阅读说明：本技术 一种化机浆高浓滤液处理方法 (Method for treating high-concentration filtrate of chemi-mechanical pulp ) 是由 王长建 张武 孙长亮 于 2019-12-09 设计创作，主要内容包括：一种化机浆高浓滤液处理方法,包括如下步骤：步骤一：将化机浆生产线产生的高浓滤液送入化学浆热水槽中,加入洗涤用水混合；步骤二：将化学浆热水槽中的高浓滤液与洗涤用水的混合液抽出,送入鼓式真空洗浆机进行浆层过滤；步骤三：将经过鼓式真空洗浆机内浆层过滤的高浓滤液与洗涤用水的混合液送入黑液槽暂时储存；步骤四：将黑液槽中的液体抽出,经过机械过滤后送入碱回收车间蒸发工段,经过多效蒸发器进行蒸发浓缩；步骤五：经过蒸发浓缩到工艺要求后送入碱回收锅炉进行燃烧处理,融物进入绿液槽,经过苛化处理回收碱液。本发明能除去大部分的细小纤维,有效的减轻碱回收蒸发器结垢现象,提高蒸发效率,节约能源消耗。(A method for treating high-concentration filtrate of chemi-mechanical pulp comprises the following steps: the method comprises the following steps: sending high-concentration filtrate generated by a chemical-mechanical pulp production line into a chemical pulp hot water tank, and adding washing water for mixing; step two: pumping out a mixed solution of high-concentration filtrate and washing water in a chemical pulp hot water tank, and feeding the mixed solution into a drum type vacuum pulp washer for pulp layer filtration; step three: sending a mixed solution of high-concentration filtrate filtered by a pulp layer in a drum type vacuum pulp washer and washing water into a black liquid tank for temporary storage; step four: pumping out the liquid in the black liquid tank, mechanically filtering, sending the liquid to an evaporation section of an alkali recovery workshop, and carrying out evaporation concentration by a multi-effect evaporator; step five: after the process is carried out by evaporation and concentration, the mixture is sent into an alkali recovery boiler for combustion treatment, the molten substance enters a green liquor tank, and alkali liquor is recovered by causticization treatment. The invention can remove most of fine fibers, effectively reduce the scaling phenomenon of the alkali recovery evaporator, improve the evaporation efficiency and save the energy consumption.)

1. A method for treating high-concentration filtrate of chemi-mechanical pulp is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: sending high-concentration filtrate generated by a chemical-mechanical pulp production line into a chemical pulp hot water tank, and adding washing water for mixing;

step two: pumping out a mixed solution of high-concentration filtrate and washing water in a chemical pulp hot water tank, mixing and concentrating a part of the mixed solution of the high-concentration filtrate and the washing water and pulp, and then sending the mixed solution into a drum-type vacuum pulp washer, forming a pulp layer through the upper wire of the drum-type vacuum pulp washer, and sending the remaining mixed solution of the high-concentration filtrate and the washing water into the drum-type vacuum pulp washer to spray and wash the pulp layer;

step three: sending a mixed solution of high-concentration filtrate filtered by a pulp layer in a drum type vacuum pulp washer and washing water into a black liquid tank for temporary storage;

step four: pumping out the liquid in the black liquid tank, mechanically filtering, sending the liquid to an evaporation section of an alkali recovery workshop, and carrying out evaporation concentration by a multi-effect evaporator;

step five: after the process is carried out by evaporation and concentration, the mixture is sent into an alkali recovery boiler for combustion treatment, the molten substance enters a green liquor tank, and alkali liquor is recovered by causticization treatment.

2. The method for treating the high-concentration filtrate of the chemi-mechanical pulp according to claim 1, wherein the method comprises the following steps: the mixing volume ratio of the high-concentration filtrate to the washing water in the step one is 1: 0.8-1.2.

3. The method for treating the high-concentration filtrate of the chemi-mechanical pulp according to claim 1, wherein the method comprises the following steps: and the pulp layer in the second step can play a role in filtering.

4. The method for treating the high-concentration filtrate of the chemi-mechanical pulp according to claim 1, wherein the method comprises the following steps: the evaporation temperature is 60-100 ℃ when evaporation concentration operation is carried out in the fourth step; the evaporation pressure is 0.01-0.025 MPa.

5. The method for treating the high-concentration filtrate of the chemi-mechanical pulp according to claim 1, wherein the method comprises the following steps: the process requirement in the step five is to concentrate the liquid sent to the evaporation section to 45-55% of the original volume.

6. The method for treating the high-concentration filtrate of the chemi-mechanical pulp according to claim 1, wherein the method comprises the following steps: the combustion temperature of the alkali recovery boiler in the step five for combustion treatment is 500-800 ℃.

Technical Field

The invention belongs to the field of high-concentration filtrate treatment of chemi-mechanical pulp, and particularly relates to a method for treating high-concentration filtrate of chemi-mechanical pulp.

Background

At present, high-concentration filtrate generated in a chemi-mechanical pulp production line has the characteristics of high temperature (about 80 ℃) and high COD content (generally 15000-; therefore, at present, part of enterprises adopt a mode of firstly using an evaporation station for evaporation and concentration and then sending alkali for recovery and incineration treatment to treat the high-concentration filtrate of the chemical-mechanical pulp, but certain problems still exist, because the high-concentration filtrate of the chemical-mechanical pulp contains a large amount of fine fibers, an evaporator is easily covered and scaled by the fibers after contacting the filtrate, a heat insulation layer is formed, the evaporation efficiency is reduced, and the treatment cost is higher. The discharge of non-standard waste water causes a series of environmental problems. The method for treating the high-concentration filtrate of the chemi-mechanical pulp can solve the problem economically.

Disclosure of Invention

In order to economically treat the high-concentration filtrate of the chemi-mechanical pulp, the process of pulp washing production water in the chemical pulp extraction section is utilized, the characteristic that the high-concentration filtrate of the chemi-mechanical pulp has high temperature and is beneficial to pulp washing is fully utilized, the high-concentration filtrate of the chemi-mechanical pulp is reasonably used for extracting and washing the pulp of the chemical pulp, the black liquor of the chemical pulp is formed and then sent to an alkali recovery workshop for incineration treatment, and the problem of treatment of the high-concentration filtrate of the chemi-mechanical pulp can be solved.

The invention is realized by the following technical scheme:

a method for treating high-concentration filtrate of chemi-mechanical pulp comprises the following steps:

the method comprises the following steps: sending high-concentration filtrate generated by a chemical-mechanical pulp production line into a chemical pulp hot water tank, and adding washing water for mixing;

step two: pumping out a mixed solution of high-concentration filtrate and washing water in a chemical pulp hot water tank, mixing and concentrating a part of the mixed solution of the high-concentration filtrate and the washing water and pulp, and then sending the mixed solution into a drum-type vacuum pulp washer, forming a pulp layer through the upper wire of the drum-type vacuum pulp washer, and sending the remaining mixed solution of the high-concentration filtrate and the washing water into the drum-type vacuum pulp washer to spray and wash the pulp layer;

step three: sending a mixed solution of high-concentration filtrate filtered by a pulp layer in a drum type vacuum pulp washer and washing water into a black liquid tank for temporary storage;

step four: pumping out the liquid in the black liquid tank, mechanically filtering, sending the liquid to an evaporation section of an alkali recovery workshop, and carrying out evaporation concentration by a multi-effect evaporator;

step five: after the process is carried out by evaporation and concentration, the mixture is sent into an alkali recovery boiler for combustion treatment, the molten substance enters a green liquor tank, and alkali liquor is recovered by causticization treatment.

In the method for treating the high-concentration filtrate of the chemi-mechanical pulp, the mixing volume ratio of the high-concentration filtrate to the washing water in the first step is 1: 0.8-1.2.

In the method for treating the high-concentration filtrate of the chemi-mechanical pulp, the pulp layer in the second step can play a role in filtering.

According to the method for treating the high-concentration filtrate of the chemi-mechanical pulp, the evaporation temperature is 60-100 ℃ when evaporation concentration operation is carried out in the fourth step; the evaporation pressure is 0.01-0.025 MPa.

In the method for treating the high-concentration filtrate of the chemi-mechanical pulp, the process requirement in the fifth step is to concentrate the liquid fed into the evaporation section to 45-55% of the original volume.

In the method for treating the high-concentration filtrate of the chemi-mechanical pulp, the combustion temperature of the combustion treatment performed by the alkali recovery boiler in the fifth step is 500-800 ℃.

The invention has the advantages that: the invention combines the production flow of chemical pulp, firstly mixes the high-concentration filtrate of the chemical-mechanical pulp with washing water, dilutes the high-concentration filtrate, improves the fluidity of the high-concentration filtrate, and prevents the situation that the filtrate is difficult to extract and transfer due to overhigh concentration and poor fluidity; then, a pulp layer is filtered by using a pulp washer at an extraction section of a chemical pulp production line, so that part of fine fibers can be removed, and meanwhile, the existing operation of a workshop is utilized, so that equipment is effectively prevented from being purchased again, and the cost is effectively saved; then through traditional mechanical filtration again, if the filter screen filters, can ensure to detach most tiny fibre to avoid tiny fibre to get into the evaporimeter along with liquid and cover the scale deposit formation insulating layer on the evaporimeter inner wall and reduce the condition emergence of evaporation efficiency, the effectual alkali recovery evaporimeter scale deposit phenomenon that alleviates improves evaporation efficiency, energy saving consumption, can also retrieve partial thick liquids when filtering through the pulp washer simultaneously, reduce whole pollution control expense, changing waste into valuables, make full use of water resource, the effectual resource of having practiced thrift.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic flow diagram of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.