A kind of calcium carbonate coal powder high pressure forming carbonized pellets and calcium carbide and preparation method thereof

Abstract

The invention discloses a calcium carbonate coal powder high pressure forming carbonized pellet and calcium carbide and a preparation method thereof, belonging to the technical field of calcium coal pelletization, and solves the problems of low raw material utilization rate in the existing calcium carbide preparation process and low pellet strength obtained by the existing pellet preparation method. Its preparation method comprises the following steps: grinding calcium carbonate and raw coal, then adding a binder for compression molding, and finally pyrolysis carbonization to obtain. The present invention eliminates the process links of pyrolysis of blue charcoal furnace to generate semi-coke and lime kiln calcining limestone in the traditional calcium carbide production process, combines the two into one, saves construction investment, reduces carbon dioxide emissions, reduces pollution, and reduces energy consumption by 10%-15%; expands the scope of use of raw materials, improves the utilization rate of raw materials, and reduces raw material costs by 10%-20%; effectively improves the room temperature and high temperature compressive strength of the obtained carbonized pellets to meet the needs of subsequent calcium carbide furnaces for calcium carbide processing.

Description

Technical Field

[0001] The invention relates to the technical field of calcium carbonate coal pellets, and in particular to calcium carbonate coal powder high pressure formed carbonized pellets and calcium carbide and preparation methods thereof. Background Art

[0002] Calcium carbide is a widely used chemical raw material, mainly used in the production of polymer materials such as ethylene and polyethylene, as well as the preparation of metallic calcium compounds such as calcium oxide and heavy calcium. With the development of social economy, the demand for calcium carbide market is also growing.

[0003] The initial raw materials for traditional calcium carbide production are limestone and raw coal. First, after the limestone block is calcined into calcium oxide, the low-rank coal is pyrolyzed in the blue charcoal furnace to become semi-coke (blue charcoal), coal tar and coal gas; then the calcium oxide and blue charcoal react chemically at high temperature in the calcium carbide furnace to produce calcium carbide. The production process is relatively long and requires supporting facilities such as lime kilns, blue charcoal furnaces and calcium carbide furnaces. In the production process, since the calcination of the lime kiln and the production of the blue charcoal furnace require block raw materials, powdered calcium carbonate, powdered raw coal, powdered calcium oxide and powdered blue charcoal are all wasted because they are not fully utilized. There are reports of a method of reprocessing powdered raw materials into block raw materials and then preparing pellets, but this kind of pellets are not conducive to entering the calcium carbide furnace for calcium carbide production due to their poor strength. Therefore, how to make full use of a large amount of powdered calcium carbonate and powdered coal, overcome the problem that powdered calcium oxide and powdered blue charcoal cannot be used in the calcium carbide furnace, expand the scope of raw material use, and improve the utilization rate of raw materials is one of the key issues to be solved in this field. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a calcium carbonate coal powder high-pressure formed carbonized pellet and calcium carbide and a preparation method thereof, so as to solve the problems of low raw material utilization rate, low energy utilization efficiency and low strength of pellets obtained by the existing pellet preparation method in the existing calcium carbide preparation process.

[0005] In order to achieve the above object, an object of the present invention is to provide a method for preparing calcium carbonate coal powder high pressure forming carbonized pellets, comprising the following steps:

[0006] The calcium carbonate and raw coal are ground into powder, then a binder is added to press them into shape, and finally pyrolysis and carbonization are performed to obtain the product.

[0007] Furthermore, the raw coal is long flame coal; after the calcium carbonate is ground, the calcium carbonate with a particle size of 0.5-1 mm accounts for 65%-70% of the total mass of the calcium carbonate, the calcium carbonate with a particle size of 0.3-0.5 mm accounts for 15%-20% of the total mass of the calcium carbonate, and the calcium carbonate with a particle size less than 0.3 mm accounts for 10%-15% of the total mass of the calcium carbonate.

[0008] Furthermore, after the grinding process, the raw coal with a particle size of 0.5-1 mm accounts for 60%-70% of the total mass of the raw coal, the raw coal with a particle size of 0.3-0.5 mm accounts for 15%-20% of the total mass of the raw coal, and the raw coal with a particle size less than 0.3 mm accounts for 15%-20% of the total mass of the raw coal.

[0009] Furthermore, the mass ratio of calcium carbonate to raw coal is 55-65:35-45; the mass of the binder is 1%-4% of the total mass of calcium carbonate and raw coal.

[0010] Preferably, the mass ratio of calcium carbonate to raw coal is 60:40; and the mass fraction of the binder is 2% of the total mass of calcium carbonate and raw coal.

[0011] Furthermore, the binder is prepared by mixing an organic binder and an inorganic binder in a mass ratio of 60-80:20-40.

[0012] Preferably, the binder is prepared by mixing an organic binder and an inorganic binder in a mass ratio of 70:30.

[0013] Furthermore, the organic binder is at least one of polyvinyl alcohol, polyethylene glycol and sodium humate, and the inorganic binder is at least one of saponified clay, borax and water glass.

[0014] Furthermore, the pyrolysis carbonization conditions are: first treating at 30-200 °C for 60-120 min, then treating at 200-550 °C for 150-210 min, then treating at 550-750 °C for 60-120 min, and finally treating at 750-950 °C for 30-90 min.

[0015] The second object of the present invention is to provide a calcium carbonate coal powder high pressure formed carbonized pellets, which are prepared by the above preparation method.

[0016] The third object of the present invention is to provide a method for producing calcium carbide by high-pressure forming carbonized pellets of calcium carbonate coal powder, comprising the following steps: placing the above-mentioned high-pressure forming carbonized pellets of calcium carbonate coal powder in a calcium carbide furnace, performing a high-temperature melting reaction at 1800-2200°C to obtain calcium carbide.

[0017] Furthermore, the method for producing calcium carbide comprises the following steps: placing the pressed product in a pyrolysis furnace A and a pyrolysis furnace B, wherein the high-temperature calcium carbide furnace gas enters the pyrolysis furnace A, and the sensible heat of the high-temperature calcium carbide furnace gas is used to pyrolyze the green pellets, and the pyrolysis conditions are: firstly treating at 30-200°C for 60-120 min, then treating at 200-550°C for 150-210 min, then treating at 550-750°C for 60-120 min, and finally treating at 750-950°C for 30-90 min, the green pellets are pyrolyzed into cooked hot pellets and enter the calcium carbide furnace to produce calcium carbide and calcium carbide furnace gas, the mixed gas of the raw coal gas and the calcium carbide furnace gas with a temperature not lower than 200°C generated by the pyrolysis furnace A is the pyrolysis furnace gas A, and a part of the pyrolysis furnace gas A and air are subjected to oxygen-deficient combustion in a burner;

[0018] The temperature of hot flue gas is adjusted by introducing part of pyrolysis furnace gas B produced by pyrolysis furnace B, and the temperature of hot flue gas is controlled between 800-1200℃. The hot flue gas is used as a heat source to heat and pyrolyze the green pellets in pyrolysis furnace B. The pyrolysis conditions are: first treat at 30-200℃ for 60-120 min, then treat at 200-550℃ for 150-210 min, then treat at 550-750℃ for 60-120 min, and finally treat at 750-950℃ for 30-90 min to obtain cooked hot pellets which enter the calcium carbide furnace to produce calcium carbide and calcium carbide furnace gas. The waste gas with a temperature of not less than 200℃ produced by pyrolysis furnace B is used for exhaust gas temperature adjustment after combustion in the burner and for steam production or steam power generation in the tail gas boiler. A part of pyrolysis furnace gas A produced by pyrolysis furnace A is used for combustion to provide pyrolysis furnace B with the heat required for pyrolysis of green pellets, and the excess pyrolysis furnace gas A is used to produce steam or steam power generation in the tail gas boiler.

[0019] Further, the method for producing calcium carbide comprises the following steps:

[0020] (1) The pressed product (green pellets) is placed in pyrolysis furnace A and pyrolysis furnace B. The temperature of the calcium carbide furnace gas produced in the calcium carbide furnace is controlled at 800-1200°C, and the calcium carbide furnace gas is introduced into pyrolysis furnace A for heating. The green pellets in pyrolysis furnace A are heated to 900-950°C for pyrolysis. The limestone in the green pellets is decomposed into quicklime and carbon dioxide is discharged. The coal is pyrolyzed into lignite and raw coal gas is produced.

[0021] (2) A portion of the pyrolysis furnace gas A generated by the pyrolysis furnace A is introduced into a burner at a temperature not lower than 200°C to provide heat for the pyrolysis furnace B, and the remaining portion enters the tail gas boiler to produce steam or perform steam power generation. The tail gas generated by the tail gas boiler is treated and discharged after meeting the standards. The hot pellets obtained after pyrolysis in the pyrolysis furnace A are heat-fed into the calcium carbide furnace for calcium carbide production.

[0022] (3) Part of the pyrolysis furnace gas A produced by pyrolysis furnace A and air are burned in the burner under oxygen, and the pyrolysis furnace gas A produced by pyrolysis furnace B is refluxed to the burner to adjust the hot flue gas after combustion. The hot flue gas temperature is 800-1200°C. The hot flue gas is used as the heat source of pyrolysis furnace B to heat and pyrolyze the green pellets in pyrolysis furnace B, and the cooked hot pellets with a temperature of about 900°C are produced and sent to the calcium carbide furnace for calcium carbide production. The pyrolysis furnace gas B produced is used to adjust the temperature of the hot flue gas after combustion in the burner and to produce steam or steam power generation in the tail gas boiler, thereby realizing recycling.

[0023] The beneficial effect of adopting the above-mentioned further technical scheme is as follows: the present invention combines the production of carbonized pellets with the calcium carbide production process, thereby making full use of the high-temperature calcium carbide furnace gas generated by the calcium carbide furnace and the coal gas generated by the pyrolysis of coal in the pyrolysis furnace, avoiding the heat loss generated in the pyrolysis furnace and the calcium carbide furnace, and effectively reducing the production cost.

[0024] The present invention has the following beneficial effects:

[0025] (1) The present invention eliminates the process steps of pyrolysis of semi-coke in a semi-coke furnace to generate semi-coke and calcination of limestone in a lime kiln in the traditional calcium carbide production process, and combines the two into one, thereby saving construction investment, reducing carbon dioxide emissions, reducing pollution, and reducing energy consumption by 10%-15%; by using calcium carbonate powder and pulverized coal as raw materials for carbonization pellet processing and preparation, the problem that powdered calcium oxide and powdered semi-coke cannot be used in calcium carbide furnaces is overcome, thereby expanding the scope of use of raw materials, improving the utilization rate of raw materials, and reducing raw material costs by 10%-20%.

[0026] (2) The present invention improves the room temperature and high temperature compressive strength of the carbonized pellets by mixing an organic binder and an inorganic binder, and further improves the room temperature and high temperature compressive strength of the carbonized pellets by processing them in a step-by-step pyrolysis carbonization manner to meet the needs of subsequent calcium carbide processing in a calcium carbide furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the preparation process of high pressure forming carbonized pellets of calcium carbonate coal powder in Example 1-3;

[0028] Figure 2 This is a schematic diagram of the process of preparing high-pressure carbonized pellets of calcium carbonate coal powder and producing calcium carbide in Example 4-5. DETAILED DESCRIPTION

[0029] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0030] Embodiment 1:

[0031] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets (preparation flow chart as shown in Figure 1 As shown), comprising the following steps:

[0032] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0033] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol, saponified clay and borax mixed in a mass ratio of 70:15:15.

[0034] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0035] (4) The calcium carbonate coal pellets obtained in step (3) are sent to a vertical furnace for carbonization. The vertical furnace is divided into a preheating section (30-200°C), a low-temperature dry distillation section (200-550°C), a medium-temperature dry distillation section (550-750°C) and a high-temperature pyrolysis section (750-950°C) from top to bottom. The calcium carbonate coal pellets are treated in the preheating section for 120 min, the low-temperature dry distillation section for 120 min, the medium-temperature dry distillation section for 120 min, and the high-temperature pyrolysis section for 60 min. The coal in the calcium carbonate coal pellets is pyrolyzed into semi-coke and raw coal gas in the medium and low temperature sections, and the calcium carbonate in the calcium carbonate coal pellets is decomposed into calcium oxide and carbon dioxide.

[0036] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0037] Embodiment 2:

[0038] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets comprises the following steps:

[0039] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0040] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyethylene glycol, saponified clay and water glass mixed in a mass ratio of 70:15:15.

[0041] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0042] (4) The calcium carbonate coal pellets obtained in step (3) are sent to a vertical furnace for carbonization. The vertical furnace is divided into a preheating section (30-200°C), a low-temperature dry distillation section (200-550°C), a medium-temperature dry distillation section (550-750°C) and a high-temperature pyrolysis section (750-950°C) from top to bottom. The calcium carbonate coal pellets are treated in the preheating section for 120 min, the low-temperature dry distillation section for 120 min, the medium-temperature dry distillation section for 120 min, and the high-temperature pyrolysis section for 60 min. The coal in the calcium carbonate coal pellets is pyrolyzed into semi-coke and raw coal gas in the medium and low temperature sections, and the calcium carbonate in the calcium carbonate coal pellets is decomposed into calcium oxide and carbon dioxide.

[0043] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0044] Embodiment 3:

[0045] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets comprises the following steps:

[0046] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0047] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is a mixture of sodium alginate, water glass and borax in a mass ratio of 70:15:15.

[0048] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0049] (4) The calcium carbonate coal pellets obtained in step (3) are sent to a vertical furnace for carbonization. The vertical furnace is divided into a preheating section (30-200°C), a low-temperature dry distillation section (200-550°C), a medium-temperature dry distillation section (550-750°C) and a high-temperature pyrolysis section (750-950°C) from top to bottom. The calcium carbonate coal pellets are treated in the preheating section for 120 min, the low-temperature dry distillation section for 120 min, the medium-temperature dry distillation section for 120 min, and the high-temperature pyrolysis section for 60 min. The coal in the calcium carbonate coal pellets is pyrolyzed into semi-coke and raw coal gas in the medium and low temperature sections, and the calcium carbonate in the calcium carbonate coal pellets is decomposed into calcium oxide and carbon dioxide.

[0050] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0051] Embodiment 4:

[0052] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets (preparation flow chart as shown in Figure 2 As shown), comprising the following steps:

[0053] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0054] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol, saponified clay and borax mixed in a mass ratio of 70:15:15.

[0055] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0056] (4) The calcium carbonate coal pellets (green pellets) obtained in step (3) are placed in pyrolysis furnace A and pyrolysis furnace B, the temperature of the calcium carbide furnace gas produced in the calcium carbide furnace is controlled to be 800-1200°C, and the calcium carbide furnace gas is introduced into the pyrolysis furnace A for heat supply, the green pellets in the pyrolysis furnace A are heated to 900-950°C for pyrolysis to obtain carbonized pellets; the limestone in the green pellets is decomposed into quicklime and emits carbon dioxide, and the coal is pyrolyzed into lignite and produces raw coal gas; a portion of the pyrolysis furnace gas A produced by the pyrolysis furnace A is introduced into a burner at a temperature not lower than 200°C to provide heat for the pyrolysis furnace B, and the remaining portion is introduced into the tail gas boiler to produce steam or perform steam power generation, and the tail gas produced by the tail gas boiler is treated and discharged after meeting the standards.

[0057] (5) Part of the pyrolysis furnace gas A produced by the pyrolysis furnace A and air are burned in the burner under oxygen. The hot flue gas temperature is adjusted between 800-1200°C by introducing part of the pyrolysis furnace gas B. The hot flue gas is used as a heat source to heat and pyrolyze the green pellets in the pyrolysis furnace B to produce carbonized pellets. The generated pyrolysis furnace gas B is used to adjust the temperature of the exhaust gas after combustion in the burner and to produce steam or steam power generation in the tail gas boiler, thereby realizing recycling.

[0058] Embodiment 5:

[0059] A method for producing calcium carbide by high pressure forming carbonized pellets of calcium carbonate coal powder (preparation flow chart as shown in Figure 2 As shown), comprising the following steps:

[0060] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0061] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol, saponified clay and borax mixed in a mass ratio of 70:15:15.

[0062] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0063] (4) The calcium carbonate coal pellets (green pellets) obtained in step (3) are placed in pyrolysis furnace A and pyrolysis furnace B, the temperature of the calcium carbide furnace gas produced in the calcium carbide furnace is controlled to be 800-1200°C, and the calcium carbide furnace gas is introduced into the pyrolysis furnace A for heat supply. The green pellets in the pyrolysis furnace A are heated to 900-950°C for pyrolysis. The limestone in the green pellets is decomposed into quicklime and carbon dioxide is discharged. The coal is pyrolyzed into lignite and raw coal gas is produced.

[0064] (5) A portion of the pyrolysis furnace gas A generated by the pyrolysis furnace A is introduced into a burner at a temperature not lower than 200°C to provide heat for the pyrolysis furnace B, and the remaining portion enters the tail gas boiler to produce steam or perform steam power generation. The tail gas generated by the tail gas boiler is treated and discharged after meeting the standards. The hot pellets obtained after pyrolysis in the pyrolysis furnace A are hot-sent to the calcium carbide furnace for calcium carbide production.

[0065] (6) Part of the pyrolysis furnace gas A and air produced by the pyrolysis furnace A are burned in the burner under oxygen. The hot flue gas temperature is adjusted between 800-1200°C by introducing pyrolysis furnace gas B. The hot flue gas is used as a heat source to heat and pyrolyze the green pellets in the pyrolysis furnace B. The cooked hot pellets with a temperature of about 900°C are directly sent to the calcium carbide furnace for calcium carbide production. The pyrolysis furnace gas B produced is used to adjust the temperature of the exhaust gas after combustion in the burner and to produce steam or steam power generation in the tail gas boiler, thereby realizing recycling.

[0066] Embodiment 6:

[0067] A method for producing calcium carbide by high pressure forming carbonized pellets of calcium carbonate coal powder (preparation flow chart as shown in Figure 2 As shown), comprising the following steps:

[0068] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0069] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol, saponified clay and borax mixed in a mass ratio of 70:15:15.

[0070] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0071] (4) The calcium carbonate coal pellets (green pellets) obtained in step (3) are placed in pyrolysis furnaces A and B, and the temperature of the calcium carbide furnace gas discharged from the calcium carbide furnace is controlled to be 800-1200°C by controlling the height of the material layer in the calcium carbide furnace. The main components of the calcium carbide furnace gas are CO, N2, CO2, etc. The high-temperature calcium carbide furnace gas enters the pyrolysis furnace A, and the green pellets are pyrolyzed using the sensible heat of the high-temperature calcium carbide furnace gas. The pyrolysis and carbonization conditions are: first, treat at 30-200°C for 60-120 min, then treat at 200-550°C for 150-210 min, then treat at 550-750°C for 60-120 min, and finally treat at 750-950°C for 30-90 min. min, the green pellets are pyrolyzed into cooked hot pellets which enter the calcium carbide furnace to produce calcium carbide. The green pellets are pyrolyzed into cooked hot pellets which enter the calcium carbide furnace to produce calcium carbide. The gas produced by the pyrolysis furnace A with a temperature not lower than 200°C (to ensure that tar does not precipitate) is the pyrolysis furnace gas A. A part of it is burned with air in the burner under oxygen to generate hot flue gas. The hot flue gas is used to provide the heat required for the pyrolysis of the green pellets to the pyrolysis furnace B. The excess pyrolysis furnace gas A is sent to the tail gas boiler for full combustion to produce steam or steam power generation.

[0072] The temperature of the hot flue gas is adjusted by introducing part of the pyrolysis furnace gas B produced by the pyrolysis furnace B, and the temperature of the hot flue gas is controlled between 800-1200°C. The conditions for pyrolysis carbonization are: first treat at 30-200°C for 60-120 min, then treat at 200-550°C for 150-210 min, then treat at 550-750°C for 60-120 min, and finally treat at 750-950°C for 30-90 min. The obtained cooked pellets enter the calcium carbide furnace to produce calcium carbide and pyrolysis furnace gas B. The temperature of the pyrolysis furnace gas B is not lower than 200°C (to ensure that tar does not precipitate), and a part of it is used as temperature regulating gas for pyrolysis furnace B, and the excess pyrolysis furnace gas B is sent to the tail gas boiler for full combustion to produce steam or steam power generation.

[0073] The gas produced by pyrolysis furnace A with a temperature not lower than 200°C (to ensure that tar does not precipitate) is pyrolysis furnace gas A. A part of it is burned with air in a burner under oxygen to generate hot flue gas. The hot flue gas is used to provide heat required for pyrolysis of green pellets to pyrolysis furnace B. The excess pyrolysis furnace gas A is fully burned in the tail gas boiler to produce steam or steam power generation.

[0074] The temperature of the hot flue gas is adjusted by introducing part of the pyrolysis furnace gas B produced by the pyrolysis furnace B, and the temperature of the hot flue gas is controlled between 800-1200°C. The conditions for pyrolysis carbonization are: first treat at 30-200°C for 60-120 min, then treat at 200-550°C for 150-210 min, then treat at 550-750°C for 60-120 min, and finally treat at 750-950°C for 30-90 min. The obtained cooked pellets enter the calcium carbide furnace to produce calcium carbide and pyrolysis furnace gas B. The temperature of the pyrolysis furnace gas B is not lower than 200°C (to ensure that tar does not precipitate), and a part of it is used as temperature regulating gas for pyrolysis furnace B, and the excess pyrolysis furnace gas B is sent to the tail gas boiler for full combustion to produce steam or steam power generation.

[0075] Comparative Example 1:

[0076] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets comprises the following steps:

[0077] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0078] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol.

[0079] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0080] (4) The calcium carbonate coal pellets obtained in step (3) are sent to a vertical furnace for carbonization. The vertical furnace is divided into a preheating section (30-200°C), a low-temperature dry distillation section (200-550°C), a medium-temperature dry distillation section (550-750°C) and a high-temperature pyrolysis section (750-950°C) from top to bottom. The calcium carbonate coal pellets are treated in the preheating section for 120 min, the low-temperature dry distillation section for 120 min, the medium-temperature dry distillation section for 120 min, and the high-temperature pyrolysis section for 60 min. The coal in the calcium carbonate coal pellets is pyrolyzed into semi-coke and raw coal gas in the medium and low temperature sections, and the calcium carbonate in the calcium carbonate coal pellets is decomposed into calcium oxide and carbon dioxide.

[0081] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0082] Comparative Example 2:

[0083] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets comprises the following steps:

[0084] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0085] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is a mixture of saponified clay and borax in a mass ratio of 1:1.

[0086] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0087] (4) The calcium carbonate coal pellets obtained in step (3) are sent to a vertical furnace for carbonization. The vertical furnace is divided into a preheating section (30-200°C), a low-temperature dry distillation section (200-550°C), a medium-temperature dry distillation section (550-750°C) and a high-temperature pyrolysis section (750-950°C) from top to bottom. The calcium carbonate coal pellets are treated in the preheating section for 120 min, the low-temperature dry distillation section for 120 min, the medium-temperature dry distillation section for 120 min, and the high-temperature pyrolysis section for 60 min. The coal in the calcium carbonate coal pellets is pyrolyzed into semi-coke and raw coal gas in the medium and low temperature sections, and the calcium carbonate in the calcium carbonate coal pellets is decomposed into calcium oxide and carbon dioxide.

[0088] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0089] Comparative Example 3:

[0090] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets comprises the following steps:

[0091] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0092] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol, saponified clay and borax mixed in a mass ratio of 70:15:15.

[0093] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0094] (4) The calcium carbonate coal pellets obtained in step (3) are fed into a vertical furnace for carbonization at a carbonization temperature of 750-950° C. for 60 min.

[0095] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0096] Comparative Example 4:

[0097] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets comprises the following steps:

[0098] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0099] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol, saponified clay and borax mixed in a mass ratio of 70:15:15.

[0100] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0101] (4) The calcium carbonate coal pellets obtained in step (3) are sent to a vertical furnace for carbonization. The vertical furnace is divided into a preheating section (30-200°C), a low-temperature dry distillation section (200-550°C), a medium-temperature dry distillation section (550-750°C) and a high-temperature pyrolysis section (750-950°C) from top to bottom. The calcium carbonate coal pellets are treated in the preheating section for 120 min, the low-temperature dry distillation section for 120 min, the medium-temperature dry distillation section for 120 min, and the high-temperature pyrolysis section for 60 min. The coal in the calcium carbonate coal pellets is pyrolyzed into semi-coke and raw coal gas in the medium and low temperature sections, and the calcium carbonate in the calcium carbonate coal pellets is decomposed into calcium oxide and carbon dioxide.

[0102] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0103] Comparative Example 5:

[0104] A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets (preparation flow chart as shown in Figure 1 As shown), comprising the following steps:

[0105] (1) Calcium carbonate and long flame coal are ground by mills respectively, and the powder particle size reaches 1 mm or less. Among them, the mass proportion of calcium carbonate powder with a particle size of 0.5-1 mm is 68%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 14%; the mass proportion of long flame coal powder with a particle size of 0.5-1 mm is 65%, the mass proportion of particle size of 0.3-0.5 mm is 18%, and the mass proportion of particle size below 0.3 mm is 17%.

[0106] (2) Calcium carbonate powder and long flame coal powder are blended in a mass ratio of 60:40, and a binder is added in a mass ratio of 2% of the total mass of the calcium carbonate powder and the long flame coal powder to mix evenly to obtain a mixture, wherein the binder is polyvinyl alcohol, saponified clay and borax mixed in a mass ratio of 70:15:15.

[0107] (3) The mixture obtained in step (2) is fed into a high-pressure roll forming machine and pressed into calcium carbonate coal pellets.

[0108] (4) The calcium carbonate coal pellets obtained in step (3) are sent to a vertical furnace for carbonization. The vertical furnace is divided into a preheating section (30-200°C), a low-temperature dry distillation section (200-550°C), a medium-temperature dry distillation section (550-750°C) and a high-temperature pyrolysis section (750-950°C) from top to bottom. The calcium carbonate coal pellets are treated in the preheating section for 120 min, the low-temperature dry distillation section for 120 min, the medium-temperature dry distillation section for 120 min, and the high-temperature pyrolysis section for 60 min. The coal in the calcium carbonate coal pellets is pyrolyzed into semi-coke and raw coal gas in the medium and low temperature sections, and the calcium carbonate in the calcium carbonate coal pellets is decomposed into calcium oxide and carbon dioxide.

[0109] (5) The high-temperature pellets obtained after the carbonization in step (4) are sent to a dry quenching chamber for cooling, and are discharged after being cooled to 120° C. to obtain carbonized pellets.

[0110] Test example:

[0111] According to GB3002-2004 "Test Method for High-Temperature Bending Strength of Refractory Materials", the carbonized pellets obtained in Examples 1-3 and Comparative Examples 1-3 were tested for room temperature and high temperature compressive strength, using a fully automatic high temperature bending tester for refractory materials. The number of test samples in each group was 4, and the average value was taken. The test temperature was room temperature and a high temperature of 1000 °C.

[0112] The test results are shown in Table 1.

[0113] Table 1 Compressive strength test results at room temperature and high temperature

[0114]

[0115] According to the data in the above table, the room temperature compressive strength and high temperature compressive strength of the carbonized pellets obtained in Examples 1-3 of the present invention are significantly lower than those obtained in Examples 1-3. According to the test results of Examples 1-2 and Example 1, the carbonized pellets obtained by using different binders have different effects on the room temperature compressive strength and high temperature compressive strength. The room temperature compressive strength of Example 1 using only an organic binder is improved relative to that of Example 2 using only an inorganic binder, but the high temperature compressive strength is significantly reduced. The present invention effectively improves the room temperature compressive strength and high temperature compressive strength of the carbonized pellets by combining the two. At the same time, according to the experimental results of Example 3, the present invention also effectively improves the room temperature compressive strength and high temperature compressive strength of the carbonized pellets by using the segmented heating carbonization method during pyrolysis carbonization, which better meets the strength requirements for subsequent calcium carbide processing in the calcium carbide furnace, makes full use of powdered calcium carbonate and pulverized coal, improves the utilization rate of raw materials, expands the scope of use of raw materials, and reduces the cost of raw materials by 10%-20%. According to the experimental results of Comparative Examples 4 and 5, when the proportion of calcium carbonate powder in the raw material for preparing carbonized pellets is too high or too low, it will have a negative impact on the room temperature compressive strength and high temperature compressive strength of the carbonized pellets.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing calcium carbonate coal powder high pressure forming carbonized pellets, characterized in that: The following steps are involved: The calcium carbonate and raw coal are ground into powder, then a binder is added to press and form, and finally pyrolysis and carbonization are performed to obtain the product; Wherein, the raw coal is long flame coal; after the calcium carbonate is ground, the calcium carbonate with a particle size of 0.5-1 mm accounts for 65%-70% of the total mass of the calcium carbonate, the calcium carbonate with a particle size of 0.3-0.5 mm accounts for 15%-20% of the total mass of the calcium carbonate, and the calcium carbonate with a particle size less than 0.3 mm accounts for 10%-15% of the total mass of the calcium carbonate; After the raw coal is ground, the raw coal with a particle size of 0.5-1 mm accounts for 60%-70% of the total mass of the raw coal, the raw coal with a particle size of 0.3-0.5 mm accounts for 15%-20% of the total mass of the raw coal, and the raw coal with a particle size less than 0.3 mm accounts for 15%-20% of the total mass of the raw coal; The mass ratio of calcium carbonate to raw coal is 55-65:35-45; the mass of the binder is 1%-4% of the total mass of calcium carbonate and raw coal; The binder is prepared by mixing an organic binder and an inorganic binder in a mass ratio of 60-80:20-40; The organic binder is at least one of polyvinyl alcohol, polyethylene glycol and sodium humate, and the inorganic binder is at least one of saponified clay, borax and water glass; The pyrolysis carbonization conditions are: first treating at 30-200°C for 60-120 min, then treating at 200-550°C for 150-210 min, then treating at 550-750°C for 60-120 min, and finally treating at 750-950°C for 30-90 min.

2. A calcium carbonate coal powder high pressure forming carbonized pellet, characterized in that: The preparation method according to claim 1 is adopted.

3. A method for producing calcium carbide by high pressure forming carbonized pellets of calcium carbonate coal powder, characterized in that: The method comprises the following steps: placing the calcium carbonate coal powder high pressure formed carbonized pellets as claimed in claim 2 in a calcium carbide furnace, and performing a high temperature melting reaction at 1800-2200°C to obtain calcium carbide.

4. The method for producing calcium carbide by high pressure forming carbonized pellets of calcium carbonate coal powder according to claim 3, characterized in that: The following steps are involved: The pressed and formed products are placed in a pyrolysis furnace A and a pyrolysis furnace B, wherein the high-temperature calcium carbide furnace gas enters the pyrolysis furnace A, and the sensible heat of the high-temperature calcium carbide furnace gas is used to pyrolyze the green pellets, and the pyrolysis conditions are: firstly treated at 30-200 ℃ for 60-120 min, then treated at 200-550 ℃ for 150-210 min, then treated at 550-750 ℃ ​​for 60-120 min, and finally treated at 750-950 ℃ for 30-90 min, the green pellets are pyrolyzed into cooked hot pellets and enter the calcium carbide furnace to produce calcium carbide and calcium carbide furnace gas, the mixed gas of the raw coal gas and the calcium carbide furnace gas with a temperature not lower than 200 ℃ generated by the pyrolysis furnace A is the pyrolysis furnace gas A, and a part of the pyrolysis furnace gas A and air are subjected to under-oxygen combustion in the burner; The temperature of hot flue gas is adjusted by introducing part of pyrolysis furnace gas B produced by pyrolysis furnace B, and the temperature of hot flue gas is controlled between 800-1200℃. The hot flue gas is used as a heat source to heat and pyrolyze the green pellets in pyrolysis furnace B. The pyrolysis conditions are: first treat at 30-200℃ for 60-120 min, then treat at 200-550℃ for 150-210 min, then treat at 550-750℃ for 60-120min, and finally treat at 750-950℃ for 30-90 min to obtain cooked hot pellets which enter the calcium carbide furnace to produce calcium carbide and calcium carbide furnace gas. The waste gas with a temperature of not less than 200℃ produced by pyrolysis furnace B is used for exhaust gas temperature adjustment after combustion in the burner and for steam production or steam power generation in the tail gas boiler. A part of pyrolysis furnace gas A produced by pyrolysis furnace A is used for combustion to provide pyrolysis furnace B with the heat required for pyrolysis of green pellets, and the excess pyrolysis furnace gas A is used to produce steam or steam power generation in the tail gas boiler.

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