Equipment for reducing carbon dioxide emission of dry quenching device and dry quenching system
By introducing a gas-to-gas heat exchanger, a washing tower and a crystallizer into the dry quenching system and utilizing ammonia water reaction to generate carbonates, the problem of high CO2 emissions in the dry quenching system was solved, and CO2 emissions were reduced and coke production was increased.
Patent Information
- Application Number
- CN202422674498.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-04
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-11-04
AI Technical Summary
The existing dry quenching system has the problem of high CO2 emissions, especially in the circulating gas release process, where CO2 emissions account for a large proportion, affecting the development of low-carbon metallurgy.
A combination of an air-to-air heat exchanger, a scrubber, a crystallizer, and a circulating pump is used to convert CO2 in the circulating gas into ammonium carbonate or ammonium bicarbonate using ammonia water, which reacts with the ammonia water through a spray head to generate carbonate, thereby reducing the CO2 and moisture content and the total amount of circulating gas.
It significantly reduces the CO2 emissions of the dry quenching system, lowers the coke burn-out rate, increases coke production, and reduces the CO2 and water vapor content in the circulating gas.
Smart Images
Figure CN223386077U_ABST
Abstract
Description
Technical Field
[0001] The utility model provides a device for reducing carbon dioxide emission of a dry coke quenching device, belonging to the field of chemical equipment. Background Art
[0002] The CDQ system is a device used in coking plants to quench coke. It uses inert gas to reduce the temperature of the red coke (~1000°C) pushed out of the coke oven to below 200°C, while also recovering the waste heat from the red coke. During the CDQ process, red coke is loaded from the top of the CDQ furnace. Low-temperature inert gas is blown into the red coke layer in the CDQ furnace's cooling chamber by a circulating fan, absorbing the heat from the red coke. The cooled coke is then discharged from the bottom of the CDQ furnace. The high-temperature inert gas exiting the CDQ furnace's annular flue undergoes heat exchange in the CDQ boiler, generating steam. The cooled inert gas is then blown back into the CDQ furnace by the circulating fan for recycling.
[0003] To reduce the presence of combustible gases (H2 and CO) in the circulating gas, the CDQ system introduces air into the CDQ furnace's annular flue to burn off the combustible gas components, which gradually increases the amount of circulating gas. To ensure the overall balance of the system's circulating gas volume, a circulating gas vent pipe is generally installed in the pipeline after the economizer, discharging 5-15% of the total circulating gas. This vented gas released into the atmosphere contains 10-18% CO2, which is why the CDQ system emits CO2 during the quenching process. CO2 is a greenhouse gas, and reducing CO2 emissions from the CDQ system is the development direction of low-carbon metallurgy. Utility Model Content
[0004] Technical problem: In order to solve the defects of the existing technology, the utility model provides an apparatus and method for reducing carbon dioxide emissions from a dry quenching device.
[0005] Technical solution: The utility model provides an apparatus for reducing carbon dioxide emissions from a dry coke quenching device, comprising an air-to-air heat exchanger, a washing tower, a crystallizer, and a circulation pump; the heat medium pipeline outlet of the air-to-air heat exchanger is connected to the lower part of the washing tower, and the refrigerant pipeline inlet is connected to the upper part of the washing tower, and the heat medium pipeline and the refrigerant pipeline exchange heat in the air-to-air heat exchanger; a spray head is provided at the upper part of the washing tower, and the bottom of the washing tower is connected to the spray head via a connecting pipe provided with a circulation pump, and the crystallizer is connected to the connecting pipe; an ammonia water inlet is also connected to the connecting pipe between the bottom of the washing tower and the crystallizer.
[0006] As an improvement, it further includes a dust collector, which is connected to the heat medium pipeline inlet of the air-to-air heat exchanger.
[0007] As another improvement, it further includes a regulating valve, which is connected to the refrigerant pipeline outlet of the air-to-air heat exchanger.
[0008] The utility model also provides a dry quenching system for reducing carbon dioxide emissions from a dry quenching device, comprising a dry quenching furnace, a dry quenching boiler, a fan, and an economizer connected in sequence to form a ring, a circulating gas discharge pipe being provided on the pipeline between the economizer and the dry quenching furnace, and an air-to-air heat exchanger, a washing tower, a crystallizer, and a circulating pump; the heat medium pipeline inlet of the air-to-air heat exchanger is connected to the pipeline between the economizer and the circulating gas discharge pipe, the heat medium pipeline outlet is connected to the lower part of the washing tower, the refrigerant pipeline inlet of the air-to-air heat exchanger is connected to the upper part of the washing tower, and the refrigerant pipeline outlet is connected to the air intake pipeline of the dry quenching furnace; the heat medium pipeline and the refrigerant pipeline exchange heat in the air-to-air heat exchanger; a spray head is provided on the upper part of the washing tower, the bottom of the washing tower is connected to the spray head through a connecting pipeline provided with a circulating pump, and the crystallizer is connected to the connecting pipeline; an ammonia water inlet is also connected to the connecting pipeline between the bottom of the washing tower and the crystallizer.
[0009] As an improvement, it further includes a dust collector, which is arranged on the pipeline between the economizer and the heat medium pipeline inlet of the gas-to-gas heat exchanger.
[0010] As another improvement, it further includes a regulating valve, which is arranged on the pipeline between the refrigerant pipeline outlet of the gas-to-gas heat exchanger and the dry quenching furnace.
[0011] Beneficial effects: The utility model utilizes ammonia water to solidify the CO2 in the CDQ circulating gas into ammonium carbonate or ammonium bicarbonate, thereby greatly reducing the content of CO2 and water in the CDQ circulating gas, thereby reducing the CO2 emissions of the CDQ system; at the same time, it also reduces the carbon melting reaction and water-gas reaction in the CDQ furnace, reduces the coke burning rate in the CDQ furnace, and increases the coke yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a structural schematic diagram of a dry quenching system for reducing carbon dioxide emissions from a dry quenching device according to the present invention. DETAILED DESCRIPTION
[0013] The utility model is further described below.
[0014] The dry quenching system for reducing carbon dioxide emissions from a dry quenching device comprises a dry quenching furnace 7, a dry quenching boiler 8, a fan 9, and an economizer 10 connected in sequence to form a ring. A circulating gas discharge pipe 11 is provided on the pipeline between the economizer 10 and the dry quenching furnace 7. The system also comprises a dust collector 1, an air-to-air heat exchanger 2, a washing tower 3, a crystallizer 4, a circulating pump 5, and a regulating valve 6. The dust collector 1 is connected to the pipeline between the economizer 10 and the circulating gas discharge pipe 11. The heat medium pipeline inlet of the air-to-air heat exchanger 2 is connected to the dust collector 1, and the heat medium pipeline outlet is connected to the dust collector 1. The outlet of the gas-to-gas heat exchanger 2 is connected to the lower part of the washing tower 3, the refrigerant pipeline inlet of the gas-to-gas heat exchanger 2 is connected to the upper part of the washing tower 3, and the refrigerant pipeline outlet is connected to the air intake pipeline of the dry quenching furnace 7 through the regulating valve 6; the heat medium pipeline and the refrigerant pipeline exchange heat in the gas-to-gas heat exchanger 2; a spray head is provided at the upper part of the washing tower 3, and the bottom of the washing tower 3 is connected to the spray head through a connecting pipeline provided with a circulation pump 5, and the crystallizer 4 is connected to the connecting pipeline; an ammonia water inlet is also connected to the connecting pipeline between the bottom of the washing tower 3 and the crystallizer 4.
[0015] When the system is in operation, part of the circulating gas coming out of the economizer 10 enters the heat medium pipe of the gas-to-gas heat exchanger 2, exchanges heat with the gas in the refrigerant pipe, and then enters the scrubbing tower 3; in the scrubbing tower, the CO2 in the circulating gas mixes with the sprayed ammonia water to react to produce ammonium carbonate or ammonium bicarbonate; the remaining gas enters the refrigerant pipe of the gas-to-gas heat exchanger 2, exchanges heat with the gas in the heat medium pipe, and then enters the dry quenching furnace 7.
[0016] The following is a more detailed description of the working process of the system.
[0017] A portion of circulating gas is drawn from the post-coal economizer circulating gas pipeline of the original CDQ system. The temperature of this portion of gas is between 120 and 140°C, the pressure is between 3 and 6 kPa, and the CO2 content in this portion of circulating gas is 10 to 18%. The circulating gas passes through the dust collector 1 to remove dust, and then passes through the gas-to-gas heat exchanger 2 to exchange heat with the washed low-temperature gas, reducing the temperature to 30 to 50°C. It enters the washing tower 3, where it is fully mixed with the external raw material ammonia water for washing. The CO2 in the circulating gas reacts with the ammonia in the ammonia water to produce ammonium carbonate or ammonium bicarbonate. The washing liquid is then pumped through the circulating pump 5 in the washing tower. Circulating spray scrubbing is performed in the scrubbing tower 3 to absorb ammonia in the gas. After the solubility of ammonium carbonate or ammonium bicarbonate in the scrubbing liquid increases, a portion is separated and sent to the crystallizer 4 for crystallization to separate solid ammonium carbonate and / or ammonium bicarbonate products (for example, part of the ammonium carbonate or ammonium bicarbonate solution is sent to the crystallizer, where it is crystallized and separated into ammonium carbonate or ammonium bicarbonate). In this way, the CO2 and moisture content of the CDQ circulating gas are reduced, and the CO2 content is reduced to below 5%. The scrubbed gas passes through the gas-to-gas heat exchanger 2 and is returned to the air inlet pipe of the original CDQ system through the regulating valve 6.
[0018] The scrubbed gas is drawn into the CDQ circulating gas path through the CDQ furnace's annular flue. Since the volume of gas after scrubbing is less than the volume of gas drawn out (CO2 and some water vapor have been removed), the total volume of circulating gas in the original CDQ system can be reduced, lowering the CO2 concentration in the circulating gas. This, in turn, reduces the amount of circulating gas released and its CO2 concentration, thereby reducing the CDQ system's CO2 emissions. For a typical 140 t / h CDQ unit, this can reduce CO2 emissions by 15,000 to 25,000 tons per year. This reduces the CO2 and water vapor content in the CDQ circulating gas, further minimizing carbon melting and water-gas reactions in the high-temperature zone of the CDQ furnace, and reducing the coke burnout rate by 0.3% to 0.7%. This increases coke yield by 0.3% to 0.7%.
[0019] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.
Claims
1. A device for reducing carbon dioxide emissions from a coke dry quenching unit, characterized by: The invention comprises an air-to-air heat exchanger (2), a washing tower (3), a crystallizer (4), and a circulation pump (5); the outlet of the heat medium pipeline of the air-to-air heat exchanger (2) is connected to the lower part of the washing tower (3), and the inlet of the refrigerant pipeline is connected to the upper part of the washing tower (3); the heat medium pipeline and the refrigerant pipeline exchange heat in the air-to-air heat exchanger (2); a spray head is provided at the upper part of the washing tower (3); the bottom of the washing tower (3) is connected to the spray head via a connecting pipeline provided with a circulation pump (5), and the crystallizer (4) is connected to the connecting pipeline; an ammonia water inlet is also connected to the connecting pipeline between the bottom of the washing tower (3) and the crystallizer (4).
2. The device for reducing carbon dioxide emissions from a coke dry quenching unit according to claim 1, characterized in that: It also includes a dust collector (1), which is connected to the heat medium pipeline inlet of the air-to-air heat exchanger (2).
3. The device for reducing carbon dioxide emissions from a coke dry quenching unit according to claim 1, characterized in that: It also includes a regulating valve (6), which is connected to the refrigerant pipeline outlet of the air-to-air heat exchanger (2).
4. A dry quenching system for reducing carbon dioxide emissions from a dry quenching device, comprising a dry quenching furnace (7), a dry quenching boiler (8), a blower (9), and an economizer (10) connected in sequence to form a ring, wherein a circulating gas discharge pipe (11) is provided on the pipeline between the economizer (10) and the dry quenching furnace (7), and characterized in that: It also includes an air-to-air heat exchanger (2), a washing tower (3), a crystallizer (4), and a circulation pump (5); the heat medium pipeline inlet of the air-to-air heat exchanger (2) is connected to the pipeline between the economizer (10) and the circulating gas discharging pipe (11), the heat medium pipeline outlet is connected to the lower part of the washing tower (3), the refrigerant pipeline inlet of the air-to-air heat exchanger (2) is connected to the upper part of the washing tower (3), and the refrigerant pipeline outlet is connected to the air intake pipeline of the dry quenching furnace (7); the heat medium pipeline and the refrigerant pipeline exchange heat in the air-to-air heat exchanger (2); a spray head is provided at the upper part of the washing tower (3), the bottom of the washing tower (3) is connected to the spray head through a connecting pipeline provided with a circulation pump (5), and the crystallizer (4) is connected to the connecting pipeline; The connecting pipe between the bottom of the washing tower (3) and the crystallizer (4) is also connected to an ammonia water inlet.
5. The dry quenching system for reducing carbon dioxide emissions from a dry quenching device according to claim 4, characterized in that: It also includes a dust collector (1), which is arranged on the pipeline between the economizer (10) and the heat medium pipeline inlet of the gas-to-gas heat exchanger (2).
6. The dry quenching system for reducing carbon dioxide emissions from a dry quenching device according to claim 4, characterized in that: It also includes a regulating valve (6), which is arranged on the pipeline between the refrigerant pipeline outlet of the gas-to-gas heat exchanger (2) and the dry quenching furnace (7).