阅读说明：本技术 一种生物酶与碱协同制备化机浆的生产方法 (Production method for preparing chemi-mechanical pulp by synergy of biological enzyme and alkali ) 是由 吉兴香 陈洪国 孙炳伟 王鲁燕 张革仓 于 2019-09-10 设计创作，主要内容包括：本发明提供一种生物酶与碱协同制备化机浆的生产方法,该生产方法具体包括原料预处理、生物酶处理、一次挤压疏解、二次挤压疏解、药液浸渍、漂白步骤。本发明利用本工艺产生的废水对木片进行预处理,结合生物酶的处理,既充分利用残余化学品,又减少了废水排放,后续漂白过程氢氧化钠及过氧化物的用量也大大减少,具有环保与现实的双重意义。采用本发明的生产工艺制备的化机浆,成浆质量好,浆料ISO白度达到82.97-85.36,同时浆料撕裂指数达到4.24-4.35N?mm<Sup>2</Sup>/g,抗张强度达到27.8-29.1 N?m/g,纸浆纤维结合牢固。(The invention provides a production method for preparing chemi-mechanical pulp by combining biological enzyme and alkali. The invention utilizes the original workersThe wood chips are pretreated by the waste water generated in the process, and the treatment of biological enzyme is combined, so that residual chemicals are fully utilized, the waste water discharge is reduced, the consumption of sodium hydroxide and peroxide in the subsequent bleaching process is greatly reduced, and the method has double meanings of environmental protection and reality. The chemi-mechanical pulp prepared by the production process has good pulp forming quality, the ISO whiteness of the pulp reaches 82.97-85.36, and the tearing index of the pulp reaches 4.24-4.35N as much as mm 2 G, the tensile strength reaches 27.8-29.1N, and the pulp fibers are firmly bonded.)

1. A production method for preparing chemi-mechanical pulp by the synergy of biological enzyme and alkali is characterized by comprising the steps of raw material pretreatment, biological enzyme treatment, primary extrusion defibering, secondary extrusion defibering, liquid medicine impregnation and bleaching.

2. The production method according to claim 1, characterized in that the raw material pretreatment is carried out by softening treatment with washing water, and the treatment temperature is 50-70 ℃; the pH value of the washing water is 9-10, wherein the content of hydrogen peroxide is 0.8-0.9%.

3. The production method according to claim 1, wherein the biological enzyme treatment is carried out at a temperature of 35 to 40 ℃ for 60 to 70 min; the biological enzyme consists of xylanase, cellulase and pectinase, wherein the mass ratio of the xylanase, the cellulase and the pectinase is 4:3.5-4: 2-2.5.

4. According to claimThe production process according to 1, wherein the primary extrusion defibering, H₂O₂The dosage is 1.5-1.8% of the weight of the oven-dried wood chips, and the dosage of NaOH is 3.8-4.0% of the weight of the oven-dried wood chips.

5. The method of claim 1, wherein the secondary extrusion fluffing, H₂O₂The dosage is 3.0-3.5% of the weight of the oven-dried wood chips, and the dosage of NaOH is 3.0-3.5% of the weight of the oven-dried wood chips.

6. The production method of claim 1, wherein the primary extrusion fluffing is carried out by adding an accelerator, wherein the accelerator comprises sodium dodecyl sulfate, polyethylene glycol and copper dibromide, and the mixing mass ratio of the sodium dodecyl sulfate, the polyethylene glycol and the copper dibromide is 8:1.5-2: 0.2-0.3; the amount of the accelerant is 0.1-0.15% of the weight of the oven-dried wood chips.

7. The production method according to claim 1, wherein the secondary extrusion fluffing is carried out by adding a stabilizer, wherein the stabilizer consists of trimethylolpropane and potassium monododecyl phosphate, and the mixing ratio of the trimethylolpropane to the potassium monododecyl phosphate is 1: 0.5-0.7; the amount of the stabilizer is 0.13-0.15% of the weight of the oven-dried wood chips.

8. The production method according to claim 1, wherein the impregnation is carried out by using a chemical solution, the chemical solution comprises ammonium sulfite and potassium pyrosulfate, the mixing ratio of the ammonium sulfite to the potassium pyrosulfate is 1:1, and the mass concentration of the chemical solution is 6-9%.

9. The method of claim 1, wherein the bleaching agent comprises thiourea dioxide, melamine, and H₂O₂NaOH, DTPA; the dosage of the thiourea dioxide is 0.3 to 0.35 percent of the weight of the oven dry slurry; the dosage of the melamine is 0.12 to 0.15 percent of the weight of the oven dry sizing agent; h₂O₂The dosage is 1.5-1.8% of the weight of the oven-dry slurry; the amount of NaOH is 0.8-1.1% of the weight of the oven-dried slurry; for DTPAThe amount is 0.15-0.2% by weight of the oven dried pulp.

10. The production method of claim 1, wherein the ISO brightness of the prepared chemi-mechanical pulp reaches 82.97-85.36, and the tensile strength of the pulp reaches 27.8-29.1N.

Technical Field

The invention belongs to the field of pulping and papermaking, and particularly relates to a production method for preparing chemi-mechanical pulp by using biological enzyme and alkali in a synergistic manner.

Background

With the rapid development of the paper industry in China and the rapid increase of the total paper output, the insufficient supply of paper making raw materials becomes an important factor restricting the development of the paper industry in China. With the further increase of the economy of China, the living standard of people is continuously improved, the demand of people on paper products is also continuously increased, and the demand of the market can not be met by high-quality wood raw materials.

The chemi-mechanical pulp has the advantages of high bulk, good stiffness and the like, and simultaneously has unique performance due to higher fiber content, so that the chemi-mechanical pulp is more and more widely applied in the field of papermaking. In recent years, the biological enzyme technology is widely applied to the paper making industry, the pollution of the pulping and paper making processes to the environment can be reduced by using the biological enzyme treatment, the product performance is improved, and the biological enzyme treatment method has double values of environmental protection and reality.

CN108374292A provides a production process for preparing chemi-mechanical pulp by using a specific composite biological enzyme preparation, wherein the specific biological enzyme preparation is composed of glutamate dehydrogenase, citrate synthase, bacillus subtilis freeze-dried powder, bacillus aceticus freeze-dried powder, organic acid nutrient solution and water, the biological enzyme is added twice during wood chip thread rolling, but the enzymolysis reaction temperature reaches about 80 ℃, the temperature of a chemi-mechanical pulp making system is high, the biological enzyme utilization efficiency is not high along with the stirring and shearing processes, the pulping resistance is high, and the energy consumption is high.

CN105155322A provides a method for producing natural-color household paper by using biological enzyme pretreatment and alkaline straw pulping, which comprises the steps of firstly carrying out biological enzyme pretreatment on a straw raw material and then adding an amount of alkali lower than that of common cooking for pulping, but specific biological enzyme components are not disclosed, the enzyme treatment time at 50 ℃ is as long as 50h, the amount of alkali used for cooking is 8%, the pulp is used for specially manufacturing the natural-color household paper, lignin and other components do not need to be removed, bleaching treatment is not carried out, the amount of alkali used is inevitably reduced, and the strength of the prepared pulp is low and the paper is crisp.

Disclosure of Invention

In order to solve the problems in the prior art and further optimize the prior art, the invention provides a production method for preparing chemi-mechanical pulp by combining biological enzyme and alkali, which aims to realize the following purposes:

(1) improving the strength and whiteness of paper pulp

(2) Reducing pulping energy consumption of chemi-mechanical pulp

(3) Reduce the amount of chemicals

In order to solve the technical problems, the invention adopts the following technical scheme:

a production method for preparing chemi-mechanical pulp by using biological enzyme and alkali in a synergistic manner comprises the steps of raw material pretreatment, biological enzyme treatment, pre-steaming, primary extrusion defibering, primary liquid medicine impregnation, secondary extrusion defibering, secondary liquid medicine impregnation, high-concentration pulp grinding, cyclone separation, bleaching, squeezing dehydration, latency elimination treatment and low-concentration grinding;

the raw material pretreatment adopts softening treatment of washing water, the treatment temperature is 50-70 ℃, and the treatment time is 30-35 min; then adding water for washing, and then feeding the wood chips into a concentration regulating tank for inclined spiral dehydration, wherein the water content of the wood chips is controlled to be 40-42%;

the pH of the washing slurry water, which is the wastewater obtained in the squeezing and dewatering steps of the process, is 9-10, wherein the content of hydrogen peroxide is 0.8-0.9%;

the alkaline biological compound enzyme comprises xylanase, cellulase and pectinase, and the mass ratio of the xylanase, the cellulase and the pectinase is 4:3.5-4: 2-2.5; the treatment temperature is 35-40 deg.C, and the treatment time is 60-70 min;

the pre-steaming is carried out, the pre-steaming temperature is controlled to be 85-87 ℃, the pre-steaming time is 15min, and the addition amount of NaOH solution is 0.5-0.6% of the weight of the oven-dried wood chips;

the first extrusion is conducted for defibering, a first defibering agent is added, the temperature is controlled to be 70-75 ℃, and the reaction is conducted for 3 min;

the primary defibering agentComposed of accelerator, MgO, H₂O₂、NaOH、DTPA、Na₂SiO₃、MgSO₄Composition is carried out;

the accelerant consists of sodium dodecyl sulfate, polyethylene glycol and copper dibromide, and the mixing mass ratio of the sodium dodecyl sulfate, the polyethylene glycol and the copper dibromide is 8:1.5-2: 0.2-0.3;

the amount of the accelerant is 0.1-0.15% of the weight of the oven-dried wood chips; the amount of MgO is 0.1-0.12% of the weight of the oven-dried wood chips; h₂O₂The using amount is 1.5-1.8% of the weight of absolutely dry wood chips; the amount of NaOH is 3.8-4.0% of the weight of the oven-dried wood chips; the amount of DTPA is 0.2-0.25% of the weight of the oven-dried wood chips; na (Na)₂SiO₃The dosage is 4-4.5% of the weight of the oven-dried wood chips; MgSO (MgSO)₄The dosage is 0.08-0.1% of the weight of the oven-dried wood chips;

soaking the raw materials in the first medicinal liquid at room temperature for 10-30 min; the liquid medicine comprises ammonium sulfite and potassium pyrosulfate, the mixing ratio of the ammonium sulfite to the potassium pyrosulfate is 1:1, and the mass concentration of the liquid medicine is 6-9%;

performing secondary extrusion and defibering, adding a secondary defibering agent, controlling the defibering temperature at 70-72 ℃, and reacting for 3 min;

the secondary defibering agent consists of a stabilizing agent and H₂O₂NaOH and DTPA;

the stabilizer consists of trimethylolpropane and potassium monododecyl phosphate, and the mixing ratio of the trimethylolpropane to the potassium monododecyl phosphate is 1: 0.5-0.7;

the dosage of the stabilizer is 0.13-0.15% of the weight of the oven-dried wood chips; h₂O₂The using amount is 3.0-3.5% of the weight of the oven-dried wood chips; the amount of NaOH is 3.0-3.5% of the weight of the oven-dried wood chips; the amount of DTPA is 0.25-0.28% of the weight of the oven-dried wood chips;

the high-concentration pulping is carried out, the temperature is controlled to be 110-120 ℃, the pulping pressure is controlled to be 1.0-1.1kg/cm2, the pulping concentration is controlled to be 35-40%, and the freeness of the pulp is controlled to be 150-180 CSF;

performing cyclone separation, and adding water to dilute the slurry until the concentration of the slurry is 20-25% after the cyclone separation is finished;

bleaching, namely adding a bleaching agent into a bleaching tower, wherein the bleaching temperature is 90-100 ℃, and bleaching for 50-60 min;

the bleaching agent is prepared from thiourea dioxide, melamine and H₂O₂NaOH and DTPA;

the dosage of the thiourea dioxide is 0.3 to 0.35 percent of the weight of the oven dry slurry; the dosage of the melamine is 0.12 to 0.15 percent of the weight of the oven dry sizing agent; h₂O₂The dosage is 1.5-1.8% of the weight of the oven-dry slurry; the amount of NaOH is 0.8-1.1% of the weight of the oven-dried slurry; the amount of DTPA is 0.15-0.2% of the weight of the oven dry pulp;

the squeezing dehydration is carried out, the bleached pulp is diluted by adding water, the pulp concentration is controlled to be 10-12%, the squeezing dehydration is carried out after the dilution, and the pulp concentration is controlled to be 3-5%;

performing latency elimination treatment, wherein the temperature is controlled at 60 ℃, and latency elimination is performed for 60-70 min;

the low-concentration pulping is carried out, wherein the pulping concentration is 3-5%, the pulping freeness is 80-90CSF, and after the low-concentration pulping is finished, water is added for dilution, and the pulp concentration is 1.5-2%.

The wood chips are pretreated by using the washing water, and biological enzyme treatment is carried out at the front end of the pulping system of the chemi-mechanical pulp, so that the wood structure is loosened, more lignin, pectin and the like are exposed, the contact area of the bleaching agent and the lignin is increased, and the adjustment of process control parameters of the subsequent processes of defibering and extrusion, liquid medicine impregnation, bleaching, squeezing and dewatering, grinding and the like is combined, so that the bleaching is facilitated, the consumption of the bleaching agent is reduced, the pulping energy consumption is reduced, the pulp strength is higher, the fiber combination is firm, and the method has important use value.

By adopting the technical scheme, the invention has the beneficial effects that:

1. the chemi-mechanical pulp prepared by the production method for preparing the chemi-mechanical pulp by the biological enzyme and alkali synergy has good pulp forming quality, the ISO whiteness of the pulp reaches 82.97-85.36, and meanwhile, the tearing index of the pulp reaches 4.24-4.35N to be changed into mm²G, the tensile strength reaches 27.8-29.1N, and m/g is generated;

2. the folding strength of the chemi-mechanical pulp prepared by the production method for preparing the chemi-mechanical pulp by the biological enzyme and alkali synergy reaches 43-46 times, the pulp is strong and tough, and the fiber is firmly bonded;

3. by adopting the production method for preparing the chemi-mechanical pulp by the biological enzyme and alkali synergy, lignin, pectin and other components can be effectively dissolved out, the energy consumption of pulping can be reduced to 650 plus 700kwh, and compared with the energy consumption of pulping per ton in the prior art, the energy consumption is reduced by more than 100 kwh;

4. by adopting the production method for preparing the chemi-mechanical pulp by the biological enzyme and alkali synergy, the enzymolysis reaction temperature can be reduced to 35-40 ℃, the enzyme treatment time is shortened to 60-70min, and the reaction condition is mild;

5. the production method for preparing the chemi-mechanical pulp by the biological enzyme and the alkali in a synergistic way can reduce H₂0₂And the consumption of chemicals such as NaOH and the like reduces anionic garbage in the system, reduces the amount of alkali-containing wastewater, and further saves the production cost.

6. The production method for preparing the chemi-mechanical pulp by the biological enzyme and the alkali in a synergistic manner can recycle the washing water generated by the process, recycle the waste and change waste into valuable.

The specific implementation mode is as follows:

the invention is further illustrated below with reference to specific examples.