Method for producing clean formed coke based on lignin transition state binder

Abstract

A method for producing clean formed coke based on a lignin transition state binder. The method is to select bauxite, silica and coal liquefaction residue, crush them respectively, then add lignin, hydrated lime and pregelatinized starch, stir and mix evenly, and then carry out dry grinding to obtain the lignin transition state binder; select blended coal, mix it evenly according to the ratio of the blended coal to the lignin transition state binder, cold press it into shape, carry out dry distillation in a vertical dry distillation furnace, and then after the red-hot furnace charge is discharged from the furnace, it is cooled to room temperature through the coke quenching process, and then the clean formed coke is obtained; the raw materials of the present invention are wide and rich in source, low in price, and have the functions of both cold and hot state binders, and play a binding function before the cold state binder fails and the hot state binder comes into play during the pyrolysis process, ensuring the forming rate and the strength of the formed coke in the dry distillation furnace.

Description

Technical Field

[0001] The present invention relates to a method for preparing clean formed coke, in particular to a method for producing clean formed coke based on a lignin transition state binder. Background Art

[0002] China's special primary energy endowment of rich coal, poor oil and less gas determines that coal combustion is the main way to obtain energy in China at present and for a quite long time in the future. However, the direct combustion of a large amount of coal emits dust, sulfur dioxide, nitrogen oxides, etc., which cause serious harm to the atmospheric environment, resulting in serious atmospheric environmental pollution in China and frequent haze weather. According to statistics, the amount of coal used for civil scattered combustion in China in 2014 was 160 million tons, accounting for only 3.8% of the total coal consumption in the country. Taking sulfur dioxide emissions as an example, the annual emissions of power plants in China are 2 million tons, while the emissions from civil scattered combustion are as high as 3.2 million tons, which is 1.6 times the total emissions of power plants. In addition, a series of problems such as soot pollution, nitrogen oxide pollution, and ash residue pollution caused by civil scattered combustion of coal have an immeasurable impact on the ecological environment. However, due to the influence of factors such as region, economy, and culture, it is very difficult to solve. To fundamentally solve the coal combustion pollution problem in rural areas and small towns, it is urgent to provide high-quality, low-cost, and clean alternative fuels for these areas.

[0003] Moreover, the thermal coal used as fuel is mainly low-rank coal. With the improvement of the degree of coal mining mechanization, the proportion of slack coal in the mining process is increasing, and more and more attention is paid to the efficient utilization of slack coal.

[0004] Clean formed coke is a clean solid fuel mainly made of low-rank slack coal, supplemented with a small amount of sulfur-fixing agent, combustion aid, binder, etc. Using the existing production equipment of semi-coke plants, it is obtained through medium-temperature dry distillation after pre-forming. It has the advantages of high forming rate, good strength, low volatility, low sulfur emission, and not easy to slag. Without desulfurization facilities, the tail gas can meet the national emission standards; moreover, it is easy to ignite, has strong afterburning ability, fast heating rate, and long combustion duration, and is an ideal fuel for various civil household stoves.

[0005] There are relatively few patents on the method of briquetting and dry distillation of pulverized coal at present. For example, in the patent with the publication number CN106635217A, coal liquefaction residue is used as its cold and hot state binder and directly mixed with pulverized coal for briquetting and then dry distillation; in the patent with the publication number CN106701133A, asphalt and tar residue are used as binders and mixed with pulverized coal for dry distillation to obtain formed coke; in the patent with the publication number CN106753496A, tar residue is used as the basic binder and supplemented with corn flour and inorganic magnesium salt for briquetting and then dry distillation; in the patent with the publication number CN106929063A, waste heavy coal tar pitch, tar residue and polyaluminum ferric chloride are mixed and heated to soften, and then dolomite powder is added to obtain a binder, which is mixed with pulverized coal, first cold pressed into formed coal, and then dry distilled to obtain formed coke. The binders used in the patent formulas for preparing formed coke mainly play a role in the cold state binder during the cold forming process below 200°C and the hot state binder during the dry distillation process above 400°C. However, during the actual dry distillation process, there is a stage where the cold state binder fails and the hot state binder does not work between 200-400°C. Due to the lack of the use of a transition state binder in this temperature range, the problem of high breakage rate of formed coke during the dry distillation process occurs.

[0006] After retrieval, there is no report on the lignin transition state binder used for producing clean formed coke. Summary of the Invention

[0007] Based on the above prior art, the specific technical problem to be solved by the present invention is the problem of high breakage rate of formed coke during the dry distillation process due to the failure of the cold state binder and the non-function of the hot state binder between 200-400°C, and to provide a method for producing clean formed coke based on the lignin transition state binder.

[0008] The present invention uses lignin, coal direct liquefaction residue, slaked lime and starch in combination for producing clean formed coke. Its function is mainly manifested in having the triple functions of cold state, hot state and transition state binders. The traditional formed coke binder only considers the cold and hot state binders, and does not consider the transition time when the cold state starch binder fails and the hot state binder does not take effect in the temperature range of 200-400°C during the dry distillation of the formed coke after the fine coal is formed. This is the stage when the formed coke is most likely to break. The innovation of the present invention lies in providing a lignin transition state binder for pre-forming fine coal to produce clean formed coke, which can act in the temperature range of 200-400°C. Lignin contains a variety of active functional groups and has good dispersion, penetration, absorption and bonding properties, and its intermolecular long chain structure is intertwined with each other, which can improve the bonding strength of the pulverized coal, thus avoiding the breakage of the clean formed coke caused by the pressure and its own expansion or compression during the forming process at this temperature stage.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions.

[0010] A method for producing clean formed coke based on a lignin transition state binder, characterized in that the preparation method is carried out according to the following steps:

[0011] ⑴ Select the raw material composition and its quality indexes of the lignin transition state binder as lignin: purity ≥ 55 wt%, bauxite Al2O3 ≥ 54 wt%, silica SiO2 ≥ 96 wt%, pregelatinized starch: viscosity ≥ 600 mPa·s, hydrated lime: CaO + MgO ≥ 60 wt%, and coal liquefaction residue: residual oil + asphaltene ≥ 60 wt%;

[0012] ⑵ Crush the raw materials of the lignin transition state binder, namely bauxite, silica and coal liquefaction residue, to a particle size ≤ 3 mm respectively, and reserve lignin, hydrated lime and pregelatinized starch;

[0013] ⑶ Weigh 10 - 20 parts of crushed bauxite, 5 - 10 parts of silica and 50 - 60 parts of coal liquefaction residue by weight respectively, and also weigh 20 - 30 parts of lignin, 10 - 20 parts of hydrated lime and 10 - 20 parts of pregelatinized starch, and mix them together in sequence and stir to mix evenly;

[0014] ⑷ Grind the mixture dryly so that the particle size of the raw materials ≤ 100 mesh, and thus obtain the lignin transition state binder;

[0015] ⑸ Select slack coal as the blended coal, and its quality indexes are: dry ash - free basis volatile matter V daf ≥ 25%, dry - basis ash content A d ≤ 15%, dry - basis fixed carbon FC d ≥ 55%, dry - basis total sulfur S t,d < 1.5%;

[0016] ⑹ The weight ratio of the lignin transition state binder to the blended coal is 10 - 30∶100. Crush the blended coal to - 3 mm and then mix it evenly with the lignin transition state binder. First, carry out cold pressing and shaping, select the shaping pressure of 10 - 15 MPa, and under this shaping pressure, the briquette strength meets > 800 N / ball. Then, subject the prepared briquette to dry distillation in an upright dry distillation furnace at a temperature of 600 - 900 °C for 2 - 4 h. Then, take out the red - hot furnace charge and cool it to room temperature through the coke quenching process, and thus obtain the clean formed coke.

[0017] Among them, the strength indexes of the clean formed coke are: compressive strength 800 N / ball - 2000 N / ball, forming rate > 80%, and fines rate < 10%.

[0018] Implementing the technical solution of the method for producing clean formed coke based on lignin transition state binder provided by the present invention, compared with the prior art, its advantages and positive effects are that the lignin transition state binder used in this method has a wide and rich raw material source and a low price. It has the functions of both cold and hot state binders, and plays a binding role before the cold state binder fails and the hot state binder takes effect during the pyrolysis process, ensuring the forming rate and formed coke strength of the material in the retort furnace.

[0019] The present invention realizes the efficient utilization of low-rank fine coal and improves the utilization value of fine coal. Specific embodiments

[0020] The following further describes the specific embodiments of the present invention.

[0021] Example 1

[0022] Implementing the technical solution of the method for producing clean formed coke based on lignin transition state binder provided by the present invention, in specific implementation, it should be carried out according to the following steps:

[0023] (1) Select the raw material composition and its quality indexes of the lignin transition state binder as lignin: purity 90 wt%, bauxite Al2O3 73 wt%, silica SiO2 96 wt%, pregelatinized starch: viscosity 1000 mPa·s, hydrated lime: CaO + MgO 60 wt%, and coal liquefaction residue: residual oil + asphaltene 80 wt%;

[0024] (2) Crush the raw materials of the lignin transition state binder, namely bauxite, silica and coal liquefaction residue, to a particle size ≤ 3 mm respectively, and reserve lignin, hydrated lime and pregelatinized starch;

[0025] (3) Weigh 10 kg of crushed bauxite, 20 kg of silica and 50 kg of coal liquefaction residue by weight respectively, and also weigh 20 kg of lignin, 20 kg of hydrated lime and 10 kg of pregelatinized starch, and mix them together in sequence and stir to mix evenly;

[0026] (4) Grind the mixture dryly to make the raw material particle size ≤ 100 mesh; thus, the lignin transition state binder is obtained;

[0027] (5) The fine coal charged into the furnace is blended coal, and its quality indexes are: dry ash-free basis volatile matter V daf 30.0 wt%, dry basis ash content A d 13.5 wt%, dry basis fixed carbon FC d 59.1 wt%, dry basis total sulfur S t,d 1.46 wt%;

[0028] ⑹ The weight ratio of the lignin transition binder to the blended coal is 10:100. The blended coal is crushed to -3 mm and then evenly mixed with the lignin transition binder. First, it is cold-pressed into shape, and the forming pressure is selected as 15 MPa. The briquettes obtained are then carbonized in an upright retort furnace at a temperature of 900 °C for 2 hours. Then, the red-hot furnace charge is taken out of the furnace and cooled to room temperature through the coke quenching process, and clean formed coke is obtained.

[0029] Comparative Example 1

[0030] The furnace charge uses the same blended coal without adding the lignin transition binder. The blended coal is crushed to -3 mm and then evenly mixed with the binder. First, it is cold-pressed into shape, and the forming pressure is selected as 15 MPa. The briquettes obtained are then carbonized in an upright retort furnace at a temperature of 900 °C for 2 hours. Then, the red-hot furnace charge is taken out of the furnace and cooled to room temperature through the coke quenching process, and the control coke is obtained.

[0031] The compressive strength, forming rate, and fines rate of the obtained clean formed coke and the control coke are measured respectively using a Jinan Zhonglu Chang YAW-300D type strength tester and a Xinxiang Chenwei YBS-1000 type screening instrument. The test results are shown in Table 1 below.

[0032] Table 1 Comparison of compressive strength, forming rate, and fines rate

[0033] Sample Compressive strength (N / ball) Forming rate / % Powder rate / % Control coke 650 70.5 18.6 Clean coke with added transition binder 860 81.3 9.8

[0034] Example 2

[0035] Implement the technical solution of a method for clean formed coke based on a lignin transition binder provided above in the present invention. When specifically implementing, the following steps should be carried out:

[0036] ⑴ Select the raw material composition and quality indexes of the lignin transition binder as follows: lignin: purity 82 wt%, bauxite Al2O3 69 wt%, silica SiO2 96.6 wt%, pregelatinized starch: viscosity 900 mPa·s, slaked lime: CaO + MgO 62.5 wt%, and coal liquefaction residue: residual oil + asphaltene 75 wt%;

[0037] ⑵ The raw materials of the lignin transition binder, namely bauxite, silica, and coal liquefaction residue, are respectively crushed to a particle size of ≤3 mm, and lignin, slaked lime, and pregelatinized starch are reserved;

[0038] ⑶ Weigh 9 kg of crushed bauxite, 16 kg of silica, and 52.5 kg of coal liquefaction residue by weight respectively, and also weigh 22.5 kg of lignin, 17.5 kg of slaked lime, and 12.5 kg of pregelatinized starch. Then, mix them together in sequence and stir evenly;

[0039] ⑷The mixture is further ground dry to make the particle size of the raw materials ≤ 100 mesh, and thus the lignin transition binder is obtained.

[0040] ⑸The fine coal charged into the furnace is blended coal, and its quality indexes are as follows: volatile matter V on dry ash-free basis daf 29.0 wt%, ash content A on dry basis d 12.4 wt%, fixed carbon FC on dry basis d 61.2 wt%, total sulfur S on dry basis t,d 0.97 wt%.

[0041] ⑹The weight ratio of the lignin transition binder to the blended coal is 15:100. The blended coal is crushed to -3 mm and then mixed evenly with the lignin transition binder. First, it is cold-pressed into briquettes, and the forming pressure is selected as 14 MPa. The prepared briquettes are carbonized in an upright retort furnace at a temperature of 850 °C for 2.5 h. Then, the red-hot furnace charge is taken out of the furnace and cooled to room temperature through the coke quenching process, and thus clean formed coke is obtained.

[0042] Comparative Example 2

[0043] The coal charge charged into the furnace uses the same blended coal without adding the lignin transition binder. The blended coal is crushed to -3 mm and then mixed evenly with the binder. First, it is cold-pressed into briquettes, and the forming pressure is selected as 14 MPa. The prepared briquettes are carbonized in an upright retort furnace at a temperature of 850 °C for 2.5 h. Then, the red-hot furnace charge is taken out of the furnace and cooled to room temperature through the coke quenching process, and thus the control coke is obtained.

[0044] The compressive strength, forming rate and fines rate indexes of the obtained clean formed coke and the control coke are measured respectively by a Jinan Zhonglu Chang YAW-300D type strength tester and a Xinxiang Chenwei YBS-1000 type screening instrument. The test results are shown in Table 2 below.

[0045] Table 2 Comparison of compressive strength, forming rate and fines rate indexes

[0046] Sample Compressive strength (N / ball) Forming rate / % Powder rate / % Control coke 745 72.2 17.5 Clean coke with added transition binder 950 84.7 8.3

[0047] Example 3

[0048] To implement the technical solution of a method for clean formed coke based on a lignin transition binder provided by the present invention above, in specific implementation, the following steps should be carried out:

[0049] ⑴Select the raw material composition and its quality indexes of the lignin transition binder as follows: lignin: purity 73 wt%, bauxite Al2O3 64 wt%, silica SiO2 97.2 wt%, pregelatinized starch: viscosity 800 mPa·s, hydrated lime: CaO + MgO 65 wt%, and coal liquefaction residue: residual oil + asphaltene 70 wt%.

[0050] ⑵Crush the raw materials of the lignin transition binder, namely bauxite, silica and coal liquefaction residue, to a particle size of ≤3 mm respectively, and reserve the lignin, hydrated lime and pregelatinized starch.

[0051] ⑶Weigh 8 kg of crushed bauxite, 12 kg of silica and 55 kg of coal liquefaction residue respectively by weight, and also weigh 25 kg of lignin, 15 kg of hydrated lime and 15 kg of pregelatinized starch. Mix them together in sequence and stir to mix evenly.

[0052] ⑷Further grind the mixture dryly to make the particle size of the raw materials ≤100 mesh, thus obtaining the lignin transition binder.

[0053] ⑸The end coal fed into the furnace is blended coal, and its quality indexes are as follows: volatile matter V on dry ash-free basis daf 32.0 wt%, ash content A on dry basis d 11.7 wt%, fixed carbon FC on dry basis d 59.2 wt%, total sulfur S on dry basis t,d 0.84 wt%.

[0054] ⑹The weight ratio of the lignin transition binder to the blended coal is 20∶100. Crush the blended coal to -3 mm and mix it evenly with the lignin transition binder. First, carry out cold pressing molding with the molding pressure selected as 13 MPa. For the briquettes obtained, carry out dry distillation in an upright dry distillation furnace at a temperature of 800 °C for 3 h. Then, after the red-hot furnace charge is taken out of the furnace, it is cooled to room temperature through the coke quenching process, thus obtaining clean formed coke.

[0055] Comparative Example 3

[0056] Use the same blended coal for the coal charge fed into the furnace, without adding the lignin transition binder. After crushing the blended coal to -3 mm, mix it evenly with the binder. First, carry out cold pressing molding with the molding pressure selected as 13 MPa. For the briquettes obtained, carry out dry distillation in an upright dry distillation furnace at a temperature of 800 °C for 3 h. Then, after the red-hot furnace charge is taken out of the furnace, it is cooled to room temperature through the coke quenching process, thus obtaining the reference coke.

[0057] Measure the compressive strength, forming rate and fines rate indexes of the obtained clean formed coke and the reference coke respectively in the Jinan Zhonglu Chang YAW-300D type strength tester and the Xinxiang Chenwei YBS-1000 type screening instrument. The test results are shown in Table 3 below.

[0058] Table 3 Comparison of compressive strength, forming rate and fines rate indexes

[0059] Sample Compressive strength (N / ball) Forming rate / % Powder rate / % Control coke 810 76.5 15.3 Clean coke with added transition binder 1120 88.9 7.6

[0060] Example 4

[0061] To implement the technical solution of the method for clean coke based on lignin transition binder provided by the present invention, in specific implementation, the following steps should be carried out:

[0062] ⑴ Select the raw material composition and quality indexes of the lignin transition binder as follows: lignin: purity 64 wt%, bauxite Al2O3 59 wt%, silica SiO2 97.8 wt%, pregelatinized starch: viscosity 700 mPa·s, hydrated lime: CaO + MgO 67.5 wt%, and coal liquefaction residue: residual oil + asphaltene 65 wt%;

[0063] ⑵ Crush the raw materials of the lignin transition binder, namely bauxite, silica and coal liquefaction residue, to a particle size of ≤ 3 mm respectively, and reserve lignin, hydrated lime and pregelatinized starch;

[0064] ⑶ Weigh 7 kg of crushed bauxite, 8 kg of silica and 57.5 kg of coal liquefaction residue by weight respectively, and also weigh 27.5 kg of lignin, 12.5 kg of hydrated lime and 17.5 kg of pregelatinized starch, and mix them together in sequence and stir to mix evenly;

[0065] ⑷ Grind the mixture dryly to make the particle size of the raw materials ≤ 100 mesh; thus, the lignin transition binder is obtained;

[0066] ⑸ The end coal charged into the furnace is blended coal, and its quality indexes are: dry ash-free basis volatile matter V daf 25.0 wt%, dry basis ash content A d 14.1 wt%, dry basis fixed carbon FC d 63.2 wt%, dry basis total sulfur S t,d 1.23 wt%;

[0067] ⑹ The weight ratio of the lignin transition binder to the blended coal is 25∶100. Crush the blended coal to -3 mm and mix it evenly with the lignin transition binder. First, carry out cold pressing molding, and select the molding pressure of 12 MPa. The briquettes obtained are coked in an upright retort furnace at a temperature of 700 °C for 3.5 h. Then, after the red-hot furnace charge is taken out of the furnace, it is cooled to room temperature through the coke quenching process, and thus clean coke is obtained.

[0068] Comparative Example 4

[0069] Use the same blended coal for the coal charge into the furnace, without adding the lignin transition binder. Crush the blended coal to -3 mm and mix it evenly with the binder. First, carry out cold pressing molding, and select the molding pressure of 12 MPa. The briquettes obtained are coked in an upright retort furnace at a temperature of 700 °C for 3.5 h. Then, after the red-hot furnace charge is taken out of the furnace, it is cooled to room temperature through the coke quenching process, and thus the control coke is obtained.

[0070] The compressive strength, forming rate and fines rate of the obtained clean formed coke and the control coke were measured using the Chang YAW-300D strength tester in Jinan Middle Road and the Xinxiang Chenwei YBS-1000 sieving instrument respectively. The test results are shown in Table 4 below.

[0071] Table 4 Comparison of compressive strength, forming rate and fines rate

[0072] Sample Compressive strength (N / ball) Forming rate / % Powder rate / % Control coke 805 75.2 15.8 Clean coke with added transition binder 1030 86.8 8.1

[0073] Example 5

[0074] To implement the technical solution of the method for producing clean formed coke based on lignin transition state binder provided above in the present invention, the following steps should be carried out during specific implementation:

[0075] ⑴ Select the raw material composition and its quality indexes of the lignin transition state binder as follows: lignin: purity 55 wt%, bauxite Al2O3 54 wt%, silica SiO2 98.5 wt%, pregelatinized starch: viscosity 600 mPa·s, hydrated lime: CaO + MgO 70 wt%, and coal liquefaction residue: residual oil + asphaltene 60 wt%;

[0076] ⑵ Crush the raw materials of the lignin transition state binder, namely bauxite, silica and coal liquefaction residue, to a particle size of ≤ 3 mm respectively, and reserve lignin, hydrated lime and pregelatinized starch;

[0077] ⑶ Weigh 5 kg of crushed bauxite, 5 kg of silica and 60 kg of coal liquefaction residue respectively by weight, and also weigh 30 kg of lignin, 10 kg of hydrated lime and 20 kg of pregelatinized starch. Then mix them together in sequence and stir to mix evenly;

[0078] ⑷ Grind the mixture dryly to make the particle size of the raw materials ≤ 100 mesh; thus, the lignin transition state binder is obtained;

[0079] ⑸ The pulverized coal fed into the furnace is blended coal, and its quality indexes are: dry ash-free basis volatile matter V daf 34.0 wt%, dry basis ash content A d 15.0 wt%, dry basis fixed carbon FC d 55.4 wt%, dry basis total sulfur S t,d 0.70 wt%;

[0080] ⑹ The weight ratio of the lignin transition state binder to the blended coal is 30∶100. Crush the blended coal to -3 mm and mix it evenly with the lignin transition state binder. First, carry out cold pressing molding with a molding pressure of 10 MPa. Then, subject the formed coal to dry distillation in an upright dry distillation furnace at a temperature of 600 °C for 4 h. After that, take out the red-hot furnace charge and cool it to room temperature through the coke quenching process to obtain the clean formed coke.

[0081] Comparative Example 5

[0082] The blended coal used for the coal charged into the furnace is the same, without adding the lignin transition binder. The blended coal is crushed to -3 mm and then mixed evenly with the binder. First, it is cold-pressed into briquettes, and the forming pressure is selected as 10 MPa. The obtained briquettes are carbonized in an upright carbonization furnace at a temperature of 600 °C for 4 h. Then, the red-hot furnace charge is taken out of the furnace and cooled to room temperature through the coke quenching process to obtain the reference coke.

[0083] In the Chang YAW-300D type strength tester in Jinan Middle Road and the Xinxiang Chenwei YBS-1000 type screening instrument

[0084] The compressive strength, forming rate and fines rate indexes of the obtained clean briquette coke and the reference coke are measured respectively, and the test results are shown in Table 5 below.

[0085] Table 5 Comparison of compressive strength, forming rate and fines rate indexes

[0086] Sample Compressive strength (N / ball) >30mm <10mm Control coke 780 74.6 16.3 Clean coke with added transition binder 940 83.5 8.6

Claims

1. A method for producing clean formed coke based on a lignin transition state binder, characterized in that: The method for producing clean formed coke is carried out according to the following steps: ⑴ Select the raw material composition and its quality indexes of the lignin transition binder as follows: lignin: purity ≥ 55 wt%, bauxite Al2O3 ≥ 54 wt%, silica SiO2 ≥ 96 wt%, pregelatinized starch: viscosity ≥ 600 mPa·s, hydrated lime: CaO + MgO ≥ 60 wt%, and coal liquefaction residue: residual oil + asphaltene ≥ 60 wt%; ⑵ Crush the raw materials of the lignin transition binder, namely bauxite, silica, and coal liquefaction residue, to a particle size of ≤ 3 mm respectively, and reserve lignin, hydrated lime, and pregelatinized starch; ⑶ Weigh 10 - 20 parts by weight of the crushed bauxite, 5 - 10 parts by weight of silica, and 50 - 60 parts by weight of coal liquefaction residue respectively, and also weigh 20 - 30 parts by weight of lignin, 10 - 20 parts by weight of hydrated lime, and 10 - 20 parts by weight of pregelatinized starch. Then mix them together in sequence and stir to mix evenly; ⑷ Grind the mixture dryly to make the particle size of the raw materials ≤ 100 mesh, thus obtaining the lignin transition binder; ⑸ Select the clean coal as the blended coal, and its quality indexes are: volatile matter on dry ash-free basis V daf ≥25%, ash content on dry basis A d ≤15%, fixed carbon on dry basis FC d ≥55%, total sulfur on dry basis S t,d <1.5%; ⑹ The weight ratio of the lignin transition binder to the blended coal is 10 - 30∶100. Crush the blended coal to - 3 mm and then mix it evenly with the lignin transition binder. First, carry out cold pressing molding, and select the molding pressure of 10 - 15 MPa. Under this molding pressure, the briquette strength meets > 800 N / ball. Heat the obtained briquette in an upright retort furnace at a temperature of 600 - 900 °C for 2 - 4 h of dry distillation. Then, after the red - hot furnace charge is taken out of the furnace, it is cooled to room temperature through the coke quenching process, thus obtaining clean formed coke.