Carbon dioxide comprehensive utilization system taking dry quenching as core

Abstract

The utility model relates to a carbon dioxide comprehensive utilization system taking dry quenching as a core. The carbon dioxide comprehensive utilization system comprises a dry quenching circulation system, a carbon dioxide preparation system, a carbon monoxide separation device and a hydrogen separation device, the dry quenching circulating system comprises a dry quenching furnace, a primary dust remover, a boiler, a secondary dust remover and a circulating fan which are sequentially connected through a circulating gas pipeline; the carbon monoxide separation device and the hydrogen separation device are connected with a circulating gas pipeline at the downstream of the circulating fan; the carbon dioxide preparation system comprises a coke oven flue, a carbon dioxide separation device and a chimney. According to the system disclosed by the utility model, carbon dioxide separated from industrial waste gas is used as dry quenching circulating gas, a new way for consuming carbon dioxide is developed, the emission of carbon dioxide is reduced, the safety of dry quenching production is ensured, and carbon monoxide and hydrogen are obtained.

Description

Technical Field

[0001] The utility model relates to the technical field of coking, in particular to a carbon dioxide comprehensive utilization system with dry coke quenching as the core. Background Art

[0002] Against the backdrop of carbon peak and carbon neutrality, all industries are striving to find ways to reduce or convert carbon dioxide emissions.

[0003] In the current field of coking technology, the exhaust gas emitted from the coke oven chimney contains a large amount of carbon dioxide, but there is no process in the coking plant that can consume carbon dioxide. In order to effectively reduce the carbon dioxide emissions of coking enterprises and obtain certain economic benefits, a comprehensive carbon dioxide utilization technology is needed.

[0004] A Chinese invention patent with authorization publication number CN 113941236 B discloses a "dry quenching flue gas treatment system and method thereof." The dry quenching flue gas treatment system is used to decarbonize the circulating gas flowing between the exhaust port and the return air port of the dry quenching coke oven. The system includes a gas activation device, a gas decarbonization device, and a gas treatment device, wherein the gas activation device includes a heat storage unit and an activation unit. The circulating gas discharged during the dry quenching production process is used to provide part of the heat for the activation reaction. On the other hand, the carbon dioxide in the circulating gas is separated and used to form a reaction gas source together with pure oxygen and water vapor to undergo an activation reaction with the carbonized material to produce synthesis gas. In other words, the carbon dioxide in the circulating gas is recycled to produce synthesis gas, and the synthesis gas can be used as a chemical raw material, which can not only reduce waste gas emissions and achieve low-carbon dry quenching production, but also enrich coking products.

[0005] Chinese patent application publication number CN 114181720 A discloses a "coal chemical carbon dioxide capture and reuse process," implemented through an energy-saving recovery system comprising a carbon dioxide recovery and processing unit, a dry quenching furnace generator, a dry quenching furnace dust removal unit with multi-stage dust removal, a waste heat collection device, and a plasma reactor. The process includes the steps of coke oven flue gas separation and treatment, carbon dioxide utilization, carbon dioxide circulation, and gas purification and separation. This process utilizes purified carbon dioxide as a cooling recycle gas, replacing the nitrogen used in existing dry quenching technology. This overturns the existing concept of using nitrogen as recycle gas in dry quenching technology. Furthermore, it utilizes carbon dioxide from the exhaust gas as a gas source and converts the difficult-to-sell, low-value coke fines into high-value, truly achieving the fundamental reuse of carbon dioxide, turning waste into treasure.

[0006] Chinese invention patent publication number CN 114790396 B discloses a "High-Efficiency Coke Dry Quenching Method and Carbon Monoxide Production System for Emission Reduction." The method uses carbon dioxide and carbon dioxide-rich gas as the inlet to the CDQ circulating gas stream. While exchanging heat with red coke, some of the carbon dioxide contained in the CDQ circulating gas reacts with the high-temperature red coke to produce carbon monoxide, increasing the carbon monoxide content in the circulating gas stream to 30-80% by volume. This endothermic reaction of carbon dioxide with the high-temperature red coke to produce carbon monoxide effectively utilizes the heat of the high-temperature red coke, ensuring the stability of the CDQ process and the quality of the coke product. The CDQ unit's produced gas stream is further purified and separated to produce carbon monoxide product gas for external supply, while the separated carbon dioxide-rich gas is returned to the CDQ unit's circulating gas system for reuse. This is a technically feasible and economically sound carbon dioxide reduction process. Summary of the Invention

[0007] The utility model provides a carbon dioxide comprehensive utilization system with dry coke quenching as the core, integrating multiple monomer technologies. The dry coke quenching circulating gas after primary dust removal can be used for supercritical power generation. The supercritical power generation uses compressed carbon dioxide instead of desalted water as a heat exchange medium, and has the advantages of high power generation efficiency and small footprint. The circulating gas is then passed through a boiler for heat exchange to generate steam and cool down, and carbon monoxide and hydrogen are extracted. The remaining circulating gas, the main component of which is carbon dioxide, re-enters the dry coke quenching furnace for quenching, and carbon dioxide gas from other sources is supplemented to the dry coke quenching furnace. The safety of dry coke quenching production is ensured, and carbon monoxide and hydrogen are obtained.

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

[0009] A carbon dioxide comprehensive utilization system with dry coke quenching as its core comprises a dry coke quenching circulation system, a carbon dioxide production system, a carbon monoxide separation device and a hydrogen separation device; the dry coke quenching circulation system comprises a dry quenching furnace, a primary dust collector, a boiler, a secondary dust collector and a circulating fan connected in sequence via a circulating gas pipeline; the carbon monoxide separation device and the hydrogen separation device are connected to the circulating gas pipeline downstream of the circulating fan; the carbon dioxide production system comprises a coke oven flue, a carbon dioxide separation device and a chimney; the coke oven flue is directly connected to the chimney, and a valve is provided on the coke oven flue near the chimney; a flue exhaust gas outlet is provided on the coke oven flue upstream of the valve, and is connected to the carbon dioxide separation device via a flue exhaust pipe; a waste gas inlet is also provided on the chimney, the decarbonization waste gas outlet of the carbon dioxide separation device is connected to the waste gas inlet of the chimney, and the carbon dioxide gas outlet of the carbon dioxide separation device is connected to the supplementary circulating gas inlet of the dry quenching furnace; the supplementary circulating gas inlet is provided at the top of the dry quenching furnace annular air duct and / or the outlet pipeline of the primary dust collector.

[0010] A kind of carbon dioxide comprehensive utilization system with dry quenching as core, still include supercritical power generation device, the supercritical power generation device is located in the circulating gas pipeline between primary dust collector and boiler.

[0011] The carbon monoxide separation device and hydrogen separation device are arranged on the circulating gas pipeline downstream of the circulating fan.

[0012] The carbon monoxide separation device and hydrogen separation device are arranged on the circulating gas branch pipeline downstream of the circulating fan; a circulating gas outlet is sequentially arranged on the circulating gas pipeline downstream of the circulating fan; the circulating gas outlet is connected to the circulating gas branch pipeline, and the carbon monoxide separation device and the hydrogen separation device are sequentially arranged on the circulating gas branch pipeline; the circulating gas branch pipeline downstream of the hydrogen separation device is connected to the circulating gas inlet of the dry quenching furnace.

[0013] Compared with the prior art, the utility model has the beneficial effects that:

[0014] 1) carbon dioxide in coke oven flue gas or other waste gas is captured by using a chemical method, and then the captured carbon dioxide with high purity is supplemented into a dry quenching circulating system;

[0015] 2) carbon dioxide is used to replace conventional quenching gas-nitrogen to cool coke, and carbon monoxide is produced by the reaction between carbon dioxide and coke powder and trace coke in the dry quenching furnace; at the present time when carbon dioxide from coke oven flue gas or other sources is consumed and converted, carbon monoxide and hydrogen gas that can be used as fuel or raw materials are produced;

[0016] 3) the carbon dioxide and carbon monoxide mixed gas after quenching can be used for supercritical power generation after removing coke powder by a primary dust collector, and then steam is generated by heat exchange through a boiler; different from conventional steam turbine power generation, supercritical power generation uses compressed carbon dioxide instead of desalted water as a heat exchange medium, and has the technical advantages of high power generation efficiency and small occupied area;

[0017] 4) the carbon monoxide and hydrogen gas in the mixed gas after heat exchange with the boiler are extracted, so that the H2 concentration of the circulating gas entering the dry quenching furnace is less than 3%, the CO concentration is less than 6%, the H2 concentration of the circulating gas at the outlet of the dry quenching furnace is less than 4%, and the CO concentration is less than 12.5%, all of which are less than the explosion limit of combustible components, thereby eliminating the risk of CO and H2 explosion caused by using carbon dioxide for quenching;

[0018] 5) a new way of consuming carbon dioxide is developed, and carbon dioxide gas emission is effectively reduced.

[0019] 6) carbon dioxide is converted into carbon monoxide, and the carbon monoxide can be used as a chemical raw material or fuel. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1It is a structural diagram of the carbon dioxide comprehensive utilization system with dry coke quenching as the core described in Example 1.

[0021] Figure 2 It is a structural diagram of the carbon dioxide comprehensive utilization system with dry coke quenching as the core described in Example 2.

[0022] Figure: 1. Recycled gas inlet 2. CDQ furnace 3. Carbon dioxide and carbon reaction zone 4. Recycled gas outlet 5. Supercritical power generation unit 6. Carbon monoxide separation unit 7. Hydrogen separation unit 8. Primary dust collector 9. Boiler 10. Secondary dust collector 11. Recycle fan 12. Coke oven flue 13. Chimney 14. Carbon dioxide separation unit DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0024] like Figure 1 、 Figure 2 As shown, the utility model discloses a carbon dioxide comprehensive utilization system with dry coke quenching as the core, including a dry coke quenching circulation system, a carbon dioxide production system, a carbon monoxide separation device and a hydrogen separation device; the dry coke quenching circulation system includes a dry quenching furnace 2, a primary dust collector 8, a boiler 9, a secondary dust collector 10 and a circulating fan 11 connected in sequence through a circulating gas pipeline; the carbon monoxide separation device 6 and the hydrogen separation device 7 are connected to the circulating gas pipeline downstream of the circulating fan 11; the carbon dioxide production system includes a coke oven flue 12, a carbon dioxide separation device 14 and a chimney 13; the coke oven flue 12 is directly connected to the chimney 13, and a valve is provided on the coke oven flue 12 near the chimney 13; a flue exhaust gas outlet is provided on the coke oven flue 12 upstream of the valve, which is connected to the carbon dioxide separation device 14 through a flue exhaust gas pipe; a waste gas inlet is also provided on the chimney 13, the decarbonization waste gas outlet of the carbon dioxide separation device 14 is connected to the waste gas inlet of the chimney 13, and the carbon dioxide gas outlet of the carbon dioxide separation device 14 is connected to the supplementary circulating gas inlet of the dry quenching furnace 2; the supplementary circulating gas inlet is provided at the top of the annular air duct of the dry quenching furnace 2 and / or the outlet pipe of the primary dust collector 8.

[0025] A carbon dioxide comprehensive utilization system with dry coke quenching as the core also includes a supercritical power generation device 5, which is arranged on the circulating gas pipeline between the primary dust collector 8 and the boiler 9.

[0026] The carbon monoxide separation device 6 and the hydrogen separation device 7 are arranged on the circulating gas pipeline downstream of the circulating fan 11 .

[0027] Alternatively, the carbon monoxide separation device 6 and the hydrogen separation device 7 are arranged on the circulating gas branch pipe downstream of the circulating fan 11; a circulating gas outlet is provided on the circulating gas pipe downstream of the circulating fan 11 to connect to the circulating gas branch pipe, the carbon monoxide separation device 6 and the hydrogen separation device 7 are sequentially arranged on the circulating gas branch pipe, and the circulating gas branch pipe under the hydrogen separation device 7 is connected to the circulating gas inlet 1 of the dry quenching furnace 2.

[0028] The working principle of the carbon dioxide comprehensive utilization system with dry coke quenching as the core described in the utility model is as follows: circulating gas whose main component is carbon dioxide enters the dry quenching furnace 2 from the circulating gas inlet 1, and the carbon dioxide reacts with coke powder and trace coke to produce carbon monoxide. The high-temperature circulating gas discharged from the circulating gas outlet mainly consists of carbon dioxide and carbon monoxide; the high-temperature circulating gas is filtered out of the coke powder by the primary dust collector 8 and then passes through the boiler 9 to recover the waste heat; the low-temperature circulating gas after the waste heat is recovered is first separated from the carbon monoxide and hydrogen, and then the remaining circulating gas whose main component is carbon dioxide returns to the dry quenching furnace 2 from the circulating gas inlet 1 for recycling, and new carbon dioxide gas is added to the dry quenching furnace 2 at the same time.

[0029] The source of the circulating gas is the flue gas of the coke oven; carbon dioxide is separated from the flue gas of the coke oven by using the carbon dioxide separation device 14 and is fed into the CDQ furnace 2 as the circulating gas and new carbon dioxide gas.

[0030] The source of the circulating gas can also be the combustion waste gas generated by burning coal or coke in furnaces including sintering and blast furnaces in the steel industry; carbon dioxide is separated from the combustion waste gas using a carbon dioxide separation device 14 and fed into the dry quenching furnace 2 as circulating gas and new carbon dioxide gas.

[0031] After the high-temperature circulating gas passes through the primary dust collector 8 to remove the coke powder, it first enters the supercritical power generation device 5 to generate electricity, and then recovers the waste heat through the boiler 9.

[0032] The supplementary inlet of new carbon dioxide gas is arranged at the top of the annular air duct of the dry quenching furnace 2 and / or on the outlet pipe of the primary dust collector 8.

[0033] The H2 concentration in the circulating gas at the circulating gas inlet 1 is less than 3%, and the CO concentration is less than 6%; the H2 concentration in the circulating gas at the circulating gas outlet is less than 4%, and the CO concentration is less than 12.5%.

[0034] As an alternative, a portion of the low-temperature circulating gas after waste heat recovery is drawn out from the circulating gas pipeline, and only the carbon monoxide and hydrogen in the drawn-out low-temperature circulating gas are separated. The circulating gas not drawn out from the circulating gas pipeline and the circulating gas whose main component is carbon dioxide after separation are returned to the dry quenching furnace 2 for recycling.

[0035] The utility model discloses a carbon dioxide comprehensive utilization system with dry coke quenching as the core, which adopts a brand-new process flow. The process flow includes multiple monomer technologies. The core principle of carbon reduction is to separate carbon dioxide from industrial waste gases such as coke oven waste gas, and then use carbon dioxide gas as the circulating gas for dry coke quenching. While cooling the coke, part of the carbon dioxide is converted into carbon monoxide, and then the carbon monoxide and hydrogen in all or part of the circulating gas are separated.

[0036] The monomer technologies involved in the process flow of the system described in the utility model mainly include carbon dioxide extraction technology, dry quenching technology, carbon monoxide extraction technology, carbon monoxide application technology and hydrogen extraction technology. Among them, carbon dioxide is used instead of nitrogen as the circulating gas in the dry quenching technology, and the CO and H2 separation technology eliminates the risk of explosion caused by excessive CO and H2 concentrations when using carbon dioxide to quench coke.

[0037] First, carbon dioxide is chemically captured from coke oven flue gases or other industrial waste gases. The captured, high-purity carbon dioxide is then fed into the CDQ system as both circulating gas and make-up circulating gas. The CDQ circulating gas is primarily composed of carbon dioxide, with a certain proportion of carbon monoxide, a small amount of hydrogen, a small amount of water, and trace amounts of sulfur dioxide.

[0038] In the dry quenching furnace 2, carbon dioxide and red-hot coke exchange heat in countercurrent, and react with coke powder and a small amount of coke to produce carbon monoxide. The red coke is cooled to below 200°C and discharged. The mixed gas of carbon dioxide and carbon monoxide is heated by the red coke to raise its temperature. After passing through the primary dust collector 8 to remove part of the coke powder, it can be used for supercritical power generation, and then heat exchanged through the boiler 9 to generate steam, or directly through the boiler 9 to generate steam. Different from conventional steam turbine power generation, the supercritical power generation device 5 uses compressed carbon dioxide instead of desalted water as the heat exchange medium, which has the advantages of high power generation efficiency and small footprint. When using supercritical power generation, the primary dust collector 8 can adopt a cyclone dust removal device (the conventional primary dust collector is a gravity dust removal device).

[0039] Before the cooled mixed gas is returned to the dry quenching furnace 2 as the dry quenching circulating gas, the entire mixed gas or part of the mixed gas is first subjected to carbon monoxide separation to extract the carbon monoxide in the mixed gas. The extracted carbon monoxide can be used as fuel or chemical raw material. Since the residual volatile matter of red coke contains H2, there is a risk of explosion when the continuously accumulated H2 reaches a certain concentration; therefore, the utility model separates and extracts H2 while separating and extracting carbon monoxide. After extracting carbon monoxide and H2, the remaining circulating gas, whose main component is carbon dioxide, is returned to the dry quenching furnace 2. The utility model controls the H2 concentration in the circulating gas entering the dry quenching furnace 2 to be less than 3% and the CO concentration to be less than 6%. Since the concentrations of CO and H2 in the inlet circulating gas are controlled, the H2 concentration in the circulating gas at the outlet of the dry quenching furnace 2 is less than 4%, and the CO concentration is less than 12.5%, both of which are less than the explosion limit of the combustible components, and can effectively avoid the risk of explosion in the dry quenching circulating system.

[0040] The carbon monoxide separation device 6 and the hydrogen separation device 7 can be independent devices or integrated devices.

[0041] Because a portion of the recycled gas returning to the CDQ furnace 2 is extracted, it needs to be replenished with new carbon dioxide gas. This replenishment of carbon dioxide gas also comes from the coke oven flue gas or other industrial waste gas, i.e., high-purity carbon dioxide captured from the waste gas using chemical methods. The inlet for the replenishment recycled gas is located at the top of the annular air duct of the CDQ furnace 2 and / or the outlet duct of the primary dust collector.

[0042] In order to more intuitively embody the present invention, the embodiments of the present invention are further described in conjunction with the examples. The following examples are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solution that can be obviously obtained by a person skilled in the art within the technical scope disclosed in the present invention, including simple changes or equivalent replacements, is within the scope of protection of the present invention.

[0043] [Example 1]

[0044] like Figure 1 As shown, in this embodiment, the working process of the carbon dioxide comprehensive utilization system with dry coke quenching as the core is as follows:

[0045] Carbon dioxide is separated from the exhaust gas of the coke oven flue 12 by a carbon dioxide separation device 14, and the separated carbon dioxide gas is fed into the dry quenching furnace 2 from the circulating gas inlet 1 as cooling gas. In the cooling chamber of the dry quenching furnace 2, carbon dioxide and coke are in countercurrent contact to cool the coke. In the dry quenching furnace 2, the temperature in the chute and a certain area below the chute exceeds 800°C, which is the reaction zone 3 between carbon dioxide and carbon. In this area, carbon dioxide reacts with coke powder and trace coke to produce carbon monoxide. Since this reaction is an endothermic reaction, it can also enhance the cooling of the coke.

[0046] The mixed gas produced by the contact between carbon dioxide and coke is discharged from high-temperature circulating gas outlet 4. Its main components are carbon dioxide and carbon monoxide. In a conventional CDQ cycle system, the high-temperature circulating gas passes through the primary dust collector 8, boiler 9, secondary dust collector 10, and circulating fan 11 before returning to the CDQ furnace 2. In this embodiment, the high-temperature circulating gas first enters the ultra-closed power generation device 5 for power generation before entering the boiler 9. The low-temperature circulating gas at the outlet of the circulating fan 11 first enters the carbon monoxide separation device 6, where the separated carbon monoxide is used as a high-value-added product.

[0047] The main component of the remaining circulating gas after separation of carbon monoxide is carbon dioxide, but it also contains a small amount of hydrogen. In order to prevent the continuous accumulation of H2 in the CDQ circulation system, this embodiment further separates the hydrogen through the hydrogen separation device 7.

[0048] Ultimately, the main component, carbon dioxide, is recycled as circulating gas. Since carbon monoxide and hydrogen are separated from the circulating gas, the total amount of circulating gas decreases, necessitating additional carbon dioxide. In this embodiment, the carbon dioxide used as the supplemental circulating gas also originates from coke oven flue exhaust gas, namely, carbon dioxide separated from the exhaust gas of the coke oven flue 12 by the carbon dioxide separation device 14. After the carbon dioxide is separated, the coke oven flue exhaust gas can be directly discharged into the atmosphere through the chimney 13.

[0049] [Example 2]

[0050] like Figure 2 As shown, in this embodiment, the main process flow of the carbon dioxide comprehensive utilization system with dry coke quenching as the core is the same as that in Example 1, with the difference that: the circulating gas pipeline at the outlet of the circulating fan 11 is not equipped with a carbon monoxide separation device 6 and a hydrogen separation device 7, and these two separation devices are installed on the circulating gas branch pipeline.

[0051] In this embodiment, in order to reduce the difficulty of gas separation, only a portion of the low-temperature circulating gas at the outlet of the circulating fan 11 is introduced into the circulating gas branch pipe, and the carbon monoxide and hydrogen therein are separated by the carbon monoxide separation device 6 and the hydrogen separation device 7; the unseparated portion of the circulating gas is mixed with the other portion of the circulating gas whose main component is carbon dioxide after separation, and then enters the dry quenching furnace 2 from the circulating gas inlet, which can also effectively reduce the concentrations of CO and H2 in the dry quenching circulation system, and the process cost is lower than that of Example 1.

[0052] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on 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 carbon dioxide comprehensive utilization system with dry coke quenching as the core, characterized in that: It includes a dry coke quenching circulation system, a carbon dioxide production system, a carbon monoxide separation device and a hydrogen separation device; the dry coke quenching circulation system includes a dry quenching furnace, a primary dust collector, a boiler, a secondary dust collector and a circulating fan connected in sequence through a circulating gas pipeline; the carbon monoxide separation device and the hydrogen separation device are connected to the circulating gas pipeline downstream of the circulating fan; the carbon dioxide production system includes a coke oven flue, a carbon dioxide separation device and a chimney; the coke oven flue is directly connected to the chimney, and a valve is provided on the coke oven flue near the chimney; a flue exhaust gas outlet is provided on the coke oven flue upstream of the valve, and is connected to the carbon dioxide separation device through a flue exhaust gas pipe; a waste gas inlet is also provided on the chimney, the decarbonization waste gas outlet of the carbon dioxide separation device is connected to the waste gas inlet of the chimney, and the carbon dioxide gas outlet of the carbon dioxide separation device is connected to the supplementary circulating gas inlet of the dry quenching furnace; the supplementary circulating gas inlet is provided at the top of the dry quenching furnace annular air duct and / or the outlet pipe of the primary dust collector.

2. The carbon dioxide comprehensive utilization system with dry coke quenching as the core according to claim 1 is characterized in that: It also includes a supercritical power generation device, which is arranged on the circulating gas pipeline between the primary dust collector and the boiler.

3. The carbon dioxide comprehensive utilization system with dry coke quenching as the core according to claim 1 is characterized in that: The carbon monoxide separation device and the hydrogen separation device are arranged on the circulating gas pipeline downstream of the circulating fan.

4. The carbon dioxide comprehensive utilization system with dry coke quenching as the core according to claim 1 is characterized in that: The carbon monoxide separation device and the hydrogen separation device are arranged on the circulating gas branch pipeline downstream of the circulating fan; the circulating gas pipeline downstream of the circulating fan is provided with circulating gas outlets in sequence; the circulating gas outlets are connected to the circulating gas branch pipeline, the carbon monoxide separation device and the hydrogen separation device are arranged on the circulating gas branch pipeline in sequence, and the circulating gas branch pipeline under the hydrogen separation device is connected to the circulating gas inlet of the dry quenching furnace.

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