A production process of high combustion efficiency coke
By combining a three-stage thermal regime of formulation A solution spray loading, formulation B pore construction, and surface treatment, the problems of long ignition induction period, unstable combustion, and high loss of unburned carbon during coke combustion were solved, achieving high combustion efficiency and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- OTOG BANNER JIANYUAN COKING CO LTD
- Filing Date
- 2026-05-12
- Publication Date
- 2026-06-12
AI Technical Summary
Existing coke combustion processes suffer from problems such as long ignition induction period, unstable combustion, insufficient burnout, and high loss of unburned carbon. Furthermore, existing improvement measures are not always effective and may lead to a decrease in thermal efficiency.
The formulation A solution is spray-loaded and cured at low temperature. Combined with formulation B to construct a connected pore structure and surface treatment slurry, and with a three-stage thermal regime, the active components are uniformly distributed and the pores are connected, ash film formation is inhibited, and efficient combustion is achieved throughout the combustion cycle.
It achieves rapid ignition, stable combustion, and complete burnout of coke, while reducing the loss of unburned carbon, improving combustion efficiency, and maintaining coke strength and process operability.
Smart Images
Figure CN122188684A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coking technology, specifically relating to a production process for high-combustion-efficiency coke. Background Technology
[0002] Coke is a porous carbonaceous material produced by high-temperature dry distillation of coking coal or blended coal under air-isolated conditions. It is widely used in metallurgy, casting, and some industrial combustion fields. For coke primarily used for combustion and heating, its overall performance depends not only on its high calorific value but also on indicators such as ignition performance, combustion stability, and burnout degree. In actual combustion processes, existing coke often exhibits characteristics such as a long ignition induction period, difficulty in stabilizing the combustion process in the early stages, a significant decrease in reaction rate in the middle and later stages of combustion, and high losses of residual or unburned carbon. This results in insufficient effective heat utilization, large fluctuations in the combustion process, and an increased risk of incomplete combustion products.
[0003] The key reason for the above problems lies in the fact that coke combustion is a complex process dominated by solid-phase reactions and significantly controlled by mass transfer. On the one hand, coke has a low volatile content and lacks the ignition and enhancement effect of gas-phase volatile combustion on solid-phase ignition, resulting in a relatively high ignition temperature and a long ignition induction period, which easily leads to difficulty in ignition or uneven ignition. On the other hand, coke combustion requires oxygen to enter the pores and reach the reaction interface, while combustion products need to escape smoothly. When the coke pore connectivity is insufficient, the pore structure collapses during thermal contraction, or is blocked by ash phase, the oxygen diffusion resistance increases significantly, causing combustion to gradually shift from surface reaction to diffusion restriction. This manifests as vigorous combustion on the outer surface but insufficient burnout inside, resulting in high residual char and unburned carbon loss.
[0004] Furthermore, coke ash and mineral components are prone to softening, sintering, or partial melting at high temperatures, forming a dense coating layer. This ash film effect isolates the reaction interface for extended periods, making it difficult for oxygen to continuously reach effective reaction sites. Consequently, the combustion rate decreases significantly in the later stages, leading to burnout difficulties. Existing technologies often employ methods such as increasing furnace temperature, increasing air supply, altering particle size, or adding combustion aids to improve combustion, but these methods still have several limitations. For example, simply increasing air supply or furnace temperature can easily lead to a combination of localized excess air and localized oxygen deficiency, resulting in decreased thermal efficiency and increased fluctuations. Simply adding metal salt combustion aids often causes uneven distribution of active sites due to migration and aggregation in the plastic phase of the coal, leading to localized failures or abnormal ash phases. Moreover, the repeatability of the effect is poor under different coal sources and operating conditions. Simply creating pores or increasing specific surface area can lead to pore structure collapse or blockage under the effects of high-temperature shrinkage during coking and ash phase evolution, making it difficult to sustain the improvement effect in the later stages of combustion. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-combustion-efficiency coke production process. This process solves the problems of traditional coke, which suffers from low volatile matter content, long ignition induction period leading to difficult ignition and unstable early combustion. Furthermore, during combustion, insufficient pore connectivity, high-temperature shrinkage during coking causing pore collapse, and the formation of a dense ash film during ash phase formation and sintering all contribute to the hindered internal diffusion of oxygen and the escape of combustion products, resulting in prolonged isolation of the reaction interface and a significant decrease in reaction rate in the later stages of combustion, incomplete internal burnout, and high losses of residual or unburned carbon. The invention also solves the problems encountered in existing technologies where simple addition of combustion aids is limited by the active components in the plasticity of the coal. The phase stage is prone to migration and aggregation, resulting in uneven distribution of active sites, large fluctuations and poor repeatability of combustion-supporting effect. In addition, simply relying on increasing air supply or furnace temperature can easily cause combustion fluctuations and thermal efficiency loss. Simply modifying the pore structure can easily cause the pore structure to collapse or be blocked by ash at high temperature, making it difficult to improve the effect throughout the entire combustion cycle. Therefore, coke can maintain lower diffusion resistance and higher effective reaction interface utilization in the ignition, steady-state combustion and later deep burnout stages, so as to achieve the goal of high combustion efficiency with faster ignition, more stable combustion, more complete burnout and reduced incomplete combustion loss.
[0006] The technical effects described in this invention are achieved through the following technical solution: a production process for high-combustion-efficiency coke, specifically including the following steps: S1: Select coking coal; crush and screen it, and adjust the initial moisture content of the coal to 7-12%; S2: Place the coal material from S1 into a drum mixer and mix at 300-600 rpm. Spray the solution of preparation A into the mixture using an atomizing nozzle for 3-10 minutes, continue mixing for 5-15 minutes, and then use a hot air drum to cure at a low temperature of 80-110℃, controlling the moisture content to 6-10%. S3: Add formulation B to the coal treated with S2 and mix at high speed of 400-600 rpm to make the powder evenly coat the surface of the coal particles; spray water in a small amount of 0.2-1 wt% to suppress dust and promote adhesion. S4: The coal processed in step S3 is then loaded into the furnace, with the density controlled at 0.70–0.95 t / m³. 3 ; S5: Employs a three-stage thermal process. Stage I involves preheating, dehydration, and slow-release pore formation, controlling the heating rate and holding conditions to ensure the smooth release of moisture and low-boiling-point volatiles, preventing localized overheating and smoldering caused by instantaneous gas release. Stage II involves plastic phase homogenization and site fixation. Stage III involves high-temperature shaping and strength formation. Post-coking coke moisture content is controlled to be <5%. S6: Screen the coke from step S5 to the target particle size, prepare a surface treatment slurry, impregnate it to form a thin layer of enrichment on the surface; dry it at a low temperature of 100-140℃ for 20-60 minutes to obtain coke with high combustion efficiency.
[0007] Preferably, in step S1, the particle size distribution of the coal is controlled as follows: 0-2mm accounts for 60-65%; 0-3mm accounts for 90-95%; and larger than 3mm accounts for 5-10%.
[0008] Preferably, in step S2, the preparation A solution is composed of the following components: 0.1-0.3 wt% iron source, 0.3-0.8 wt% calcium source, 0.1-0.2 wt% citric acid, 0.01-0.1 wt% dispersant, and 0.01-0.1 wt% carrier powder, with the balance being industrial softened water, and the sum of the mass percentages of each component being 100%; the spray volume of preparation A solution is 1-3 wt% based on the dry coal mass; wherein, due to the atomized spray and low-temperature curing, the active components are preferentially enriched on the surface of the coal particles and the pore area, so preparation A can still achieve effective conditioning with a relatively low total introduction amount.
[0009] Preferably, the iron source is either ferric ammonium citrate or ferric nitrate, and more preferably ferric ammonium citrate.
[0010] Preferably, the calcium source is either calcium acetate or calcium nitrate.
[0011] Preferably, the dispersant is any one of polyvinylpyrrolidone, sodium carboxymethyl cellulose, and sodium lignosulfonate.
[0012] Preferably, the carrier powder is either zeolite powder or kaolin; all carrier powders are screened through a 200-mesh sieve.
[0013] Preferably, in step S3, the formulation B consists of fine SiO2 and a pore-forming agent; the D of the fine SiO2 50 The particle size is 0.5-2 μm; the pore-forming agent is any one of ammonium bicarbonate, ammonium carbonate and starch, more preferably starch; the amount of fine SiO2 used is 0.6-1.2 wt% based on dry coal mass; the amount of the pore-forming agent used is 0.1-0.3 wt%; wherein the particle size of the pore-forming agent is all screened through a 150-mesh sieve.
[0014] Preferably, steps S2 and S3 can be arranged downstream of the coal tower, in the coal conditioning process before charging; step S4 charging can be done by top charging or tamping charging. When tamping charging is used, the coal can be fed by shaking and then enter the tamping process to form coal cakes, which are then sent into the carbonization chamber by the coal charging and pushing car; step S5 can be carried out in the carbonization chamber of a conventional coke oven, and the raw coal gas generated during the coking process can be discharged through the riser pipe, bridge pipe and gas collecting pipe and enter the conventional coal gas recovery system; step S6 can be connected with dry quenching or wet quenching and subsequent coke screening processes.
[0015] Preferably, in step S4, when tamping is used for charging, the coal is tamped by a tamping machine after being fed by shaking to form coal cakes, and then sent into the carbonization chamber by a coal charging and coking car.
[0016] Preferably, in step S5, the specific operating parameters of the three-stage thermal regime are as follows: Stage I: Preheating, dehydration, and slow-release pore formation, heating from room temperature to 350-450°C at a heating rate of 1-3°C / min, holding for 30-60 min, mild dehydration, and decomposition of pore-forming components to form primary pores without damaging the structure; Stage II: Homogenization of the plastic phase and fixing of sites, heating to 450-600°C at a heating rate of 0.5-2°C / min, holding for 60-120 min, redistribution of components within the plastic phase, uniform anchoring of sites, and enhanced pore connectivity, laying the foundation for subsequent burnout; Stage III: High-temperature shaping and strength formation, heating to 950-1100°C at a heating rate of 2-5°C / min, holding at the final temperature for 1-3 h, shaping of the coke structure, strength formation, and tendency of the skeleton retaining phase to form a non-dense film structure in the ash phase.
[0017] Preferably, in step S5, the raw coal gas generated during the coking process is discharged through the riser pipe, bridge pipe and gas collecting pipe.
[0018] Preferably, in step S6, the target particle size is 30-60 mm.
[0019] Preferably, in step S6, the surface treatment slurry is composed of the following components: 2-8 wt% calcium carbonate, 2-6 wt% kaolin, 0.05-0.2 wt% iron source, 0.1-0.3 wt% calcium source, and 0.1-0.2 wt% sodium carboxymethyl cellulose; wherein the mass ratio of calcium carbonate to kaolin is 1-4:1-3; the balance is industrial softened water, and the sum of the mass percentages of each component is 100%; based on the mass of coke, the amount of the surface treatment slurry applied is 0.5-2 wt% on a dry basis.
[0020] It should be noted that in step S6, the iron source and calcium source are the same as those in the preparation A solution in step S2.
[0021] The present invention has the following beneficial effects: This invention utilizes anchoring catalytic combustion-enhancing modification of formulation A, pore structure construction and framework maintenance of formulation B, and ash film suppression and easy-ignition surface construction of surface treatment slurry, coupled with a three-stage thermal regime, to enable coke to obtain targeted structural and reaction kinetic advantages throughout the entire process of ignition, steady-state combustion, and deep burnout, thereby systematically improving combustion efficiency.
[0022] During the ignition and initial combustion stages, the iron and calcium sources introduced by formulation A achieve uniform loading through citric acid complexation and anchoring, as well as low-temperature solidification. The active components tend to accumulate on the surface of coal particles and in the pore area, mitigating the problems of uneven activity and fluctuating effects caused by the easy migration, agglomeration, and localized enrichment of metal salts when directly mixed. The preferred use of ferric ammonium citrate and calcium acetate as the iron and calcium sources further reduces the risk of localized exothermic side reactions that may be triggered by oxidizing salts in the early stages of pyrolysis, making it easier to achieve gentle dehydration and stable gas escape in stage I. Because the active sites are closer to the combustion reaction interface, a continuous and stable exothermic reaction front is more easily formed on the coke surface, thus shortening the ignition induction period and improving initial combustion stability. Simultaneously, the calcium component regulates the initial ash phase formation morphology, reducing the tendency for a dense covering layer to form rapidly on the surface, further reducing combustion fluctuations caused by surface obstruction during the ignition stage.
[0023] During the steady-state combustion and mass transfer-limited stages, this invention utilizes formulation B to construct and maintain an effective interconnected pore structure, enabling combustion to transition from being confined to the external surface to involving the bulk phase. The pore-forming agent decomposes or pyrolyzes in the low-temperature region during the initial curing and heating phases, forming primary pores and gas migration channels. Upon entering the Stage I temperature zone, gentle dehydration and gradual structural solidification further stabilize these pores and channels, enhancing their connectivity and providing a continuous and effective mass transfer pathway for oxygen diffusion and combustion product escape. Simultaneously, fine SiO2, acting as a framework retaining phase, inhibits pore collapse and localized blockage during high-temperature shrinkage and structural stabilization, maintaining a relatively rich and continuous interconnected pore network within the coke. This reduces the rapid increase in diffusion resistance and incomplete internal burnout problems commonly seen in the later stages of combustion in traditional coke. This structural advantage couples with the catalytic site distribution of formulation A, making it easier for oxygen to reach the vicinity of the active sites and effectively converting the catalytic promotion effect into burnout gain, thereby increasing the effective heat release and burnout rate per unit time and reducing residual char and incomplete combustion losses at a fixed combustion time.
[0024] During the high-temperature combustion and ash film formation stages, this invention introduces a surface treatment slurry, which causes CaCO3 and kaolin to form a thin-layer enriched structure on the coke surface. Trace amounts of iron and calcium sources can be added to enhance the interfacial reactivity during the combustion development stage. As combustion progresses, the surface enriched structure reduces diffusion resistance in the later stages and minimizes incomplete combustion losses by inhibiting ash densification and ash film coverage. The synergistic effect of CaCO3 and kaolin can regulate the evolution of the ash phase from a path that easily forms a continuous, dense film to a more loose, easily broken-down, and detachable structural morphology. Kaolin provides an aluminum-silicon framework to inhibit the formation of a continuous glassy phase, while the Ca component promotes loose agglomeration of the ash phase and reduces the tendency for dense film formation. The enriched surface structure makes it easier to renew the ash layer under the scouring action of the combustion airflow, so that the reaction interface is continuously exposed. This weakens the long-term barrier of the ash film to oxygen diffusion and the reaction interface, significantly improves the defects of traditional coke in the later stage of combustion, such as decreased reaction rate, difficulty in burnout, and increase of unburned carbon. It also helps to reduce loss indicators that characterize incomplete combustion, such as carbon content in fly ash or residual carbon in slag.
[0025] In the three-stage thermal process, Stage I reduces the probability of structural defects caused by rapid gas release and local overheating through gentle dehydration and stable volatile release, and together with the primary pores formed in the low-temperature zone, establishes a stable gas migration channel. Stage II provides plastic phase homogenization and site fixation windows, so that the anchored active components maintain uniform distribution during bonding and rearrangement, reducing migration and aggregation and local deactivation, while promoting enhanced pore connectivity, laying the foundation for mass transfer in subsequent burnout. Stage III ensures the formation of coke strength while solidifying the skeleton phase (fine SiO2, etc.) and ash phase structure in the expected direction, taking into account both improved combustion efficiency and stable mechanical strength, avoiding side effects such as pulverization, entrainment, and decreased combustion stability caused by simply pursuing reactivity.
[0026] In summary, this invention focuses on stabilizing the distribution of active sites with formulation A, maintaining the interconnected pore structure with formulation B, and inhibiting the ash film and constructing an easily ignitable surface layer through surface treatment slurry. By employing a specific thermal regime, these effects are released and solidified systematically throughout the coking process. This allows the coke to maintain lower diffusion resistance and higher effective reaction interface utilization throughout the entire combustion cycle, thereby achieving the goal of faster ignition, more stable combustion, more complete burnout, and lower unburned carbon. Furthermore, while ensuring coke strength and process operability, it overcomes key shortcomings in existing technologies such as unstable combustion-supporting effects, easy pore collapse and blockage, and difficulties in later burnout due to ash film obstruction. Simultaneously, the coal conditioning step of this invention can be arranged in the coal processing stage downstream of the coal tower to before charging, and the three-stage thermal regime can be implemented in the conventional coke oven carbonization chamber and can be integrated with dry or wet quenching processes, thus facilitating implementation in conjunction with existing coking production lines. Attached Figure Description
[0027] Figure 1The graph shows the CO-t curve data of coke ignition and combustion stability test obtained under different processes in Example 1 and Comparative Examples 1-5; Figure 2 The graph shows the CO2-t curve data of coke ignition and combustion stability test obtained under different processes in Example 1 and Comparative Examples 1-5; Figure 3 The graph shows the burnout rate test results of coke obtained under different processes in Example 1 and Comparative Examples 1-5; Figure 4 The graph shows the test results of unburned carbon residue from coke obtained under different processes in Example 1 and Comparative Examples 1-5. Detailed Implementation
[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the raw materials involved in the present invention are all purchased through conventional commercial channels. Experimental methods without specific conditions are conventional methods and conditions well known in the art, or according to the conditions recommended by the instrument manufacturer.
[0029] Example 1: A production process for high-combustion-efficiency coke, specifically including the following steps: S1: Select coking coal; crush and screen it, controlling the coal particle size distribution as follows: 0-2mm 62%; 0-3mm 90%; >3mm 10%; adjust the initial moisture content of the coal to 10%. S2: Steps S2 and S3 are arranged downstream of the coal tower, in the coal conditioning process before charging; specifically, after the coal from S1 is discharged from the coal tower, it is placed in a drum mixer and mixed at 500 rpm. The atomizing nozzle sprays the preparation A solution for 6 minutes, and the mixing continues for 10 minutes. The hot air drum is then used to solidify at a low temperature of 95°C to control the moisture content to 8%. The formulation A solution comprises the following components: 0.2 wt% ferric ammonium citrate, 0.5 wt% calcium acetate, 0.15 wt% citric acid, 0.05 wt% polyvinylpyrrolidone, and 0.05 wt% kaolin, with the balance being industrial softened water. The sum of the mass percentages of each component is 100%. The spray volume of formulation A solution is 2 wt% based on the dry coal mass. S3: Add formulation B to the coal treated with S2 and mix at a high speed of 500 rpm to make the powder evenly coat the surface of the coal particles; add 0.5 wt% water by micro-spray to suppress dust and promote adhesion; The formulation B is composed of fine SiO2 and starch; the D of the fine SiO2 50 The particle size is 1 μm; the amount of fine SiO2 used is 1 wt% based on the dry coal mass; the amount of starch used is 0.2 wt%. S4: The coal processed in step S3 is fed into a tamping machine after being shaken and tamped to form coal cakes. The charging density is controlled at 0.85 t / m³. 3 Then, the coal cake is sent into the carbonization chamber by the coal charging and coke pushing car for furnace loading. S5: A three-stage thermal regime is adopted in the conventional coke oven carbonization chamber. Stage I involves preheating, dehydration, and slow-release pore formation, with the temperature increased from room temperature to 400℃ at a rate of 2℃ / min and held for 45 min. This process involves gentle dehydration and the decomposition of pore-forming components, forming primary pores without damaging the structure. Stage II involves homogenization of the plastic phase and fixing of sites, with the temperature increased to 520℃ at a rate of 1℃ / min and held for 90 min. This process involves redistribution of components within the plastic phase, maintaining uniformity of anchored sites, and enhancing pore connectivity, laying the foundation for subsequent burnout. Stage III involves high-temperature shaping and strength formation, with the temperature increased to 1050℃ at a rate of 3℃ / min and held at the final temperature for 2 h. This process shapes the coke structure, forms strength, and the skeleton retainer phase tends to form a non-dense film structure in the ash phase. The raw coal gas generated during coking is discharged through riser pipes, bridge pipes, and gas collecting pipes and enters the conventional coal gas recovery system. After coking, the coke is sent to the dry quenching process via coke quenching, controlling the coke moisture content to <5%. S6: The coke after dry quenching in step S5 is sieved to the target particle size of 40mm, a surface treatment slurry is prepared, and the coke is impregnated to form a thin layer of enrichment on the surface; it is then dried at 120℃ for 40min to obtain coke with high combustion efficiency. The surface treatment slurry is composed of the following components: 5 wt% calcium carbonate, 2.5 wt% kaolin, 0.1 wt% ferric ammonium citrate, 0.2 wt% calcium acetate, and 0.15 wt% sodium carboxymethyl cellulose; wherein the mass ratio of calcium carbonate to kaolin is 2:1; the balance is industrial softened water, and the sum of the mass percentages of each component is 100%; based on the mass of coke, the amount of the surface treatment slurry applied is 1 wt% on a dry basis.
[0030] Example 2: A production process for high-combustion-efficiency coke, specifically including the following steps: S1: Select coking coal; crush and screen it, controlling the coal particle size distribution as follows: 0-2mm 65%; 0-3mm 95%; >3mm 5%; adjust the initial moisture content of the coal to 7%. S2: Steps S2 and S3 are arranged downstream of the coal tower, in the coal conditioning process before charging; specifically, after the coal from S1 is discharged from the coal tower, it is placed in a drum mixer and mixed at 300 rpm. The atomizing nozzle sprays the preparation A solution for 3 minutes, and the mixing continues for 5 minutes. The hot air drum is used to solidify at a low temperature of 80°C to control the moisture content to 6%. The formulation A solution is composed of the following components: 0.1 wt% ferric nitrate, 0.3 wt% calcium nitrate, 0.1 wt% citric acid, 0.01 wt% sodium carboxymethyl cellulose, and 0.01 wt% zeolite powder, with the balance being industrial softened water. The sum of the mass percentages of each component is 100%. The spray volume of formulation A solution is 1 wt% based on the dry coal mass. S3: Add formulation B to the coal treated with S2 and mix at a high speed of 400 rpm to make the powder evenly coat the surface of the coal particles; add 0.2 wt% water by micro-spraying to suppress dust and promote adhesion; The formulation B is composed of fine SiO2 and ammonium bicarbonate; the D of the fine SiO2 50 The particle size is 2 μm; the amount of fine SiO2 used is 0.6 wt% based on the dry coal mass; the amount of ammonium bicarbonate used is 0.1 wt%. S4: The coal processed in step S3 is loaded into the carbonization chamber via the coal charging system using a top-loading method, with the charging density controlled at 0.70 t / m³. 3 ; S5: A three-stage thermal regime is adopted in the conventional coke oven carbonization chamber. Stage I involves preheating, dehydration, and slow-release pore formation, with the temperature increased from room temperature to 350℃ at a rate of 1℃ / min and held for 60 min. This process involves gentle dehydration and the decomposition of pore-forming components, forming primary pores without damaging the structure. Stage II involves homogenization of the plastic phase and fixing of pore sites, with the temperature increased to 450℃ at a rate of 0.5℃ / min and held for 120 min. This process redistributes the components within the plastic phase, maintains uniformity of anchored pore sites, and establishes pores. Enhanced connectivity lays the foundation for subsequent burnout; Stage III involves high-temperature shaping and strength formation, with the temperature increased to 950℃ at a rate of 2℃ / min and held at the final temperature for 3 hours. This process shapes the coke structure and strengthens it, with the skeleton retaining phase tending to form a non-dense film structure in the ash phase. The raw coal gas generated during coking is discharged through riser pipes, bridge pipes, and gas collecting pipes and enters the conventional coal gas recovery system. After coking, the coke is sent to the wet quenching process via coke quenching and undergoes conventional dewatering treatment. Before impregnation treatment, the moisture content of the coke is controlled to be <5%. S6: The coke after wet quenching and dewatering in step S5 is screened to the target particle size of 60mm, a surface treatment slurry is prepared, and the coke is impregnated to form a thin layer of enrichment on the surface; it is then dried at 100℃ for 60min to obtain coke with high combustion efficiency. The surface treatment slurry is composed of the following components: 2 wt% calcium carbonate, 2 wt% kaolin, 0.05 wt% ferric nitrate, 0.1 wt% calcium nitrate, and 0.1 wt% sodium carboxymethyl cellulose; wherein the mass ratio of calcium carbonate to kaolin is 1:1; the balance is industrial softened water, and the sum of the mass percentages of each component is 100%; based on the mass of coke, the amount of the surface treatment slurry applied is 0.5 wt% on a dry basis.
[0031] Example 3: A production process for high-combustion-efficiency coke, specifically including the following steps: S1: Select coking coal; crush and screen it, controlling the coal particle size distribution as follows: 0-2mm 60%; 0-3mm 90%; >3mm 10%; adjust the initial moisture content of the coal to 12%. S2: Steps S2 and S3 are arranged downstream of the coal tower, in the coal conditioning process before charging; specifically, after the coal from S1 is discharged from the coal tower, it is placed in a drum mixer and mixed at 600 rpm. The atomizing nozzle sprays the preparation A solution for 10 minutes, and the mixing continues for 15 minutes. The hot air drum is used to solidify at a low temperature of 110°C to control the moisture content to 10%. The formulation A solution is composed of the following components: 0.3 wt% ferric ammonium citrate, 0.8 wt% calcium acetate, 0.2 wt% citric acid, 0.1 wt% sodium lignosulfonate, and 0.1 wt% kaolin, with the balance being industrial softened water. The sum of the mass percentages of each component is 100%. The spray volume of formulation A solution is 3 wt% based on the dry coal mass. S3: Add formulation B to the coal treated with S2 and mix at a high speed of 600 rpm to make the powder evenly coat the surface of the coal particles; add 1wt% water by micro-spray to suppress dust and promote adhesion. The formulation B is composed of fine SiO2 and ammonium carbonate; the D of the fine SiO2 50 The particle size is 0.5 μm; the amount of fine SiO2 used is 1.2 wt% based on the dry coal mass; the amount of ammonium carbonate used is 0.3 wt%. S4: The coal processed in step S3 is fed into a tamping machine after being shaken and tamped to form coal cakes. The charging density is controlled at 0.95 t / m³. 3 Then, the coal cake is sent into the carbonization chamber by the coal charging and coke pushing car for furnace loading. S5: A three-stage thermal regime is adopted in the conventional coke oven carbonization chamber. Stage I involves preheating, dehydration, and slow-release pore formation, with the temperature increased from room temperature to 450℃ at a rate of 3℃ / min and held for 30 min. This process involves gentle dehydration and the decomposition of pore-forming components, forming primary pores without damaging the structure. Stage II involves homogenization of the plastic phase and fixing of sites, with the temperature increased to 600℃ at a rate of 2℃ / min and held for 60 min. This process involves redistribution of components within the plastic phase, maintaining uniformity of anchored sites, and enhancing pore connectivity, laying the foundation for subsequent burnout. Stage III involves high-temperature shaping and strength formation, with the temperature increased to 1100℃ at a rate of 5℃ / min and held at the final temperature for 1 h. This process shapes the coke structure, forms strength, and the skeleton retainer phase tends to form a non-dense film structure in the ash phase. The raw coal gas generated during coking is discharged through riser pipes, bridge pipes, and gas collecting pipes and enters the conventional coal gas recovery system. After coking, the coke is sent to the dry quenching process via coke quenching, controlling the coke moisture content to <5%. S6: The coke after dry quenching in step S5 is sieved to the target particle size of 30mm, a surface treatment slurry is prepared, and the coke is impregnated to form a thin layer of enrichment on the surface; it is then dried at 140℃ for 20 minutes to obtain coke with high combustion efficiency. The surface treatment slurry is composed of the following components: 8 wt% calcium carbonate, 6 wt% kaolin, 0.2 wt% ferric ammonium citrate, 0.3 wt% calcium acetate, and 0.2 wt% sodium carboxymethyl cellulose; wherein the mass ratio of calcium carbonate to kaolin is 4:3; the balance is industrial softened water, and the sum of the mass percentages of all components is 100%; based on the mass of coke, the amount of the surface treatment slurry applied is 2 wt% on a dry basis.
[0032] Comparative Example 1: In the coal conditioning process downstream of the coal tower and before loading into the furnace, the coal was treated with preparation A by spraying according to step S2 of Example 1, but without hot air drum low-temperature curing. After spraying, the mixture continued and proceeded directly to step S3; the remaining steps and parameters were consistent with those of Example 1.
[0033] Comparative Example 2: In the coal conditioning process downstream of the coal tower and before charging, no preparation A solution is prepared. An equal volume of industrial softened water equal to the A solution is sprayed into the coal through an atomizing nozzle for low-temperature curing. The iron source, calcium source, citric acid, dispersant, and carrier powder from Example 1 are added directly to the coal in the same amount by dry mixing, and then the process proceeds to step S3. The remaining steps and parameters are consistent with those of Example 1.
[0034] Comparative Example 3: In the coal conditioning process downstream of the coal tower and before charging, step S3 only adds the same amount of pore-forming agent as in Example 1, without adding fine SiO2; the remaining steps and parameters are consistent with those in Example 1.
[0035] Comparative Example 4: In the conventional coke oven carbonization chamber, step S5 adopts a two-stage heating method, specifically: in stage I, the temperature is raised and held according to Example 1; then, without setting stage II, the temperature is raised directly at the heating rate of stage III and held at the final temperature, keeping the total coking time consistent; the method of removing raw coal gas during coking and the dry quenching process after pushing coke are consistent with Example 1; the remaining steps and parameters are consistent with Example 1.
[0036] Comparative Example 5: The coke after dry quenching in step S5 was sieved to the target particle size of 40mm, without surface impregnation treatment or low-temperature drying, and directly used as the test sample; the remaining steps and parameters were consistent with those in Example 1.
[0037] Performance testing: Comprehensive performance testing of coke: For coke samples obtained under different processes in Examples 1-3 and Comparative Examples 1-5, the coke reactivity index (CRI) and post-reaction strength (CSR) were tested according to GB / T 4000-2017; the porosity was tested according to GB / T 4511.1-2008; the moisture content, volatile matter and fixed carbon were tested according to GB / T 2001-2013; and the crush strength (M40) and abrasion resistance (M10) were tested according to GB / T 2006-2008. The test results are shown in Table 1 below.
[0038] Table 1. Test results of comprehensive coke performance under different processes in the examples and comparative examples
[0039] Based on the results in Table 1, Example 1 still exhibits the best overall balance in terms of reactivity, post-reaction strength, shatter resistance, and abrasion resistance, indicating that while improving the reactivity of coke, it also maintains the stability of the coke skeleton and the mechanical integrity of the particles. Combined with the porosity results, it can be seen that Example 1 formed a relatively favorable interconnected pore structure; simultaneously, although its fixed carbon was slightly lower than some comparative examples, its overall performance was still the best, indicating that the introduction of a small amount of functional components did not weaken the overall thermal performance, but rather was more conducive to improving combustion efficiency. Compared with Example 1, the overall performance of Example 2 was slightly lower, indicating that under these conditions, the degree of pore structure optimization and the ability to maintain mechanical properties were weakened; although the reactivity and pore development of Example 3 were further enhanced, the post-reaction strength, shatter resistance, and abrasion resistance were not as good as those of Example 1, indicating that while the pore structure was further developed, it also brought about a decrease in skeleton stability.
[0040] The overall performance of Comparative Example 1 is lower than that of Example 1, indicating that spraying Formulation A without hot air drum low-temperature curing weakens the subsequent structural retention and mechanical integrity of the coke. If the iron / calcium active components after liquid-phase spraying are not fixed in time, they are more likely to migrate and redistribute in the subsequent conditioning and plastic phase stages, thus limiting the improvement of reactivity and not conducive to post-reaction structural stability. Comparative Example 2 is even lower than Comparative Example 1, indicating that even if the same volume of industrial softened water spraying and low-temperature curing process are retained, it is difficult to achieve the effect of Example 1 by only using powder dry mixing to add iron source, calcium source, citric acid, dispersant and carrier micro powder. The complexation dispersion and liquid-phase anchoring effect of Formulation A in solution state plays an important role in the uniform distribution of active components; when this effect is weakened, reactivity, strength retention and wear resistance all decrease accordingly. The overall performance of Comparative Example 3 is more significantly reduced, especially the deterioration of structural retention and wear resistance, indicating that the micro-fine SiO2 skeleton plays an important role in maintaining the relative pore structure stability. Although pore-forming agents can still form primary pores, the lack of fine SiO2 support makes the channels more prone to collapse or blockage during subsequent thermal shrinkage and gray phase evolution, leading to a significant decrease in strength and mechanical integrity. The overall performance of Comparative Example 4 is also significantly lower than that of Example 1, indicating that removing the plastic phase homogenization and site fixation window in Stage II is detrimental to the stable formation of coke structure and active site distribution. Stage II not only affects the uniform shaping of the channel structure but also the redistribution and fixation of active components during carbonization; therefore, the absence of this stage simultaneously weakens reactivity and structural stability. Although Comparative Example 5 still outperforms most of the comparative examples with weakened front-end processes, its overall performance is still lower than that of Example 1, indicating that surface impregnation treatment and low-temperature drying still have a further optimizing effect on coke performance. These results show that, given the foundation laid by front-end coal conditioning, channel construction, and thermal regime control, further enrichment and fixation of surface mineral components still help improve particle surface integrity and wear resistance.
[0041] Ignition and Combustion Stability Test: Coke samples obtained from Example 1 and Comparative Examples 1-5 were selected and tested using a fixed-bed combustion device. The single charge mass was approximately 5 kg. The combustion gas was atmospheric pressure air, and the air volume remained constant across all groups (apparent gas velocity of 0.2 m / s based on the device cross-sectional area). The ignition test was conducted using a programmed temperature rise method: Under constant air volume, the temperature was increased from room temperature to 400℃ at a rate of 10℃ / min and held for 20 min to allow bed moisture and low-boiling-point volatiles to escape smoothly. Subsequently, the temperature was increased to 900℃ at a rate of 10℃ / min. The ignition criterion was defined as the moment when the temperature of the representative temperature measuring point of the bed showed a significant self-accelerated temperature rise relative to the programmed temperature rise baseline and remained stable, while the CO2 concentration continued to increase and the CO signal peaked and then tended to decrease or enter a stable plateau (the ignition criterion is defined as the moment when the following conditions are met simultaneously: ① the temperature of the representative temperature measuring point of the bed shows a significant self-accelerated temperature rise relative to the programmed temperature rise baseline and remains stable for ≥3 min; ② the CO in the flue gas...). 2 The concentration continuously increases and the rate of change is >1% / min; ③ The CO concentration in the flue gas reaches its peak and then declines or enters a stable plateau within a short period of time (<5min); The temperature at which the ignition criterion is triggered is recorded as the ignition temperature, and the time from the start of holding at 400℃ to the triggering of the ignition criterion is recorded as the ignition time. Combustion stability is characterized after the ignition criterion is triggered: Under the same airflow conditions, it continues to run for 30min, and the fluctuation range of CO and CO2 concentrations, as well as the peak height and decline rate of CO, are recorded within this time window; The test results are shown in Table 2 below. Figure 1-2 As shown.
[0042] Table 2. Results of coke ignition performance and flue gas stability under different processes in the examples and comparative examples
[0043] Based on Table 2 and Figure 1-2The results showed that Example 1 performed best in terms of ignition temperature, ignition time, peak CO value, peak fall rate, and steady-state flue gas fluctuations, indicating that it was easier to ignite and had a more stable and complete combustion process. This indicates that in Example 1, after spray loading of formulation A and low-temperature curing, the distribution of active components was more uniform. Combined with the interconnected channels constructed by formulation B and the homogenization and site fixation of the plastic phase in stage II, it was more conducive to the formation of a stable reaction front in the early stage of ignition and to maintaining a low diffusion resistance in subsequent combustion. The ignition and steady-state combustion performance of Comparative Example 1 were lower than those of Example 1, indicating that the removal of low-temperature curing resulted in insufficient fixation of active components, which was detrimental to ignition and stable combustion. Comparative Example 2 was even worse than Comparative Example 1, indicating that even with the same volume of industrial softened water spraying and low-temperature curing process, it was still difficult to achieve the effect of formulation A solution loading by only using powder dry mixing to add active components. This indicates that the complexation dispersion and liquid phase anchoring effect of formulation A in solution state play an important role in improving the uniformity of active site distribution and ignition stability. Although Comparative Example 3 still outperformed some of the other comparative examples in terms of ignition performance, its CO decline was slower and steady-state fluctuations increased, indicating that the removal of fine SiO2 reduced the stability of the pore structure and made the combustion process more susceptible to diffusion limitations. Comparative Example 4 performed the worst overall, indicating that the removal of the stage II window significantly worsened the uniformity of structural stabilization and active site distribution, thus weakening ignition and steady-state combustion performance. Comparative Example 5, while still close to Example 1, performed slightly worse overall, suggesting that surface impregnation treatment and low-temperature drying still have a further optimizing effect on the stability in the later stages of combustion.
[0044] Characterization of burnout performance and combustion efficiency: The characterization of burnout performance and combustion efficiency was carried out under the same apparatus, the same charging method, and the same air volume conditions as the ignition test described above. After heating to 900℃ and determining ignition, the temperature was further increased to the burnout evaluation temperature zone of 1100℃ and held at this temperature for 60 minutes to form distinguishable burnout differences. After the burnout stage, heating was stopped and the mixture was cooled to a safe temperature under air isolation or inert gas conditions. The residual solids were removed and weighed. Based on the ash content determination results of the residual solids, the burnout rate at a fixed time was calculated to evaluate the burnout performance of each group of cokes. During the heat preservation burnout stage, the changes in CO and CO2 concentrations over time were continuously recorded online, and the CO integral (ppm·min) was calculated accordingly. Combustion efficiency was characterized using flue gas component indicators: under the same airflow conditions, the CO and CO2 concentrations during the heat preservation and burnout stage were averaged over time, and the CO / CO2 ratio (calculated as the direct ratio of the time averages of CO (ppm) and CO2 (%) over the same time period for relative comparison) and the cumulative CO emission level were used as relative indicators of incomplete combustion loss; the lower the CO / CO2 ratio and the smaller the CO integral, the more complete the combustion and the higher the effective heat release ratio. To further reflect burnout completeness and support the mechanism of ash film inhibition and later burnout improvement, unburned carbon was measured in the combustion residue after each burnout test; the residue obtained from the test was mixed and sampled, and the unburned carbon content in the residue was determined using the loss on ignition method or the fixed carbon determination method; the loss on ignition method involves igniting in a muffle furnace at 815℃ to constant weight, and the percentage of mass difference before and after ignition is calculated as the characterization index of unburned carbon; the burnout rate and unburned carbon test results are as follows: Figure 3-4 As shown in the figure, the test results for the remaining parameters are shown in Table 3 below.
[0045] Table 3. Characterization results of coke combustion efficiency under different processes in the examples and comparative examples
[0046] Based on Table 3 and Figure 3-4The results analysis showed that Example 1 performed best overall in terms of burnout rate, unburned carbon residue, CO / CO2 ratio, and CO integral, indicating the lowest incomplete combustion loss and the best combustion completeness and sufficiency. This suggests that the synergistic effect between the spray loading and low-temperature curing of Formulation A, the construction and maintenance of interconnected channels by Formulation B, the homogenization and site fixation of the plastic phase in Stage II, and the surface impregnation treatment in Example 1 was more conducive to maintaining low diffusion resistance and a more stable reaction interface in the later stages of combustion. The burnout performance of Comparative Example 1 was lower than that of Example 1, indicating that the removal of low-temperature curing made the active components more prone to migration, which was not conducive to the uniform reaction in the burnout stage. Comparative Example 2 was even lower than Comparative Example 1, indicating that even with the same volume of industrial softened water spraying and low-temperature curing process, it was still difficult to achieve the effect of Formulation A solution loading by only using powder dry mixing. This indicates that the complexation dispersion and liquid phase anchoring effect of Formulation A in solution state play an important role in improving the reaction uniformity in the burnout stage. The burnout performance of Comparative Example 3 showed a more significant decline, indicating that after removing the fine SiO2, the pores were more prone to collapse or blockage under high temperature and ash phase effects, thus exacerbating the limitation of diffusion in the middle and later stages. Comparative Example 4 performed the worst overall, indicating that removing the stage II window was not conducive to structural stabilization and the stable formation of active sites, resulting in the highest incomplete combustion loss. Although Comparative Example 5 was still better than most of the comparative examples with weakened front-end processes, it was still lower than Example 1 overall, indicating that surface impregnation treatment and low-temperature drying still have a further optimizing effect on the burnout sufficiency in the middle and later stages of combustion.
[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A process for producing high-combustion-efficiency coke, characterized in that, Specifically, the process includes the following steps: S1: Select coking coal; crush and screen it, and adjust the initial moisture content of the coal. S2: Place the coal material from S1 into a drum mixer, mix, spray the preparation A solution into the mixture using an atomizing nozzle, continue mixing until uniform, and use a hot air drum for low-temperature curing to control the moisture content; S3: Add formulation B to the coal treated with S2 and mix at high speed; spray water to replenish the mixture. S4: Load the coal processed in step S3 into the furnace; S5: Adopts a three-stage thermal process; controls the moisture content of coke after coking; S6: The coke from step S5 is sieved to the target particle size, a surface treatment slurry is prepared, and the coke is impregnated; then it is dried at low temperature to obtain coke with high combustion efficiency.
2. The production process for high-combustion-efficiency coke according to claim 1, characterized in that, In step S1, the particle size distribution of the coal is controlled as follows: 0-3mm accounts for 20-40%; 3-10mm accounts for 50-75%; and >10mm accounts for 0-10%.
3. The production process for high-combustion-efficiency coke according to claim 1, characterized in that, In step S2, the preparation A solution is composed of the following components: 0.1-0.3 wt% iron source, 0.3-0.8 wt% calcium source, 0.1-0.2 wt% citric acid, 0.01-0.1 wt% dispersant and 0.01-0.1 wt% carrier powder, with the balance being industrial softened water. The sum of the mass percentages of each component is 100%. The spray volume of preparation A solution is 1-3 wt% based on the dry coal mass.
4. The production process for high-combustion-efficiency coke according to claim 3, characterized in that, The iron source is either ferric ammonium citrate or ferric nitrate; the calcium source is either calcium acetate or calcium nitrate.
5. The production process for high-combustion-efficiency coke according to claim 3, characterized in that, The dispersant is any one of polyvinylpyrrolidone, sodium carboxymethyl cellulose, and sodium lignosulfonate.
6. The production process for high-combustion-efficiency coke according to claim 3, characterized in that, The carrier powder is either zeolite powder or kaolin; all carrier powders are screened through a 200-mesh sieve.
7. The production process for high-combustion-efficiency coke according to claim 1, characterized in that, In step S3, the formulation B consists of fine SiO2 and a pore-forming agent; the D of the fine SiO2 50 The particle size is 0.5-2 μm; the pore-forming agent is any one of ammonium bicarbonate, ammonium carbonate and starch; the amount of fine SiO2 used is 0.6-1.2 wt% based on the dry coal mass; the amount of the pore-forming agent used is 0.1-0.3 wt%.
8. The production process for high-combustion-efficiency coke according to claim 1, characterized in that, In step S5, the specific operating parameters of the three-stage thermal regime are as follows: Stage I: preheating, dehydration, and slow-release pore formation, heating from room temperature to 350-450℃ at a heating rate of 1-3℃ / min, and holding for 30-60 min; Stage II: homogenization of plastic phase and fixation of site windows, heating to 450-600℃ at a heating rate of 0.5-2℃ / min, and holding for 60-120 min; Stage III: high-temperature shaping and strength formation, heating to 950-1100℃ at a heating rate of 2-5℃ / min, and holding at the final temperature for 1-3 h.
9. The production process for high-combustion-efficiency coke according to claim 1, characterized in that, In step S6, the target particle size is 30-60 mm.
10. The production process for high-combustion-efficiency coke according to claim 1, characterized in that, In step S6, the surface treatment slurry is composed of the following components: 2-8 wt% calcium carbonate, 2-6 wt% kaolin, 0.05-0.2 wt% iron source, 0.1-0.3 wt% calcium source, and 0.1-0.2 wt% sodium carboxymethyl cellulose; the iron source is either ferric ammonium citrate or ferric nitrate; the calcium source is either calcium acetate or calcium nitrate; wherein the mass ratio of calcium carbonate to kaolin is 1-4:1-3; the balance is industrial softened water, and the sum of the mass percentages of all components is 100%; based on the mass of coke, the amount of surface treatment slurry applied is 0.5-2 wt% on a dry basis.