阅读说明：本技术 一种竹柳的prc-apmp制浆方法 (PRC-APMP pulping method of bamboo willow ) 是由 禚昊 朱宏伟 刘成良 肖友年 林本平 周训富 赵靖 刘永丰 洪嘉远 于 2018-08-08 设计创作，主要内容包括：本发明公布了一种竹柳的PRC-APMP制浆方法,采用竹柳为纤维原材料,包括以下步骤,将1段挤压后的木片加入1段预浸器,并加入1段预浸液,2段挤压疏解、2段化学药液预浸、1段盘磨机高浓磨浆、旋风分离、冷却螺旋冷却、高浓漂白、脱水压榨机脱水、2段高浓磨浆、旋风分离、消潜、双盘磨浆、压力筛、多盘浓缩制得成品浆。提供一种竹柳的PRC-APMP制浆方法,有效拓宽了化机浆原料资源,根据竹柳与杨木材性上的差异,制浆工艺流程进行了优化,制浆成本更低,浆料质量更好,具有节约木材资源效益和环保效益。(The invention discloses a PRC-APMP pulping method of bamboo willow, which adopts the bamboo willow as a fiber raw material and comprises the following steps of adding 1 section of extruded wood chips into a 1 section of presoaking device, adding 1 section of presoaking liquid, 2 sections of extrusion defibering, 2 sections of chemical liquid presoaking, 1 section of disc grinder high-concentration pulp grinding, cyclone separation, cooling spiral cooling, high-concentration bleaching, dewatering by a dewatering squeezer, 2 sections of high-concentration pulp grinding, cyclone separation, latency elimination, double-disc pulp grinding, pressure screen and multi-disc concentration to prepare finished pulp. The PRC-APMP pulping method of the bamboo willow effectively widens the raw material resources of the chemi-mechanical pulp, optimizes the pulping process flow according to the difference of the wood properties of the bamboo willow and the poplar, has lower pulping cost and better pulp quality, and has the benefit of saving wood resources and environmental protection.)

1. A PRC-APMP pulping method of bamboo willow is characterized in that the bamboo willow is adopted as a fiber raw material, and the method comprises the following steps of adding 1 section of extruded wood chips into a 1 section of presoaking device, adding 1 section of presoaking liquid, 2 sections of extrusion defibering, 2 sections of chemical liquid presoaking, 1 section of disc grinder high-concentration pulp grinding, cyclone separation, cooling spiral cooling, high-concentration bleaching, dehydration by a dewatering press, 2 sections of high-concentration pulp grinding, cyclone separation, latency elimination, double-disc pulp grinding, a pressure screen and multi-disc concentration to prepare finished pulp; the pre-immersion liquid at the 1 section adopts mixed liquid of NaOH, Mg (OH)2 and Na2SiO 3; in the 2-stage chemical liquid, the dosage of NaOH to the oven-dry pulp is 2.0-3.5%, the dosage of H2O2 to the oven-dry pulp is 1.0-3.0%, the dosage of Na2SiO3 to the oven-dry pulp is 1.0-2.0%, and the dosage of MgSO4 to the oven-dry pulp is 0-0.5%.

2. The PRC-APMP pulping method of bamboo willows according to claim 1, characterized in that the adopted bamboo willows are characterized in that: the length of the wood chip is 19-25 mm, the thickness is 4.0 +/-1 mm, the qualification rate of the wood chip is not less than 75% (mass percent), the bark rate is not less than 0.5%, and the water content of the wood chip is not less than 38%.

3. The PRC-APMP pulping method of bamboo willows according to claim 1, wherein a 1-section disc mill blowing pipe and a cooling screw at the upper part of a high concentration tower are the addition points of bleaching liquid, and the dosage of NaOH to oven dry pulp is as follows: 1.0-1.8%, Mg (OH)2 for the dosage of oven dry pulp 0.3-1.0%, H2O2 for the dosage of oven dry pulp: 1.5-4.5%, the dosage of Na2SiO3 to oven-dried pulp: 1.0-3.0%; bleaching concentration: 20-35%, bleaching temperature: bleaching at 80-95 ℃ for: 60-90 min.

4. The PRC-APMP pulping method of bamboo willows according to claim 3, characterized in that the pre-immersion liquid in the 1 section adopts high-concentration bleaching waste liquid, wherein the liquid level is 10-15%, the amount of NaOH to absolute dry pulp is 0-0.05%, the material level of a reaction bin of the pre-immersion device in the 1 section is 40-70%, and the steam exhaust temperature is 50-90 ℃.

5. The PRC-APMP pulping method of bamboo willows according to claim 1, characterized in that a disulfonic acid group liquid whitening agent is added at a cooling spiral inlet, and the dosage is 1-3.5 kg/t of oven dry pulp.

6. The PRC-APMP pulping method of bamboo willows according to claim 1, characterized in that the process conditions include: (A)1 log sheet extruder (MSD): the speed is not less than 55rpm, the torque is 50-100kN.m, the power is 400-800kw, and the torque control is prior; (B) 2 segment wood chip extruder (MSD): the speed is not less than 55rpm, the torque is 48-95kN.m, the power is 400-800kw, and the torque control is prior; (C) the double-disc mill has the milling concentration of 4.5-5.5%, the milling power of 500-1400 kw, the unit energy consumption of 25-120 kw/admt, the mill inlet pressure of 1.0-1.8 bar, the mill outlet pressure of 2.6-4.6 bar, and the pressure difference between the front and the back of the mill outlet pressure regulating valve of 0.1-0.5 bar; (F) the operating conditions of the 1-3 # pressure screen are as follows: the screen gap of the pressure screen is 0.15-0.2 mm, and the pulp inlet concentration is 1.2-2%; the pulp inlet pressure is 2.0-4.0 bar; the pressure difference between the inlet and the outlet (P outlet-P inlet) is not more than 50 kPa; the flow ratio of the slag pulp to the fine pulp is 25-40%; the operation load is 40-85%; the ratio of the good pulp flow rate of the 2-section/1-section pressure screen is 25-40%.

Technical Field

The invention relates to the technical field of papermaking, in particular to a PRC-APMP pulping method of bamboo willow.

Background

At present, PRC-APMP pulping raw materials are mainly poplar wood chips, and the used wood species are single. Due to the good processing performance of the poplar, the poplar becomes the raw wood material which is consumed the most in the plate industry in China, the purchase of the poplar fiber raw material is comprehensive competition in the industry and among the industries, and the supply requirement of the poplar raw material is difficult to meet at present. Bamboo willow is a multi-element hybridization rapid new tree species which is cultivated by the united research of the American California agricultural university and a plurality of large paper industry and seedling companies, and the bamboo willow is planted in large area in China. The tree species has the characteristics of fine wood structure, high natural whiteness, soft fiber, high heat value and the like, has potential excellent quality of pulping and papermaking materials, but has not been utilized in the papermaking industry to produce chemi-mechanical pulp.

Disclosure of Invention

The invention aims to provide a PRC-APMP pulping method of bamboo willows, which effectively widens the raw material resources of chemi-mechanical pulp, optimizes the pulping process flow according to the difference of the properties of the bamboo willows and poplar wood, has lower pulping cost and better pulp quality, and has the benefits of saving wood resources and protecting environment.

In order to realize the purpose, the invention adopts the technical scheme that: a PRC-APMP pulping method of bamboo willow is characterized in that the bamboo willow is adopted as a fiber raw material, and the method comprises the following steps of adding 1 section of extruded wood chips into a 1 section of presoaking device, adding 1 section of presoaking liquid, 2 sections of extrusion defibering, 2 sections of chemical liquid presoaking, 1 section of disc grinder high-concentration pulp grinding, cyclone separation, cooling spiral cooling, high-concentration bleaching, dehydration by a dewatering press, 2 sections of high-concentration pulp grinding, cyclone separation, latency elimination, double-disc pulp grinding, a pressure screen and multi-disc concentration to prepare finished pulp; the pre-immersion liquid at the 1 section adopts mixed liquid of NaOH, Mg (OH)2 and Na2SiO 3; in the 2-stage chemical liquid, the dosage of NaOH to the oven-dry pulp is 2.0-3.5%, the dosage of H2O2 to the oven-dry pulp is 1.0-3.0%, the dosage of Na2SiO3 to the oven-dry pulp is 1.0-2.0%, and the dosage of MgSO4 to the oven-dry pulp is 0-0.5%.

Preferably, the bamboo willow is characterized in that: the length of the wood chip is 19-25 mm, the thickness is 4.0 +/-1 mm, the qualification rate of the wood chip is not less than 75% (mass percent), the bark rate is not less than 0.5%, and the water content of the wood chip is not less than 38%.

Preferably, the 1-section disc mill blow-off pipe and the cooling screw at the upper part of the high-concentration tower are the addition points of the bleaching liquor, and the dosage of NaOH to the oven dry pulp is as follows: 1.0-1.8%, Mg (OH)2 for the dosage of oven dry pulp 0.3-1.0%, H2O2 for the dosage of oven dry pulp: 1.5-4.5%, the dosage of Na2SiO3 to oven-dried pulp: 1.0-3.0%; bleaching concentration: 20-35%, bleaching temperature: bleaching at 80-95 ℃ for: 60-90 min.

Preferably, the pre-immersion liquid at the 1 section adopts high-concentration bleaching waste liquid, wherein the liquid level is 10-15%, the dosage of NaOH to absolute dry pulp is 0-0.05%, the material level of a reaction bin of the pre-immersion device at the 1 section is 40-70%, and the exhaust temperature is 50-90 ℃.

Preferably, a disulfonic acid group liquid whitening agent is added at the inlet of the cooling screw, and the using amount of the disulfonic acid group liquid whitening agent is 1-3.5 kg/t of oven-dried slurry.

Preferably, the process conditions include: (A)1 log sheet extruder (MSD): the speed is not less than 55rpm, the torque is 50-100kN.m, the power is 400-800kw, and the torque control is prior; (B) 2 segment wood chip extruder (MSD): the speed is not less than 55rpm, the torque is 48-95kN.m, the power is 400-800kw, and the torque control is prior; (C) the double-disc mill has the milling concentration of 4.5-5.5%, the milling power of 500-1400 kw, the unit energy consumption of 25-120 kw/admt, the mill inlet pressure of 1.0-1.8 bar, the mill outlet pressure of 2.6-4.6 bar, and the pressure difference between the front and the back of the mill outlet pressure regulating valve of 0.1-0.5 bar; (F) the operating conditions of the 1-3 # pressure screen are as follows: the screen gap of the pressure screen is 0.15-0.2 mm, and the pulp inlet concentration is 1.2-2%; the pulp inlet pressure is 2.0-4.0 bar; the pressure difference between the inlet and the outlet (P outlet-P inlet) is not more than 50 kPa; the flow ratio of the slag pulp to the fine pulp is 25-40%; the operation load is 40-85%; the ratio of the good pulp flow rate of the 2-section/1-section pressure screen is 25-40%.

The invention has the beneficial effects that: according to the characteristics of bamboo willow, the consumption of chemicals is reduced, and the wastewater treatment load of the system is reduced; not only ensures the bleaching effect, but also reduces the bleaching loss and increases the bulk of the pulp;

1. meanwhile, in process control, the speed of a screw machine and a wood chip extruder (MSD) can be correspondingly improved by 2-13%, so that the production efficiency is improved;

2. compared with other fiber raw materials, the bamboo willow wood has a fine structure and high natural whiteness, so high-concentration bleaching wastewater can be adopted in the first pre-soaking section, bleaching residual hydrogen peroxide is utilized, the hydrogen peroxide addition in the section is cancelled, and the cost is saved;

3. in order to reduce the consumption of hydrogen peroxide, adding a disulfonic acid whitening agent into a cooling screw, and reducing the amount of alkali used for high-concentration bleaching and the amount of hydrogen peroxide, wherein the amount of the disulfonic acid whitening agent is 1-3.5 kg/t of absolute dry pulp;

4. the bulk of the pulp is improved, the bleaching alkali source adopts the combination of magnesium alkali and sodium alkali, and the dosage of NaOH to the oven-dried pulp is as follows: 1.0-1.8%, and Mg (OH)2 is 0.3-1.0% of oven dry pulp.

Detailed Description

The present invention is described in detail below for the purpose of better understanding technical solutions of the present invention by those skilled in the art, and the description of the present invention is only exemplary and explanatory and should not be construed as limiting the scope of the present invention in any way.