Coal gasification treatment system of circulating fluidized bed gasifier coupled with carbon residue furnace

Abstract

The utility model discloses a coal gasification treatment system for coupling a circulating fluidized bed gasification furnace with a carbon residue furnace, which is used for carrying out coal gasification treatment on pulverized coal and comprises a circulating fluidized bed gasification furnace coal gas production system and a circulating fluidized bed carbon residue furnace waste heat recovery system coupled with the circulating fluidized bed gasification furnace coal gas production system, the circulating fluidized bed gasification furnace coal gas production system comprises a gasification furnace system, a waste heat recovery system and a first dust removal and purification system, and the circulating fluidized bed carbon residue furnace waste heat recovery system comprises a carbon residue furnace system, a waste heat recovery and denitration system and a second dust removal and purification system. According to the utility model, the circulating fluidized bed gasification furnace system is coupled with the carbon residue furnace system, so that the heat value of fly ash is fully utilized, and the carbon utilization rate and economic benefit of raw coal are greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of coal chemical industry, in particular to a coal gasification processing system of a circulating fluidized bed gasifier coupled with a residual carbon furnace. Background Art

[0002] Coal gasification technology is a key approach to the clean and efficient utilization of coal. Currently, commonly used coal gasification processes are categorized as fixed-bed, fluidized-bed, entrained-bed, and molten-bed, depending on the fuel's movement within the furnace. Fluidized-bed and entrained-bed gasification technologies, by comparison, are more widely used in industry because they produce cleaner gas and eliminate tar and phenol emissions during the gasification process. They have become the mainstream technology for clean gas production.

[0003] Existing coal gasification technology, due to the structural characteristics of fluidized bed gasifiers and the relatively low reaction temperature (around 1000°C), produces coal gas containing unreacted fly ash with a high carbon content, which depletes some of the coal's calorific value. However, the high ash content in fly ash makes it difficult to ignite, making it difficult to process in conventional coal-fired boilers. Even when burned at high temperatures with excessive oxygen, fly ash produces pollutants such as nitrogen oxides and sulfides, and can easily cause problems such as furnace coking. Currently, environmental protection authorities have tightened regulations on fly ash landfill, and the high carbon content (~50%) of fly ash prevents it from being used in the building materials industry, making effective fly ash disposal difficult.

[0004] Chinese invention patent application number 201610240238.0 and publication number CN105779008A disclose a method and system for processing pulverized coal. This method combines a circulating fluidized bed gasification system with an entrained flow gasification system. The entrained flow gasification system uses fly ash from the circulating fluidized bed gasification system as a raw material to address the shortcomings of the circulating fluidized bed, such as low coal utilization and large, difficult-to-handle fly ash volumes, thereby improving coal conversion. However, entrained flow gasifiers utilize gasification reactions, which have lower carbon conversion rates than combustion reactions. Incomplete fly ash treatment results in a high carbon content in the entrained flow ash, hindering subsequent processing, resulting in low overall coal utilization and high equipment investment.

[0005] The Chinese invention patent application document with application number 201410117504.1 and publication number CN103911179A discloses a coal gasification method and device, in which pulverized coal and a gasifying agent are fed into a circulating fluidized bed gasifier for reaction. The gasifier flue gas generated by the reaction is separated into return pulverized coal and a gas flow carrying pulverized coal through a first gas-solid separator, and the return pulverized coal is circulated back to the circulating fluidized bed gasifier for further reaction. The gas flow carrying pulverized coal is passed through a second gas-solid separator to separate coal gas and carbon-containing fly ash. The carbon-containing fly ash is fed into a hot blast furnace and burned at a temperature above 1300°C. The generated hot blast furnace flue gas is returned to the circulating fluidized bed gasifier to participate in the reaction, and the liquid slag produced by the combustion is discharged after cooling. However, the combustion temperature of the hot blast furnace is higher than 1300℃, and the high temperature is prone to coking, etc., and higher requirements are placed on the heat-resistant materials of the equipment; the hot blast furnace uses a liquid slag pool, which requires higher investment, occupies a larger area, and has low heat utilization rate; and the flue gas generated by the hot blast furnace is invalid gas. After being introduced into the gasifier, it will reduce the proportion of effective gas components in the gasifier gas, thereby reducing the calorific value of the gas. Under the same calorific value requirements, the scale of the hot blast furnace is larger, and the investment and area are higher. Utility Model Content

[0006] In response to the shortcomings of the above-mentioned existing coal gasification treatment systems and methods, the applicant provides a coal gasification treatment system that couples a circulating fluidized bed gasification furnace with a residual carbon furnace. The circulating fluidized bed gasification furnace system is coupled with the circulating fluidized bed residual carbon furnace system, which greatly improves the carbon utilization rate and economic effect while simplifying the process and reducing the investment in equipment and system.

[0007] The technical solutions adopted in this utility model are as follows:

[0008] A coal gasification processing system of a circulating fluidized bed gasifier coupled with a residual carbon furnace comprises a circulating fluidized bed gasifier coal gasification system and a circulating fluidized bed residual carbon furnace waste heat recovery system coupled thereto;

[0009] The high-temperature gas output end of the gasifier system of the circulating fluidized bed gasifier gasification system is connected to the waste heat recovery system and the first dust removal and purification system in sequence along the gas processing route; the gasification fly ash output end of the first dust removal and purification system is connected to the residual carbon furnace system of the circulating fluidized bed residual carbon furnace waste heat recovery system;

[0010] The high-temperature flue gas output end of the residual carbon furnace system of the circulating fluidized bed residual carbon furnace waste heat recovery system is followed by the waste heat recovery and denitrification system and the second dust removal and purification system along the flue gas treatment route;

[0011] The gasification furnace system and the residual carbon furnace system are respectively connected to the air supply device through air pipelines and are respectively connected to the coal bunker through coal feeders.

[0012] As a further improvement of the above technical solution:

[0013] A residual carbon furnace front bin is set between the gasification fly ash output end of the first dust removal and purification system and the residual carbon furnace system. The residual carbon furnace front bin is connected to the gasification fly ash output end of the first dust removal and purification system through a pneumatic conveying system and is connected to the residual carbon furnace system through a feeder.

[0014] The softened water supply device is connected to the cold side of the waste heat recovery system through a softened water pipeline, and a deaerator is installed on the softened water pipeline.

[0015] The steam output end of the waste heat recovery system is connected to the cold side of the waste heat recovery and denitrification system through a fourth steam pipeline.

[0016] The steam output end of the waste heat recovery system is connected to the gasifier system through a first steam pipeline, connected to the steam delimiting area through a second steam pipeline, and connected to the deaerator through a third steam pipeline.

[0017] The first air preheater is connected between the high-temperature gas output end of the gasifier system and the waste heat recovery system. The air supply device is connected to the cold side of the first air preheater through a gasification air pipeline and then to the gasifier system.

[0018] A second air preheater is connected between the waste heat recovery and denitrification system and the second dust removal and purification system. The air supply device is connected to the cold side of the second air preheater through a combustion air pipeline and then to the residual carbon furnace system.

[0019] The gas output end of the first dust removal and purification system is connected to the gas cooling system; the flue gas output end of the second dust removal and purification system is connected to the desulfurization system.

[0020] The gasification furnace system includes a gasification furnace body, a first cyclone separator and a first return material, the flue gas outlet of the gasification furnace body is connected to the first cyclone separator, the outlet at the bottom of the first cyclone separator is connected to the circulation inlet of the gasification furnace body through the first return material, and the first return material forms an external circulation loop with the gasification furnace body and the first cyclone separator; the residual char furnace system includes a residual char furnace body, a second cyclone separator and a second return material, the flue gas outlet of the residual char furnace body is connected to the second cyclone separator, the outlet at the bottom of the second cyclone separator is connected to the circulation inlet of the residual char furnace body through the second return material, and the second return material forms an external circulation loop with the residual char furnace body and the second cyclone separator; the first return material and the second return material are connected to the return air supply device through air pipelines respectively; the first steam pipeline is connected to the first return material; the slag outlet of the gasification furnace body is connected to the slag cooler.

[0021] The gasification furnace body is cylindrical as a whole and is insulated by castables. A gasification air distributor is arranged inside the gasification furnace body, and a return air distributor is arranged inside the first return material hopper. The residual carbon furnace body is square as a whole and is insulated by water-cooled walls. A fluidizing air distributor is arranged inside the residual carbon furnace body, and a return air distributor is arranged inside the second return material hopper. The gasifying agent used in the gasification furnace body can be one, two or more of air, oxygen and steam.

[0022] The beneficial effects of the utility model are as follows:

[0023] The utility model couples a circulating fluidized bed gasification furnace system with a residual carbon furnace system: on the one hand, the fly ash that is a by-product of the gasification furnace system and is difficult to utilize is sent to the residual carbon furnace system for combustion. The residual carbon furnace adopts a combustion reaction, the fly ash can fully react, the fly ash carbon utilization rate is high, the waste heat of the fly ash reaction can be recycled, and the calorific value of the fly ash is fully utilized. The by-product steam is used as factory steam or for power generation; the carbon content of the ash after reburning in the residual carbon furnace is less than 2%, and can be sold to building materials companies to turn waste into treasure; by coupling the gasification furnace with the residual carbon furnace, the carbon conversion rate of the raw coal can be increased from the traditional 84-88% to more than 99%, which greatly improves the carbon utilization rate and economic benefits of the raw coal. Furthermore, coupling the gasifier system with the residual carbon furnace system not only allows for comprehensive equipment layout, rational and efficient land use, and unified design of instrumentation, electrical systems, and central control systems, reducing operator workload and staffing requirements, but also reduces the number of equipment required for coal loading, ash conveying, water supply, and utilities. This process coupling allows for flexible steam specifications tailored to process conditions, optimized heat exchange networks, and efficient heat recovery, significantly reducing equipment investment. Compared to traditional coal-fired boilers (industrial or power plant boilers), the residual carbon furnace system not only ignites and effectively treats fly ash, significantly reducing the carbon content of the ash residue, allowing it to be directly used as a raw material in the building materials industry without generating solid waste, but also fully recovers the calorific value of the fly ash, achieving greater energy conservation and environmental protection. The carbon conversion rate of raw coal has been increased from the traditional 84-88% to over 99%, significantly improving carbon utilization and economic benefits. Circulating fluidized bed (CFB) charcoal furnaces have a lower combustion temperature, effectively preventing coking. Furthermore, they utilize waste heat recovery followed by low-temperature pneumatic ash conveying, reducing material requirements, saving investment, and achieving high heat utilization. Compared to existing hot air furnaces, CFB charcoal furnaces offer smaller scale and lower investment footprint, providing the same calorific value.

[0024] The steam output end of the waste heat recovery system of the circulating fluidized bed gasification furnace gasification system of the utility model is connected to the waste heat recovery and denitrification system of the residual charcoal furnace through the fourth steam pipeline, thereby connecting the waste heat recovery system of the gasification furnace and the waste heat recovery and denitrification system of the residual charcoal furnace in series to realize the step-by-step heat exchange of steam. Part of the steam from the waste heat recovery system enters the waste heat recovery and denitrification system through the fourth steam pipeline and undergoes heat exchange again to obtain medium and high pressure (superheated) steam. The medium and high pressure steam can be used for factory steam or power generation, fully recovering and utilizing the calorific value of fly ash, improving energy utilization, and being more green, energy-saving and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the system architecture of the present invention.

[0026] In the picture:

[0027] 10. Gasification furnace; 11. First cyclone separator; 12. First material return device; 13. First air preheater; 14. Waste heat recovery system; 15. First dust removal and purification system; 16. Coal gas cooling system; 17. Deaerator; 18. Slag cooler; 19. Air supply device; 20. Softened water supply device;

[0028] 21. Residual carbon furnace body; 22. Second cyclone separator; 23. Second return feeder; 24. Waste heat recovery and denitrification system; 25. Second air preheater; 26. Second dust removal and purification system; 27. Desulfurization system;

[0029] 28. Pneumatic conveying system; 29. ​​Residual carbon furnace front bin; 30. Feeder;

[0030] 31. Coal bunker; 32. First coal feeder; 33. Second coal feeder;

[0031] 101. Gasification air pipeline; 102. Combustion air pipeline; 200. Softened water pipeline; 201. First steam pipeline; 202. Second steam pipeline; 203. Third steam pipeline; 204. Fourth steam pipeline; 301. First return air pipeline; 302. Second return air pipeline. DETAILED DESCRIPTION

[0032] The specific implementation of the present utility model will be described below with reference to the accompanying drawings.

[0033] like Figure 1 As shown, the coal gasification treatment system described in the present invention includes a circulating fluidized bed gasification furnace coal gasification system and a circulating fluidized bed residual carbon furnace waste heat recovery system coupled thereto.

[0034] The circulating fluidized bed gasification furnace gasification system mainly includes a gasification furnace system, a first air preheater 13, a waste heat recovery system 14, a first dust removal and purification system 15, a gas cooling system 16, a deaerator 17, and a slag cooler 18. The first dust removal and purification system 15 and the gas cooling system 16 constitute the dust removal and cooling system, and the slag cooler 18 constitutes the slag discharge system. The gasification furnace system includes a gasification furnace body 10, a first cyclone separator 11, and a first returner 12. The flue gas outlet of the gasification furnace body 10 is connected to the first cyclone separator 11. The semi-coke outlet at the bottom of the first cyclone separator 11 is connected to the semi-coke inlet of the gasification furnace body 10 through the first returner 12. The first returner 12, the gasification furnace body 10, and the first cyclone separator 11 form an external circulation loop. The slag outlet at the bottom of the gasification furnace body 10 is connected to the slag cooler 18. The waste slag produced after the reaction in the gasification furnace body 10 is cooled by the slag cooler 18 and then sent out. The high-temperature gas separated by the first cyclone separator 11 is firstly subjected to waste heat recovery by the first air preheater 13 and the waste heat recovery system 14, and then the dust content of the gas is reduced to 10mg / Nm 3 After the gas is cooled by the gas cooling system 16, qualified gas is obtained. Depending on the owner's downstream raw gas requirements, the qualified gas can be processed through different processes such as desulfurization and pressurization before being delivered. The air supply device 19 is connected to the cold side of the first air preheater 13 via the gasification air pipeline 101 and then to the fluidizing air inlet at the bottom of the gasification furnace body 10. The gasification air supplied to the gasification furnace body 10 is preheated with the high-temperature gas generated by the gasification furnace body 10, further recovering waste heat, improving heat recovery rate, increasing energy utilization, and being more environmentally friendly. The softened water supply device 20 is connected to the cold side of the waste heat recovery system 14 via a softened water pipeline 200. A deaerator 17 is installed on this softened water pipeline 200. The deoxygenated water, passing through the waste heat recovery system 14, generates saturated or superheated steam, which is transported in four different ways: the first route is delivered to the steam inlet of the first return feeder 12 via a first steam pipeline 201 as a gasifying agent; the second route is delivered to the delimited area via a second steam pipeline 202; the third route is returned to the deaerator 17 via a third steam pipeline 203, where the heat of the steam is used to deoxygenate the softened water; and the fourth route is delivered to the circulating fluidized bed charcoal furnace waste heat recovery system via a fourth steam pipeline 204, where high-pressure / superheated steam is produced for internal use or external distribution, depending on the client's needs. The first return feeder 12, the deoxygenated water, and the circulating fluidized bed charcoal furnace waste heat recovery system all effectively utilize the heat generated by the waste heat recovery system 14, providing steam of varying specifications to meet the client's needs. This further improves heat utilization and enhances environmental protection. The return air is connected to the return air inlet of the first return device 12 through the first return air pipeline 301 as the return air during the startup phase. The gasified fly ash separated by the first dust removal and purification system 15 is transported to the residual carbon furnace front bin 29 for temporary storage through the pneumatic conveying system 28.

[0035] The waste heat recovery system for the circulating fluidized bed charcoal furnace primarily includes the charcoal furnace system, a waste heat recovery and denitrification system 24, a second air preheater 25, a second dust removal and purification system 26, and a desulfurization system 27. The charcoal furnace system comprises the charcoal furnace body 21, a second cyclone separator 22, and a second returner 23. The flue gas outlet of the charcoal furnace body 21 is connected to the second cyclone separator 22, and the bottom outlet of the second cyclone separator 22 is connected to the return air inlet of the charcoal furnace body 21 via the second returner 23. The second returner 23, the charcoal furnace body 21, and the second cyclone separator 22 form an external circulation loop. The fly ash inlet of the charcoal furnace body 21 is connected to the charcoal furnace forehouse 29 via a feeder 30. The charcoal furnace forehouse 29 delivers fly ash to the charcoal furnace body 21 for combustion via the feeder 30. The high-temperature flue gas separated by the second cyclone separator 22 is first subjected to waste heat recovery and denitrification treatment in the waste heat recovery and denitrification system 24, and then further recovered by the second air preheater 25. The flue gas is then purified by the second dust removal and purification system 26. The flue gas obtained by the purification treatment is desulfurized by the desulfurization system 27 to obtain clean flue gas and discharged to the outside. The ash obtained by the purification treatment is sent out for recycling. The air supply device 19 is connected to the cold side of the second air preheater 25 through the combustion air pipeline 102 and then to the air inlet at the bottom of the residual carbon furnace body 21. The air supplied to the residual carbon furnace body 21 is preheated with the high-temperature flue gas generated by the residual carbon furnace body 21, further recovering the waste heat, thereby improving the heat recovery rate, improving the energy utilization rate, and being more green, energy-saving and environmentally friendly. The residual carbon furnace body 21 and the gasification furnace body 10 share the same air supply device 19 to provide air, which reduces equipment investment, operation difficulty, and project land occupation, thereby reducing investment costs. The steam output of the waste heat recovery system 14 of the circulating fluidized bed gasifier gasification system is connected to the cold side of the waste heat recovery and denitrification system 24 via a fourth steam pipeline 204. This connects the waste heat recovery system 14 and the waste heat recovery and denitrification system 24 in series, achieving a step-by-step heat exchange of steam. A portion of the steam from the waste heat recovery system 14 enters the waste heat recovery and denitrification system 24 via the fourth steam pipeline 204, and after further heat exchange, produces medium- and high-pressure (superheated) steam. This medium- and high-pressure steam can be used for factory steam or power generation, fully recovering the calorific value of fly ash, improving energy utilization, and being more environmentally friendly. Return air is connected to the air inlet of the second return feeder 23 via a second return air pipeline 302 as return air during the startup phase. The second return feeder 23 and the first return feeder 12 share a return air supply device to provide air, reducing equipment investment, operational difficulty, and project footprint, thereby reducing investment costs.

[0036] The coal bunker 31 is connected to the pulverized coal inlet of the gasification furnace body 10 via a first coal feeder 32 and to the pulverized coal inlet of the charcoal residue furnace body 21 via a second coal feeder 33. The pulverized coal provided by the coal bunker 31 has a particle size range of 0 to 10 mm. The gasification furnace body 10 and the charcoal residue furnace body 21 share a common coal bunker 31 for pulverized coal. The coal bunker 31 only adds pulverized coal to the charcoal residue furnace body 21 during the startup phase, reducing equipment investment, operational difficulty, and project footprint, ultimately lowering investment costs. The ash residue produced by combustion of gasified fly ash in the charcoal residue furnace front bin 29, after combustion in the charcoal residue furnace body 21, has a carbon content of less than 2%. This low-carbon ash can be used as a raw material in the building materials industry, achieving the goal of turning waste into valuable resources and increasing energy efficiency. Compared to traditional coal-fired boilers (industrial or power plant boilers), the charcoal residue furnace system not only ignites and burns fly ash at a lower temperature, significantly reducing its carbon content, but also allows the ash discharged from the charcoal residue furnace to be directly used as a raw material in the building materials industry, eliminating the generation of solid waste. The fly ash treatment process also recovers heat from coal combustion, increasing the carbon conversion rate of raw coal from the traditional 84-88% to over 99%, significantly improving carbon utilization and economic benefits. Furthermore, the circulating fluidized bed residual carbon furnace, coupled with denitrification and desulfurization systems, ensures that flue gas nitrogen oxide levels meet environmental emission standards.

[0037] The gasification reaction mainly takes place in the gasification furnace body 10, and the carbon content of the fly ash in the coal gas produced after the gasification reaction is about 50%. The gasification furnace body 10 is cylindrical as a whole and is insulated by castables. A gasification air distributor is provided in the gasification furnace body 10 to evenly distribute the gasification air fed into the gasification furnace body 10. A return air distributor is provided in the first return material 12 to evenly distribute the air or steam fed into the first return material 12 and achieve the purpose of external circulation. The gasifying agent used in the gasification furnace body 10 can be one, two or more of air, oxygen and steam, depending on the owner's requirements for the calorific value and use of the coal gas, to produce coal gas with different compositions and calorific values.

[0038] The combustion reaction primarily occurs within the charcoal furnace body 21, and the carbon content of the ash in the flue gas produced after the combustion reaction is less than 2%. The charcoal furnace body 21 is generally square and insulated with water-cooled walls. A fluidizing air distributor is installed within the charcoal furnace body 21 to evenly distribute the combustion air entering the charcoal furnace body 21. A return air distributor is also installed within the second return feeder 23 to evenly distribute the return air entering the second return feeder 23 and achieve external circulation.

[0039] The charcoal residue furnace pre-storage bin 29 is used as a temporary storage bin for temporarily storing the gasified fly ash generated by the circulating fluidized bed gasification furnace gasification system. Compared with the ash bin of the traditional coal gasification process (large capacity, long-term storage), the charcoal residue furnace pre-storage bin 29 can adjust the temporary storage time according to the owner's requirements and actual needs, greatly reducing the bin capacity, saving floor space, the number of steel structures, and reducing investment.

[0040] The coal gasification treatment method for treating raw coal using the coal gasification treatment system of the utility model mainly includes the following steps:

[0041] S10: Pulverized coal is fed from the coal bunker 31 into the gasification furnace body 10 via the first coal feeder 32; at the same time, gasification air is provided by the air supply device 19 and is also fed into the gasification furnace body 10 after being preheated by the first air preheater 13; the pulverized coal undergoes rapid pyrolysis reaction at high temperature, and the generated semi-coke reacts in the reduction zone of the gasification furnace body 10 under the action of the gasifying agent to produce high-temperature coal gas; the high-temperature coal gas and semi-coke enter the first cyclone separator 11 for separation, and high-temperature coal gas and semi-coke particles are obtained; the semi-coke particles return to the gasification furnace body 10 through the first return feeder 12 to continue to participate in the gasification reaction, and the waste slag generated by the gasification furnace body 10 is cooled by the slag cooler 18 and then sent out.

[0042] S20: The high-temperature coal gas separated by the first cyclone separator 11 is purified by the first air preheater 13 and the waste heat recovery system 14 to obtain clean coal gas after the sensible heat is recovered. The clean coal gas is then cooled by the coal gas cooling system 16 and then sent out. The gasified fly ash is sent to the residual carbon furnace front bin 29 for temporary storage through the pneumatic conveying system 28.

[0043] S30: During the start-up phase, pulverized coal is fed from the coal bunker 31 into the charcoal furnace body 21 via the second coal feeder 33, and the fly ash temporarily stored in the charcoal furnace front bin 29 is fed into the charcoal furnace body 21 through the feeder 30. At the same time, combustion air is provided by the air supply device 19 and is also fed into the charcoal furnace body 21 after being preheated by the second air preheater 25. The pulverized coal and fly ash burn with the preheated combustion air at high temperature. After the charcoal furnace body 21 operates normally, the pulverized coal feeding is stopped. The fly ash reacts and burns with the preheated combustion air at high temperature to produce high-temperature flue gas and ash. After the high-temperature flue gas and ash are separated by the second cyclone separator 22, the ash returns to the charcoal furnace body 21 through the second return feeder 23 to continue to participate in combustion. The return air of the second return air pipeline 302 is passed into the second return feeder 23 to establish an external circulation loop.

[0044] S40: The high-temperature flue gas separated by the second cyclone separator 22 is subjected to waste heat recovery and denitrification in the waste heat recovery and denitrification system 24. It then passes through the second air preheater 25 to further recover waste heat. It then passes through the second dust removal and purification system 26 to produce clean flue gas. The clean flue gas is desulfurized in the desulfurization system 27 before being discharged into the atmosphere. The ash removed by the dust removal system can be used by the building materials industry. The waste heat recovered by the waste heat recovery and denitrification system 24 produces medium- and high-pressure (superheated) steam. The waste heat recovered by the second air preheater 25 is used to preheat the combustion air.

[0045] This utility model couples a circulating fluidized bed gasifier system with a residual carbon furnace system. On the one hand, the fly ash, a byproduct of the gasifier system that is difficult to utilize, is fed into the residual carbon furnace system for combustion, fully utilizing the calorific value of the fly ash. The byproduct steam is used as factory steam or for power generation. The carbon content of the ash after reburning in the residual carbon furnace is less than 2%, which can be sold to building materials companies, turning waste into treasure. By coupling the gasifier with the residual carbon furnace, the carbon conversion rate of the raw coal can be increased from the traditional 84-88% to over 99%, significantly improving the carbon utilization rate and economic benefits of the raw coal. On the other hand, the coupled design of the gasifier system and the residual carbon furnace system not only allows for overall consideration of equipment layout, rational and efficient land use, and unified design of instrumentation, electrical equipment, and central control, reducing worker workload and staffing requirements, but also rationally sharing equipment can reduce the number of equipment in the coal loading, ash conveying, water supply, and public auxiliary systems. According to the process design and the owner's needs, the steam specifications can be flexibly set, the heat exchange network can be optimized, and heat can be efficiently recovered, significantly reducing equipment investment.

[0046] The above description is an explanation of the present invention, not a limitation of the present invention. The present invention may be modified in any form without violating the spirit of the present invention.

Claims

1. A coal gasification system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace, characterized in that: It includes a circulating fluidized bed gasification furnace gasification system and a coupled circulating fluidized bed residual carbon furnace waste heat recovery system; The high-temperature coal gas output end of the gasification furnace system of the circulating fluidized bed gasification furnace gasification system is connected to the waste heat recovery system (14) and the first dust removal and purification system (15) in sequence along the coal gas processing route; the gasification fly ash output end of the first dust removal and purification system (15) is connected to the residual carbon furnace system of the circulating fluidized bed residual carbon furnace waste heat recovery system; The high-temperature flue gas output end of the residual carbon furnace system of the circulating fluidized bed residual carbon furnace waste heat recovery system is sequentially followed by a waste heat recovery and denitrification system (24) and a second dust removal and purification system (26) along the flue gas treatment route; The gasification furnace system and the residual carbon furnace system are connected to the air supply device (19) through air pipelines, and are connected to the coal bunker (31) through coal feeders.

2. The coal gasification treatment system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 1, characterized in that: A residual charcoal furnace front bin (29) is provided between the gasification fly ash output end of the first dust removal and purification system (15) and the residual charcoal furnace system. The residual charcoal furnace front bin (29) is connected to the gasification fly ash output end of the first dust removal and purification system (15) through a pneumatic conveying system (28) and is connected to the residual charcoal furnace system through a feeder (30).

3. The coal gasification treatment system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 1, characterized in that: The softened water supply device (20) is connected to the cold side of the waste heat recovery system (14) through a softened water pipeline (200), and a deaerator (17) is provided on the softened water pipeline (200).

4. The coal gasification treatment system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 3, characterized in that: The steam output end of the waste heat recovery system (14) is connected to the cold side of the waste heat recovery and denitration system (24) via a fourth steam pipeline (204).

5. The coal gasification treatment system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 3, characterized in that: The steam output end of the waste heat recovery system (14) is connected to the gasifier system via a first steam pipeline (201), connected to the steam delimiting area via a second steam pipeline (202), and connected to the deaerator (17) via a third steam pipeline (203).

6. The coal gasification treatment system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 1, characterized in that: A first air preheater (13) is connected between the high-temperature coal gas output end of the gasifier system and the waste heat recovery system (14), and an air supply device (19) is connected to the cold side of the first air preheater (13) through a gasification air pipeline (101) and then connected to the gasifier system.

7. The coal gasification treatment system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 1, characterized in that: A second air preheater (25) is connected between the waste heat recovery and denitrification system (24) and the second dust removal and purification system (26). The air supply device (19) is connected to the cold side of the second air preheater (25) through the combustion air pipeline (102) and then connected to the residual carbon furnace system.

8. The coal gasification treatment system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 1, characterized in that: The coal gas output end of the first dust removal and purification system (15) is connected to the coal gas cooling system (16); and the flue gas output end of the second dust removal and purification system (26) is connected to the desulfurization system (27).

9. The coal gasification processing system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 1, characterized in that: The gasification furnace system includes a gasification furnace body (10), a first cyclone separator (11) and a first return material (12), the flue gas outlet of the gasification furnace body (10) is connected to the first cyclone separator (11), the outlet at the bottom of the first cyclone separator (11) is connected to the circulation inlet of the gasification furnace body (10) through the first return material (12), and the first return material (12) and the gasification furnace body (10) and the first cyclone separator (11) form an external circulation loop; the residual carbon furnace system includes a residual carbon furnace body (21), a second cyclone separator (22) and a second return material (23), the residual carbon furnace The flue gas outlet of the gasification furnace (21) is connected to the second cyclone separator (22), and the outlet at the bottom of the second cyclone separator (22) is connected to the circulation inlet of the residual char furnace body (21) through the second return material device (23). The second return material device (23), the residual char furnace body (21), and the second cyclone separator (22) form an external circulation loop; the first return material device (12) and the second return material device (23) are respectively connected to the return air supply device through air pipelines; the first steam pipeline (201) is connected to the first return material device (12); and the slag outlet of the gasification furnace body (10) is connected to the slag cooler (18).

10. The coal gasification processing system comprising a circulating fluidized bed gasifier coupled with a residual carbon furnace according to claim 9, characterized in that: The gasification furnace body (10) is cylindrical in shape as a whole and is insulated by castable material. A gasification air distributor is provided in the gasification furnace body (10), and a return air distributor is provided in the first return material device (12). The residual carbon furnace body (21) is square in shape as a whole and is insulated by water-cooled wall. A fluidizing air distributor is provided in the residual carbon furnace body (21), and a return air distributor is provided in the second return material device (23).

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