阅读说明：本技术 一种造纸用草类秸秆中木质素的分离方法 (Method for separating lignin from papermaking straw ) 是由 吴学军 *** 岳金权 李满风 庞树军 于 2019-12-05 设计创作，主要内容包括：本发明公开了一种造纸用草类秸秆中木质素的分离方法,方法包括以下步骤：将草类植物秸秆挤压并切割成丝状；浸泡60分钟以上；将浸泡后的秸秆丝放入高压釜中,加热升温；打开高压釜的出料阀门,使釜内物料喷入混合室并与冷却水混合；降温后的物料经100目过筛；粗浆经常规造纸工艺中的磨浆,洗涤后,即可得到抄纸用的细浆。本发明的木质素分离全过程不加入任何化学制剂,仅通过物理方法实现木质素的分离,为原料的综合利用创造了很好的基础；分离出的液体经厌氧发酵制得沼气,沼液和沼渣再经好氧发酵等处理都是很好的有机质肥料；对分离出的液体进一步分离或再加工可实现了造纸废料资源化利用,不对环境造成压力；降低了纸浆成本；回收率高。(The invention discloses a method for separating lignin from papermaking straw, which comprises the following steps: extruding and cutting straw of grass plants into filaments; soaking for more than 60 minutes; putting the soaked straw filaments into a high-pressure kettle, and heating to raise the temperature; opening a discharge valve of the high-pressure kettle to spray the materials in the kettle into the mixing chamber and mix the materials with cooling water; sieving the cooled material by a 100-mesh sieve; the coarse pulp is ground into pulp in the conventional papermaking process, and the fine pulp for papermaking can be obtained after washing. In the whole process of lignin separation, no chemical preparation is added, and the lignin separation is realized only by a physical method, so that a good foundation is created for the comprehensive utilization of raw materials; the separated liquid is subjected to anaerobic fermentation to prepare biogas, and the biogas slurry and biogas residues are treated by aerobic fermentation and the like to form good organic fertilizer; the separated liquid is further separated or reprocessed, so that the resource utilization of the papermaking waste can be realized, and the pressure on the environment is not caused; the cost of the paper pulp is reduced; the recovery rate is high.)

1. A method for separating lignin from papermaking straw is characterized by comprising the following steps: the method comprises the following steps:

i, extruding and cutting straw of grass plants into filaments;

II, mixing water and the straw filaments according to the proportion of more than 1:1, soaking, and standing for more than 60 minutes;

III, putting the soaked straw filaments into a high-pressure kettle, heating to 170-220 ℃, and keeping the temperature for 5-30 minutes;

IV, opening a discharge valve of the high-pressure kettle, spraying the materials in the kettle into the mixing chamber, mixing the materials with cooling water injected into the mixing chamber at the same time, and cooling the materials;

v, sieving the cooled material by a 100-mesh sieve, wherein the oversize part is coarse pulp, and the undersize part is hemicellulose, lignin, mixed cells and impurities;

and VI, grinding the coarse pulp obtained in the step V into thick pulp in a conventional papermaking process, and washing to obtain fine pulp, so that papermaking can be further manufactured.

2. The method for separating lignin from papermaking straw straws as claimed in claim 1, wherein the lignin is obtained by a method comprising the following steps: the length of the cut straw is 10-60 mm, and the width of the cut straw is less than 0.5 mm.

3. The method for separating lignin from papermaking straw straws as claimed in claim 2, wherein the lignin is obtained by a method comprising the following steps: the water temperature of the cooling water is 0-60 ℃.

4. The method for separating lignin from papermaking straw straws as claimed in claim 3, wherein the lignin is obtained by a method comprising the following steps: the straw is corn straw.

5. The method for separating lignin from papermaking straw straws as claimed in claim 4, wherein the lignin is obtained by a method comprising the following steps: the papermaking paper includes but is not limited to toilet paper and corrugated paper; when the sanitary paper is produced, the temperature of the high-pressure kettle is over 195 ℃ and the time is 30 minutes; when corrugated paper is produced, the temperature of the autoclave is above 185 ℃ and the time is 15 minutes.

6. The method for separating lignin from papermaking straw straws as claimed in claim 1, wherein the lignin is obtained by a method comprising the following steps: the pulping method of the coarse pulp comprises a high-consistency mill, a medium-consistency mill and a low-consistency mill; the washing method of the brown stock is countercurrent washing.

Technical Field

The invention relates to a method for separating lignin, in particular to a method for separating lignin from papermaking straw.

Background

Internationally, paper industry is second only to telecommunications and steel, and is one of the important signs of the state economic development level. However, the domestic paper making industry faces two dilemmas of large raw material gap and small environment capacity. Wood is poor in China, two thirds of wood pulp and one third of waste paper pulp need to be imported, and the annual import amount reaches two thousand tons and more. Meanwhile, nearly billions of tons of crop straws are to be treated every year in China, the environmental pressure caused by straw burning is increased day by day, the resource treatment of the straws becomes a major topic related to the national civilians, people pay increasing attention to straw papermaking, but the pollution of the conventional straw pulping to the environment is more serious, and thus, the large-scale production is not available. On one hand, the papermaking raw materials are seriously lacked, and on the other hand, the pressure of straw treatment is huge. Research on an industrialized pollution-free straw pulping mode is very urgent.

In the pulp and paper industry, the traditional cellulose separation method, such as a sulfate method or an alkali method, generates black liquid with extremely high pollution load in the cooking process, and causes great pressure on the environment. At present, some new pulping methods such as blasting pulping technology, puffing pulping technology, oxidation cleaning pulping technology, catalytic pulping technology, organic solution pulping technology, biological pulping technology and the like reduce pollution caused by the pulping process to a certain extent. But all have different degrees of limitations, can not replace the traditional process, and does not form large-scale mass production. The method separates cellulose, hemicellulose, lignin and other components of the grass fiber in a physical mode of high-temperature cooking by considering the great difference between the grass fiber and the wood fiber.

Disclosure of Invention

In order to solve the defects of the technology, the invention provides a method for separating lignin from straw for papermaking.

In order to solve the technical problems, the invention adopts the technical scheme that: a method for separating lignin from papermaking straw comprises the following steps:

i, extruding and cutting straw of grass plants into filaments;

II, mixing water and the straw filaments according to the proportion of more than 1:1, soaking, and standing for more than 60 minutes;

III, putting the soaked straw filaments into a high-pressure kettle, heating to 170-220 ℃, and keeping the temperature for 5-30 minutes;

IV, opening a discharge valve of the high-pressure kettle, spraying the materials in the kettle into the mixing chamber, mixing the materials with cooling water injected into the mixing chamber at the same time, and cooling the materials;

v, sieving the cooled material by a 100-mesh sieve, wherein the oversize part is coarse pulp, and the undersize part is hemicellulose, lignin, mixed cells and impurities;

and VI, grinding the coarse pulp obtained in the step V into thick pulp in a conventional papermaking process, and washing to obtain fine pulp, so that papermaking can be further manufactured.

Further, the length of the cut straws is 10-60 mm, and the width of the cut straws is less than 0.5 mm.

Furthermore, the water temperature of the cooling water is 0-60 ℃.

Further, the straw is corn straw.

Further, papermaking includes, but is not limited to, toilet paper and corrugated paper; when the sanitary paper is produced, the temperature of the high-pressure kettle is over 195 ℃ and the time is 30 minutes; when corrugated paper is produced, the temperature of the autoclave is above 185 ℃ and the time is 15 minutes.

Further, the temperature of the autoclave was 185 ℃ or more and the time was 15 minutes when corrugated paper was produced.

Further, the refining method of the coarse pulp comprises a high-consistency mill, a medium-consistency mill and a low-consistency mill; the washing method of the brown stock is countercurrent washing.

In the whole process of lignin separation, no chemical preparation is added, the lignin separation is realized only by a physical method, and the separated substances basically keep the natural characteristics of each component of the original plant material plant, so that a good foundation is created for the comprehensive utilization of the raw materials; the separated liquid is subjected to anaerobic fermentation to prepare biogas, and the biogas slurry and biogas residues are treated by aerobic fermentation and the like to form good organic fertilizer; the separated liquid is further separated or reprocessed, so that the resource utilization of the papermaking waste can be realized, and the pressure on the environment is not caused; the cost of the paper pulp is reduced without adding chemical agents; the recovery rate is high.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments.

A method for separating lignin from papermaking straw comprises the following steps:

i, extruding and cutting straw of grass plants into filaments; the length of the cut straw is 10-60 mm, and the width of the cut straw is less than 0.5 mm;

II, mixing water and the straw filaments according to the proportion of more than 1:1, soaking, and standing for more than 60 minutes;

III, putting the soaked straw filaments into a high-pressure kettle, heating to 170-220 ℃, and keeping the temperature for 5-30 minutes;

IV, opening a discharge valve of the high-pressure kettle, spraying the materials in the kettle into the mixing chamber, mixing the materials with cooling water injected into the mixing chamber at the same time, and cooling the materials; the water temperature of the cooling water can be selected from 0-60 ℃, and the cooling effect on high-temperature materials can be achieved;

v, sieving the cooled material by a 100-mesh sieve, wherein the oversize part is coarse pulp, and the undersize part is hemicellulose, lignin, mixed cells and impurities;

VI, the coarse pulp is washed by a high-concentration mill, a medium-concentration mill, a low-concentration mill and other pulp grinding methods in the conventional papermaking process by a counter-current washing method to obtain fine pulp, and then papermaking can be further manufactured.

The invention is further illustrated by the following specific examples: