Compact composite absorption tower suitable for carbon capture in peaking coal-fired power plant

Abstract

Disclosed in the present invention is a compact composite absorption tower suitable for carbon capture in a peaking coal-fired power plant. The compact composite absorption tower comprises a tower body; the tower body is internally divided into a water washing section, an absorption section and a pre-washing section from top to bottom; a water washing section cooler, a first liquid collection tank and a second liquid collection tank are sequentially arranged in the water washing section from top to bottom; a first spray layer, an interstage cooling heat exchanger and a third liquid collection tank are sequentially arranged in the absorption section from top to bottom; and a second spray layer, a phase separator and a fourth liquid collection tank are sequentially arranged in the pre-washing section from top to bottom, wherein a lean phase outlet of the phase separator is communicated with the inlet of the second spray layer and the inlet of the first spray layer. The absorption tower has the characteristics of a small occupied area and low costs, and can meet the requirement for CO2 capture after variable-load peaking of coal-fired power plants.

Description

Compact composite absorption tower suitable for carbon capture of peak-shaving coal-fired power station TECHNICAL FIELD

[0001] The present application belongs to the technical field of flue gas treatment, and relates to a compact composite absorption tower suitable for carbon capture of peak-shaving coal-fired power station. BACKGROUND

[0002] Since the existing coal-fired power station gradually undertakes the role of grid peak shaving, under the background of flexible peak shaving of coal-fired units, the flue gas flow of the CO2 capture device of the coal-fired power plant will fluctuate with the change of the unit load, therefore, the absorption tower of the CO2 capture system also requires corresponding variable load regulation capacity, and parameters such as solvent circulation flow in the absorption tower need to have certain regulation capacity, which not only ensures the CO2 capture rate in the flue gas, but also can change with the change of the flue gas flow, thereby reducing the solvent loss. Since the existing large-scale CO2 capture demonstration project of coal-fired power plants has high investment cost and large occupied area, for example, the inter-stage cooling heat exchanger in the absorption tower system is arranged outside the tower, therefore, multiple pipeline systems need to be arranged outside the absorption tower, thereby leading to complex design and high construction cost. For the phase change type CO2 capture device, the phase separation tank is generally arranged outside the absorption tower, thereby leading to large occupied area and complex pipeline system. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art, and provides a compact composite absorption tower suitable for carbon capture of peak-shaving coal-fired power station, which has the characteristics of small occupied area and low cost, and can meet the demand of CO2 capture after variable load peak shaving of the coal-fired power plant.

[0004] To achieve the above-mentioned purpose, the present application discloses a compact composite absorption tower suitable for carbon capture of peak-shaving coal-fired power station, which comprises a tower body, the tower body is sequentially divided into a water washing section, an absorption section and a pre-washing section from top to bottom, the water washing section is sequentially provided with a water washing section cooler, a first liquid collecting tank and a second liquid collecting tank from top to bottom, the absorption section is sequentially provided with a first spraying layer, an inter-stage cooling heat exchanger and a third liquid collecting tank from top to bottom; the pre-washing section is sequentially provided with a second spraying layer, a phase separator and a fourth liquid collecting tank from top to bottom, wherein the lean phase outlet of the phase separator is in communication with the inlet of the second spraying layer and the inlet of the first spraying layer.

[0005] Further comprising a first circulating pump and a solution circulation bypass, the lean phase outlet of the phase separator is divided into two routes after the first circulating pump, one of which is in communication with the inlet of the second spraying layer, and the other is in communication with the outlet of the second circulating pump through a pipeline and a pipe, and then is in communication with the inlet of the first spraying layer through the solution circulation bypass.

[0006] The bottom of the tower body is provided with a flue gas inlet, and the top of the tower body is provided with a flue gas outlet.

[0007] The flue gas inlet is provided with a double-row vane gas distributor.

[0008] The rich phase outlet of the phase separator is communicated with a lean-rich liquid heat exchanger.

[0009] The inlet of the first spray layer and the outlet of the first circulating pump are both communicated with a lean-rich liquid heat exchanger.

[0010] The outlet of the third collecting tank is communicated with the inlet of the first spray layer.

[0011] In operation, the solution sprayed by the first spray layer is contacted with flue gas in counterflow, and then enters the third collecting tank after heat exchange in the inter-stage cooling heat exchanger.

[0012] In operation, the solution in the third collecting tank is sprayed downward by the second spray layer, contacted with flue gas in counterflow, and then enters the phase separator for phase separation.

[0013] In operation, the lean phase solution output by the phase separator is divided into two routes after passing through the first circulating pump, one of which enters the second spray layer, and the other of which enters the first spray layer after being combined with the solution in the third collecting tank pumped by the second circulating pump.

[0014] The present application has the following beneficial effects:

[0015] In the operation of the compact composite absorption tower for carbon capture of the coal-fired power station suitable for peak regulation, the lean phase outlet of the phase separator is communicated with the inlet of the second spray layer and the inlet of the first spray layer, that is, a circulating bypass is added to each absorption stage of the composite absorption tower, and the solution flowing from top to bottom in the absorption stage is sent back to the top of the absorption stage, so that the spray density of the absorption stage can be adjusted, and the capture rate of CO2 in the flue gas can be ensured. In addition, the phase separator is integrated in the absorption tower, and the absorbent after absorbing CO2 can be quickly sent back to the top of the absorption stage after phase separation to improve the operation flexibility of the composite absorption tower equipment and reduce the floor area. In addition, it should be noted that the water washing section cooler and the inter-stage cooling heat exchanger are arranged in the tower body, the water washing section cooler and the inter-stage cooling heat exchanger are built-in, and the scrubbing liquid or absorbent flowing from the water washing section or the absorption section can be collected by the collecting tank and then sent into the heat exchanger above, so that the flowing time of the scrubbing liquid or absorbent in the pipeline is greatly reduced, the heat exchange effect is improved, and the floor area is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 is a structural diagram of the present application.

[0017] Wherein, 1 is a water washing section cooler, 2 is a first liquid collecting tank, 3 is a second liquid collecting tank, 4 is an inter-stage cooling heat exchanger, 5 is a third liquid collecting tank, 6 is a phase separator, 7 is a fourth liquid collecting tank, 8 is a first circulating pump, 9 is a second circulating pump, 10 is a double-row blade gas distributor, 11 is a first spray layer, and 12 is a second spray layer. Embodiments of the present application

[0018] In order to make the personnel in the technical field better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments, and are not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concepts disclosed in the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0019] The structural schematic diagrams according to the disclosed embodiments of the present application are shown in the drawings. These drawings are not drawn to scale, in which some details are enlarged for the purpose of clear expression, and some details can be omitted. The shapes of various regions, layers and their relative size and positional relationship shown in the drawings are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0020] Referring to FIG. 1, the compact composite absorption tower suitable for peak-shaving coal-fired power plant carbon capture according to the present application comprises a tower body, which is sequentially divided into a water washing section, an absorption section and a pre-washing section from top to bottom. The water washing section is sequentially provided with a water washing section cooler 1, a first liquid collecting tank 2 and a second liquid collecting tank 3 from top to bottom. The absorption section is sequentially provided with a first spray layer 11, an inter-stage cooling heat exchanger 4 and a third liquid collecting tank 5 from top to bottom. The pre-washing section is sequentially provided with a second spray layer 12, a phase separator 6 and a fourth liquid collecting tank 7 from top to bottom.

[0021] The lean phase outlet of the phase separator 6 is divided into two routes after the first circulating pump 8, one of which is connected to the inlet of the second spray layer 12, and the other of which is connected to the outlet of the second circulating pump 9 through a pipeline and a pipe, and then connected to the inlet of the first spray layer 11 through a solution circulating bypass.

[0022] In this embodiment, the bottom of the tower body is provided with a flue gas inlet, and the top of the tower body is provided with a flue gas outlet. The flue gas inlet is provided with a double-row blade gas distributor 10.

[0023] In the embodiment, the rich phase outlet of the phase separator 6 is communicated with the lean-rich liquid heat exchanger.

[0024] In the embodiment, the inlet of the first spray layer 11 and the outlet of the first circulating pump 8 are both communicated with the lean-rich liquid heat exchanger.

[0025] In the embodiment, the outlet of the third collecting tank 5 is communicated with the inlet of the first spray layer 11.

[0026] It should be noted that the working process of the present application is as follows:

[0027] The flue gas is treated in sequence by the pre-washing section, the absorption section and the water washing section, and then discharged through the flue gas outlet.

[0028] The water in the first collecting tank 2 is sprayed downward through the nozzle and finally enters the second collecting tank 3; the solution sprayed by the first spray layer 11 is contacted with the flue gas in counterflow, and then enters the third collecting tank 5 after heat exchange by the inter-stage cooling heat exchanger 4; the solution in the third collecting tank 5 is sprayed downward by the second spray layer 12 and contacted with the flue gas in counterflow, and then enters the phase separator 6 for phase separation, wherein the rich phase solution output by the phase separator 6 continues to be sprayed downward and finally enters the fourth collecting tank 7, and the lean phase solution output by the phase separator 6 is divided into two routes after the first circulating pump 8, one of which enters the second spray layer 12, and the other of which enters the first spray layer 11 after converging with the solution in the third collecting tank 5 drawn by the second circulating pump 9.

[0029] It should be noted that the present application has the following characteristics:

[0030] a) Setting a multi-stage circulating bypass of the solution: in order to adjust the influence of the flue gas flow change on the CO2 capture rate of the composite absorption tower during the variable load operation of the coal-fired power plant, a circulating bypass is added to each absorption section of the composite absorption tower, the solution flowing into the absorption section from top to bottom is punched back to the top of the absorption section by the first circulating pump 8 and the second circulating pump 9, so that under the condition of low solution circulation amount, the spray density of the absorption section is ensured, and then the capture rate of CO2 in the flue gas is ensured.

[0031] b) Built-in phase separator 6: the conventional phase change type CO2 capture process needs to set a phase separation tank outside the absorption tower, which occupies a large area and needs to set multiple pipelines, thereby causing complex process design and high construction cost. By integrating the phase separator 6 in the tower body, the land occupation area of the demonstration project can be reduced, and the absorbent after absorbing CO2 can be quickly sent back to the top of the absorption section for continuous circulation after phase separation, thereby improving the operation flexibility of the composite absorption tower equipment.

[0032] c) The inter-stage cooling heat exchanger 4 is built-in, and the water washing section cooler 1 is built-in: the heat exchangers in the conventional CO2 capture process, such as the lean liquid cooler, the inter-stage cooling heat exchanger and the like, are arranged outside the composite absorption tower, thus resulting in a large occupied area and a complex pipe connection system. Therefore, by the built-in method of the inter-stage cooling heat exchanger 4 and the water washing section cooler, the occupied area of the heat exchanger can be greatly reduced, and the washing liquid or the absorbent flowing down from the water washing section or the absorption section can be first collected by the liquid collecting tank and then sent into the upper heat exchanger, thus greatly reducing the flow time of the washing liquid or the absorbent in the pipe and improving the heat exchange effect.

[0033] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by the equivalent, without departing from the spirit and scope of the present application. Any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered within the protection scope of the claims of the present application.

Claims

1. A compact hybrid absorption column suitable for carbon capture in a peaking coal-fired power plant, characterized in that, The application relates to a tower body, which is sequentially divided into a water washing section, an absorption section and a pre-washing section from top to bottom; the water washing section is sequentially provided with a water washing section cooler (1), a first collecting tank (2) and a second collecting tank (3) from top to bottom; the absorption section is sequentially provided with a first spraying layer (11), an inter-stage cooling heat exchanger (4) and a third collecting tank (5) from top to bottom; the pre-washing section is sequentially provided with a second spraying layer (12), a phase separator (6) and a fourth collecting tank (7) from top to bottom; the poor phase outlet of the phase separator (6) is communicated with the inlet of the second spraying layer (12) and the inlet of the first spraying layer (11).

2. A compact composite absorption column suitable for carbon capture in a peak-shaving coal-fired power plant according to claim 1, characterized in that, The poor phase outlet of the phase separator (6) is divided into two paths after the first circulating pump (8), one of which is communicated with the inlet of the second spraying layer (12), and the other is communicated with the outlet of the second circulating pump (9) through a pipeline and a pipe and then communicated with the inlet of the first spraying layer (11) through a solution circulating bypass.

3. The compact integrated absorber column for carbon capture from a peak-shaving coal-fired power plant according to claim 1, wherein, The bottom of the tower body is provided with a flue gas inlet, and the top of the tower body is provided with a flue gas outlet.

4. The compact integrated absorber column for carbon capture from a peak-shaving coal-fired power plant according to claim 3, wherein, The flue gas inlet is provided with a double-row vane gas distributor (10).

5. The compact integrated absorber column for carbon capture from a peak-shaving coal-fired power plant according to claim 1, wherein, The rich phase outlet of the phase separator (6) is communicated with a lean-rich liquid heat exchanger.

6. The compact integrated absorption column for carbon capture suitable for peak shaving coal-fired power plants according to claim 1, wherein, The inlet of the first spraying layer (11) and the outlet of the first circulating pump (8) are both communicated with a lean-rich liquid heat exchanger.

7. The compact integrated absorption column for carbon capture suitable for peak shaving coal-fired power plants according to claim 1, wherein, The outlet of the third collecting tank (5) is communicated with the inlet of the first spraying layer (11).

8. The compact integrated absorption column for carbon capture suitable for peak shaving coal-fired power plants according to claim 1, wherein, In working, the solution sprayed by the first spraying layer (11) is contacted with flue gas in counterflow, and then enters the third collecting tank (5) after heat exchange by the inter-stage cooling heat exchanger (4).

9. The compact integrated absorber column for carbon capture from a peak-shaving coal-fired power plant according to claim 1, wherein, In working, the solution in the third collecting tank (5) is sprayed downward by the second spraying layer (12) and contacted with flue gas in counterflow, and then enters the phase separator (6) to be separated.

10. The compact integrated absorber column for carbon capture from a peak-shaving coal-fired power plant according to claim 2, wherein, In working, the poor phase solution output by the phase separator (6) is divided into two paths after the first circulating pump (8), one of which enters the second spraying layer (12), and the other enters the first spraying layer (11) after being converged with the solution in the third collecting tank (5) extracted by the second circulating pump (9). In working, the solution sprayed by the first spraying layer (11) is contacted with flue gas in counterflow, and then enters the third collecting tank (5) after heat exchange by the inter-stage cooling heat exchanger (4). In working, the solution in the third collecting tank (5) is sprayed downward by the second spraying layer (12) and contacted with flue gas in counterflow, and then enters the phase separator (6) to be separated. In working, the poor phase solution output by the phase separator (6) is divided into two paths after the first circulating pump (8), one of which enters the second spraying layer (12), and the other enters the first spraying layer (11) after being converged with the solution in the third collecting tank (5) extracted by the second circulating pump (9).

Images