Hydrogen-oxygen co-production and diffused gas treatment system utilizing waste heat of high-temperature red coke

Abstract

The utility model relates to an oxyhydrogen co-production and diffused gas treatment system utilizing high-temperature red coke waste heat. The oxyhydrogen co-production and diffused gas treatment system comprises a red coke heat recovery system, an oxyhydrogen co-production system, a water vapor circulation system, a power supply system and a diffused gas treatment system, a red coke heat recovery and high-temperature electrolysis co-coupling mode is adopted, high-temperature internal energy of red coke is converted into chemical energy of hydrogen and oxygen, and the produced oxygen is used for harmless treatment of process diffused gas, namely high-temperature water vapor produced by high-temperature red coke is electrolyzed to produce hydrogen and oxygen, and then carbon monoxide contained in the diffused gas is electrolyzed to produce hydrogen, so that the process diffused gas is recycled. The emission gas is sequentially reduced and oxidized, fine removal of sulfur dioxide and oxidation of carbon monoxide are completed step by step on the premise of not additionally adding heat, and finally the standard requirement for directly discharging the emission gas to the atmosphere is met while hydrogen and oxygen are co-produced.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial waste heat and hydrogen production, and in particular to a hydrogen-oxygen cogeneration and vent gas treatment system utilizing high-temperature red coke waste heat. Background Art

[0002] During the coke oven production process, the high-temperature waste heat of 950-1050℃ brought out by red coke accounts for 45% of the total heat expenditure of the coke oven. The efficient recovery and utilization of this high-quality heat is of great significance to the coking industry in achieving the "dual carbon" goal. Dry coke quenching is a method of recovering the waste heat of red coke using inert gas (usually nitrogen). In the "Technical Guidelines for the Formulation of Emergency Emission Reduction Measures for Key Industries in Heavy Pollution Weather (2020 Revised Edition)" issued by my country, it is not only listed as a "must-use" coke quenching process for Class A enterprises, but also requires "dust removal and desulfurization measures" for the exhaust gas from dry coke quenching.

[0003] As environmental protection standards have become increasingly stringent in recent years, many provinces and cities are implementing stricter carbon monoxide emission limits (allowable emission concentration <2000mg / Nm 3 ), the exhaust gas from the current CDQ process cannot meet the environmental protection requirements for direct discharge into the atmosphere.

[0004] The composition (volume fraction) of CDQ exhaust gas is: 18% carbon dioxide, less than 1% oxygen, less than 6% carbon monoxide, less than 3% hydrogen, and 75% nitrogen, of which the concentration of carbon monoxide can be as high as 75,000 mg / Nm 3, which is far from the allowable emission standard and must be purified. Due to the chemical inertness of carbon monoxide, it is difficult to remove it by chemical absorption. It can only be oxidized to carbon dioxide by oxidation to meet the standard. However, the CDQ exhaust gas itself has the composition characteristics of "rich in nitrogen and poor in oxygen", and does not have the oxidation conditions required for complete oxidation of carbon monoxide, which can only be compensated by adding oxygen. For example: the "A treatment system for exhaust gas from coke ovens and CDQ furnaces" disclosed in the Chinese utility model patent with the authorization announcement number CN211921415U realizes the treatment of pollutants in exhaust gas through combustion method (addition of air). The "A pre-conditioning treatment system and method for exhaust gas from CDQ furnaces" disclosed in the Chinese invention patent with the authorization announcement number CN113122289B also changes the flue gas composition by the method of full combustion (addition of air), thereby achieving terminal emissions. The above method is based on combustion to achieve complete oxidation of carbon monoxide, which not only has high energy consumption, but also may produce new pollutants (such as nitrogen oxides) during the combustion process. Therefore, the optimal solution should be to catalyze the oxidation reaction of carbon monoxide under the premise of oxygen supplementation. This avoids very high combustion temperatures and does not generate new pollutants. It is an energy-saving and environmentally friendly process. The Chinese patent application with publication number CN117210231A discloses "a method, system and graded catalytic reactor for treating flue gas commonly used in dry coke quenching". Its catalytic oxidation process is to first perform dry desulfurization, then use a palladium catalyst to oxidize and remove hydrogen and a small amount of carbon monoxide, and use the large amount of reaction heat generated to increase the flue gas temperature. Finally, the remaining carbon monoxide is oxidized and removed by a copper-manganese catalyst. This scheme uses a calcium-based dry desulfurization process. Due to adsorption equilibrium, it can only reduce the sulfur dioxide concentration in the exhaust gas to a minimum of 10 mg / Nm 3 (See the article "Research on the coordinated treatment of desulfurization and dust removal of exhaust gas from dry coke quenching", "Fuel and Chemical Engineering", Vol. 54, No. 3, May 2023). Since the concentration of sulfur dioxide in the exhaust gas is still very high, it is very easy to adsorb on the palladium catalyst to poison it, thereby blocking the continued activation of the reactants, and ultimately causing the catalytic oxidation device to be unable to continue operating in the short term (see the article "Sulfur poisoning mechanism of supported precious metal catalysts - adsorption and conversion of sulfur on palladium catalysts with different carriers", "Molecular Catalysis", 1991, 5(4)).

[0005] Solid oxide electrolysis cell (SOEC) is an all-solid-state device that can directly convert heat and electrical energy into chemical energy in fuel under high temperature conditions. It can be regarded as the reverse process of solid oxide fuel cell (SOFC). Compared with low-temperature water electrolysis hydrogen production technologies such as alkaline water electrolysis, solid oxide high-temperature electrolysis hydrogen production has the following outstanding technical advantages: (1) Theoretical electrical efficiency is close to 100%, and the system efficiency is expected to reach 90%, which is considered to be the most efficient water electrolysis hydrogen production technology; (2) High temperature operation, no need to use precious metal catalysts, mainly using perovskite-type rare earth oxide catalysts, and lower material costs; (3) All-solid-state structure, safer and more reliable. Therefore, solid oxide high-temperature electrolysis hydrogen production technology has broad application prospects.

[0006] In general, the high-temperature electrolysis system mainly includes: electrolysis stack, gas supply, water vapor preparation, gas preheating, electrolysis cell power supply, tail gas treatment and other units. In the hydrogen production mode of the high-temperature electrolysis system, the intake gas is generally a mixture of hydrogen and water vapor, and a sufficiently high content of water vapor is required to ensure the smooth progress of electrolysis. Whether high-temperature water vapor can be supplied continuously, accurately and stably is one of the key factors affecting the smooth operation of the high-temperature electrolysis system, and it is also a technical problem that urgently needs to be overcome. The Chinese patent application with publication number CN 111853753 A discloses "a steam generation system based on SOEC and its control method", which includes a water storage tank, a magnetic pump, a pressure-resistant water tank, a liquid mass flow meter and a steam generator, but it mainly involves a control system and does not explain the specific method of generating steam. A Chinese patent application with publication number CN 111043520A discloses "a system and method for high-temperature electrolytic hydrogenation at a hydrogenation station". The system includes a water vaporization system, a hydrogen production system and a hydrogen storage and hydrogenation system. It uses electric heating to vaporize liquid water, but no heat recovery system is set during the heating and cooling process. It is a less economical hydrogen production method. Summary of the invention

[0007] The utility model provides a hydrogen-oxygen cogeneration and vented gas treatment system utilizing the waste heat of high-temperature red coke. Different from the existing dry coke quenching vented gas treatment system, the utility model uses the red coke of the metallurgical coking enterprise as the "heat source", utilizes the high-temperature water vapor generated in the dry coke quenching process as the "steam source", and adopts the high-temperature solid oxide electrolysis water vapor technology to co-produce hydrogen and oxygen. The hydrogen is used as the hydrogen source for downstream users, and part of the oxygen is returned to the dry coke quenching vented gas treatment system, and the remaining oxygen is used for oxygen-enriched combustion or chemical synthesis in the heating process, thereby injecting new vitality into the "green and low-carbon" development. The dry coke quenching vented gas treatment system utilizes the "self-waste heat" of the vented gas, and uses a non-precious metal catalyst for "reduction" and "oxidation" without adding external heat, so as to complete the precise removal of sulfur dioxide and the oxidation of carbon monoxide in a step-by-step and orderly manner, thereby avoiding catalyst poisoning, and ensuring the long-term stable operation of the system while meeting the environmental protection standard for direct discharge of vented gas into the atmosphere.

[0008] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0009] A hydrogen-oxygen cogeneration and vented gas treatment system utilizing high-temperature red coke waste heat, comprising a red coke heat recovery system, a hydrogen-oxygen cogeneration system, a water vapor circulation system, a power supply system and a vented gas treatment system; the red coke heat recovery system is a dry quenching coke circulation system consisting of a dry quenching furnace, a primary dust collector, a waste heat boiler, a secondary dust collector, a circulating fan and a heat pipe heat exchanger; the hydrogen-oxygen cogeneration system comprises a solid oxide electrolysis device, a hydrogen cooling device and a gas-liquid separator; the gas-liquid mixture inlet of the gas-liquid separator is connected to the gas-liquid mixture outlet of the solid oxide electrolysis device through a gas-liquid mixture pipeline, and a hydrogen cooling device is provided on the gas-liquid mixture pipeline; the red coke heat recovery system A three-way valve is provided on the high-temperature steam pipeline of the dry quenching furnace, the inlet of the three-way valve is connected to the high-temperature steam pipeline led out from the waste heat boiler, one outlet of the three-way valve is connected to the cathode inlet of the solid oxide electrolysis device, and the other outlet of the three-way valve is connected to the high-temperature steam inlet of the steam turbine; the water vapor circulation system is arranged between the power supply system and the waste heat boiler; the vented gas treatment system includes a coarse desulfurization and dust removal device, a catalytic reduction device and a catalytic oxidation device, the vented gas outlet of the dry quenching furnace is connected to the coarse desulfurization and dust removal device, the catalytic reduction device and the catalytic oxidation device in sequence through the vented gas pipeline, and the oxygen inlet on the catalytic oxidation device is connected to the oxygen outlet of the hydrogen-oxygen cogeneration system through an oxygen pipeline.

[0010] Furthermore, the power supply system includes a self-generating system consisting of a steam turbine and a generator, and an external power system including renewable energy power generation and traditional secondary energy power generation; a double-way switch is provided on the power supply circuit connecting the solid oxide electrolysis device to the self-generating system and the external power system; inverters are respectively provided on the power supply circuit of the self-generating system and the power supply circuit of the external power system.

[0011] Furthermore, the water vapor circulation system includes a condenser, a condensate pump, a desalted water tank, a deoxygenated feed water pump, a deaerator and a boiler feed water pump; the saturated steam outlet of the steam turbine is connected to the desalted water inlet of the heat pipe exchanger through a steam-water circulation pipeline, and the steam-water circulation pipeline is sequentially provided with a condenser, a condensate pump, a desalted water tank and a deoxygenated feed water pump; the desalted water outlet of the heat pipe exchanger is connected to the water inlet of the waste heat boiler through a feed water pipeline, and a deaerator and a boiler feed water pump are provided on the feed water pipeline.

[0012] Furthermore, the hydrogen and oxygen cogeneration and venting gas treatment system utilizing the waste heat of high-temperature red coke also includes a reboiler and a heat exchanger; the reboiler is arranged on the pipeline connecting the outlet of the three-way valve and the cathode inlet of the solid oxide electrolysis device; the heat exchanger is arranged on the gas-liquid mixture pipeline upstream of the hydrogen cooling device; the high-temperature water vapor inlet of the reboiler is connected to the outlet of the three-way valve, and the steam outlet of the reboiler is connected to the steam inlet of the heat exchanger; the steam outlet of the heat exchanger is connected to the steam inlet of the turbine; the water inlet of the reboiler is connected to the condensate outlet and the deionized water replenishment inlet of the gas-liquid separator, and the secondary steam outlet of the reboiler is connected to the cathode inlet of the solid oxide electrolysis device.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1) The utility model makes full use of the waste heat steam generated in the production process of the enterprise, especially the high-temperature steam with a temperature of more than 400°C generated in the cooling process of red coke in metallurgical coking enterprises, and adopts solid oxide electrolysis steam technology to directly co-produce hydrogen and oxygen.

[0015] 2) Since the waste heat utilization saves the energy consumption of heating and vaporizing liquid water, the efficiency is improved by 20% on the basis of the existing technology. In addition, the use of oxygen-enriched combustion or chemical synthesis associated with electrolysis will further reduce the cost of hydrogen. After the method described in this utility model is promoted, the expected power consumption is no more than 3.8kWh / Nm 3 The corresponding electricity cost of hydrogen is 2.28 yuan. Combined with the "hydrogen-oxygen combined" technology, the comprehensive cost of each standard cubic meter of hydrogen can be reduced to about 1.6 yuan, which can save 1.4 yuan compared with low-temperature, non-hydrogen-oxygen combined technology. According to the "China Hydrogen Energy and Fuel Cell Industry White Paper", my country's demand for hydrogen production by water electrolysis will be close to 470 billion cubic meters in 2050. If the method described in this utility model is promoted on a large scale, it can save 658 billion yuan each year, with considerable economic benefits.

[0016] 3) The utility model makes full use of the reducing property of carbon monoxide in the exhaust gas of CDQ to reduce the residual sulfur dioxide in the crude desulfurization to liquid sulfur under the catalysis of iron oxide, thus avoiding poisoning and deactivation of the subsequent oxidation catalyst, reducing the number of catalyst replacements and extending the operation time of the device.

[0017] 4) Part of the produced oxygen is returned to the exhaust gas treatment system, and the exhaust gas's own waste heat is used to catalytically oxidize the carbon monoxide in it into carbon dioxide in an oxygen-rich atmosphere, meeting the environmental protection standards for direct discharge into the atmosphere. This avoids the high combustion temperature of traditional processes and does not generate new pollutants. It is an energy-saving and environmentally friendly process system.

[0018] 5) The catalysts used in the catalytic reduction device and the catalytic oxidation device of the utility model are all non-precious metal catalysts, which reduces the investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the hydrogen and oxygen cogeneration and gas treatment system using the waste heat of high-temperature red coke according to the embodiment of the utility model. Figure 1 .

[0020] Figure 2 This is a schematic diagram of the structure of the hydrogen and oxygen cogeneration and gas treatment system using the waste heat of high-temperature red coke according to the embodiment of the utility model. Figure 2 .

[0021] In the figure: 0. Coke drum 1. CDQ furnace 2. Primary dust collector 3. Waste heat boiler 4. Secondary dust collector 5. Circulating fan 6. Heat pipe heat exchanger 7. Steam turbine 8. Generator 9. Condenser 10. Condensate pump 11. Desalted water tank 12. Deaerator feed water pump 13. Deaerator 14. Boiler feed water pump 20. Three-way valve 21. Inverter 22. Solid oxide electrolysis device 23. Two-way switch 24. Hydrogen cooling device 25. Gas-liquid separator 26. Reboiler 27. Heat exchanger 28. Rough desulfurization and dust removal device 29-1. Catalytic reduction device 29-2. Catalytic oxidation device 30. Inert gas 31. High-temperature steam 32. Turbine condensate 33. Desalted water 34. Boiler feed water 35. Hydrogen-water vapor mixture 36. Condensate 37. Deionized water 38. Emitted gas 39. Liquid sulfur DETAILED DESCRIPTION

[0022] The specific implementation of the utility model is further described below in conjunction with the accompanying drawings:

[0023] like Figure 1As shown, the utility model discloses a hydrogen-oxygen cogeneration and venting gas treatment system utilizing high-temperature red coke waste heat, including a red coke heat recovery system, a hydrogen-oxygen cogeneration system, a water vapor circulation system, a power supply system and a venting gas treatment system; the red coke heat recovery system is a dry quenching circulation system composed of a dry quenching furnace 1, a primary dust collector 2, a waste heat boiler 3, a secondary dust collector 4, a circulating fan 5 and a heat pipe heat exchanger 6; the hydrogen-oxygen cogeneration system includes a solid oxide electrolysis device 22, a hydrogen cooling device 24 and a gas-liquid separator 25; the gas-liquid mixture inlet of the gas-liquid separator 25 is connected to the gas-liquid mixture outlet of the solid oxide electrolysis device 22 through a gas-liquid mixture pipeline, and a hydrogen cooling device 24 is provided on the gas-liquid mixture pipeline; the high-temperature water vapor circulation system of the red coke heat recovery system A three-way valve 20 is provided on the steam pipeline, the inlet of the three-way valve 20 is connected to the high-temperature steam pipeline led out from the waste heat boiler 3, one outlet of the three-way valve 20 is connected to the cathode inlet of the solid oxide electrolysis device 22, and the other outlet of the three-way valve 20 is connected to the high-temperature steam inlet of the turbine 7; the water vapor circulation system is provided between the power supply system and the waste heat boiler 3; the vented gas treatment system comprises a coarse desulfurization and dust removal device 28, a catalytic reduction device 29-1 and a catalytic oxidation device 29-2, the vented gas outlet of the dry quenching furnace 1 is connected to the coarse desulfurization and dust removal device 28, the catalytic reduction device 29-1 and the catalytic oxidation device 29-2 in sequence through the vented gas pipeline, and the oxygen inlet on the catalytic oxidation device 29-2 is connected to the oxygen outlet of the hydrogen-oxygen cogeneration system through an oxygen pipeline.

[0024] Furthermore, the power supply system includes a self-generating system consisting of a steam turbine 7 and a generator 8, and an external power system including renewable energy power generation and traditional secondary energy power generation; a double-way switch 23 is provided on the power supply circuit connecting the solid oxide electrolysis device 22 with the self-generating system and the external power system; inverters 21 are respectively provided on the power supply circuit of the self-generating system and the power supply circuit of the external power system.

[0025] Furthermore, the water vapor circulation system includes a condenser 9, a condensate pump 10, a desalted water tank 11, a deoxygenated feed water pump 12, a deaerator 13 and a boiler feed water pump 14; the saturated steam outlet of the steam turbine 7 is connected to the desalted water inlet of the heat pipe heat exchanger 6 through a steam-water circulation pipeline, and the condenser 9, the condensate pump 10, the desalted water tank 11 and the deoxygenated feed water pump 12 are sequentially arranged on the steam-water circulation pipeline; the desalted water outlet of the heat pipe heat exchanger 6 is connected to the water inlet of the waste heat boiler 3 through a feed water pipeline, and a deaerator 13 and a boiler feed water pump 14 are arranged on the feed water pipeline.

[0026] Further, such as Figure 2As shown, the utility model discloses a hydrogen and oxygen cogeneration and venting gas treatment system utilizing the waste heat of high-temperature red coke, which also includes a reboiler 26 and a heat exchanger 27; the reboiler 27 is arranged on a pipeline connecting the outlet of the three-way valve 20 and the cathode inlet of the solid oxide electrolysis device 22; the heat exchanger 27 is arranged on a gas-liquid mixture pipeline upstream of the hydrogen cooling device 24; the high-temperature water vapor inlet of the reboiler 26 is connected to the outlet of the three-way valve 20, and the steam outlet of the reboiler 26 is connected to the steam inlet of the heat exchanger 27; the steam outlet of the heat exchanger 27 is connected to the steam inlet of the turbine 7; the water inlet of the reboiler 26 is connected to the condensate outlet and the deionized water replenishment inlet of the gas-liquid separator 25, and the secondary steam outlet of the reboiler 26 is connected to the cathode inlet of the solid oxide electrolysis device 22.

[0027] The utility model discloses a hydrogen and oxygen cogeneration and vented gas treatment system utilizing waste heat from high-temperature red coke. The system adopts a red coke heat recovery and high-temperature electrolysis co-coupling method to convert the high-temperature internal energy of the red coke into the chemical energy of hydrogen and oxygen. The produced oxygen is used to harmlessly treat the process vented gas. That is, the high-temperature water vapor 31 produced by the high-temperature red coke is firstly electrolyzed to produce hydrogen and oxygen. The carbon monoxide contained in the vented gas and the oxygen produced by electrolysis are then used to reduce and oxidize the vented gas in turn. Under the premise of not adding external heat, the sulfur dioxide removal and carbon monoxide oxidation are completed in steps. Finally, while hydrogen and oxygen are co-produced, the standard requirement of direct discharge of the vented gas 38 into the atmosphere is met.

[0028] Furthermore, the process of the hydrogen-oxygen cogeneration and venting gas treatment system using the waste heat of high-temperature red coke described in the utility model is as follows:

[0029] 1) The red coke heat recovery system uses inert gas 30 as an intermediate medium to transfer the heat of the red coke to high-temperature steam 31;

[0030] 2) The hydrogen and oxygen cogeneration system uses the solid oxide electrolysis device 22 to achieve self-heating electrolysis and co-produce hydrogen and oxygen by utilizing the high-temperature water vapor 31 produced by the red coke heat recovery system under the action of a direct current electric field. The electrolysis adopts a method of using external electricity or self-generation alone, or a method of using external electricity and self-generation together. When the quality of the circulating water vapor deteriorates, the normal electrolysis of the hydrogen and oxygen cogeneration system can still be guaranteed. When the quality of the circulating water vapor meets the requirements of direct electrolysis, the high-temperature water vapor 31 is directly connected to the cathode inlet of the solid oxide electrolysis device 22. When the quality of the circulating water vapor does not meet the requirements of direct electrolysis, the high-temperature water vapor 31 is first indirectly heat-exchanged with deionized water 37 in the reboiler 26, and then the secondary steam with a temperature of not less than 100°C is connected to the cathode inlet of the solid oxide electrolysis device 22.

[0031] 3) The water vapor circulation system is used to connect the red coke heat recovery system and the hydrogen and oxygen cogeneration system to form a circulation loop of condensed water-high temperature steam-condensed water; a three-way valve 20 is provided in the water vapor circulation system, the inlet of the three-way valve 20 is connected to the upstream high temperature steam outlet pipeline, and the other two outlets of the three-way valve 20 are respectively connected to the water vapor inlet pipeline of the hydrogen and oxygen cogeneration system and the water vapor inlet pipeline of the steam turbine; the control method of the three-way valve 20 is as follows:

[0032] (1) When the hydrogen-oxygen cogeneration system uses the self-generated electricity in the system alone for electrolysis, or uses the self-generated electricity in the system and external electricity for electrolysis, the three-way valve 20 connecting the hydrogen-oxygen cogeneration system and the outlet of the steam turbine 7 is kept open, and the opening is dynamically adjusted according to the load conditions;

[0033] (2) When the hydrogen-oxygen cogeneration system uses external electricity alone for electrolysis, the outlet of the three-way valve 20 connected to the hydrogen-oxygen cogeneration system is opened to 100% and the outlet connected to the steam turbine 7 is closed.

[0034] 4) The power supply system connects the generator 8 and the external power grid to the hydrogen-oxygen cogeneration system to provide direct current for electrolysis to the solid oxide electrolysis device 22; the power supply system is provided with a dual-way switch 23, which can be used for electrolysis with external power or self-generated electricity alone, or can be used for electrolysis with external power and self-generated electricity together.

[0035] 5) The vented gas treatment system first performs coarse desulfurization and dust removal treatment on the vented gas 38 generated by the red coke heat recovery system in the coarse desulfurization and dust removal device 28, then uses the carbon monoxide contained in the vented gas to reduce the residual sulfur dioxide to liquid sulfur in the catalytic reduction device, and finally uses the waste heat of the vented gas 38 and high-temperature electrolytic oxygen production in the catalytic oxidation device 29 to catalytically oxidize the remaining carbon monoxide to carbon dioxide, so that the vented gas 38 meets the standard requirements for direct discharge to the atmosphere.

[0036] After the process exhaust gas is roughly desulfurized and dusted, the residual concentration is not higher than 30mg / Nm 3 The sulfur dioxide in the exhaust gas 38 is catalytically reduced to liquid sulfur by the carbon monoxide in the exhaust gas 38 under the catalytic action of the iron oxide catalyst, so that the sulfur dioxide content is reduced to below 10ppm, and then enters the catalytic oxidation device 29. The exhaust gas 38 entering the catalytic oxidation device 29 still contains 0.2% to 11% carbon monoxide by volume. Without external heat, the carbon monoxide is catalytically oxidized to carbon dioxide by the oxygen produced by the hydrogen and oxygen cogeneration system under the cobalt catalyst and the temperature of 100 to 300°C, so that the volume fraction of carbon monoxide is reduced to below 0.15%, that is, the concentration is 2000mg / Nm 3 The following meets the direct discharge into the atmosphere standard requirements.

[0037] To ensure implementation, the utility model has designed a complete new process route of "red coke waste heat transfer to produce steam - high temperature electrolysis of water vapor to produce gas - catalytic reduction fine desulfurization - catalytic oxidation to remove carbon monoxide". First, the heat of the red coke is transferred to the high temperature water vapor through inert gas, and then the high temperature water vapor is electrolyzed to produce hydrogen and oxygen using external electricity or self-generated electricity. On the basis of catalytic reduction fine desulfurization, part of the oxygen is used to catalytically oxidize the carbon monoxide in the dry quenching exhaust gas (temperature of 100-300°C) to make its concentration reach 2000mg / Nm 3 The following emission standards are allowed. The reaction equations for each step are as follows:

[0038] Red coke waste heat transfer to produce steam:

[0039] High temperature steam electrolysis gas production:

[0040] Catalytic reduction desulfurization:

[0041] Catalytic oxidation to remove carbon monoxide:

[0042] Because coke production is a continuous and stable industrial process that can achieve a continuous and stable supply of high-temperature water vapor, the utility model can ensure the long-term and smooth operation of the high-temperature electrolysis system. Due to the coupling of high-temperature red coke waste heat, the energy consumption of "liquid water" heating and vaporization in the existing high-temperature electrolysis process is eliminated, so the system efficiency can be further improved by 20%, creatively realizing the efficient electrochemical utilization of red coke waste heat. When treating the discharged gas from dry quenching, the sulfur dioxide and smoke in the discharged gas are first roughly removed, and then the reduction effect of carbon monoxide in the discharged gas is used to deeply catalytically remove the residual sulfur dioxide from the crude desulfurization. Finally, part of the oxygen generated by electrolysis is used as an oxidant for "self-thermal catalytic oxidation" to oxidize the remaining carbon monoxide into carbon dioxide, ensuring that the discharged gas meets the emission standards.

[0043] The utility model is deeply coupled with my country's existing industrial resources and can be easily promoted to related industrial fields with abundant waste heat and huge carbon reduction pressure. It has broad prospects for promotion and application, and its potential social significance and economic benefits are very significant.

[0044] The following embodiments are implemented on the premise of the technical solution of the utility model, and provide detailed implementation methods and specific operation processes, but the protection scope of the utility model is not limited to the following embodiments.

[0045] [Example 1]

[0046] like Figure 1As shown, in this embodiment, the hydrogen and oxygen cogeneration and dry quenching vented gas treatment system using high-temperature red coke waste heat includes a red coke heat recovery system, a hydrogen and oxygen cogeneration system, a water vapor circulation system, a power supply system and a vented gas treatment system; the red coke heat recovery system is connected to the hydrogen and oxygen cogeneration system through the water vapor circulation system; the hydrogen and oxygen cogeneration system is also connected to the power supply system; the power supply system includes a power generation device and an external power grid; the vented gas treatment system includes a coarse desulfurization and dust removal device 28, a catalytic reduction device and a catalytic oxidation device 29 arranged in sequence along the flow direction of the vented gas; the catalytic oxidation device is connected to the oxygen outlet of the hydrogen and oxygen cogeneration system through an oxygen pipeline.

[0047] In this embodiment, a dry quenching furnace is used to first transfer the waste heat of red coke to an inert gas, and then the heat of the inert gas is used to produce high-temperature steam in a waste heat boiler. The steam then enters a solid oxide electrolysis device in a direct or indirect manner to co-produce hydrogen and oxygen, and finally a portion of the oxygen is used to catalytically oxidize the carbon monoxide in the gas released after fine desulfurization. The specific steps are as follows:

[0048] 1) Red coke heat recovery system:

[0049] The red coke (950-1050℃) produced from the coke oven in the coke tank 0 enters the pre-storage section and cooling section of the dry quenching furnace 1 from the top of the dry quenching furnace 1 in turn, and directly contacts and exchanges heat with the low-temperature inert gas at 130℃ from the bottom of the furnace in reverse. After the coke cools to below 180℃, it is discharged from the bottom of the dry quenching furnace 1. The high-temperature inert gas heated to 880-960℃ by heat exchange passes through the primary dust collector 2 to separate the coarse coke powder, enters the waste heat boiler 3 to indirectly exchange heat with the boiler feed water 34 at 100-110℃ to reduce the temperature to 160-180℃, and then passes through the secondary dust collector 4 to separate the fine coke powder, so that the dust concentration is reduced to 1g / m 3 After the temperature is lower than 100 °C, the coke is pressurized by the circulating fan 5, cooled to below 130 °C by the heat pipe heat exchanger 6, and then returned to the lower part of the CDQ furnace 1 for recycling. Through the above process, 80% of the high-temperature waste heat in the red coke is transferred to the high-temperature steam 31 with the inert gas 30 as the intermediate medium.

[0050] 2) Hydrogen and oxygen cogeneration system: The high-temperature steam generated by the waste heat boiler has two electrolysis operation modes:

[0051] When the quality of circulating water vapor meets the requirements of direct electrolysis: high-temperature water vapor 31 directly enters the solid oxide electrolysis device 22, and after electrolysis at 600-900°C, part of the oxygen generated at the anode is connected to the catalytic oxidation device 29 of the exhaust gas treatment system, and the other part is sent to the downstream unit for oxygen-enriched combustion or chemical synthesis; the hydrogen-water vapor mixture 35 generated at the cathode is first cooled to 40°C by the hydrogen cooling device 24, and then separated by the gas-liquid separator 25, the separated hydrogen is sent to the downstream unit for continued use, and the separated condensate 36 goes to the desalted water tank 11 to re-enter the water circulation.

[0052] When the circulating water vapor quality does not meet the direct electrolysis requirements: the high-temperature water vapor is first indirectly heat-exchanged with deionized water in the reboiler, and the secondary steam generated enters the solid oxide electrolysis device. After electrolysis at 600-900°C, part of the oxygen generated at the anode is connected to the catalytic oxidation device of the exhaust gas treatment system, and the other part is sent to the downstream unit for oxygen-enriched combustion or chemical synthesis. The mixture of hydrogen generated at the cathode and the unreacted water vapor is first cooled by the heat exchanger, and then cooled to 40°C by the hydrogen cooling device, and finally separated by the gas-liquid separator. The hydrogen is sent to the downstream unit for continued use, and the condensed water returns to the deionized water loop of the reboiler for recycling. After the high-temperature water vapor and deionized water exchange heat in the reboiler, they are sent to the steam turbine through the heat exchanger to re-enter the cycle.

[0053] 3) Water vapor circulation system:

[0054] The saturated steam at 40°C from the steam turbine 7 is condensed into turbine condensate 32 at 40°C by the condenser 9, and is pressurized by the condensate pump 10 and transported to the desalted water tank 11, where it is mixed with make-up water and condensate 36 from the gas-liquid separator 25 (the first operating mode), and is pressurized by the deoxygenation feed water pump 12 to enter the heat pipe heat exchanger 6 to be heated to 70°C, and is further deoxygenated by the deaerator 13, and is pressurized by the boiler feed water pump 14 to enter the waste heat boiler 3, and is indirectly heat exchanged with the high-temperature inert gas in the waste heat boiler 3 in the reverse direction to generate high-temperature water vapor 31 with a temperature of more than 400°C. After these high-temperature water vapors are drawn out from the upper part of the waste heat boiler 3, they are controlled by the three-way valve 20, and a part (or all) of them are used as feed for the high-temperature solid oxide electrolysis device 22, and the other part (or none) is used to drive the steam turbine 7 to generate electricity.

[0055] 4) Power supply system:

[0056] The electricity for electrolysis can be derived from renewable energy and traditional secondary energy generation (external electricity), or from the self-generation of the steam turbine generator 8. The two sources of electricity can be selected by the two-way switch 23. During electrolysis, either external electricity or self-generation can be used alone, or external electricity and self-generation can be used together. When self-generation electrolysis is used alone, it should be ensured that the self-generation can meet the power demand of the electrolysis process. Before electrolysis, it should be ensured that the alternating current has been converted into direct current by the inverter 21.

[0057] 5) Exhaust gas treatment system: mainly includes crude desulfurization and dust removal process, catalytic reduction process and catalytic oxidation process.

[0058] The exhaust gas 38 at 100-300°C from the dry quenching furnace 1 first enters the rough desulfurization and dust removal device 28 to reduce the sulfur dioxide and smoke to 30 mg / Nm 3 and 10mg / Nm 3After the exhaust gas is reduced to less than 10 ppm, it enters the catalytic reduction device 29-1. The residual sulfur dioxide after the rough desulfurization is reduced to liquid sulfur 39 under the catalysis of iron oxide by utilizing the reducing property of carbon monoxide in the exhaust gas, and the sulfur dioxide content is reduced to less than 10 ppm before entering the catalytic oxidation device 29-2; in the catalytic oxidation device, the exhaust gas 38 uses its own waste heat and oxygen from the hydrogen and oxygen cogeneration system to undergo oxidation reaction on the active center of the cobalt catalyst to generate carbon dioxide, reducing the carbon monoxide content to 0.15% (corresponding to a concentration of 2000 mg / Nm 3 ) and finally discharge the exhaust gas 38 that meets the standards into the atmosphere.

[0059] [Example 2]

[0060] like Figure 2 As shown, in this embodiment, the hydrogen and oxygen cogeneration and dry quenching vented gas treatment system using high-temperature red coke waste heat includes a red coke heat recovery system, a hydrogen and oxygen cogeneration system, a water vapor circulation system, a power supply system and a vented gas treatment system; the red coke heat recovery system is connected to the hydrogen and oxygen cogeneration system through the water vapor circulation system; the hydrogen and oxygen cogeneration system is also connected to the power supply system; the power supply system includes a power generation device and an external power grid; the vented gas treatment system includes a coarse desulfurization and dust removal device 28, a catalytic reduction device and a catalytic oxidation device 29 arranged in sequence along the flow direction of the vented gas; the catalytic oxidation device is connected to the oxygen outlet of the hydrogen and oxygen cogeneration system through an oxygen pipeline.

[0061] The red coke produced from the coke oven in the coke tank 0 enters the pre-storage section and cooling section of the dry quenching furnace 1 from the top of the dry quenching furnace 1 in turn, and directly contacts and exchanges heat with the low-temperature inert gas at 130°C from the bottom of the furnace in reverse. After the coke cools to below 180°C, it is discharged from the bottom of the dry quenching furnace 1. The high-temperature inert gas heated to 880-960°C by heat exchange passes through the primary dust collector 2 to separate the coarse coke powder, and then enters the waste heat boiler 3 to indirectly exchange heat with the boiler feed water 34 at 104°C to reduce the temperature to 160-180°C, and then passes through the secondary dust collector 4 to separate the fine coke powder, so that the dust concentration is reduced to 1g / m 3 After that, the coke is pressurized by the circulating fan 5, cooled to 130°C by the heat pipe heat exchanger 6, and then returned to the lower part of the CDQ furnace 1 for recycling. Through the above process, 80% of the high-temperature waste heat in the red coke is transferred to the high-temperature steam 31 with the inert gas 30 as the intermediate medium.

[0062] The high-temperature steam 31 is first indirectly heat-exchanged with deionized water 37 in the reboiler 26, and the secondary steam generated enters the solid oxide electrolysis device 22. After electrolysis at 600-900°C, part of the oxygen generated at the anode is connected to the catalytic oxidation device 29 of the exhaust gas treatment system, and the other part of the oxygen is sent to the downstream unit for oxygen-enriched combustion or chemical synthesis; the hydrogen generated at the cathode and the unreacted steam mixture 35 are first cooled by the heat exchanger 27, then cooled to 40°C by the hydrogen cooling device 24, and finally separated by the gas-liquid separator 25. The separated hydrogen is sent to the downstream unit for further use, and the separated condensed water returns to the deionized water circuit of the reboiler 26 for recycling. After the high-temperature steam 31 and the deionized water 37 are heat-exchanged in the reboiler 26, they are sent to the steam turbine 7 through the heat exchanger 27 to re-enter the cycle.

[0063] The saturated steam at 40°C from the turbine 7 is condensed by the condenser 9 into turbine condensate 32 at 40°C, which is pressurized by the condensate pump 10 and transported to the desalted water tank 11, where it is mixed with make-up water and used as desalted water 33, which is pressurized by the deoxygenation feed water pump 12 and enters the heat pipe heat exchanger 6 to be heated to 70°C. After being deoxygenated by the deaerator 13, it is pressurized by the boiler feed water pump 14 and enters the waste heat boiler 3, where it indirectly exchanges heat with the high-temperature inert gas in a reverse direction to generate high-temperature water vapor 31 with a temperature above 400°C. After being drawn out from the upper part of the waste heat boiler 3, the high-temperature water vapor 31 is controlled by the three-way valve 20 and all used as feed for the high-temperature solid oxide electrolysis device 22.

[0064] The electricity used for electrolysis can be derived from renewable energy and traditional secondary energy generation, or from self-generation of the steam turbine generator 8, and the two sources of electricity can be selected by the two-way switch 23. During electrolysis, either external electricity or self-generation can be used alone, or external electricity and self-generation can be used together. When self-generation electrolysis is used alone, it should be ensured that the self-generation can meet the power demand of the electrolysis process. Before electrolysis, it should be ensured that the alternating current has been converted into direct current by the inverter 21.

[0065] The exhaust gas 38 at 100-300°C from the dry quenching furnace 1 first enters the rough desulfurization and dust removal device 28 to reduce the sulfur dioxide and smoke to 30 mg / Nm 3 and 10mg / Nm 3 After that, it enters the catalytic reduction device 29-1. In the catalytic reduction device 29-1, the sulfur dioxide remaining from the crude desulfurization is reduced to liquid sulfur 39 by utilizing the reducing property of carbon monoxide in the exhaust gas 38 under the catalysis of iron oxide, and the sulfur dioxide content is reduced to below 10ppm. Then, it enters the catalytic oxidation device 29-2, and then the exhaust gas 38 itself is used The waste heat and the oxygen from the hydrogen and oxygen cogeneration system are used to react with the active center of the cobalt catalyst to generate carbon dioxide, so that the carbon monoxide content is reduced to 0.15% (corresponding to a concentration of 2000mg / Nm 3) and finally discharge the exhaust gas 38 that meets the standards into the atmosphere.

[0066] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes within the technical scope disclosed by the present invention according to the technical solution and inventive concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A hydrogen and oxygen cogeneration and venting gas treatment system using high-temperature red coke waste heat, characterized in that: It includes a red coke heat recovery system, a hydrogen-oxygen cogeneration system, a water vapor circulation system, a power supply system and a vented gas treatment system; the red coke heat recovery system is a dry quenching coke circulation system composed of a dry quenching furnace, a primary dust collector, a waste heat boiler, a secondary dust collector, a circulating fan and a heat pipe heat exchanger; the hydrogen-oxygen cogeneration system includes a solid oxide electrolysis device, a hydrogen cooling device and a gas-liquid separator; the gas-liquid mixture inlet of the gas-liquid separator is connected to the gas-liquid mixture outlet of the solid oxide electrolysis device through a gas-liquid mixture pipeline, and a hydrogen cooling device is provided on the gas-liquid mixture pipeline; the high-temperature steam pipeline of the red coke heat recovery system is provided with three A three-way valve is provided, wherein the inlet of the three-way valve is connected to the high-temperature steam pipeline led out from the waste heat boiler, one outlet of the three-way valve is connected to the cathode inlet of the solid oxide electrolysis device, and the other outlet of the three-way valve is connected to the high-temperature steam inlet of the steam turbine; the water vapor circulation system is arranged between the power supply system and the waste heat boiler; the vented gas treatment system comprises a coarse desulfurization and dust removal device, a catalytic reduction device and a catalytic oxidation device, the vented gas outlet of the dry quenching furnace is connected to the coarse desulfurization and dust removal device, the catalytic reduction device and the catalytic oxidation device in sequence through the vented gas pipeline, and the oxygen inlet on the catalytic oxidation device is connected to the oxygen outlet of the hydrogen-oxygen cogeneration system through the oxygen pipeline.

2. According to claim 1, a hydrogen and oxygen cogeneration and venting gas treatment system using high-temperature red coke waste heat is characterized in that: The power supply system includes a self-generating system consisting of a steam turbine and a generator, and an external power system including renewable energy power generation and traditional secondary energy power generation; a double-circuit switch is provided on the power supply circuit connecting the solid oxide electrolysis device with the self-generating system and the external power system; inverters are respectively provided on the power supply circuit of the self-generating system and the power supply circuit of the external power system.

3. According to claim 1, a hydrogen and oxygen cogeneration and venting gas treatment system using high-temperature red coke waste heat is characterized in that: The water vapor circulation system comprises a condenser, a condensate pump, a desalted water tank, a deoxygenated feed water pump, a deaerator and a boiler feed water pump; the saturated steam outlet of the steam turbine is connected to the desalted water inlet of the heat pipe heat exchanger through a steam-water circulation pipeline, and the condenser, the condensate pump, the desalted water tank and the deoxygenated feed water pump are sequentially arranged on the steam-water circulation pipeline; the desalted water outlet of the heat pipe heat exchanger is connected to the water inlet of the waste heat boiler through a feed water pipeline, and the deaerator and the boiler feed water pump are arranged on the feed water pipeline.

4. According to claim 1, a hydrogen and oxygen cogeneration and venting gas treatment system using high-temperature red coke waste heat is characterized in that: It also includes a reboiler and a heat exchanger; the reboiler is arranged on the pipeline connecting the outlet of the three-way valve and the cathode inlet of the solid oxide electrolysis device; the heat exchanger is arranged on the gas-liquid mixture pipeline upstream of the hydrogen cooling device; the high-temperature water vapor inlet of the reboiler is connected to the outlet of the three-way valve, and the steam outlet of the reboiler is connected to the steam inlet of the heat exchanger; the steam outlet of the heat exchanger is connected to the steam inlet of the steam turbine; the water inlet of the reboiler is connected to the condensate outlet and the deionized water replenishment inlet of the gas-liquid separator, and the secondary steam outlet of the reboiler is connected to the cathode inlet of the solid oxide electrolysis device.

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