CN108774557A - A kind of formed coke and preparation method thereof based on complex biological matter binder - Google Patents

Abstract

The invention discloses a form coke based on a composite biomass binder and a preparation method thereof. The form coke comprises the following raw materials in parts by mass: 45-55 parts of semi-coke, 5-15 parts of biomass, and 1-3 parts of bentonite Parts, 1-3 parts of sodium carboxymethylcellulose, 1-4 parts of chitosan solution; In addition, the present invention also discloses a method for preparing coke based on composite biomass binder, and the coke prepared by the present invention It has excellent characteristics such as good thermal stability, high temperature resistance, and high mechanical strength. After the coke is dried and cooled, the measured cold compressive strength is greater than 600N/ball, and the drop strength is greater than 95%. It has good thermal stability and will not loosen at high temperatures above 1100°C.

Description

Form coke based on composite biomass binder and preparation method thereof

technical field

The invention belongs to the technical field of low-rank coal pyrolysis semi-coke molding, and in particular relates to a coke based on a composite biomass binder and a preparation method thereof.

Background technique

Semi-coke, also known as semi-coke, is a solid carbonaceous product produced by medium and low-temperature pyrolysis technology using lignite, long-flame coal, non-caking coal or weakly caking coal and other medium-low metamorphic coal as raw materials. It has fixed carbon High, low ash, low sulfur, low price and so on. In recent years, a large number of coal low-temperature distillation enterprises have been established in the western region of my country, especially in the Yushen mining area in northern Shaanxi, forming industrial chains such as calcium carbide, metallurgy, chemical fertilizers, and fuel oil. The semi-coke fine powder produced in the low-temperature carbonization process of coal cannot be directly used due to the particle size, thus greatly reducing the utilization rate of semi-coke. Formed coke can effectively solve the problem of comprehensive utilization of fine coke.

Form coke uses binders to form coke powder into blocks under high pressure, thereby improving its mechanical strength and increasing its particle size. In the coke preparation process, in order to improve the mechanical strength, combustibility and other parameters of the coke, it is usually necessary to add a binder. At present, the binders that have been developed can be divided into three categories: inorganic binders, organic binders and composite binders according to their chemical state. Among them, inorganic binders mainly include lime, cement, gypsum, water glass, inorganic salt, etc. The molded coke produced by it has good thermal strength and thermal stability, but the molded coke has a large ash content and poor water resistance. Organic binders mainly include tar, asphalt, sodium humate, polyvinyl alcohol, biomass, etc. They have high calorific value, and the coke made of them has good cold and hot strength, but it is easy to cause secondary pollution. Biomass binders have the advantages of wide sources, no increase in mold coke ash, high calorific value, good combustion performance of the produced mold coke, low ignition point, no slagging, and waste utilization. Composite binders are composed of the above-mentioned multiple binders, so they continue the advantages of various binders and have attracted more attention from scholars. The most common composite binders are mainly tar and tar pitch Binders with inorganic binders as the main components, binders with petroleum asphalt and bentonite as the main components, and binders with biomass and inorganic binders as the main components. At present, the molded coke prepared by the prior art has low cold strength, high molded coke ash content due to the large amount of inorganic binder added, and secondary pollution caused by adding tar pitch and the like.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a form coke based on a composite biomass binder and its preparation method, which has the characteristics of low production cost, simple preparation method, non-toxic, green and environmental protection.

In order to achieve the above object, the technical solution adopted in the present invention is: a form coke based on composite biomass binder, including the following raw materials in parts by mass: 45-55 parts of semi-coke, 5-15 parts of biomass, 1 part of bentonite -3 parts, 1-3 parts of sodium carboxymethylcellulose and 1-4 parts of chitosan solution.

Biomass is the residue obtained from the hydrolysis of sunflower stalks in a Ca(OH) ₂ saturated solution, followed by pressure filtration.

The water content of the residue obtained by pressure filtration is 30-40%.

The semi-coke is semi-coke obtained by pyrolyzing medium-low metamorphic degree coal.

The chitosan solution is a viscous liquid formed by dissolving 0.01-0.04 parts by mass of industrial flake chitosan in 1-4 parts of acetic acid solution with a concentration of 0.08-0.12mol/L.

The present invention also provides a method for preparing coke based on composite biomass binder, comprising the following steps:

Step 1: Dried the sunflower stalks and crushed them to less than 3mm, mixed the sunflower stalks with saturated Ca(OH) ₂ solution at a mass ratio of 1:8-1:12, hydrolyzed at 70-100°C for 2-5 hours under stirring, and pressed After filtering, the hydrolyzed residue of sunflower stalks was obtained;

Step 2: Pulverize the semi-coke, the particle size of which is not greater than 3mm after pulverization.

Step 3: Industrial flaky chitosan is dissolved in an acetic acid solution with a concentration of 0.08-0.12mol/L at 80°C to prepare a chitosan solution;

Step 4: In parts by mass, mix 5-15 parts of sunflower stalk hydrolysis residue, 1-3 parts of bentonite, 1-3 parts of sodium carboxymethyl cellulose, and 1-4 parts of chitosan solution prepared in step 3 with In step 2, 45-55 parts of semi-coke pulverized are mixed, stirred evenly to obtain a mixed material, and matured for 2-5 hours to obtain a matured mixture;

Step 5: Compress the matured mixture obtained in Step 4 to a pressure of 20-35MPa, hold the pressure for 30-60s, then place it in a cool and ventilated place for 4-6 hours, and then dry it at 100°C-105°C for 1-2h. Form coke is obtained after cooling.

The water content of the mixed material in step 4 is 12-15%.

In the third step, in parts by mass, 0.01-0.04 parts of industrial flake chitosan, and 1-4 parts of acetic acid solution.

Among the present invention, the specific effect of each component of binder is described as follows:

Sunflower stalk hydrolysis residue: after alkaline hydrolysis of biomass sunflower stalks, the cellulose in the biomass can be fully exposed, so that it has cohesive properties. Increase its combustibility, while biomass is combustible, and its combustion will increase the calorific value.

Bentonite: Bentonite is mainly aluminosilicate, which has the characteristics of being able to expand into a viscous paste after adding water, high temperature stability and chemical stability. thermal stability in.

Sodium carboxymethyl cellulose: it has the functions of thickening, thickening, water retention, cohesiveness and combustion support.

Chitosan solution: Industrial flake chitosan becomes a viscous liquid after being dissolved in dilute acid, which has cohesiveness. In addition, after the chitosan solution contacts with the alkaline substances in the hydrolysis residue of sunflower stalks, it can form a network porous Gel that increases the mechanical strength and water resistance of the coke.

In addition, the present invention also provides a method for preparing coke based on a composite biomass binder, which is characterized in that it comprises the following steps:

Step 1: drying and pulverizing the sunflower stalks, mixing saturated Ca(OH) ₂ solution with the pulverized sunflower stalks, hydrolyzing for a certain period of time under the conditions of stirring and heating, pressing and drying to obtain the hydrolyzed sunflower stalk residues.

Step 2: Pulverize the semi-coke, the particle size of which is not greater than 3mm after pulverization.

Step 3: dissolving chitosan in acetic acid solution under heating to obtain chitosan solution.

Step 4: Mix the pulverized semi-coke with sunflower stalk hydrolysis residue, bentonite, sodium carboxymethylcellulose and chitosan solution in a certain proportion and stir evenly to obtain the mixed material and mature it for 2-5 hours;

Step 5: Compress the mixed material matured in Step 3, then place it in a cool and ventilated place for 4-6 hours, then dry it at 100°C-105°C for 1-2h, and obtain the coke after cooling.

Compared with the prior art, the present invention has at least the following beneficial effects:

1. The present invention uses biomass sunflower stalk hydrolysis residue as the main component of the coke binder, and supplementarily adds bentonite, sodium humate and chitosan solution as the functional binder. Among them, the hydrolysis residue of sunflower stalks has high volatile content and strong cohesiveness, which can improve the cold strength and combustion performance of the coke, sodium humate can improve the cold strength of the coke, and bentonite can improve the thermal strength and thermal strength of the coke. Stability, chitosan solution has strong cohesiveness, which can significantly improve the cold strength of coke. The synergy between the various components makes the prepared coke have better cold strength, hot strength and combustion performance.

2. The present invention prepares molded coke through the synergistic cooperation between sunflower stalk hydrolysis residue, bentonite, sodium humate and chitosan solution components, wherein biomass sunflower stalks hardly increase the ash content of molded coke, while bentonite, carboxymethyl fiber The added amount of plain sodium and chitosan is small, so the raw material cost is low, and the ash content increase of the prepared coke is small.

3. The present invention uses biomass to form semi-coke, and the coke produced has good combustion performance, low ignition point, no slagging, and no black heart problem. It can combine China's limited coal resources with a large number of waste such as straw and trees in rural areas , to realize the efficient and clean utilization of coal, especially low-rank coal, and the resource and energy utilization of agricultural and forestry waste biomass.

4. The molded coke of the present invention has the characteristics of low production cost, simple preparation method, non-toxic, and environmental protection.

The form coke prepared by the invention has excellent properties such as good thermal stability, high temperature resistance, high mechanical strength and the like. After the coke is dried and cooled, the measured cold compressive strength is greater than 600N/ball, and the drop strength is greater than 95%. It has good thermal stability and will not loosen at high temperatures above 1100°C.

Detailed ways

The technical solutions of the present invention will be described in further detail below through examples.

Example 1

Prepare the compound type biomass briquette binder of this embodiment according to the following methods:

Step 1. In terms of parts by mass, dry 50 parts of semi-coke and 15 parts of biomass sunflower stalks and grind them to less than 3mm, mix the saturated calcium hydroxide solution with the pulverized biomass sunflower stalks, and perform hydrolysis under stirring conditions , the sunflower stalk hydrolysis residue was obtained after pressure filtration, and the water content of the hydrolysis residue was 35%; the hydrolysis conditions were that the mass ratio of sunflower stalk to Ca(OH) ₂ saturated solution was 1:10, the hydrolysis temperature was 70°C, and the hydrolysis time was 3h ;

Step 2, 0.01 part of industrial flaky chitosan is dissolved in 3 parts of 0.08mol/L acetic acid solution at 80° C. to make a chitosan solution;

Step 3: Mix 1 part of bentonite, 3 parts of sodium carboxymethylcellulose and 1 part of chitosan solution with the semi-coke powder and sunflower stalk hydrolysis residue (wet residue) obtained in step 1, stir evenly, and mature for 3 hours , to obtain a slaking mixture with a water content of 12%.

Step 4: Compress the matured mixture to a pressure of 20 MPa, hold the pressure for 30 seconds, then place the coke in a cool and ventilated place for 6 hours, then dry it at 100°C for 1 hour, and obtain the coke after cooling.

Example 2

Prepare the compound type biomass briquette binder of this embodiment according to the following methods:

Step 1. In terms of parts by mass, dry 45 parts of semi-coke and 5 parts of biomass sunflower stalks and pulverize them to less than 3mm respectively, mix saturated calcium hydroxide solution with the pulverized biomass sunflower stalks, and perform hydrolysis under stirring conditions , the sunflower stalk hydrolysis residue was obtained after pressure filtration, the water content of the hydrolysis residue was 40%; the hydrolysis conditions were that the mass ratio of sunflower stalk to Ca(OH) ₂ saturated solution was 1:8, the hydrolysis temperature was 90°C, and the hydrolysis time was 5h ;

Step 2, 0.04 part of industrial flaky chitosan is dissolved in 4 parts of 0.12mol/L acetic acid solution at 80 DEG C to make chitosan solution;

Step 3: Mix 3 parts of bentonite, 1 part of sodium carboxymethyl cellulose and 4 parts of chitosan solution with the semi-coke powder and sunflower stalk hydrolysis residue (wet residue) obtained by crushing in step 1, stir evenly, and mature for 2 hours , to obtain a slaking mixture with a water content of 10%.

Step 4: Compress the matured mixture to a pressure of 35 MPa, hold the pressure for 50 seconds, then place the coke in a cool and ventilated place for 4 hours, then dry it at 105°C for 2 hours, and obtain the coke after cooling.

Example 3

Prepare the compound type biomass briquette binder of this embodiment according to the following methods:

Step 1. In terms of parts by mass, dry 55 parts of semi-coke and 12.5 parts of biomass sunflower stalks and grind them to less than 3mm respectively, mix the saturated calcium hydroxide solution with the pulverized biomass sunflower stalks, and perform hydrolysis under stirring conditions , the sunflower stalk hydrolysis residue was obtained after pressure filtration, and the water content of the hydrolysis residue was 40%; the hydrolysis conditions were that the mass ratio of sunflower stalk to Ca(OH) ₂ saturated solution was 1:12, the hydrolysis temperature was 100°C, and the hydrolysis time was 2h ;

Step 2, 0.03 part of chitosan is dissolved in 1 part of 0.1mol/L acetic acid solution at 80 DEG C to make chitosan solution;

Step 3: Mix 2.5 parts of bentonite, 2.5 parts of sodium carboxymethylcellulose and 3 parts of chitosan solution with the semi-coke powder and sunflower stalk hydrolysis residue (wet residue) pulverized in step 1, stir evenly, and ripen for 5 hours , to obtain a slaking mixture with a water content of 15%.

Step 4: Compress the matured mixture to a pressure of 30 MPa, hold the pressure for 60 seconds, then place the form coke in a cool and ventilated place for 5 hours, then dry it at 103°C for 1.5 hours, and obtain the form coke after cooling.

The molded coke prepared by the invention has excellent characteristics such as good thermal stability, high temperature resistance, high mechanical strength and the like. After the coke is dried and cooled, the measured cold compressive strength is greater than 600N/ball, and the drop strength is greater than 95%. It has good thermal stability and will not loosen at high temperatures above 1100°C.

Claims (8)

1. A form coke based on a composite biomass binder, characterized in that it comprises the raw materials of the following mass parts: 45-55 parts of semi-coke, 5-15 parts of biomass, 1-3 parts of bentonite, carboxymethyl 1-3 parts of sodium cellulose and 1-4 parts of chitosan solution. 2. a kind of form coke based on composite biomass binder according to claim 1, is characterized in that, biomass is the residue that sunflower stalk is hydrolyzed in _Ca (OH) saturated solution, then obtains through pressure filtration . 3 . The molded coke based on a composite biomass binder according to claim 1 , wherein the semi-coke is a semi-coke obtained by medium-low metamorphic degree coal by medium-low temperature pyrolysis. 4 . 4. a kind of coke based on composite biomass binder according to claim 1, is characterized in that, chitosan solution is dissolved in 1- Viscous liquid formed in 4 parts of 0.08-0.12mol/L acetic acid solution. 5. A form coke based on a composite biomass binder according to claim 2, characterized in that the water content of the residue obtained by pressure filtration is 30-40%. 6. A method for preparing coke based on composite biomass binder, characterized in that, comprising the following steps: Step 1: Dried the sunflower stalks and crushed them to less than 3mm, mixed the sunflower stalks with saturated Ca(OH) ₂ solution at a mass ratio of 1:8-1:12, hydrolyzed at 70-100°C for 2-5 hours under stirring, and pressed After filtering, the hydrolyzed residue of sunflower stalks was obtained; Step 2: Pulverize the semi-coke, the particle size of which is not greater than 3mm after pulverization; Step 3: Industrial flaky chitosan is dissolved in an acetic acid solution with a concentration of 0.08-0.12mol/L at 80°C to prepare a chitosan solution; Step 4: In parts by mass, mix 5-15 parts of sunflower stalk hydrolysis residue, 1-3 parts of bentonite, 1-3 parts of sodium carboxymethyl cellulose, and 1-4 parts of chitosan solution prepared in step 3 with In step 2, 45-55 parts of semi-coke pulverized are mixed, stirred evenly to obtain a mixed material, and matured for 2-5 hours to obtain a matured mixture; Step 5: Compress the matured mixture obtained in Step 4 to a pressure of 20-35MPa, hold the pressure for 30-60s, then place it in a cool and ventilated place for 4-6 hours, and then dry it at 100°C-105°C for 1-2h. Form coke is obtained after cooling. 7. A method for preparing coke based on composite biomass binder according to claim 6, characterized in that the water content of the mixed material in step 4 is 12-15%. 8. A kind of preparation method based on composite biomass binder type coke according to claim 6, it is characterized in that, in described step 3, by mass parts, 0.01-0.04 part of industrial flake chitosan , 1-4 parts of acetic acid solution.