: 3. 5-4. 0; the degree of vulcanization is 15. 0 - 25. 0% and a pressure of 0. 65 - 0. Cooking at 75 MPa for 100 - 150 minutes, a steamed slurry is obtained.

The preparation method according to claim 5 or 6, wherein the bleaching is performed after cooking After the conventional slurry washing and sand removal, the alkali solution is added to the slurry so that the concentration of the alkali in the slurry is 60 - 200 g / m ³ , preferably the concentration of the alkali in the slurry is 60 - 150 g /m ³ ; further one or two stages of bleaching; the bleaching is carried out at a temperature of 40 - 45 ° C and a chlorine content of 0. 30 - 0. 50g / L for 60 - 180 minutes; The two-stage bleaching means that the two-stage bleaching is carried out after the bleaching of the first stage, and the two-stage bleaching is bleached at a temperature of 40 - 45 ° C and a chlorine content of 0.15 - 0.30 g / L. 30 - 120 minutes; Preferably, the alkali solution is a sodium hydroxide solution.

The preparation method according to claim 1, wherein the bleaching further comprises hypochlorite bleaching, wherein the bleaching agent is used in an amount of 2 - 8% of the absolute dry pulp and the temperature is 35 - 50. The condition of C is bleached for 1 - 3 hours, and the hypochlorite is calcium hypochlorite or sodium hypochlorite.

A method for preparing a bamboo pulp, comprising preparing, cooking, washing, sanding, concentrating, and bleaching, wherein the preparation and cooking further comprises boiling, and the boiling is specifically : placing the prepared bamboo pieces in the digester, and then adding water to make the liquid ratio 1: 3. 0 - 5. 0, preferably the liquid ratio is 1: 3. 0-4. 0; Incubate at 130 - 150 ° C for 50 - 70 minutes and then warm to 165 - 175. C, keep warm for 120 - 180 minutes, then drain the liquid to get the boiled bamboo pieces.

0 - 30. 0。 The amount of the amount of the dry material is 16. 0 - 30. 0 %, preferably, the amount of alkali used is 16-26 ° /» of the dry raw material by sodium hydroxide, and the liquid ratio is 1: 2. 5 - 6. 0, preferably the liquid ratio is 1: 2 Under the conditions of 5-3.5, the temperature is raised from 90 to 240 minutes to 155 to 175 °C, preferably from 150 to 240 minutes to 155 to 175 °C, and the temperature is maintained for 120 to 180 minutes to obtain a steamed slurry.

The preparation method according to claim 10, wherein the preparation material is a conventional preparation method or the bamboo material is first flattened into a long strip of bamboo material, and then the long strip of bamboo material is chamfered to make the oblique The cut surface is at an angle of 10-85 degrees with the central axis of the long strip of bamboo material, and a bamboo piece having a slice section spacing of 20 - Oram is obtained; preferably, the chamfered surface and the central axis of the long Nai bamboo are 20 - 70 degrees clamped. An angle is obtained, and a bamboo piece having a slice section spacing of 20 - 30 mm is obtained; more preferably, the chamfered surface is at an angle of 40 - 60 degrees with the central axis of the long strip of bamboo, and a bamboo piece having a section spacing of ²⁵ mm is obtained.

The preparation method according to any one of claims 10 to 11, wherein the bleaching is a period of hypochlorite bleaching or two-stage hypochlorite bleaching; Bleaching in the amount of bleaching agent is 2 - 8% of the absolute dry pulp amount, the temperature is 35 - 50 'C bleaching for 1-3 hours, the hypochlorite is calcium hypochlorite or sodium hypochlorite; The second stage hypochlorite bleaching is carried out after the primary hypochlorite bleaching, and the temperature is 30-40 ° C under the condition that the bleaching agent is used in an amount of 0.5 to 3%. The next bleaching is 30-60 minutes; the hypochlorite is sodium hypochlorite or hypochlorous acid.

13. A method for preparing bamboo pulp, comprising preparing, cooking, washing, concentrating, bleaching, characterized in that between preparing and cooking, the prepared bamboo piece is present in the presence of lye Condition The step of squeezing and crushing using a screw extrusion device; the screw extrusion device is preferably a variable diameter extruder; the screw extrusion device is more preferably a variable diameter single screw extruder or a reduced diameter double helix Squeezing machine.

The preparation method according to claim 13, wherein the preparation is to first flatten the bamboo into a long strip of bamboo, and then to cut the long strip of bamboo so that the chamfered surface and the long The central axis of the strip-shaped bamboo material is at an angle of 10 to 85 degrees, and a bamboo piece having a section spacing of 20 - 4 Oram is obtained; preferably, the chamfered surface and the central axis of the long strip of bamboo are at an angle of 20 - 70 degrees, A bamboo piece having a section cross-section of 20 - 30 mm; more preferably, the chamfered surface is at an angle of 40 - 60 degrees with the central axis of the long strip of bamboo, and a bamboo piece having a section spacing of 25 rara is obtained.

The preparation method according to claim 13, wherein the lye is added before the crushing of the bamboo piece or during the mashing, and the amount of the alkali in the lye is NaOH. 5-20% of the dry raw materials.

The method according to claim 13 or 14, wherein the cooking is: 5 to 25 % of the amount of the dry raw material in terms of the amount of alkali, preferably the amount of the alkali used. For the amount of 15-20% of the dry raw material in terms of NaOH, the liquid ratio is 1: 1-6, and the amount of 0 ₂ is 0-5 % of the amount of the dry raw material, and the temperature is 100-170. C, preferably at a temperature of from 120 to 170 ° C for 10 to 180 minutes, preferably for 60 to 180 minutes, more preferably for 90 to 150 minutes to obtain a steamed slurry.

The method according to claim 13, wherein the bleaching is: after the cooked slurry is subjected to conventional washing and sand removal, bleaching treatment; the bleaching treatment is two-stage variable value. Bleaching, the first stage is at pH=9-11, bleaching is carried out for 1-3% relative to the dry pulp, and the temperature is 35-50 °C for 90-180 minutes; the second stage is at pH= ² _4, the amount of chlorine used in the relative dry pulp is

0. 2-0. Bleaching time for 10-30 minutes under 5% conditions.