Low-energy-consumption CO2 capture and resource utilization system for coal chemical tail gas

Abstract

A low-energy-consumption CO2 capture and resource utilization system for coal chemical tail gas is characterized in that a dust remover is sequentially communicated with a desulfurization device and a heat exchanger through pipelines, the other output end of the dust remover is communicated with a solid recovery tank through a pipeline, and the other output end of the desulfurization device is communicated with a sulfide collection tank through a pipeline; the heat exchanger is communicated with an inlet of the condenser through an output pump mounted on a pipeline, output ports of the heat exchanger and the condenser are communicated with an input port of the CO2 trapping device through pipelines, a gas detector is arranged on the CO2 trapping device, an adsorption bed is arranged in the CO2 trapping device, and the CO2 trapping device is connected with the gas detector through a pipeline. An output port of the CO2 trapping device is communicated with an inlet of the hydrogenation synthesis device through a valve mounted on a pipeline, one output port of the hydrogenation synthesis device is communicated with a third input port of the circulating heat pump evaporator through a pipeline, and the other output port of the hydrogenation synthesis device is communicated with an input port of the product storage tank through a pipeline. The device has the advantages of low energy consumption, repeated recycling of regenerated adsorbents and the like, and can be used in the technical field of coal chemical industry.

Description

Technical Field

[0001] This utility model belongs to the field of carbon emission reduction technology in coal chemical industry, specifically involving a system for low-energy capture and resource utilization of carbon dioxide in coal chemical tail gas, which can be widely used in coking, synthetic ammonia, coal-to-hydrogen, coal-to-methanol and tail gas treatment of coal-fired power plants. Background Technology

[0002] Currently, large-scale coal chemical or coking enterprises often emit tail gas containing a high volume fraction of carbon dioxide during production. Traditional CO2 capture processes mostly use amine solvents (such as MEA and DEA), but amine solvents may degrade during use, which not only reduces capture efficiency but may also produce toxic or harmful byproducts. Solvent degradation also increases the frequency and cost of solvent replacement. Furthermore, amine solvents are generally corrosive, causing corrosion and damage to capture equipment, which not only increases the cost of equipment maintenance and replacement but may also affect the stability and reliability of the capture system. Under the global trend of advocating low-carbon development, coal chemical enterprises need a CO2 capture device that combines low energy consumption, high efficiency, and resource utilization capabilities.

[0003] Patent CN203075832U discloses a carbon dioxide capture and pyrolysis device, comprising: a flue gas inlet and conveying pipe, a carbonization tower, a pyrolysis tower, a gas-water condenser separator, a CO2 gas holder, other gas outlets, a solution mixing tank, and a solution pump. The device utilizes a sodium carbonate solution in the carbonization tower to convert CO2 in the flue gas into a sodium bicarbonate solution, which is then rapidly decomposed into high-purity CO2 in the pyrolysis tower. This invention utilizes the synergistic effect of sodium carbonate, a catalyst, and an activator to capture and pyrolyze CO2, thereby reducing the greenhouse effect. However, the thermal decomposition process of CO2 requires a large amount of energy and is accompanied by the generation of other byproducts, resulting in high energy consumption. The reaction needs to be carried out under high temperature and pressure, which is demanding and unfavorable for operation. Furthermore, the pyrolysis of CO2 wastes resources. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a low-energy CO2 capture and resource utilization system for coal chemical tail gas with low energy consumption and multiple regeneration and recycling of adsorbent.

[0005] The technical solution adopted to solve the above-mentioned technical problems is as follows: the dust collector is connected to the desulfurization unit and the heat exchanger in sequence through pipelines; the other output end of the dust collector is connected to the solid recovery tank through a pipeline; the other output end of the desulfurization unit is connected to the sulfide collection tank through a pipeline; the heat exchanger is connected to the inlet of the output pump through a pipeline; the outlet of the output pump is connected to the inlet of the condenser through a pipeline; the outlets of the heat exchanger and the condenser are connected to the inlet of the CO2 capture device through pipelines; the CO2 capture device is equipped with a gas detector; the CO2 capture device is equipped with an adsorption bed; the outlet of the CO2 capture device is connected to the inlet of the hydrogenation synthesis unit through a valve installed on the pipeline; one outlet of the hydrogenation synthesis unit is connected to the third inlet of the circulating heat pump evaporator through a pipeline, and the other outlet is connected to the inlet of the product storage tank through a pipeline.

[0006] The adsorption bed set in the CO2 capture device has 1 to 4 units.

[0007] Ideally, there should be two adsorption beds installed in the CO2 capture device.

[0008] The beneficial effects of this utility model are as follows:

[0009] 1. This utility model's CO2 capture device incorporates a multi-layer adsorption bed, filled with modified porous materials, molecular sieves, or metal-organic frameworks (MOFs) as CO2 adsorbents. High selective adsorption of CO2 is achieved at relatively low heating temperatures. A CO2 gas detector monitors the CO2 concentration at the upper outlet of the top layer of the adsorption bed, controlling the CO2 capture and regeneration process. The captured CO2 is desorbed and sent to a hydrogenation synthesis unit for hydrogenation conversion, realizing CO2 resource utilization to obtain products such as methanol, formic acid, or synthetic natural gas, increasing the added value of the enterprise's products and reducing the overall carbon emission intensity while improving carbon utilization. Furthermore, the waste heat generated during hydrogenation is used for CO2 desorption, simultaneously regenerating the adsorbent, significantly reducing desorption and regeneration energy consumption and allowing the adsorbent to be recycled multiple times.

[0010] 2. This invention enables the resource utilization of captured CO2, recovering the waste heat generated during the process to meet emission reduction targets, create added economic value, and reduce energy consumption. Waste heat utilization allows for multiple cycles of adsorbent regeneration. The use of functionalized adsorbents reduces corrosion problems associated with traditional amine methods. Coupled with hydrogenation, CO2 is utilized as a resource, increasing the added value of enterprise products, improving carbon emission structure, adapting to various coal chemical tail gas environments, and flexibly connecting with various production units in coal chemical enterprises. It has good resistance to particulate matter and sulfides in tail gas, combining economic and environmental benefits. Attached Figure Description

[0011] Figure 1This is a structural schematic diagram of Embodiment 1 of the present invention. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0013] Example 1

[0014] exist Figure 1 In this embodiment, the low-energy CO2 capture and resource utilization system is composed of a dust collector 1, a solid recovery tank 2, a desulfurization device 3, a sulfide collection tank 4, a heat exchanger 5, a CO2 gas detector 6, an output pump 7, a condenser 8, a CO2 capture device 9, a circulating heat pump evaporator 10, a product storage tank 11, and a hydrogenation synthesis device 12 connected together.

[0015] Dust collector 1 is connected in sequence to desulfurization unit 3 and heat exchanger 5 via pipelines. The other output end of dust collector 1 is connected to solid recovery tank 2 via a pipeline. The other output end of desulfurization unit 3 is connected to sulfide collection tank 4 via a pipeline. Heat exchanger 5 is connected to the inlet of output pump 7 via a pipeline. The outlet of output pump 7 is connected to the inlet of condenser 8 via a pipeline. The outlets of heat exchanger 5 and condenser 8 are connected to the inlet of CO2 collection device 9 via pipelines. A gas detector 6 is installed on CO2 collection device 9. The gas detector 6 monitors the CO2 inside CO2 collection device 9. The CO2 content is detected. The CO2 capture device 9 contains two adsorption beds, which are filled with CO2 adsorbents such as modified porous materials, molecular sieves or metal-organic frameworks. The output port of the CO2 capture device 9 is connected to the input port of the hydrogenation synthesis device 12 through a valve installed on the pipeline. One output port of the hydrogenation synthesis device 12 is connected to the third input port of the circulating heat pump evaporator 10 through a pipeline. The other output port of the hydrogenation synthesis device 12 is connected to the input port of the product storage tank 11 through a pipeline. The final product is stored in the product storage tank 11.

[0016] Example 2

[0017] In this embodiment, the CO2 capture device 9 contains an adsorption bed filled with CO2 adsorbents such as modified porous materials, molecular sieves, or metal-organic framework materials. Other components and their connections are the same as in Embodiment 1.

[0018] Example 3

[0019] In this embodiment, the CO2 capture device 9 contains four adsorption beds, each filled with a CO2 adsorbent such as a modified porous material, molecular sieve, or metal-organic framework material. Other components and their connections are the same as in Embodiment 1.

[0020] The working principle of this utility model is as follows:

[0021] The exhaust gas from the coal chemical production unit first enters the dust collector 1, where particulate matter and sulfides are removed by the dust collector 1 and the desulfurization unit 2. The exhaust gas is then cooled by the heat exchanger 5 and condensed and dehydrated by the condenser 8 before entering the CO2 capture unit 9. This improves the subsequent CO2 capture efficiency and adsorbent lifespan. Cooling water, after absorbing heat in the heat exchanger 5, becomes hot water and is input into the CO2 capture unit 9 to provide heat. The pretreated exhaust gas is then transported to the CO2 capture unit 9, which contains 1 to 4 adsorption beds filled with modified porous materials, molecular sieves, or metal-organic framework (MOF) adsorbents. These beds selectively adsorb CO2 at relatively low temperatures, thus capturing the CO2. During adsorption, the valve on the outlet pipe of the CO2 capture device 9 is closed. When the adsorption bed reaches adsorption saturation, the CO2 concentration at the top of the uppermost adsorption bed is monitored by the CO2 gas detector 6 and reaches the set critical value. At this time, the valve on the outlet pipe is opened, the regeneration mode is switched, the temperature is raised to release CO2 and it is concentrated into a high-purity gas flow.

[0022] The released high-purity CO2 enters the hydrogenation synthesis unit 12, where it mixes with hydrogen-rich gas (such as hydrogen produced from coal or separated from coke oven gas) and undergoes a hydrogenation reaction under catalyst and reaction conditions to synthesize methanol, formic acid, or methane. The heat generated during hydrogenation is absorbed by the circulating heat pump evaporator 10 and then enters the CO2 capture unit 9, recycling the heat required for the desorption process. After regeneration, the adsorption bed is switched back to adsorption mode and reused. This method not only ensures high selectivity but also minimizes energy consumption.

Claims

1. A coal chemical tail gas low-energy-consumption CO2 capture and resource utilization system, characterized in that: The dust remover (1) is communicated with the desulfurization device (3) and the heat exchanger (5) in sequence through pipes, another output end of the dust remover (1) is communicated with the solid recovery tank (2) through a pipe, another output end of the desulfurization device (3) is communicated with the sulfide collection tank (4) through a pipe, the heat exchanger (5) is communicated with the inlet of the output pump (7) through a pipe, the outlet of the output pump (7) is communicated with the inlet of the condenser (8) through a pipe, the outlets of the heat exchanger (5) and the condenser (8) are communicated with the input of the CO2 capture device (9) through pipes, a gas detector (6) is arranged on the CO2 capture device (9), an adsorption bed is arranged in the CO2 capture device (9), the outlet of the CO2 capture device (9) is communicated with the input of the hydrogenation synthesis device (12) through a valve installed on a pipe, one output of the hydrogenation synthesis device (12) is communicated with the third input of the circulating heat pump evaporator (10) through a pipe, and the other output is communicated with the input of the product storage tank (11) through a pipe.

2. The system for low energy consumption CO2 capture and resource utilization of coal chemical tail gas according to claim 1, characterized in that: The adsorption bed arranged in the CO2 capture device (9) is 1-4.

3. The system for low energy consumption CO2 capture and resource utilization of coal chemical tail gas according to claim 1 or 2, characterized in that: The adsorption bed arranged in the CO2 capture device (9) is 2.

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