Device and method for recycling and purifying high-temperature coal gas energy of submerged arc furnace

Abstract

The invention provides a submerged arc furnace high-temperature coal gas energy recovery and purification treatment device and method. The device comprises a high-temperature energy recovery mechanism, a high-temperature filtering mechanism and a medium and low-temperature energy recovery mechanism which are sequentially connected along a coal gas flow, and a purified ash conveying treatment mechanism and a filter regeneration mechanism which are respectively connected. According to the device, high-temperature coal gas is cooled through primary heat exchange, and high-temperature energy is recycled; then filtering and dedusting are carried out at high temperature, and ultralow emission is achieved; the purified coal gas is subjected to secondary heat exchange, and medium and low temperature energy is deeply recovered; conveying the collected purified ash under a heat preservation condition; and the purified coal gas is pressurized and regenerated to realize self-circulation ash removal. System blockage caused by tar condensation is avoided from the source, stepped efficient recovery of gas energy and high-temperature efficient purification of dust are achieved, meanwhile, the quality of purified gas is guaranteed, and the system has the comprehensive advantages of being stable, high in energy efficiency and low in operation cost.

Description

Technical Field

[0001] This invention relates to the field of industrial gas purification and energy recovery technology, specifically to an apparatus and method for energy recovery and purification of high-temperature coal gas from a submerged arc furnace. Background Technology

[0002] Submerged arc furnaces, also known as electric arc furnaces or resistance furnaces, are mainly used for the reduction smelting of ores, carbonaceous reducing agents, and solvents. They primarily produce ferrosilicon, ferromanganese, ferrochrome, ferrotungsten, and ferrosilicon-manganese alloys, which are important industrial raw materials in the metallurgical industry and chemical raw materials such as calcium carbide. The production process is energy-intensive, generating large quantities of high-temperature gas during smelting. The gas temperature typically reaches 700℃-1200℃, and the heat it carries accounts for approximately 40%-50% of the total heat input to the submerged arc furnace, indicating significant potential for energy recovery.

[0003] The coal gas has a complex composition and distinctive characteristics: high combustible content, with a carbon monoxide (CO) volume concentration as high as 80%-90%, making it highly valuable for recovery as fuel or chemical feedstock; extremely high dust concentration, reaching 150-250 g / m³; and also contains highly viscous tar components (150-300 mg / m³, with a precipitation temperature of 300℃-400℃). Therefore, efficient purification and energy recovery of the coal gas are crucial for achieving energy conservation and carbon reduction, comprehensive resource utilization, environmental protection, reduced production costs, and improved corporate economic benefits, and have significant practical implications for promoting energy conservation and emission reduction in the industry.

[0004] Currently, the traditional coal gas purification and energy utilization processes commonly used in the industry typically follow a "cooling first, dust removal later" approach. Limited by the temperature resistance of conventional high-temperature filter bag materials (usually ≤260℃) and the tendency of tar components in the coal gas to condense and precipitate at low temperatures (below approximately 200℃), traditional processes first use multi-stage air coolers or water cooling devices to forcibly cool the high-temperature coal gas (700℃-1200℃) to approximately 200℃. The cooled coal gas then enters a baghouse dust collector and other equipment for filtration and purification. The purified gas is then sent to subsequent processes for use as fuel or raw material.

[0005] However, this traditional process has several technical bottlenecks and inherent defects that urgently need to be addressed: The process is lengthy and energy-inefficient: the cooling process usually requires 3-4 stages of series equipment, the system occupies a large area, and the cooling process itself consumes a lot of electricity or water resources. Not only does it fail to recover the sensible heat of the high-temperature gas, it also increases the operating energy consumption. High-quality energy resources are seriously wasted: High-temperature coal gas at 700℃-1200℃ is directly cooled to medium and low temperatures, completely discarding its high-quality thermal energy and failing to achieve energy cascade and efficient utilization, resulting in huge energy waste. The system faces a high risk of clogging and poor operational stability: the operating temperature of traditional dust removal processes (approximately 200°C) overlaps with the condensation and precipitation temperature range of tar. The precipitated viscous tar mixes with dust, easily forming a highly adhesive, layered deposit on the surface of the dust collector filter bags, the housing, and the inner walls of subsequent pipelines. This deposit is difficult to remove, and long-term operation will lead to a sharp increase in system resistance, a reduction in flow cross-section, and even system clogging, severely impacting production continuity and equipment lifespan. Impaired purified gas quality affects subsequent utilization: To avoid the aforementioned blockages, nitrogen is introduced into some processes for ash removal. The introduction of nitrogen dilutes the CO concentration in the purified coal gas, altering its composition. This not only reduces its calorific value and quality as fuel or feedstock but may also interfere with subsequent fine utilization processes such as chemical synthesis.

[0006] In summary, existing technologies for processing blast furnace gas face prominent challenges such as energy waste, complex processes, poor operational reliability, and reduced quality of by-products (purified gas). Summary of the Invention

[0007] The purpose of this invention is to provide a device and method for energy recovery and purification of high-temperature coal gas in submerged arc furnaces, which can achieve direct and efficient purification at high temperatures, simultaneous deep recovery of high / medium / low-grade energy from coal gas, and ensure long-term stable operation of the system. This solves the problems of energy waste, complex processes, poor operational reliability, and reduced quality of by-products (purified gas) in existing submerged arc furnace gas treatment technologies.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A device for energy recovery and purification of high-temperature coal gas from a submerged arc furnace includes a high-temperature energy recovery mechanism, a high-temperature filtration mechanism, and a medium-low temperature energy recovery mechanism connected sequentially along the coal gas flow path, as well as a purified ash conveying and processing mechanism and a filter regeneration mechanism respectively connected to the high-temperature energy recovery mechanism, the high-temperature filtration mechanism, and the medium-low temperature energy recovery mechanism. The gas inlet of the high-temperature energy recovery mechanism is used to receive high-temperature gas generated by the electric arc furnace, and its outlet is connected to the gas inlet of the high-temperature filtration mechanism. The purified gas outlet of the high-temperature filtration mechanism is connected to the gas inlet of the medium-low temperature energy recovery mechanism. The high-temperature energy recovery mechanism, the high-temperature filtration mechanism, and the medium-low temperature energy recovery mechanism are all equipped with ash collectors, and the outlet of the ash collectors is connected to the purified ash conveying and processing mechanism. The air inlet of the filter regeneration mechanism is connected to the purified coal gas outlet of the high-temperature filter mechanism, and its air outlet is connected to the regeneration port of the high-temperature filter mechanism, which is used to pressurize part of the purified coal gas and return it to regenerate the high-temperature filter mechanism.

[0009] Furthermore, the high-temperature energy recovery mechanism is a heat recovery device with a membrane wall heat exchange structure, and is connected to a steam drum that integrates steam into an external steam pipeline network; the device is equipped with a forced circulation circulating water system, a water supply treatment and makeup water system.

[0010] Furthermore, the membrane wall heat exchange structure of the high-temperature energy recovery mechanism adopts a herringbone tube arrangement with an elevation angle greater than 45°.

[0011] Furthermore, the high-temperature filtration mechanism adopts a high-temperature metal filter element, and the filter element is a nickel-chromium alloy fiber filter element.

[0012] Furthermore, the medium-low temperature energy recovery mechanism is a heat recovery unit that adopts forced circulation as a whole, and is connected to a steam drum for incorporating steam into an external steam network; the device is equipped with an evaporator system, a superheater system and an economizer system; its main body is also equipped with a self-cleaning device.

[0013] Furthermore, the clean ash conveying and processing mechanism includes a pneumatic conveying pump chamber, a clean ash collection chamber, and an insulated conveying pipeline connecting the two; the pneumatic conveying pump chamber and the clean ash collection chamber are provided with heating and insulation jackets on the outside, and the insulated conveying pipeline is provided with an insulated pipeline jacket on the outside, for maintaining the temperature inside the equipment and pipeline between 280°C and 320°C.

[0014] A method for energy recovery and purification of high-temperature coal gas from a submerged arc furnace includes the following steps: S1. High-temperature gas first-stage cooling: The high-temperature gas generated by the electric arc furnace at a temperature of 700℃-1200℃ undergoes a first-stage heat exchange to recover high-temperature energy and reduce the gas temperature to 500℃-700℃. S2. High-temperature purification: The gas after primary cooling is filtered at high temperature to reduce the dust concentration in the gas to below 10mg / m³. S3, Secondary Cooling and Steam Generation: The purified coal gas undergoes secondary heat exchange to recover medium and low temperature energy and generate steam, while further reducing the coal gas temperature to below 50°C. S4. High-temperature pneumatic ash conveying: Collects the purified ash generated during filtration and heat exchange, and conveys it to the centralized silo using a positive pressure dense phase pneumatic conveying method at a temperature of 280℃-320℃. S5. Self-circulating filter regeneration: Extract a portion of the purified coal gas, pressurize it to 0.6MPa-0.9MPa, and return it to the filtration stage for regeneration.

[0015] Furthermore, in the first-stage cooling step of the high-temperature gas, saturated steam with a pressure of 1MPa-2MPa is generated through heat exchange; in the second-stage cooling and steam generation step, superheated steam with a pressure of 1MPa-2MPa and a temperature of 220℃-250℃ is generated through heat exchange.

[0016] Furthermore, in the high-temperature pneumatic ash conveying step, the conveying air pressure is 0.4MPa-0.6MPa.

[0017] Furthermore, in the self-circulating filter regeneration step, the regeneration operation is triggered based on the operating resistance of the filter mechanism or a set time period.

[0018] As can be seen from the above technical solutions, the present invention has the following technical advantages compared with the prior art: 1. This invention conducts dust separation at a high temperature of 500℃-700℃, ensuring that the tar in the coal gas remains in a gaseous state. This fundamentally avoids the problems of filter clogging, equipment scaling, and increased system resistance caused by tar condensation and dust adhesion. Combined with a high-temperature resistant and corrosion-resistant nickel-chromium alloy metal filter element, the system can operate stably at high temperatures for extended periods and achieve ultra-low emissions of dust concentration. 2. This invention employs a two-stage system of high-temperature energy recovery and medium-low temperature energy recovery, which gradually cools the coal gas from 700℃-1200℃ to below 50℃, achieving full energy recovery from high grade to low grade; it produces saturated steam and superheated steam respectively, significantly improving the overall energy utilization efficiency; 3. This invention uses a pneumatic conveying system with full heat tracing and insulation to maintain the temperature of the ash conveying equipment and pipelines at 280℃-320℃ (higher than the tar condensation point), ensuring the dry and smooth conveying of purified ash and reliable system operation; 4. This invention uses the purified coal gas from the system itself to regenerate the filter, completely eliminating the need for external nitrogen; it ensures that the CO concentration in the purified coal gas is not diluted, meeting the quality requirements of subsequent chemical raw materials or fuel gas; at the same time, it saves investment and energy consumption in the nitrogen production system, significantly reducing operating costs; 5. This invention replaces the lengthy process of traditional multi-stage cooling and medium-low temperature dust removal with a high-temperature heat recovery unit, a high-temperature metal filter, and a medium-low temperature heat recovery unit. The equipment layout is compact and occupies a small area, achieving multiple benefits such as environmental protection, carbon reduction, energy saving, and cost reduction. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the device for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to the present invention. In the diagram: 1. Mineral arc furnace; 2. First heat recovery unit; 3. High-temperature metal filter element; 4. Second heat recovery unit; 5. Pneumatic conveying pump compartment; 6. Purified ash collection compartment; 7. Heating and insulation jacket; 8. Insulated pipe jacket; 9. Steam drum; 10. Purification fan; 11. Gas compressor. Detailed Implementation

[0020] A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Example 1

[0021] like Figure 1 The device for energy recovery and purification of high-temperature coal gas from the blast furnace shown includes a high-temperature energy recovery mechanism, a high-temperature filtration mechanism, a medium-low temperature energy recovery mechanism arranged sequentially along the coal gas treatment process, as well as a purification ash conveying and treatment mechanism and a filter regeneration mechanism, forming a complete integrated treatment system.

[0022] In this preferred embodiment, the high-temperature energy recovery mechanism is specifically a first heat recovery unit 2. Its gas inlet is connected to the gas outlet of the submerged arc furnace 1 via a pipeline to receive high-temperature gas containing dust and tar at an initial temperature of 700℃-1200℃. The first heat recovery unit 2 adopts a membrane wall heat exchange structure and is equipped with a forced circulation water system, water treatment, and makeup water system to ensure heat exchange stability and reliability under high heat flux density. Specifically, its membrane wall is designed as a herringbone tube array with an elevation angle greater than 45°. This structure effectively prevents the adhesion and accumulation of fine, sticky dust unique to the submerged arc furnace on the heat exchange surface, ensuring long-term efficient heat exchange. The first heat recovery unit 2 generates saturated steam at a pressure of approximately 1MPa-2MPa through heat exchange and is connected to a steam drum 9, ultimately integrating the steam into the external (plant area) steam network for downstream units. After this stage of heat exchange, the gas temperature drops from 700℃-1200℃ to 500℃-700℃.

[0023] The high-temperature filtration mechanism described in this preferred embodiment is a high-temperature metal filter element 3. Its gas inlet is connected to the gas outlet of the first heat recovery unit 2, receiving gas cooled to 500℃-700℃. This filter uses a customized nickel-chromium alloy fiber filter element; its high nickel content ensures excellent mechanical properties and durability in a high-temperature environment of 500℃-700℃, while its high chromium content provides good corrosion resistance. After fine filtration by this filter, the dust concentration in the gas is reduced to below 10mg / m³, achieving "ultra-low emissions." A dust collector is provided at the bottom of the filter to collect the trapped dust.

[0024] In this preferred embodiment, the low-temperature energy recovery mechanism is a second heat recovery unit 4. Its gas inlet is connected to the purified gas outlet of the high-temperature metal filter element 3, receiving deeply purified gas at 500℃-700℃. This second heat recovery unit 4 also employs a forced circulation method and is equipped with a complete evaporator system, superheater system, and economizer system. Due to the extremely low dust concentration in the inlet air (<10mg / m³), the risk of heat exchange surface contamination is greatly reduced, allowing the gas to be fully cooled in the recovery unit, significantly extending the heat exchange temperature range to below 50℃, and deeply recovering low-temperature energy. During this process, superheated steam with a pressure of 1MPa-2MPa and a temperature of 220℃-250℃ is generated, which is also connected to the external (plant area) steam network via the steam drum 9. Furthermore, the unit is equipped with a self-cleaning device to further remove any possible trace amounts of ash and maintain heat exchange efficiency.

[0025] The ash conveying and processing mechanism described in this preferred embodiment is used to process dust (purified ash) collected from the high-temperature metal filter cartridge 3 and the ash collector of the second heat recovery unit 4. The system includes a pneumatic conveying pump chamber 5, a purified ash collection chamber 6, and an insulated conveying pipeline connecting the two. Considering that trace amounts of tar gas may be carried in the dust, which would increase the ash's viscosity upon condensation during cooling, a full-process insulated heating design is adopted: the pneumatic conveying pump chamber 5 and the purified ash collection chamber 6 are equipped with heating and insulation jackets 7, and the insulated conveying pipeline is equipped with an insulated pipeline jacket 8. By introducing hot air into the jackets, the temperature inside the equipment and pipeline is maintained between 280℃ and 320℃, ensuring that the purified ash remains above the tar condensation temperature throughout the entire conveying process, achieving constant temperature or rising temperature conveying, and completely avoiding the risk of pipeline blockage due to coking. The conveying adopts a positive pressure dense-phase pneumatic conveying method, with the conveying air pressure maintained at 0.4MPa-0.6MPa.

[0026] The core of the filter regeneration described in this preferred embodiment is the gas compressor 11. Its inlet is connected to the purified gas outlet pipeline of the high-temperature metal filter element 3, drawing in a portion of the purified gas (dust concentration <10mg / m³, CO concentration maintained at its original high level). This portion of gas is pressurized to 0.6MPa-0.9MPa by the gas compressor 11 and then sent through a pipeline to the regeneration port of the high-temperature metal filter element 3 to regenerate the filter element. This innovative design utilizes the system's own purified gas for dust removal, completely eliminating the need to introduce external nitrogen in traditional processes. This not only saves on the construction and operating costs of the nitrogen generation system but, more importantly, avoids the dilution of the purified gas (used as fuel or chemical raw material) by nitrogen, ensuring the high concentration and stable composition of CO in subsequent utilization processes.

[0027] In practical applications, to ensure the continuous and stable flow of gas throughout the system and to overcome the resistance of various equipment and pipelines in the process, a purification fan 10 is installed at the end of the system (e.g., before the final gas discharge or entry into the user's pipeline network). This fan provides the necessary power to the system, maintains the furnace and purification system in a suitable slightly negative pressure state, and ensures that the gas is effectively collected and safely transported. Example 2

[0028] This embodiment provides a method for energy recovery and purification of high-temperature coal gas from a submerged arc furnace based on the device described in Embodiment 1, specifically including the following steps: S1. High-temperature gas primary cooling and high-temperature energy recovery: High-temperature coal gas (700℃-1200℃, dust content 150-250g / m³, tar content 150-300mg / m³, precipitation temperature 300℃-400℃) produced by the electric arc furnace 1 is introduced into the first heat recovery unit 2. The coal gas exchanges heat with the membrane wall of the heat recovery unit, converting its sensible heat into the thermal energy of steam, producing saturated steam at a pressure of 1MPa-2MPa. This process reduces the coal gas temperature from the initial approximately 700℃-1200℃ to 500℃-700℃. This step directly recovers the highest grade of thermal energy from the coal gas, directly improving energy utilization compared to the traditional "pre-cooling" process.

[0029] S2, High-temperature fine filtration dust removal: The 500℃-700℃ coal gas, after primary cooling, is introduced into the high-temperature metal filter element 3. At 500℃, the tar components in the coal gas remain gaseous and do not condense. As the coal gas passes through the nickel-chromium alloy fiber filter element, dust is efficiently trapped, reducing the dust concentration at the outlet gas to below 10mg / m³, achieving "ultra-clean filtration" at high temperatures. This high-temperature purification fundamentally avoids the tar condensation temperature range (approximately below 200℃), eliminating the problem of dust and tar mixing and adhering, causing filter bag or equipment blockage.

[0030] S3, Secondary Deep Cooling and Medium-Low Temperature Energy Recovery: Clean, high-temperature coal gas (500℃-700℃) after fine dust removal is introduced into the second heat recovery unit 4. The coal gas flows sequentially through the evaporator, superheater, economizer, and other heating surfaces, where heat is fully recovered, generating superheated steam at a pressure of 1MPa-2MPa and a temperature of 220℃-250℃. The coal gas itself is then deeply cooled to below 50℃. Because the coal gas has been deeply purified beforehand, there is almost no dust adhering to the heat exchange surfaces, resulting in high and stable heat exchange efficiency. This achieves stepped and deep energy recovery from high to medium and low temperatures, significantly improving the overall energy recovery efficiency.

[0031] During the gas flow and processing in S1 to S3, the purification fan 10 continuously provides power to the system, ensuring that the gas flows stably through each processing unit in sequence and maintaining the overall pressure balance of the system.

[0032] S4. High-temperature constant-temperature pneumatic ash conveying: The purified ash collected by the high-temperature metal filter cartridge 3 and the second heat recovery unit 4 is sent to the pneumatic conveying pump chamber 5 via a high-temperature sealed scraper conveyor and other equipment. During the conveying process, the entire ash conveying system (including the pump chamber 5, the centralized chamber 6, and the connecting pipes) is heated and insulated by the heating and insulation jacket 7 and the insulation pipe jacket 8 to maintain the system temperature at 180℃-220℃. At this temperature, the trace amounts of tar gas entrained in the purified ash will not condense. Subsequently, compressed gas at a pressure of 0.4MPa-0.6MPa is used to safely and without blockage transport the purified ash to the purified ash centralized chamber 6 for temporary storage or external transport in a positive pressure dense phase conveying mode.

[0033] S5, Filter Regeneration: A portion of the purified gas is diverted from the main purified gas pipeline at the outlet of the high-temperature metal filter element 3 and pressurized to 0.6MPa-0.9MPa by the gas compressor 11. According to the preset control mode, the pressurized purified gas is pulse-driven back to filter 3 for regeneration, regenerating the filter element and dislodging the filter cake. The regenerated gas flow re-enters the main gas process. This step utilizes the system's own product gas (clean furnace gas) for regeneration, eliminating the need for external nitrogen. This not only reduces operating costs but, more importantly, ensures the purity of the gas returning to the main process, preventing CO concentration dilution and perfectly meeting the quality requirements of downstream chemical raw materials or fuel gas.

[0034] Through the orderly combination and synergistic operation of the above-mentioned devices and methods, this invention achieves direct and efficient purification of blast furnace gas at high temperatures, tiered deep energy recovery, long-term stable operation of the system, and assurance of product gas quality, forming a new process for efficient, energy-saving, and reliable resource utilization.

[0035] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for energy recovery and purification of high-temperature coal gas from a submerged arc furnace, characterized in that, It includes a high-temperature energy recovery mechanism, a high-temperature filtration mechanism, and a medium-low temperature energy recovery mechanism connected sequentially along the gas flow path, as well as a purification ash conveying and processing mechanism and a filter regeneration mechanism respectively connected to the high-temperature energy recovery mechanism, the high-temperature filtration mechanism, and the medium-low temperature energy recovery mechanism; The gas inlet of the high-temperature energy recovery mechanism is used to receive high-temperature gas generated by the electric arc furnace, and its gas outlet is connected to the gas inlet of the high-temperature filtration mechanism. The purified gas outlet of the high-temperature filtration mechanism is connected to the gas inlet of the medium-low temperature energy recovery mechanism. The high-temperature energy recovery mechanism, the high-temperature filtration mechanism, and the medium-low temperature energy recovery mechanism are all equipped with anti-adhesion ash collectors, and the outlet of the ash collectors is connected to the purified ash conveying and processing mechanism. The air inlet of the filter regeneration mechanism is connected to the purified gas outlet of the high-temperature filter mechanism, and its outlet is connected to the high-temperature filter mechanism, which is used to pressurize the purified gas and return it to regenerate the high-temperature filter mechanism.

2. The apparatus for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 1, characterized in that, The high-temperature energy recovery mechanism is a heat recovery device with a membrane wall structure, and is connected to a steam drum for incorporating steam into an external steam network; the device is equipped with a forced circulation water system, water treatment and water replenishment system.

3. The apparatus for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 2, characterized in that, The membrane wall heat exchange structure of the high-temperature energy recovery mechanism adopts a herringbone tube arrangement with an elevation angle greater than 45°.

4. The apparatus for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 1, characterized in that, The high-temperature filtration mechanism uses a high-temperature metal filter element, and the filter element is a nickel-chromium alloy fiber filter element.

5. The apparatus for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 1, characterized in that, The medium-low temperature energy recovery mechanism is a heat recovery unit that adopts forced circulation as a whole and is connected to a steam drum for integrating steam into an external steam network; the heat recovery unit is equipped with an evaporator system, a superheater system and an economizer system; its heat exchanger body is equipped with a self-cleaning system.

6. The apparatus for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 1, characterized in that, The clean ash conveying and processing mechanism includes a pneumatic conveying pump chamber, a clean ash collection chamber, and an insulated conveying pipeline connecting the two. The pneumatic conveying pump chamber and the clean ash collection chamber are equipped with heating and insulation jackets, and the insulated conveying pipeline is equipped with an insulated pipeline jacket, which is used to maintain the temperature inside the equipment and pipeline between 280°C and 320°C.

7. A method for energy recovery and purification of high-temperature coal gas from a submerged arc furnace, characterized in that, Includes the following steps: S1. High-temperature gas first-stage cooling: The high-temperature gas generated by the electric arc furnace at a temperature of 700℃-1200℃ undergoes a first-stage heat exchange to recover high-temperature energy and reduce the gas temperature to 500℃-700℃. S2. High-temperature purification: The gas after primary cooling is filtered at high temperature to reduce the particulate matter in the gas to below 10mg / m³. S3, Secondary Cooling and Steam Generation: The purified coal gas undergoes secondary heat exchange to recover medium and low temperature energy and generate steam, while further reducing the coal gas temperature to below 50°C. S4. High-temperature pneumatic ash conveying: Collects the purified ash generated during filtration and heat exchange, and conveys it to the centralized silo using a positive pressure dense phase pneumatic conveying method at a temperature of 280℃-320℃. S5. Self-circulating filter regeneration: Extract a portion of the filtered purified gas, pressurize it to 0.6MPa-0.9MPa, and return it to the filter stage for regeneration.

8. The method for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 7, characterized in that, In the first-stage cooling step of the high-temperature gas, saturated steam with a pressure of 1MPa-2MPa is generated through heat exchange; in the second-stage cooling and steam generation step, superheated steam with a pressure of 1MPa-2MPa and a temperature of 220℃-250℃ is generated through heat exchange.

9. The method for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 7, characterized in that, In the high-temperature pneumatic ash conveying step, the conveying air pressure is 0.4MPa-0.6MPa.

10. The method for energy recovery and purification of high-temperature coal gas from a submerged arc furnace according to claim 7, characterized in that, In the self-circulating filter regeneration step, the regeneration operation is triggered based on the operating resistance of the filter mechanism or a set time period.

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