CN102704298A - Process and device for pulping by reversely extracting grass raw materials - Google Patents

Abstract

The invention discloses a process and equipment for countercurrent extraction and pulping of grass raw materials. The pulping method adopts ethanol-water-peroxide multi-stage countercurrent extraction of grass raw materials, and the ethanol volume concentration of the extract is controlled in the cooking section 40%~65%, the temperature of each stage is 90~190°C, the extraction time is 40~180min, the liquid ratio is 1:4~1:10, and 0.5%~5% of the weight of raw materials is added at the end of the cooking stage. As an auxiliary agent, the temperature of each section of the pulp washing section is 70-100°C, the extraction time is 30-60min, and the liquid ratio is 1:3-1:6; the countercurrent extraction pulping device mainly includes an extractor and a heat exchanger , liquid storage tank, flash tank, condenser, ethanol water tank and circulation pump and other equipment units. This process is suitable for the pulping industry, and has the advantages of wide adaptability to grass raw materials, low cooking temperature, good pulp quality, easy bleaching of pulp, low investment, easy recovery of waste liquid and high value-added by-products, etc., and can realize cleaning pulping.

Description

A countercurrent extraction and pulping process and device for grass raw materials

technical field

The invention relates to a countercurrent extraction pulping process and device for grass raw materials, and relates to the technical field of pulping and papermaking engineering.

Background technique

With the rapid development of my country's economy, the demand for pulp and paper is increasing rapidly. However, as we all know, many straw pulp mills in my country still use traditional pulping methods, which bring great pressure to the environment and energy, which is contrary to the main driving force for the development of pulping. Therefore, my country will restrict the establishment of traditional straw pulp production lines in the "Pulp and Paper 'Eleventh Five-Year' Plan", and vigorously develop the clean production technology of straw pulp in the "Pulp and Paper 'Twelfth Five-Year' Plan". . In view of this, finding a new pulping method that can effectively recover useful substances such as lignin, better protect the environment, and have good adaptability to straw pulp has become an urgent problem to be solved in the paper industry.

The organic solvent pulping technology developed in recent years can provide a better delignification method. There are more reactive functional groups in the degraded lignin and hemicellulose, and it can be more easily removed from the solvent medium. Recycling and purification. Organic solvent pulping is an environmentally friendly pulping technology. Under certain conditions, organic solvents can degrade lignin in plant raw materials, thereby achieving the purpose of efficient separation of lignin, cellulose, and hemicellulose. Since the whole process uses organic solvents to separate, hydrolyze or dissolve lignin, and organic solvents can be recycled and recycled through distillation and recovery, there is no waste water or a small amount of waste water discharge, so that it can truly prevent and control the pulping and papermaking process from the source. It is an effective technical way to realize pollution-free or low-pollution "green" papermaking. It can be said that organic solvent pulping is a typical representative of "fibrous raw material refining", which can use plant fiber raw materials to "refine" products such as pulp, lignin and hemicellulose, and minimize environmental pollution.

Ethanol pulping is one of the most typical pulping methods in organic solvent pulping. There are acid-catalyzed, alkali-catalyzed and self-catalyzed ethanol pulping technologies that have been studied. This patent belongs to the category of self-catalyzed ethanol pulping. The disadvantages of traditional autocatalytic ethanol pulping are high extraction temperature, high pressure of the extractor, long extraction time, and difficult slurry washing. Multi-stage countercurrent extraction is used, and hydrogen peroxide and other peroxides are added to assist extraction. It can greatly reduce the extraction temperature, realize the efficient recycling of the extract, save energy and reduce the manufacturing cost of the extractor, and can also save the traditional pulp washing process, save water consumption, and increase the secondary The concentration of the product is beneficial to the recycling of waste liquid.

Contents of the invention

The purpose of the present invention is to provide a non-polluting, low water consumption, recyclable countercurrent extraction pulping method of high value-added by-products, the pulping method uses ethanol/water solution as the main agent, and adds hydrogen peroxide as an auxiliary agent countercurrent The extraction of grass raw materials reduces the cooking temperature, reduces the consumption of ethanol, and creates favorable conditions for the efficient recovery of waste liquid and the extraction of by-products.

The present invention is realized through the following technical solutions: a countercurrent extraction pulping method for grass raw materials, which is a multi-stage countercurrent extraction method, including cooking and pulp washing, and the process is as follows:

a. Cooking: In the extractor, use the extraction waste liquid and replenishment liquid obtained after one extraction process as the extracting liquid of the previous extraction process, and add 0.5% of the mass of grass raw materials at the end of the cooking process ～5% peroxide, the number of extraction stages is 1～4;

b. Pulp washing: hot water is used as the extraction solution in the final stage of pulp washing, and the obtained extraction waste liquid is used as the extraction solution in the previous extraction process, and the number of extraction stages is 1-3.

The raw materials described in the present invention are grass raw materials that can be used for pulping known to those skilled in the art, such as reed, wheat straw, rice straw, grass reed, bagasse, etc.; the temperature of the hot water in the present invention is 70 ° C ~ 90 °C; the extraction waste liquid is an extraction waste liquid containing ethanol, water, degraded lignin, degraded sugar, furfural and organic acids.

The method for countercurrent extraction and pulping of grass raw materials in the present invention preferably has a volume concentration of ethanol in the extract in the cooking section of 40% to 65%.

In the method for countercurrent extraction and pulping of grass raw materials in the present invention, the supplementary liquid is preferably recovered ethanol or a mixture of recovered ethanol and industrial ethanol with a concentration of 95%. Since the extraction waste liquid contains ethanol, water, degraded lignin, degraded sugar, furfural and organic acids and other components, its ethanol concentration is lower than 40%. ethanol aqueous solution. The ethanol concentration can be detected by an ultrasonic ethanol concentration online detector arranged on the pipeline.

The method for countercurrent extraction and pulping of grass raw materials according to the present invention is preferably carried out at a liquid ratio of 1:4 to 1:10 in each section of cooking, with an extraction temperature of 90 to 190°C and an extraction time of 30 to 180 minutes; The stage is carried out according to the liquid ratio of 1:3~1:6, the extraction temperature is 70~100°C, and the extraction time is 30~60min.

In the countercurrent extraction and pulping method of grass raw materials in the present invention, the preferred peroxide is hydrogen peroxide.

The method for countercurrent extraction and pulping of grass raw materials described in the present invention is preferably the following process steps:

a. Cut the grass raw materials into grass sections and put them into the pressure vessel, and perform one-stage extraction according to the liquid ratio of 1:4 to 1:10. The extraction liquid used in the first-stage extraction is the second-stage extraction waste liquid, which is recovered by adding Ethanol controls the volume concentration of ethanol to 40% to 65%, the extraction temperature is 160 to 190°C, and the extraction time is 90 to 180 minutes. Recovery system, the slurry in the pressure vessel is subjected to two-stage extraction;

b. The second-stage extraction is carried out with the third-stage extraction waste liquid at a liquid ratio of 1:4 to 1:10, and the ethanol volume concentration is controlled to be 40% to 65% by adding recovered ethanol, and the extraction temperature is 120 to 170°C. The extraction time is 40-90 minutes. After the second-stage extraction is completed, the extraction waste liquid is released for the first-stage extraction, and the slurry is subjected to the third-stage extraction;

c. The three-stage extraction is carried out with the fourth-stage extraction waste liquid at a liquid ratio of 1:4 to 1:10, and the ethanol volume concentration is controlled to be 40% to 65% by adding recovered ethanol and 95% industrial ethanol, and adding raw materials Hydrogen peroxide with a mass of 0.5% to 5%, the extraction temperature is 90 to 140°C, and the extraction time is 40 to 90 minutes. After the three-stage extraction is completed, the extraction waste liquid is released for the second-stage extraction, and the slurry is subjected to the fourth-stage extraction. carry;

d. The fourth-stage extraction uses the fifth-stage extraction waste liquid at a liquid ratio of 1:3 to 1:6, the extraction temperature is 70-100°C, and the extraction time is 30-60 minutes. After the fourth-stage extraction is completed, release the extraction The waste liquid is subjected to three-stage extraction, and the slurry is subjected to five-stage extraction;

e. The five-stage extraction is carried out with hot water at a liquid ratio of 1:3 to 1:6, the extraction temperature is 70 to 100°C, and the extraction time is 30 to 60 minutes. After the five-stage extraction is completed, the extraction waste liquid is released for the fourth Stage extraction, release the slurry from the container to obtain pulp.

Another object of the present invention is to provide a countercurrent extraction and pulping device for grass raw materials, which mainly includes the following equipment units:

at least one extractor for extractive pulping;

At least one heat exchanger, the heat exchanger is connected to the extractor by receiving the extract from at least one circulation pump, and is used to heat the extract and control the extraction temperature;

At least one liquid storage tank, the liquid storage tank receives the extraction liquid from the extractor for storing the extraction liquid, and each extraction section is equipped with a liquid storage tank;

At least one flash tank, the flash tank receives the extract from the extractor and is connected with the condenser for a section of extraction waste liquid flash, recovering part of ethanol and other low-boiling components;

at least one condenser connected to the ethanol water tank for condensation of flash vapor;

At least one ethanol water tank, the ethanol water tank is connected to the extractor through a pipeline;

At least one hot water tank, the hot water tank is connected with the condenser and the heat exchanger by receiving the hot water from the condenser and the heat exchanger; the hot water tank is connected with the extractor through pipelines.

The device for countercurrent extraction and pulping of grass raw materials in the present invention also includes at least one ultrasonic ethanol concentration online detector arranged on the pipeline for detecting ethanol concentration.

The device for countercurrent extraction and pulping of grass raw materials in the present invention also includes pipelines for connecting equipment units, pipeline connection devices and control valves.

The extractor of the present invention is a sealed pressure vessel, the upper end of the container is a feed port, and the lower end is a discharge port, which is indirectly heated. When extracting, the middle part of the circulating pump pumps liquid, and the extracted liquid is heated by a heat exchanger and divided into two parts. part, return to the extractor from the upper and lower ends of the extractor, and repeat the cycle until the end of this section of extraction.

As a preference, the extractor preferably has a length-to-diameter ratio of 5:1 to 10:1 and a pressure resistance greater than 3.0 MPa; the volume of the liquid storage tank is preferably 3 to 5 times the volume of the extractor; the heat exchange The heat exchanger is preferably a plate or tube heat exchanger, and its heat exchange area meets the requirement that the time for the extract to rise from room temperature to the highest holding temperature is not more than 60 minutes.

The beneficial effects of the present invention are:

(1) Compared with the prior art, the cooking technology of the present invention is pollution-free, saves the pulp washing process in the traditional pulping method, has less water consumption, and the water consumption is about 1/5 of the traditional pulping method, and Waste liquid is easy to recycle. Compared with the ordinary self-catalyzed ethanol pulping method, the maximum extraction temperature can be reduced by more than 20°C, which not only saves energy but also reduces the manufacturing requirements of the extractor.

(2) Investment province. Because there is no need to set up pulp washing equipment and alkali recovery equipment, and distillation technology is used for waste liquid recovery, the construction investment can be saved by about 40%.

(3) High value-added by-products can be recovered. The waste liquid contains high value-added by-products such as ethanol lignin, degraded sugar, furfural, formic acid, and acetic acid. The recovery technology is relatively simple, and these by-products are burned as fuel in traditional pulping methods. The value of recovering these by-products is higher than the profit of pulping.

(4) The pulp quality is good. The pulp has good bleaching properties, and the pulp quality is equivalent to that of alkaline pulp.

Description of drawings

2 pieces of accompanying drawings of the present invention, take single extractor, five sections of extraction as example.

Fig. 1 is a process flow diagram of a countercurrent extraction pulping method for grass raw materials;

Fig. 2 is a schematic diagram of a countercurrent extraction and pulping device for grass raw materials.

Detailed ways

The following non-limiting examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

The test methods described in the following examples, unless otherwise specified, are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from commercial sources, or can be prepared by conventional methods.

Example 1

A countercurrent extraction and pulping method for grass raw materials, which uses ethanol-water-hydrogen peroxide five-stage countercurrent pulping for reed raw materials, and the process steps are as follows:

a. Cut the reed raw material into grass sections and put them into a pressure vessel, perform one-stage extraction according to the liquid ratio (g:mL) of 1:8, the extract used in the first-stage extraction is the second-stage extraction waste liquid, and recover ethanol by adding Control the volume concentration of ethanol to 50%, extracting temperature at 170°C, and extracting time for 150 minutes. After the first stage of extraction is completed, the extraction waste liquid is released into the flash tank to recover part of the ethanol, and the other waste liquid is sent to the recovery system. The slurry in the pressure vessel The material is subjected to two-stage extraction;

b. The second-stage extraction is carried out with the third-stage extraction waste liquid according to the liquid ratio (g:mL) of 1:8, and the ethanol volume concentration is controlled to be 50% by adding recovered ethanol, the extraction temperature is 150°C, and the extraction time is 60min. After the second-stage extraction is completed, the extraction waste liquid is released for the first-stage extraction, and the slurry is subjected to the third-stage extraction;

c. The three-stage extraction is carried out with the fourth-stage extraction waste liquid according to the liquid ratio (g:mL) of 1:8, and the ethanol volume concentration is controlled to be 50% by adding recovered ethanol and 95% industrial ethanol, and adding raw material quality 1.5 % hydrogen peroxide, the extraction temperature is 120°C, and the extraction time is 60 minutes. After the third-stage extraction is completed, the extraction waste liquid is released for the second-stage extraction, and the slurry is subjected to the fourth-stage extraction;

d. The fourth-stage extraction uses the fifth-stage extraction waste liquid according to the liquid ratio (g:mL) of 1:4, the extraction temperature is 80°C, and the extraction time is 30min. After the fourth-stage extraction is completed, the extraction waste liquid is released for supply Three-stage extraction, the slurry is subjected to five-stage extraction;

e. The five-stage extraction is carried out with hot water according to the liquid ratio (g:mL) 1:4, the extraction temperature is 90°C, and the extraction time is 30 minutes. After the five-stage extraction is completed, the extraction waste liquid is released for the fourth-stage extraction , discharge the slurry from the container to obtain pulp.

Fig. 2 is a schematic diagram of a countercurrent extraction and pulping device for grass raw materials.

As shown in Figure 2, this device comprises an extractor 101, and this extractor 101 is a sealed pressure vessel, a valve 918 is set on the feed inlet of the extractor 101 upper end, and a valve 913 is set at the discharge port of the lower end; The liquid suction port in the middle part of 101 is connected with the circulating pump 301 through a pipeline, and a valve 910 is set on the pipeline; The pipeline is connected to the circulation pump 301, and a valve 909 is set on the pipeline; a heating steam inlet and a condensed water outlet are arranged on the heat exchanger 201, and the heat exchanger 201 is connected to the hot water tank 1001 through the pipeline arranged at the condensed water outlet. connected; the hot water tank 1001 is connected to the extractor 101 through a pipeline, and a valve 919 is set on the pipeline. The ultrasonic ethanol concentration online detector 1101 is arranged on the pipe connecting the extractor 101 and the heat exchanger 201 .

A valve 908 is arranged on the pipeline connected to the circulating pump 301, and the extraction waste liquid through the valve 908 can enter the flash tank 601 or the liquid storage tank 400 through the connecting pipeline and the valve 907 or valve 906 arranged on it, such as storage Liquid tank 401 , liquid storage tank 402 , liquid storage tank 403 , liquid storage tank 404 .

The flash tank 601 is connected to the circulating pump 301 through a pipeline, and the pipeline is provided with valves 907 and 908. The extraction waste liquid flashed through the flash tank 601 is flash steam mainly containing ethanol, water, and low-boiling organic acids. The steam enters the condenser 501 through the pipeline, and the condenser 501 is respectively connected to the ethanol water tank 701 and the hot water tank 1001 through the pipeline.

The extraction waste liquid pumped out by the extractor 101 enters the liquid storage tank 401, the liquid storage tank 402, the liquid storage tank 401, the liquid storage tank 402, and the tank 403 or reservoir 404 . By opening or closing the valve 914 , the valve 915 , the valve 916 or the valve 917 to control the extraction liquid to enter any one of the liquid storage tank 401 , the liquid storage tank 402 , the liquid storage tank 403 or the liquid storage tank 404 .

The fluid stored in the liquid storage tank 401, the liquid storage tank 402, the liquid storage tank 403, the liquid storage tank 404 and the ethanol water tank 701 passes through the respective pipelines and the valves 905, 904, 903, 902, Valve 901 and circulation pump 301 enter extractor 101 . By opening or closing the valve 905, the valve 904, the valve 903, the valve 902, and the valve 901, the extraction waste liquid is controlled to enter the aspirator 101.

The specific operation is as follows:

1. Loading: close the other valves and open the valve 918, put the grass section of the reed raw material into the extractor 101, and the loading is completed.

2. One-stage extraction:

a. Extraction liquid pumping and extraction: open valve 905, valve 909, valve 912, pump the extraction liquid in the liquid storage tank 401 into the extractor 101 through the medicinal liquid circulation pump 301, and reach a liquid ratio of 1:8 Afterwards, valve 905 and valve 918 are closed, and valve 910 and valve 911 are opened, and the extractant is circulated among the extractor 101, circulation pump 301, and heat exchanger 201 to heat and extract the raw grass section;

b. Extraction waste liquid treatment: After the first stage of extraction is completed, close valve 909, open valve 908 and valve 907, and the extraction liquid passes through flash tank 601, and the flash steam is ethanol, water, low-boiling point organic acid, etc. The steam enters the ethanol water tank 701 after being condensed by the condenser 501, and the non-condensable gas is sent for processing. After the flash evaporation is completed, the valve 908 and the valve 907 are closed.

3. Two-stage extraction:

a. Extraction pumping and extraction: close valve 910, open valve 904, valve 909, and valve 912, and pump the extract in liquid storage tank 402 into extractor 101 through circulating pump 301 to reach a liquid ratio of 1 : After 8, close valve 904, open valve 910 and valve 911, the extractant circulates between extractor 101, circulation pump 301, heat exchanger 201, heats and extracts a section of slurry after extraction;

b. Extraction waste liquid treatment: after the second-stage extraction is completed, close the valve 909, open the valve 914, valve 906, and valve 908 in sequence, and the extraction liquid is pumped into the liquid storage tank 401;

4. Three-stage extraction:

a. Extraction pumping and extraction: add 1.5% hydrogen peroxide of reed raw material grass section quality in liquid storage tank 403, close valve 910, open valve 903, valve 909, valve 912, through circulation pump 301 will store The extract in the liquid tank 403 is pumped into the extractor 101, closes the valve 903 after reaching a liquid ratio of 1:8, opens the valve 910 and the valve 911, and extracts the liquid in the extractor 101, the circulation pump 301, and the heat exchanger 201 cycle, heating and extracting a period of extracted slurry;

b. Extraction waste liquid treatment: after the three-stage extraction is completed, close the valve 909, open the valve 915, valve 906, and valve 908 in sequence, and the extraction liquid is pumped into the liquid storage tank 402;

5. Four-stage extraction:

a. Pumping and extraction of extract: close valve 910, open valve 902, valve 909, and valve 912, pump the extract in liquid storage tank 404 into extractor 101 through circulation pump 301, and reach a liquid ratio of 1 : After 4, close the valve 902, open the valve 910 and the valve 911, and the extract circulates between the extractor 101, the circulating pump 301, and the heat exchanger 201, and heats and extracts a section of the extracted slurry;

b. Extraction waste liquid treatment: after the four-stage extraction is completed, close the valve 909, open the valve 916, valve 906, and valve 908 in sequence, and the extraction liquid is pumped into the liquid storage tank 403;

6. Five-stage extraction:

a. Extraction liquid pumping and extraction: close valve 910, open valve 919, valve 909, and valve 912, and pump the hot water in the hot water tank 1001 into the extractor 101 through the circulation pump 301 to achieve a liquid ratio of 1:4 Finally, close the valve 919, open the valve 910 and the valve 911, the hot water circulates among the extractor 101, the circulation pump 301, and the heat exchanger 201, and heats and extracts a section of the extracted slurry;

b. Extraction waste liquid treatment: After the five-stage extraction is completed, the valve 909 is closed, and the valve 917, valve 906, and valve 908 are opened in sequence, and the extraction liquid is pumped into the liquid storage tank 404.

7. Material retrieving: close other valves, open valve 913 to take out the pulp.

During the whole extraction process, the amount of replenishing liquid entering the extractor 101 is controlled by opening or closing the valve 901 so as to achieve the concentration of ethanol in the extracting liquid to meet the requirements of each extraction stage. The ethanol concentration is detected by the ultrasonic ethanol concentration online detector 1101 arranged on the pipeline.

When starting the extraction for the first time, fresh ethanol aqueous solution is used as the extraction liquid in the first stage of extraction, and the obtained extraction waste liquid is not recycled, but is continuously circulated among the extractor 101, the circulation pump 301, and the heat exchanger 201, and By adding fresh ethanol aqueous solution to the extractor 101 to obtain the extracts required for the first-stage, second-stage, and third-stage extractions, the operating system of 4 to 5 cycles reaches a steady state, and the device after reaching the steady state is carried out according to the above-mentioned operation method extraction operation.

The obtained pulp quality is listed in Table 1.

Table 1 Pulping effect of reed five-stage countercurrent extraction

Fine pulp yield/% Hardness (Kappa price) Viscosity/mL·g ^-1 54 18 960

Example 2

A method for countercurrent extraction and pulping of grass raw materials, using ethanol-water-hydrogen peroxide five-stage countercurrent pulping for wheat straw raw materials, the process steps are as follows: the process operation is the same as that of Example 1, and the process conditions are as follows:

One-stage extraction: temperature 175°C, time 150min, liquid ratio 1:7, ethanol concentration 55%;

Two-stage extraction: temperature 150°C, time 60min, liquid ratio 1:7, ethanol concentration 55%;

Three-stage extraction: temperature 130°C, time 60min, liquid ratio 1:7, ethanol concentration 55%, hydrogen peroxide dosage 1.0%;

Four-stage extraction: temperature 80°C, time 30min; liquid ratio 1:4;

Five-stage extraction: temperature 80°C, time 30min, liquid ratio 1:4.

The obtained pulp quality is listed in Table 2.

Table 2 Pulping effect of five-stage countercurrent extraction of wheat straw

Fine pulp yield/% Hardness (Kappa price) Viscosity/mL·g ^-1 53 16 940

Example 3

A method for countercurrent extraction and pulping of grass raw materials, using ethanol-water-hydrogen peroxide five-stage countercurrent pulping for wheat straw raw materials, the process steps are as follows: the process operation is the same as that of Example 1, and the process conditions are as follows:

One-stage extraction: temperature 165°C, time 180min, liquid ratio 1:8, ethanol concentration 50%;

Two-stage extraction: temperature 150°C, time 80min; liquid ratio 1:8, ethanol concentration 50%;

Three-stage extraction: temperature 130°C, time 60min, liquid ratio 1:8, ethanol concentration 50%, hydrogen peroxide dosage 1.5%;

Four-stage extraction: temperature 80°C, time 30min, liquid ratio 1:5.

Five-stage extraction: temperature 80°C, time 30min, liquid ratio 1:5.

The obtained pulp quality is listed in Table 3.

Table 3 Pulping effect of reed five-stage countercurrent extraction

Fine pulp yield/% Hardness (Kappa price) Viscosity/mL·g ^-1 51 19 1080

Claims (10)

1. A countercurrent extraction pulping process for grass raw materials, which is a multi-stage countercurrent extraction process, including cooking and pulp washing, the process is as follows: a. Cooking: In the extractor, use the extraction waste liquid and replenishment liquid obtained after one extraction process as the extracting liquid of the previous extraction process, and add 0.5% of the mass of grass raw materials at the end of the cooking process ～5% peroxide, the number of extraction stages is 1～4; b. Pulp washing: hot water is used as the extraction liquid in the final stage of pulp washing, and the obtained extraction waste liquid is used as the extraction liquid in the previous extraction process, and the number of extraction stages is 1-3. 2. The countercurrent extraction and pulping process of grass raw materials according to claim 1, characterized in that: the volume concentration of ethanol in the extract of the cooking section is 40%-65%. 3. According to claim 1 or 2, the countercurrent extraction and pulping process of grass raw materials is characterized in that: the cooking stages are carried out at a liquid ratio of 1:4 to 1:10, and the extraction temperature is 90 to 190°C. The extraction time is 30-180 minutes; each stage of the pulp washing is carried out according to the liquid ratio of 1:3-1:6, the extraction temperature is 70-100° C., and the extraction time is 30-60 minutes. 4. The countercurrent extraction and pulping process of grass raw materials according to claim 2, characterized in that: the replenishment liquid is recovered ethanol, or a mixture of recovered ethanol and industrial ethanol with a volume concentration of 95%. 5. The countercurrent extraction and pulping process of grass raw materials according to claim 1, characterized in that: the peroxide is hydrogen peroxide. 6. The countercurrent extraction pulping process of grass raw materials according to claim 1 is characterized in that: it is a five-stage countercurrent extraction process, and the process steps are as follows: a. Cut the grass raw materials into grass sections and put them into the pressure vessel, and perform one-stage extraction according to the liquid ratio of 1:4 to 1:10. The extraction liquid used in the first-stage extraction is the second-stage extraction waste liquid, which is recovered by adding Ethanol controls the volume concentration of ethanol to be 40%-65%, the extraction temperature is 160-190°C, and the extraction time is 90-180min. Send to the recovery system, keep the slurry in the extractor, and carry out the second-stage extraction; b. The second-stage extraction is carried out with the third-stage extraction waste liquid at a liquid ratio of 1:4 to 1:10, and the volume concentration of ethanol is controlled by adding and recovering ethanol to be 40% to 65%, and the extraction temperature is 120 to 170°C. The extraction time is 40-90 minutes. After the second-stage extraction is completed, the extraction waste liquid is released for the first-stage extraction, and the slurry is subjected to the third-stage extraction; c. The three-stage extraction is carried out with the four-stage extraction waste liquid at a liquid ratio of 1:4 to 1:10, and the volume concentration of ethanol is controlled to be 40% to 65% by adding recovered ethanol and 95% industrial ethanol, and adding The raw material quality is 0.5%-5% hydrogen peroxide, the extraction temperature is 90-140°C, and the extraction time is 40-90 minutes. After the third-stage extraction is completed, the extraction waste liquid is released for the second-stage extraction, and the slurry is subjected to the fourth-stage extraction. extract; d. The fourth-stage extraction uses the fifth-stage extraction waste liquid at a liquid ratio of 1:3 to 1:6, the extraction temperature is 70-100°C, and the extraction time is 30-60 minutes. After the fourth-stage extraction is completed, release the extraction The waste liquid is subjected to three-stage extraction, and the slurry is subjected to five-stage extraction; e. The five-stage extraction is carried out with hot water at a liquid ratio of 1:3 to 1:6, the extraction temperature is 70 to 100°C, and the extraction time is 30 to 60 minutes. After the five-stage extraction is completed, the extraction waste liquid is released for the fourth Stage extraction, release the slurry from the container to obtain pulp. 7. A countercurrent extraction and pulping device for grass raw materials, mainly including the following equipment units: at least one extractor (100) for extractive pulping; At least one heat exchanger (200), the heat exchanger (200) is connected to the extractor (100) by receiving the extract from at least one circulation pump (300), for heating the extract, controlling the extraction Raise temperature; At least one liquid storage tank (400), the liquid storage tank (400) receives the extraction liquid from the extractor (100) for storing the extraction liquid, and each extraction section is equipped with a liquid storage tank (400 ); At least one flash tank (600), the flash tank (600) receives the extract from the extractor (100), and is connected with the condenser (500), used for a section of extraction waste liquid flash, recovery Part of ethanol and other low boiling point components; At least one condenser (500) connected to the ethanol water tank (700) for condensation of flash steam; At least one ethanol water tank (700), the ethanol water tank (700) is connected to the extractor (100) through a pipeline; At least one hot water tank (1000) connected to the condenser (500) and heat exchanger (200) by receiving hot water from the condenser (500) and heat exchanger (200) ; The hot water tank (1000) is connected with the extractor (100) through a pipeline. 8 . The countercurrent extraction and pulping device for grass raw materials according to claim 7 , further comprising at least one ultrasonic ethanol concentration online detector ( 1100 ) arranged on the pipeline for detecting ethanol concentration. 9. The device for countercurrent extraction and pulping of grass raw materials according to claim 7, characterized in that it further comprises a pipeline (800) for connecting equipment units, a pipeline connection device and a control valve (900). 10. The countercurrent extraction and pulping device for grass raw materials according to claim 7, characterized in that: the extractor (100) is a sealed pressure vessel, the upper end of the container is a feed port, and the lower end is a discharge port, When extracting, the middle part of the circulation pump pumps liquid, and the extracted liquid is divided into two parts after being heated by a heat exchanger, and returns to the extractor (100) from the upper and lower ends of the extractor (100) respectively, and circulates repeatedly until the extraction in this section Finish.

Images