Coke oven heating system adopting oxygen-enriched combustion

Abstract

The present invention belongs to the technical field of coking production, and in particular relates to a coke oven heating system adopting oxygen-enriched combustion. The coke oven heating system is characterized by comprising an oxygen producing unit, a coke oven heating unit, a flue gas treatment unit and a heat recovery unit, wherein an oxygen-deficient outlet of the oxygen producing unit is connected to the heat recovery unit, an oxygen-enriched outlet of the oxygen producing unit is connected to the coke oven heating unit, and a flue gas outlet of the coke oven heating unit is in communication with the flue gas treatment unit; the coke oven heating unit is connected to a fuel gas pipeline; and a return pipeline is further provided at a flue gas outlet of the coke oven heating unit and is connected to an air inlet of the oxygen producing unit. The present invention has the following beneficial effects: in the coke oven heating system, oxygen-enriched gas is used as the combustion-supporting gas of a coke oven, and main components of waste gas after combustion are carbon dioxide and water vapor which are both polar triatomic molecules having a relatively strong radiation capability, such that the radiation intensity in a combustion chamber of the coke oven can be increased, the radiation heat transfer efficiency in the combustion chamber is improved, and the coking time is shortened.

Description

A coke oven heating system using oxygen-enriched combustion Technical Field

[0001] The invention belongs to the technical field of coking production, and in particular relates to a coke oven heating system adopting oxygen-enriched combustion. Background Art

[0002] Traditional coking systems use air as the combustion-supporting gas. Air and coal gas are mixed and burned in the combustion chamber. The residual heat from the exhaust is recovered in the coke oven's regenerator before being discharged into the atmosphere through a chimney. Since the fuel gas used in coke ovens is mostly carbon-containing, the exhaust contains significant amounts of carbon dioxide. Directly discharging the exhaust into the atmosphere would not meet future carbon peak and carbon reduction targets. However, capturing and removing the carbon dioxide from the exhaust would be prohibitively expensive due to the low concentration of carbon dioxide in the exhaust. Furthermore, since approximately 78% of air is non-combustible nitrogen, the nitrogen content in the exhaust after combustion is consistently above 75% or even higher. As a non-polar diatomic molecule, nitrogen does not radiate, reducing the radiation intensity within the combustion chamber and the efficiency of radiative heat transfer within the furnace.

[0003] Furthermore, although the combustion exhaust gas is cooled to 300°C by heat exchange in the regenerator before being discharged, it still carries away a significant amount of heat. Therefore, the presence of a large amount of nitrogen in the combustion-supporting gas results in heat loss and waste during the coke oven heating process. However, the use of oxygen-enriched gas as the combustion-supporting gas requires a stable oxygen source, and large-scale industrial oxygen production typically consumes significant energy, further increasing production costs.

[0004] Taking all the above into consideration, it is necessary to develop a coke oven heating system that uses oxygen-enriched combustion to reduce the cost of industrial oxygen production, reduce coking heat loss, and reduce the cost of recovering carbon dioxide in the exhaust gas.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide a coke oven heating system using oxygen-enriched combustion, overcome the shortcomings of the existing technology, introduce oxygen-enriched combustion technology, use oxygen-enriched gas as the combustion-supporting gas of the coke oven, improve the radiation intensity in the coke oven combustion chamber, reduce the heat loss carried away by the exhaust gas, and at the same time increase the carbon dioxide content in the combustion exhaust gas, thereby reducing the cost of carbon dioxide recovery.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A coke oven heating system using oxygen-enriched combustion is characterized by comprising an oxygen production unit, a coke oven heating unit, a flue gas treatment unit, and a heat recovery unit, wherein the oxygen-depleted outlet of the oxygen production unit is connected to the heat recovery unit, the oxygen-enriched outlet of the oxygen production unit is connected to the coke oven heating unit, and the flue gas outlet of the coke oven heating unit is connected to the flue gas treatment unit; the coke oven heating unit is connected to a fuel gas pipeline; the flue gas outlet of the coke oven heating unit is also provided with a return pipeline connected to the air inlet of the oxygen production unit; the oxygen production unit uses the heat of air and high-temperature coke oven flue gas to produce oxygen, and mixes it with carbon dioxide in the flue gas to form a mixed gas of oxygen and carbon dioxide, and the remaining high-temperature oxygen-depleted air enters the heat recovery unit to recover heat; the coke oven heating unit uses the mixed gas of oxygen and carbon dioxide as a combustion-supporting gas to be mixed with the fuel gas for combustion to provide heat for coking production, and a portion of the generated high-temperature coke oven flue gas is returned to the oxygen production unit and a portion is entered into the flue gas treatment unit; the flue gas treatment unit receives the coke oven flue gas generated by the coke oven heating unit, recovers the heat of the flue gas, and processes and recovers the carbon dioxide in the flue gas.

[0009] Furthermore, the oxygen production unit is a high-temperature membrane separation oxygen production device.

[0010] Furthermore, the oxygen production unit is equipped with a chemical loop high-temperature air separation oxygen production reactor.

[0011] Furthermore, the volume percentage of oxygen in the mixed gas of oxygen and carbon dioxide output by the oxygen production unit is 28-65%.

[0012] Furthermore, the mixed gas output flow rate of the oxygen production unit is adjustable.

[0013] Furthermore, the fuel gas is any one of methane, blast furnace gas, coke oven gas, producer gas or natural gas.

[0014] Furthermore, the heat recovery unit is a plate heat exchanger or a tube heat exchanger.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) The coke oven heating system of the present invention uses oxygen-rich gas as the combustion-supporting gas of the coke oven. The main components of the exhaust gas after combustion are carbon dioxide and water vapor, both of which are polar triatomic molecules. Compared with nitrogen, they have stronger radiation capacity, which can increase the radiation intensity in the coke oven combustion chamber, improve the radiation heat transfer efficiency in the combustion chamber, and shorten the coking time;

[0017] 2) Reduce the nitrogen content in the exhaust gas, thereby reducing the heat loss carried away by the nitrogen, while increasing the carbon dioxide content in the combustion exhaust gas and reducing the cost of carbon dioxide recovery;

[0018] 3) By integrating the coke oven heating unit with the oxygen production unit, the high-temperature coke oven flue gas from the coke oven heating unit is used as the carrier gas for the oxygen production unit, providing the required energy for the oxygen production process, thereby improving energy utilization efficiency and significantly reducing oxygen production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic structural diagram of an embodiment of the present invention.

[0020] In the figure: 1-oxygen production unit, 2-coke oven heating unit, 3-flue gas treatment unit, 4-heat recovery unit, A-air, B-oxygen and carbon dioxide mixture, C-oxygen-depleted air, D-coke oven flue gas, E-fuel gas. DETAILED DESCRIPTION

[0021] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the specific embodiments required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation methods of the present invention. For ordinary technicians in this field, other specific embodiments can be obtained based on these specific embodiments without paying any creative work.

[0023] The components of the embodiments of the present invention generally described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention.

[0024] See Figure 1, which is a structural schematic diagram of an embodiment of a coke oven heating system using oxygen-enriched combustion according to the present invention, comprising an oxygen production unit 1, a coke oven heating unit 2, a flue gas treatment unit 3 and a heat recovery unit 4; the oxygen production unit 1 is configured to utilize the heat of air A and high-temperature coke oven flue gas D to produce oxygen, and mix it with carbon dioxide to form a mixed gas B of oxygen and carbon dioxide, and the remaining high-temperature oxygen-depleted air C enters the heat recovery unit 4; the coke oven heating unit 2 is configured to utilize the mixed gas B of oxygen and carbon dioxide as a combustion-supporting gas to be mixed with the fuel gas E for combustion to provide heat for coking production, and a part of the generated high-temperature coke oven flue gas D returns to the oxygen production unit 1, and the other part enters the flue gas treatment unit 3; the flue gas treatment unit 3 is configured to receive the coke oven flue gas D generated by the coke oven heating unit 2, recover the heat of the flue gas, and process and recover the carbon dioxide in the flue gas; the heat recovery unit 4 is configured to recover the heat of the oxygen-depleted air C from the oxygen production unit 1.

[0025] In this embodiment, oxygen production unit 1 utilizes high-temperature membrane separation oxygen production technology. The high-temperature membrane separation oxygen production device utilizes the heat of high-temperature coke oven flue gas D to pressurize or heat air A to the membrane separation operating pressure or temperature. The membrane's permeability selectivity is then utilized to separate oxygen from air A. Air A then exchanges heat with the high-temperature coke oven flue gas D, resulting in a temperature of air A exceeding 700°C. Oxygen production unit 1 utilizes chemical looping high-temperature air separation oxygen production technology. The chemical looping high-temperature air separation oxygen production reactor utilizes the heat of high-temperature coke oven flue gas D to provide heat for air separation. Using metal oxides as carriers, the metal oxides undergo an oxidation reaction in air A and a decomposition reaction in a carbon dioxide atmosphere to separate oxygen from air. The oxygen content of the oxygen and carbon dioxide mixture output by the oxygen production unit ranges from 28% to 65% by volume. The output flow rate of the mixed gas from the oxygen production unit can be adjusted by a valve in the pipeline.

[0026] The fuel gas used in the coke oven heating unit 2 can be any of methane, blast furnace gas, coke oven gas, producer gas, or natural gas. The heat recovery unit is a plate or tubular heat exchanger. The coke oven flue gas D produced after the combustion of the carbon fuel, oxygen, and carbon dioxide mixture B contained within the coke oven heating unit 2 is primarily composed of carbon dioxide and water vapor. Both are polar triatomic molecules. Compared to the structurally symmetrical diatomic nitrogen molecule, they have stronger radiation properties, improving the efficiency of radiative heat transfer within the combustion chamber and shortening the coking time.

[0027] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A coke oven heating system using oxygen-enriched combustion, characterized in that: It comprises an oxygen production unit, a coke oven heating unit, a flue gas treatment unit and a heat recovery unit, wherein the oxygen-poor outlet of the oxygen production unit is connected to the heat recovery unit, the oxygen-rich outlet of the oxygen production unit is connected to the coke oven heating unit, and the flue gas outlet of the coke oven heating unit is connected to the flue gas treatment unit; the coke oven heating unit is connected to a fuel gas pipeline; the flue gas outlet of the coke oven heating unit is also provided with a return pipeline connected to the air inlet of the oxygen production unit; The oxygen production unit uses the heat of air and high-temperature coke oven flue gas to produce oxygen, and mixes it with the carbon dioxide in the flue gas to form a mixed gas of oxygen and carbon dioxide. The remaining high-temperature oxygen-depleted air enters the heat recovery unit to recover heat; the coke oven heating unit uses the mixed gas of oxygen and carbon dioxide as a combustion-supporting gas to mix with the fuel gas for combustion to provide heat for coking production, and part of the generated high-temperature coke oven flue gas returns to the oxygen production unit, and part enters the flue gas treatment unit; the flue gas treatment unit receives the coke oven flue gas generated by the coke oven heating unit, recovers the heat of the flue gas, and processes and recovers the carbon dioxide in the flue gas.

2. A coke oven heating system using oxygen-enriched combustion according to claim 1, characterized in that: The oxygen production unit is a high-temperature membrane separation oxygen production device.

3. A coke oven heating system using oxygen-enriched combustion according to claim 1, characterized in that: The oxygen production unit is equipped with a chemical chain high temperature air separation oxygen production reactor.

4. A coke oven heating system using oxygen-enriched combustion according to claim 1, characterized in that: In the mixed gas of oxygen and carbon dioxide output by the oxygen production unit, the volume percentage content of oxygen is 28-65%.

5. The coke oven heating system using oxygen-enriched combustion according to claim 1, characterized in that: The mixed gas output flow rate of the oxygen production unit is adjustable.

6. A coke oven heating system using oxygen-enriched combustion according to claim 1, characterized in that: The fuel gas is any one of methane, blast furnace gas, coke oven gas, producer gas or natural gas.

7. A coke oven heating system using oxygen-enriched combustion according to claim 1, characterized in that: The heat recovery unit is a plate heat exchanger or a tube heat exchanger.

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