Modular maintenance method for wsa acid production system and wsa acid production line

Abstract

The present application relates to a kind of modular maintenance method of WSA acid production system and WSA acid production line, modular maintenance method includes boiler system maintenance, acid vapor delivery combustion system maintenance, acid circulation system maintenance and auxiliary system maintenance, multiple systems can be simultaneously maintained, also can be sequentially maintained, after completing the maintenance of all systems, interlock test is carried out, when interlock test meets the requirements, interlock is removed, when officially resuming production, each system interlock is restored.The present application is maintained in sub-system, sequentially, reduces unnecessary step, is conducive to improving maintenance efficiency.

Description

Technical Field

[0001] This invention relates to the field of acid production technology, and more specifically, to a modular maintenance method for WSA acid production systems and a WSA acid production line. Background Technology

[0002] Sulfuric acid is an important commercial chemical used in fertilizers, viscose fibers, pigments, batteries, metallurgy, and refining. The WSA process primarily converts sulfur-containing waste gas, such as hydrogen sulfide, into concentrated sulfuric acid through a series of chemical reactions. First, the sulfur-containing waste gas reacts with air in a combustion furnace to produce sulfur dioxide. Subsequently, the sulfur dioxide is further oxidized to sulfur trioxide under the action of a catalyst. Finally, the sulfur trioxide reacts directly with water vapor in a condenser to condense, forming concentrated sulfuric acid.

[0003] Currently, the maintenance methods for WSA process-related production lines are still quite disorganized. Maintenance after shutdown is time-consuming, and maintenance is not carried out systematically or sequentially, easily overlooking details. This reflects the lack of purpose in existing maintenance methods, relying solely on experience, making it easy to miss critical steps. Furthermore, the fragmented process leads to disconnected maintenance steps for each system, resulting in repetitive operations or connection failures. Therefore, this invention proposes a modular maintenance method for WSA acid production systems to solve the above problems. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a modular maintenance method for WSA acid production system and a WSA acid production line, which allows for systematic and sequential maintenance, reducing unnecessary steps and improving maintenance efficiency.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A modular maintenance method for a WSA acid production system includes boiler system maintenance, acid vapor transmission and combustion system maintenance, acid circulation system maintenance, and auxiliary system maintenance. Multiple systems can be maintained simultaneously or sequentially. After all systems are maintained, an interlock test is conducted. When the interlock test meets the requirements, the interlock is released. When production is officially resumed, the interlocks of each system are restored. The boiler system overhaul includes inspection and repair of the boiler feedwater pump, steam drum, waste heat boiler, and sulfur dioxide converter. The overhaul of the acid gas delivery and combustion system includes the inspection and handling of the acid gas pipe, the combustion air fan, the gas booster, and the incinerator. The overhaul of the acid circulation system includes inspection and handling of the WSA condenser, acid delivery pump, acid cooler, and acid intermediate tank. The maintenance of auxiliary systems includes inspection and handling of the acid mist control unit, SCR converter, ammonia / air mixing system, and acid production chimney.

[0006] In one embodiment, the boiler feedwater pump inspection process is as follows: the boiler feedwater pump is inspected; if the boiler feedwater pump is faulty, it is repaired; if the boiler feedwater pump is normal or after repair, the boiler feedwater pump is restored to standby status. The steam drum inspection and handling process is as follows: depressurize and empty the steam drum, remove all connecting valves inside the steam drum and check the flange water line, remove the steam drum electric contact level gauge and repair or replace it, remove the steam drum safety valve and send it for inspection, reassemble after completing the repair of each component, then start the boiler feed water pump to inject water and pressure test for leaks, deal with any leaks, and after ensuring that the steam drum does not leak, restore the steam drum to standby status. Waste heat boiler inspection and handling: Remove the waste heat boiler manhole, inspect and repair the waste heat boiler tube bundle, waste heat boiler rear flap actuator and waste heat boiler downstream process gas pipeline, complete the inspection and restore the manhole seal, and restore the waste heat boiler to standby status. The inspection and handling process for the sulfur dioxide converter is as follows: remove the manhole of the sulfur dioxide converter, inspect the heat exchange tube bundle of the sulfur dioxide converter, and at the same time, inspect the catalyst layer grid and the outer wall of the heat exchange tube bundle inside the sulfur dioxide converter. After the inspection is completed, reseal the manhole and restore the sulfur dioxide converter to standby status.

[0007] In one embodiment, during the inspection and handling of the sulfur dioxide converter, after ensuring that the heat exchange tube bundle is not leaking, all heat exchange tube bundles of the sulfur dioxide converter are depressurized and emptied. Then, the temperature regulating valves at the heat exchange tube bundles are removed, inspected and repaired, reinstalled, and the boiler feed water pump is restarted to inject water and pressurize for leak testing. If leakage occurs, it is dealt with until there is no leakage. The heat exchange tube bundles and the corresponding temperature regulating valves are then restored to standby status.

[0008] In one embodiment, the acid vapor pipeline inspection process is as follows: the acid vapor is switched to the Claus furnace to prevent acid vapor from entering the acid vapor pipeline; the acid vapor path regulating valve is disassembled and marked; the acid vapor path regulating valve is then inspected; the acid vapor pipeline is cleaned; then the acid vapor pipeline and the inspected acid vapor path regulating valve are reinstalled; a nitrogen pressure test is performed to check for leaks; any leaks are tightened and repaired; finally, the acid vapor pipeline is restored to standby status. The inspection and handling of the combustion air blower is as follows: the combustion air blower is inspected, and if there is a fault in the combustion air blower, it is repaired. If the combustion air blower is normal or after repair, the combustion air blower is restored to standby status. Gas booster inspection and handling: Inspect the gas booster and related gas pipes. If there is a fault in the gas booster and related gas pipes, repair them. If the gas booster and related gas pipes are normal or after repair, restore the gas booster and related gas pipes to standby status. The incinerator inspection and handling process is as follows: Open the incinerator manhole, inspect the refractory bricks, gas ignition gun, and fire baffle. After the inspection is completed, seal the manhole, then start the combustion air blower to pressurize and test for leaks. Tighten and repair any leaking parts, and finally restore the incinerator to standby status.

[0009] In one embodiment, the overhaul of the acid gas delivery and combustion system also includes inspection and treatment of the furnace head mist eliminator: opening the mist eliminator manhole for inspection and treatment and inspecting and treating the multi-stage water seal of the mist eliminator. After cleaning and clearing, the mist eliminator manhole and the multi-stage water seal of the mist eliminator are restored. Then, nitrogen pressure testing is used to test for leaks. Leaking parts are tightened and treated. Finally, the furnace head mist eliminator is restored to standby status.

[0010] In one embodiment, the WSA condenser inspection process is as follows: open the top cover of the WSA condenser, inspect the condition of the glass tubes, and replace any damaged glass tubes; disconnect the process gas pipe connected to the WSA inlet, inspect the acid pool and the internal acid-resistant lining bricks, replace any damaged parts, and then reconnect the process gas pipe connected to the WSA inlet; inspect the lower acid pipe of the WSA condenser and replace any damaged parts; after the overhaul is completed, the WSA condenser is restored to standby status. The inspection and handling of acid delivery pumps is as follows: test the acid delivery pump; if the acid delivery pump is faulty, repair it; if the acid delivery pump is normal or after repair, restore the acid delivery pump to standby status. The procedure for inspecting and handling an acid cooler is as follows: drain the medium from the acid and water circuits of the acid cooler, rinse them with water, then purge the acid and water circuits with nitrogen, and finally restore the acid cooler to standby mode. The inspection and handling process for the acid intermediate tank is as follows: drain the acid from the acid intermediate tank and the corresponding pipelines, clean the impurities in the acid intermediate tank and inspect the inner lining of the pipelines, then fill the acid intermediate tank and the corresponding pipelines with acid, and restore the acid intermediate tank to standby status.

[0011] In one embodiment, the maintenance of the acid circulation system also includes the inspection and handling of the cooling air fan: the cooling air fan is inspected, and if the cooling air fan is faulty, it is repaired; if the cooling air fan is normal or after the repair is successful, the cooling air fan is restored to standby status.

[0012] In one embodiment, the acid mist control unit inspection process is as follows: the acid mist control unit is tested; if the acid mist control unit is faulty, it is repaired; if the acid mist control unit is normal or after repair, the acid mist control unit is restored to standby status. The SCR converter inspection and handling process is as follows: open the manhole, inspect the SCR converter packing, replace the damaged parts, and finally restore the SCR converter to standby status. The inspection and handling process for the ammonia / air mixing system is as follows: the ammonia / air mixing system is tested; if a fault is found, the ammonia / air mixing system is repaired; if the ammonia / air mixing system is normal or the repair is successful, the ammonia / air mixing system is restored to standby status. The inspection and handling process for acid production chimneys is as follows: Open the manhole, check and clean the debris at the bottom of the acid production chimney, check the flexible connections connecting the chimney, replace any damaged parts, and then restore the acid production chimney to standby status.

[0013] A WSA acid production line includes a boiler system, an acid vapor conveying and combustion system, an acid circulation system, and an auxiliary system; The auxiliary systems include an acid mist control unit, an SCR converter, an ammonia / air mixing system, and an acid production chimney; The boiler system includes a deaerator, boiler feed pump, steam drum, waste heat boiler, and sulfur dioxide converter. The deaerator, boiler feed pump, steam drum, and waste heat boiler are connected in sequence. The steam drum and waste heat boiler are connected by a return pipe. The steam drum is connected to the sulfur dioxide converter to supply steam to the sulfur dioxide converter. The waste heat boiler is connected to the sulfur dioxide converter through an SCR converter. An ammonia / air mixing system is set between the waste heat boiler and the SCR converter. Ammonia / air is mixed with the process gas of the waste heat boiler and then enters the SCR converter. The acid mist control unit is connected to the sulfur dioxide converter. The acid gas delivery and combustion system includes an incinerator and a gas booster, a combustion air fan, and a vacuum pump connected to the incinerator. The incinerator is connected to a waste heat boiler. The acid circulation system includes a WSA condenser, an acid intermediate tank, an acid transfer pump, and an acid cooler connected in sequence. The WSA condenser is connected to the sulfur dioxide converter and the acid production chimney.

[0014] In summary, the present invention has the following beneficial effects: This invention can improve efficiency and reduce maintenance time; The present invention performs maintenance systematically and sequentially, which can reduce unnecessary steps; The present invention provides comprehensive maintenance details, making it convenient to continue using this method in future maintenance. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the present invention.

[0016] In the diagram: 1. Soft water entering the deaerator tank; 2. Steam entering the deaerator tank; 3. Acid steam from the stripping tower; 4. Vacuum pump; 5. Gas booster; 6. Coke oven gas from external pipeline; 7. Large return pipe for boiler feedwater; 8. Deaerator tank; 9. Small return pipe for boiler feedwater; 10. Boiler feedwater pump; 11. Combustion air blower; 12. Incinerator; 13. Inlet filter of combustion air blower; 14. Soft water entering the steam drum; 15. Steam drum self-circulation to waste heat boiler steam and water pipe; 16. Waste heat boiler return to steam drum self-circulation steam and water pipe; 17. Self-produced acid to oil storage; 18. Self-produced acid to ammonium sulfate process; 19. Waste 20. Hot boiler, steam drum, 21. Liquid ammonia and its heated ammonia gas, 22. Heated air, 23. Ammonia-air mixture enters the SCR converter for impurity removal, 24. Process gas goes to the SCR converter, 25. Cooling acid returns to the WSA condenser's lower acid pipe, 26. Online acid concentration meter, 27. SCR converter, 28. Steam drum self-circulation to the sulfur dioxide converter process cooler steam-water pipe, 29. Acid cooler, 30. Process gas enters the sulfur dioxide converter. 31. First-layer interbed cooler; 32. Second-layer catalyst packing layer; 33. Second-layer interbed cooler; 34. Third-layer catalyst packing layer; 35. Self-circulating steam-water return steam drum; 36. Silicon oil inlet acid mist control unit; 37. Acid mist control unit; 38. Coke oven gas inlet acid mist control unit; 39. Self-generated acid to acid cooler; 40. Sulfur dioxide converter; 41. First-layer catalyst packing layer; 42. Inlet heat exchange steam to the first-layer interbed cooler; 43. Outlet heat exchange steam to the second-layer interbed cooler; 44. Process gas cooler; 45. Process gas inlet WSA condenser; 46. Acid transfer pump; 47. Outlet steam from the steam drum into the first-layer interbed cooler; 48. Outlet heat exchange steam from the first-layer interbed cooler; 49. Desuperheating and pressure reducing device A; 50. Inlet cooling air to the WSA condenser; 51. WSA condenser; 52. Self-generated acid to acid intermediate tank; 53. Acid intermediate tank; 54. Desuperheating and pressure reducing device B. 55. Cooling air fan; 56. Cooling air fan inlet filter; 57. Cooling air outlet from WSA condenser; 58. Steam supplied to steam pipeline network; 59. Process gas exhaust gas to chimney; 60. Acid production chimney. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] It is worth noting that the directional terms such as "up" and "down" used in this article are all relative to the perspective of the attached figures and are only for the purpose of description. They should not be interpreted as limitations on the technical solutions.

[0019] like Figure 1 As shown, the present invention proposes a WSA acid production line, including a boiler system, an acid vapor conveying and combustion system, an acid circulation system, and an auxiliary system.

[0020] The auxiliary systems include an acid mist control unit, an SCR converter, an ammonia / air mixing system, and an acid production chimney.

[0021] The boiler system includes a deaerator, boiler feedwater pump, steam drum, waste heat boiler, and sulfur dioxide converter. The deaerator, boiler feedwater pump, steam drum, and waste heat boiler are connected in sequence. The steam drum and waste heat boiler are connected by a return pipe. The steam drum is connected to the sulfur dioxide converter to supply steam to the sulfur dioxide converter. The waste heat boiler is connected to the sulfur dioxide converter through an SCR converter. An ammonia / air mixing system is set between the waste heat boiler and the SCR converter. Ammonia / air is mixed with the process gas from the waste heat boiler and then enters the SCR converter. The acid mist control unit is connected to the sulfur dioxide converter.

[0022] The acid gas delivery and combustion system includes an incinerator and a gas booster, a combustion air fan, and a vacuum pump connected to the incinerator. The incinerator is connected to a waste heat boiler.

[0023] The acid circulation system includes a WSA condenser, an acid intermediate tank, an acid transfer pump, and an acid cooler connected in sequence. The WSA condenser is connected to the sulfur dioxide converter and the acid production chimney.

[0024] This invention proposes a modular maintenance method for a WSA (Wastewater Acid) production system, including boiler system maintenance, acid vapor transport and combustion system maintenance, acid circulation system maintenance, and auxiliary system maintenance. Multiple systems can be maintained simultaneously or sequentially. After all systems are maintained, an interlocking test is conducted. Once the interlocking test meets the requirements, the interlocking is released, and the interlocking is restored when production resumes. The technical solution of this invention is illustrated below with specific embodiments.

[0025] Boiler system overhaul includes inspection and repair of the boiler feedwater pump, steam drum, waste heat boiler, and sulfur dioxide converter. In the boiler system, the boiler feedwater pump, steam drum, and waste heat boiler are connected in sequence. The boiler feedwater pump supplies soft water to the steam drum, which in turn supplies soft water to the waste heat boiler for heat exchange. The waste heat boiler is connected to the sulfur dioxide converter, and the exhaust gas from combustion in the waste heat boiler is treated before entering the sulfur dioxide converter.

[0026] The specific steps for inspecting and handling boiler feedwater pumps are as follows: Inspect the boiler feedwater pump; if a fault is found, repair it; if the boiler feedwater pump is functioning normally or has been repaired successfully, restore it to standby mode.

[0027] like Figure 1 As shown, the boiler feedwater pump is located between the deaerator and the steam drum. Soft water and steam enter the deaerator, and the deaerated soft water is pumped into the steam drum through the boiler feedwater pump. A return pipe is also installed between the deaerator and the steam drum.

[0028] This invention prioritizes the inspection and handling of the boiler feedwater pump, which supplies water to the boiler system. After ensuring that the boiler feedwater pump is in normal condition, other equipment will be inspected and handled in order to improve maintenance efficiency.

[0029] The steam drum inspection and handling process is as follows: depressurize and empty the steam drum, remove all connecting valves inside the steam drum and check the flange water line, remove the steam drum electrical contact level gauge and repair or replace it, remove the steam drum safety valve and send it for inspection, reassemble after completing the repair of each component, then start the boiler feed water pump to inject water and pressure test for leaks, repair any leaks, and after ensuring that the steam drum does not leak, restore the steam drum to standby status.

[0030] This invention first checks the boiler feedwater pump, then checks the steam drum, which is connected to the waste heat boiler / sulfur dioxide converter. Ensuring that the boiler feedwater pump and steam drum are functioning properly will improve the efficiency of subsequent leak detection and ensure the effectiveness of water injection and pressurization.

[0031] The waste heat boiler inspection and handling process specifically involves: removing the waste heat boiler manhole; inspecting and repairing the waste heat boiler tube bundle, the waste heat boiler rear flap actuator, and the waste heat boiler downstream process gas pipeline; completing the inspection and restoring the manhole seal; and returning the waste heat boiler to standby status. This invention, based on the waste heat boiler's workflow, sequentially inspects and repairs the waste heat boiler, which helps improve inspection efficiency.

[0032] When inspecting the waste heat boiler tube bundle, start the boiler feedwater pump to inject water and pressurize it for leak testing. If leakage is found, replace the corresponding tube bundle. If no leakage is found, restore the waste heat boiler tube bundle to standby status. Preferably, the pressure of the boiler feedwater pump for injection and pressurization is 5.85 MPa.

[0033] When inspecting the rear flap actuator of the waste heat boiler, if a malfunction is detected, replace and adjust the actuator; if no malfunction is detected, the inspection is complete.

[0034] When inspecting the downstream gas pipeline of the waste heat boiler, clean the downstream gas pipeline and repair any faulty points.

[0035] The inspection and handling of the sulfur dioxide converter specifically involves: removing the manhole of the sulfur dioxide converter, inspecting the heat exchange tube bundle, and simultaneously inspecting the catalyst layer grid and the outer wall of the heat exchange tube bundle inside the sulfur dioxide converter. After the inspection is completed, the manhole is resealed, and the sulfur dioxide converter is returned to standby mode. This invention involves removing the catalyst during the inspection of the heat exchange tube bundle to facilitate subsequent inspection of the catalyst grid. The inspection of the heat exchange tube bundle also includes checking the adhesion to the outer wall of the heat exchange tube bundle. These three inspection items are closely linked and carried out in an orderly manner, which helps improve inspection efficiency and quality.

[0036] When checking for leaks in the heat exchanger tube bundle of the sulfur dioxide converter, remove the catalyst layers from each layer of the converter. Then, start the boiler feedwater pump to inject water and pressurize it for leak testing. If no leaks are found, stop injecting water. If leaks are found, stop injecting water and repair the leak. After repairing the leak by welding, inject water again until no leaks occur. Preferably, the pressure of the boiler feedwater pump during the leak detection of the heat exchanger tube bundle is 5.85 MPa.

[0037] Furthermore, after ensuring the heat exchanger tube bundles are leak-free, all heat exchanger tube bundles of the sulfur dioxide converter are depressurized and emptied. Then, the temperature regulating valves at the heat exchanger tube bundles are removed, inspected, and repaired. After reinstallation, the boiler feedwater pump is restarted for water injection and pressure testing to check for leaks. Any leaks are addressed until no leaks occur, at which point the heat exchanger tube bundles and corresponding temperature regulating valves are returned to standby status. Preferably, the pressure of the boiler feedwater pump during the temperature regulating valve leak test is 5.85 MPa.

[0038] The catalyst layer grid inspection is performed after each layer of catalyst has been removed from the sulfur dioxide converter. This inspection can be conducted simultaneously with the inspection of the heat exchange tube bundle for leaks, thus improving efficiency. During the catalyst layer grid inspection, usable grids are cleaned, and damaged grids are replaced. At the same time, the existing, still effective catalyst is sieved, and new catalyst is added. After completing all inspections related to the heat exchange tube bundle (i.e., leaks and adhesion to the outer wall), each layer of catalyst is reinstalled on the grids. The sulfur dioxide converter inspection is then complete, the manhole is restored, and the sulfur dioxide converter is returned to standby mode.

[0039] The entire process of inspecting and handling the sulfur dioxide converter avoids repetitive operations or connection failures. The catalyst reloading is the last step in the sulfur dioxide converter inspection to avoid conflict with the inspection of the heat exchange tube bundle.

[0040] Boiler system maintenance also includes the inspection and handling of boiler system instruments. When the boiler feedwater pump and all instruments in the boiler system are normal, the boiler feedwater pump and all instruments in the boiler system are restored to standby status.

[0041] The overhaul of the acid vapor delivery and combustion system includes inspection and repair of the acid vapor pipes, combustion air fans, gas booster compressors, and the incinerator. In the acid vapor combustion system, acid vapor from the stripping tower, coke oven gas from the external line, and air enter the incinerator for mixing and combustion. First, the acid vapor pipes, combustion air fans, and gas booster compressors are inspected and repaired to ensure that all parts connected to the incinerator are functioning properly. Finally, the incinerator itself is inspected.

[0042] The acid vapor pipeline inspection and handling process is as follows: The acid vapor from the acid production process is switched to the Claus furnace to prevent acid vapor from entering the acid vapor pipeline. The acid vapor regulating valve is disassembled and marked, and then repaired. The acid vapor pipeline is cleaned, and then the acid vapor pipeline and the repaired acid vapor regulating valve are reinstalled. A nitrogen pressure test is performed to check for leaks. Leaking parts are tightened and repaired. Finally, the acid vapor pipeline is returned to standby status. Preferably, the nitrogen pressure is 20 kPa.

[0043] The inspection and handling of the combustion air fan is as follows: the combustion air fan is inspected, and if a fault is found, it is repaired. If the combustion air fan is normal or after repair, it is restored to standby status.

[0044] The inspection and handling of the gas booster is as follows: the gas booster and related gas pipes are inspected. If there is a fault in the gas booster and related gas pipes, they are repaired. If the gas booster and related gas pipes are normal or have been repaired, the gas booster and related gas pipes are restored to standby status.

[0045] The incinerator inspection and handling process is as follows: Open the incinerator manhole, inspect the refractory bricks, gas ignition gun, and fire baffle. After completing the inspection, seal the manhole, then start the combustion air blower to pressure test for leaks. Tighten and repair any leaking parts, and finally restore the incinerator to standby status. Preferably, the pressure of the combustion air blower is 20 kPa.

[0046] During the inspection and maintenance of the incinerator, the combustion air blower that has been inspected beforehand is used to pressure test and leak the incinerator. This is in accordance with the maintenance sequence and can improve the efficiency and quality of the inspection.

[0047] Furthermore, the overhaul of the acid vapor delivery and combustion system also includes the inspection and handling of the furnace head mist eliminator. Specifically, this involves opening the mist eliminator manhole for inspection and handling, as well as inspecting and handling the multi-stage water seal of the mist eliminator. After cleaning and unblocking, the mist eliminator manhole and multi-stage water seal are restored. Then, nitrogen pressure testing is used to check for leaks. Leaking parts are tightened and repaired. Finally, the furnace head mist eliminator is restored to standby status. Preferably, the nitrogen pressure is 20 kPa.

[0048] Furthermore, the overhaul of the acid vapor delivery and combustion system also includes the inspection and handling of the instruments in the acid vapor delivery and combustion system. When all instruments in the acid vapor delivery and combustion system are normal, all instruments in the acid vapor delivery and combustion system are restored to standby status.

[0049] The overhaul of the acid circulation system includes inspection and handling of the WSA condenser, acid transfer pump, acid cooler, and acid intermediate tank. Within the acid circulation system, each component is inspected sequentially according to the material flow direction.

[0050] The WSA condenser inspection and handling process is as follows: Open the top cover of the WSA condenser, check the condition of the glass tubes, and replace any damaged glass tubes; disconnect the process gas pipe connected to the WSA inlet, inspect the acid pool and internal acid-resistant lining bricks, replace any damaged parts, and then reconnect the process gas pipe connected to the WSA inlet; inspect the lower acid pipe of the WSA condenser and replace any damaged parts; after completing the overhaul, the WSA condenser is restored to standby status.

[0051] The specific steps for inspecting and handling the acid delivery pump are as follows: Inspect the acid delivery pump; if a fault is found, repair the pump; if the pump is functioning normally or has been repaired, restore it to standby mode.

[0052] The specific steps for inspecting and handling the acid cooler are as follows: drain the medium from the acid and water circuits of the acid cooler, rinse them with water, then purge the acid and water circuits with nitrogen, and finally restore the acid cooler to standby mode.

[0053] The inspection and handling of the acid intermediate tank is as follows: drain the acid from the acid intermediate tank and the corresponding pipelines, clean the impurities in the acid intermediate tank and inspect the inner lining of the pipelines, then fill the acid intermediate tank and the corresponding pipelines with acid, and restore the acid intermediate tank to standby status.

[0054] Furthermore, the overhaul of the acid circulation system also includes the inspection and handling of the cooling air fan. Specifically, the cooling air fan is inspected, and if a fault is found, it is repaired. If the cooling air fan is normal or after repair, it is restored to standby status.

[0055] The maintenance of auxiliary systems includes inspection and handling of the acid mist control unit, SCR converter, ammonia / air mixing system, and acid production chimney.

[0056] The inspection and handling of the acid mist control unit is as follows: the acid mist control unit is tested; if the acid mist control unit is faulty, it is repaired; if the acid mist control unit is normal or after repair, it is restored to standby status.

[0057] The SCR converter inspection and handling process involves: opening the manhole, inspecting the SCR converter packing, replacing any damaged parts, and finally restoring the SCR converter to standby status.

[0058] The inspection and handling of the ammonia / air mixing system involves: testing the ammonia / air mixing system; repairing the ammonia / air mixing system if a fault is found; and restoring the ammonia / air mixing system to standby status if it is functioning normally or after successful repair.

[0059] The inspection and handling of the acid production chimney involves: opening the manhole, inspecting and cleaning the debris at the bottom of the acid production chimney, inspecting the flexible connection connecting the chimney, replacing any damaged parts, and then restoring the acid production chimney to standby status.

[0060] Furthermore, auxiliary system maintenance also includes checking and handling auxiliary system instruments. When all instruments in the auxiliary system are normal, they are restored to standby status.

[0061] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A modular maintenance method for a WSA acid production system, characterized in that, This includes boiler system overhaul, acid gas conveying and combustion system overhaul, acid circulation system overhaul, and auxiliary system overhaul. Multiple systems can be overhauled simultaneously or sequentially. After all systems have been overhauled, an interlock test is conducted. Once the interlock test meets the requirements, the interlock is released. When production resumes, the interlocks of each system are restored. The boiler system overhaul includes inspection and repair of the boiler feedwater pump, steam drum, waste heat boiler, and sulfur dioxide converter. The overhaul of the acid gas delivery and combustion system includes the inspection and handling of the acid gas pipe, the combustion air fan, the gas booster, and the incinerator. The overhaul of the acid circulation system includes inspection and handling of the WSA condenser, acid delivery pump, acid cooler, and acid intermediate tank. The maintenance of auxiliary systems includes inspection and handling of the acid mist control unit, SCR converter, ammonia / air mixing system, and acid production chimney.

2. The modular maintenance method for the WSA acid production system as described in claim 1, characterized in that, The inspection and handling of boiler feed water pumps is as follows: the boiler feed water pump is tested. If the boiler feed water pump is faulty, it is repaired. If the boiler feed water pump is normal or after repair, the boiler feed water pump is restored to standby status. The steam drum inspection and handling process is as follows: depressurize and empty the steam drum, remove all connecting valves inside the steam drum and check the flange water line, remove the steam drum electric contact level gauge and repair or replace it, remove the steam drum safety valve and send it for inspection, reassemble after completing the repair of each component, then start the boiler feed water pump to inject water and pressure test for leaks, deal with any leaks, and after ensuring that the steam drum does not leak, restore the steam drum to standby status. Waste heat boiler inspection and handling: Remove the waste heat boiler manhole, inspect and repair the waste heat boiler tube bundle, waste heat boiler rear flap actuator and waste heat boiler downstream process gas pipeline, complete the inspection and restore the manhole seal, and restore the waste heat boiler to standby status. The inspection and handling process for the sulfur dioxide converter is as follows: remove the manhole of the sulfur dioxide converter, inspect the heat exchange tube bundle of the sulfur dioxide converter, and at the same time, inspect the catalyst layer grid and the outer wall of the heat exchange tube bundle inside the sulfur dioxide converter. After the inspection is completed, reseal the manhole and restore the sulfur dioxide converter to standby status.

3. The modular maintenance method for the WSA acid production system as described in claim 2, characterized in that, During the inspection and handling of the sulfur dioxide converter, after ensuring that the heat exchange tube bundle is not leaking, the pressure is released and all heat exchange tube bundles of the sulfur dioxide converter are emptied. Then, the temperature regulating valves at the heat exchange tube bundles are removed, inspected and repaired, and reinstalled. The boiler feed water pump is restarted to inject water and pressurize for leak testing. If any leakage occurs, it is dealt with until there is no leakage. The heat exchange tube bundles and the corresponding temperature regulating valves are then restored to standby status.

4. The modular maintenance method for the WSA acid production system as described in claim 1, characterized in that, The acid vapor pipeline inspection and handling process is as follows: cut the acid vapor production line to the Claus furnace to prevent acid vapor from entering the acid vapor pipeline, disassemble the acid vapor line regulating valve and mark it, then repair the acid vapor line regulating valve; clean the acid vapor pipeline, then reassemble the acid vapor pipeline and the repaired acid vapor line regulating valve, and use nitrogen pressure to test for leaks. Tighten and repair any leaking parts, and finally restore the acid vapor pipeline to standby status. The inspection and handling of the combustion air blower is as follows: the combustion air blower is inspected, and if there is a fault in the combustion air blower, it is repaired. If the combustion air blower is normal or after repair, the combustion air blower is restored to standby status. Gas booster inspection and handling: Inspect the gas booster and related gas pipes. If there is a fault in the gas booster and related gas pipes, repair them. If the gas booster and related gas pipes are normal or after repair, restore the gas booster and related gas pipes to standby status. The incinerator inspection and handling process is as follows: Open the incinerator manhole, inspect the refractory bricks, gas ignition gun, and fire baffle. After the inspection is completed, seal the manhole, then start the combustion air blower to pressurize and test for leaks. Tighten and repair any leaking parts, and finally restore the incinerator to standby status.

5. The modular maintenance method for the WSA acid production system as described in claim 4, characterized in that, The overhaul of the acid gas delivery and combustion system also includes the inspection and handling of the furnace head mist eliminator: opening the mist eliminator manhole for inspection and handling, as well as the inspection and handling of the multi-stage water seal of the mist eliminator. After cleaning and unblocking, the mist eliminator manhole and the multi-stage water seal of the mist eliminator are restored. Then, nitrogen pressure testing is used to test for leaks. Leaking parts are tightened and treated. Finally, the furnace head mist eliminator is restored to standby status.

6. The modular maintenance method for the WSA acid production system as described in claim 1, characterized in that, The inspection and handling process for the WSA condenser is as follows: Open the top cover of the WSA condenser, check the condition of the glass tubes, and replace any damaged glass tubes; disconnect the process gas pipe connected to the WSA inlet, inspect the acid pool and the internal acid-resistant lining bricks, replace any damaged parts, and then reconnect the process gas pipe connected to the WSA inlet; inspect the lower acid pipe of the WSA condenser and replace any damaged parts; after the overhaul is completed, the WSA condenser is restored to standby status. The inspection and handling of acid delivery pumps is as follows: test the acid delivery pump; if the acid delivery pump is faulty, repair it; if the acid delivery pump is normal or after repair, restore the acid delivery pump to standby status. The procedure for inspecting and handling an acid cooler is as follows: drain the medium from the acid and water circuits of the acid cooler, rinse them with water, then purge the acid and water circuits with nitrogen, and finally restore the acid cooler to standby mode. The inspection and handling process for the acid intermediate tank is as follows: drain the acid from the acid intermediate tank and the corresponding pipelines, clean the impurities in the acid intermediate tank and inspect the inner lining of the pipelines, then fill the acid intermediate tank and the corresponding pipelines with acid, and restore the acid intermediate tank to standby status.

7. The modular maintenance method for the WSA acid production system as described in claim 6, characterized in that, The overhaul of the acid circulation system also includes the inspection and handling of the cooling air fan: the cooling air fan is inspected, and if there is a fault in the cooling air fan, it is repaired. If the cooling air fan is normal or after the repair is successful, the cooling air fan is restored to standby status.

8. The modular maintenance method for the WSA acid production system as described in claim 1, characterized in that, The inspection and handling process for the acid mist control unit is as follows: the acid mist control unit is tested; if the acid mist control unit is faulty, it is repaired; if the acid mist control unit is normal or after repair, the acid mist control unit is restored to standby status. The SCR converter inspection and handling process is as follows: open the manhole, inspect the SCR converter packing, replace the damaged parts, and finally restore the SCR converter to standby status. The inspection and handling process for the ammonia / air mixing system is as follows: the ammonia / air mixing system is tested; if a fault is found, the ammonia / air mixing system is repaired; if the ammonia / air mixing system is normal or the repair is successful, the ammonia / air mixing system is restored to standby status. The inspection and handling process for acid production chimneys is as follows: Open the manhole, check and clean the debris at the bottom of the acid production chimney, check the flexible connections connecting the chimney, replace any damaged parts, and then restore the acid production chimney to standby status.

9. A WSA acid production line, characterized in that, A modular maintenance method applicable to the WSA acid production system according to any one of claims 1-8, wherein the WSA acid production line includes a boiler system, an acid vapor conveying and combustion system, an acid circulation system, and an auxiliary system; The auxiliary systems include an acid mist control unit, an SCR converter, an ammonia / air mixing system, and an acid production chimney; The boiler system includes a deaerator, boiler feed pump, steam drum, waste heat boiler, and sulfur dioxide converter. The deaerator, boiler feed pump, steam drum, and waste heat boiler are connected in sequence. The steam drum and waste heat boiler are connected by a return pipe. The steam drum is connected to the sulfur dioxide converter to supply steam to the sulfur dioxide converter. The waste heat boiler is connected to the sulfur dioxide converter through an SCR converter. An ammonia / air mixing system is set between the waste heat boiler and the SCR converter. Ammonia / air is mixed with the process gas of the waste heat boiler and then enters the SCR converter. The acid mist control unit is connected to the sulfur dioxide converter. The acid gas delivery and combustion system includes an incinerator and a gas booster, a combustion air fan, and a vacuum pump connected to the incinerator. The incinerator is connected to a waste heat boiler. The acid circulation system includes a WSA condenser, an acid intermediate tank, an acid transfer pump, and an acid cooler connected in sequence. The WSA condenser is connected to the sulfur dioxide converter and the acid production chimney.

Images