Decarbonization System Compressor Inter-stage Waste Heat Utilization Device and Method

Abstract

The present invention discloses a device and method for utilizing the waste heat between stages of a compressor in a decarbonization system. The waste heat utilization device includes: an absorption tower, a regeneration tower, a rich and lean liquid heat exchanger, a multi-stage series compressor, a first rich liquid pipeline, and a second rich liquid pipeline. The waste heat utilization device divides the rich liquid discharged from the rich liquid outlet of the absorption tower into two paths. One path of the rich liquid enters the cold side of the rich and lean liquid heat exchanger to absorb the heat of the lean liquid on the hot side, and the remaining rich liquid enters the inter-stage heat exchanger. After absorbing the waste heat of the regenerated gas and increasing in temperature, it enters the regeneration tower, while realizing the cooling of the regenerated gas, reducing the flow rate of the rich liquid entering the rich and lean liquid heat exchanger, increasing the temperature rise space of the rich liquid, and being able to maximize the temperature of the rich liquid after heat exchange, reducing the steam consumption during the regeneration process, thereby reducing the regeneration heat consumption. At the same time, since the regenerated gas exchanges heat with the rich liquid in the inter-stage heat exchanger, the heat of the regenerated gas is fully utilized, improving the energy utilization rate, saving the consumption of cooling water, and reducing the operation cost.

Description

Technical Field

[0001] The present invention relates to the technical field of emission reduction, and in particular to a device and method for utilizing the inter-stage waste heat of a decarbonization system compressor. Background Art

[0002] In the technology of chemically absorbing carbon dioxide, the absorbent reacts with carbon dioxide in the absorption tower to form an unstable compound, thereby absorbing carbon dioxide in the flue gas. The absorbent rich in carbon dioxide enters the regeneration tower, and the carbon dioxide is released and regenerated by heating. The technology of chemically absorbing carbon dioxide is relatively mature, but the energy consumption is high, and the energy consumption is mainly concentrated in the heating and regeneration link. In related technologies, the rich liquid is mainly heated by heat exchange between the rich liquid and the lean liquid, but there are problems of low heating efficiency and slow temperature rise, and there is still a large temperature difference between the rich liquid after heat exchange and the lean liquid. Therefore, a reboiler is needed to continue heating and raising the temperature in the regeneration tower, resulting in a large heat consumption in the regeneration process. Summary of the Invention

[0003] The present invention is based on the inventor's discovery and recognition of the following facts and problems:

[0004] In a carbon dioxide capture and regeneration system, the regenerated carbon dioxide usually needs to be pressurized and liquefied for filling and storage or transported outside the factory through pipelines. In this process, the multi-stage compressor used needs to perform inter-stage cooling operations. At present, the inter-stage cooling method is mostly to directly spray water between stages, resulting in a greatly increased consumption of cooling water, increasing the operating cost, and it is difficult to fully utilize the energy of the recompressed and heated regeneration gas.

[0005] The present invention aims to solve at least one of the technical problems in the related technologies to some extent. For this purpose, an embodiment of the present invention provides a device and method for utilizing the inter-stage waste heat of a decarbonization system compressor.

[0006] The inter-stage waste heat utilization device of the decarbonization system compressor in the embodiment of the present invention includes: an absorption tower and a regeneration tower. The absorption tower has a lean liquid inlet and a rich liquid outlet. The regeneration tower has a first rich liquid inlet, a second rich liquid inlet, and a lean liquid outlet. A reboiler gas outlet is provided at the top of the regeneration tower; a rich-lean liquid heat exchanger, which is arranged between the absorption tower and the regeneration tower to exchange heat between the lean liquid and the rich liquid, wherein the hot side is communicated with the lean liquid outlet and the lean liquid inlet, and the cold side is communicated with the rich liquid outlet and the first rich liquid inlet; a multi-stage series-connected compressor, which is communicated with the reboiler gas outlet for compressing and liquefying the reboiler gas, and an inter-stage heat exchanger for cooling is connected between the compressors; a first rich liquid pipeline and a second rich liquid pipeline. The inlet ends of the first rich liquid pipeline and the second rich liquid pipeline are both communicated with the rich liquid outlet. The outlet end of the first rich liquid pipeline is communicated with the cold side inlet of the rich-lean liquid heat exchanger. The outlet end of the second rich liquid pipeline is communicated with the cold side inlet of the inter-stage heat exchanger. The cold side outlet of the inter-stage heat exchanger is communicated with the second rich liquid inlet;

[0007] The waste heat utilization device provided by the embodiment of the present invention divides the rich liquid discharged from the rich liquid outlet of the absorption tower into two paths. One path of the rich liquid enters the cold side of the rich-lean liquid heat exchanger to absorb the heat of the lean liquid on the hot side. The remaining rich liquid enters the inter-stage heat exchanger. After absorbing the waste heat of the reboiler gas and rising in temperature, it enters the regeneration tower, and at the same time, the temperature of the reboiler gas is reduced. The rich liquid is divided into two paths and the two paths of rich liquid are heated separately, reducing the flow rate of the rich liquid entering the rich-lean liquid heat exchanger, increasing the temperature rising space of the rich liquid, and can maximize the temperature of the rich liquid after heat exchange, thereby increasing the temperature of the rich liquid entering the tower, improving the problems of low heating efficiency and slow temperature rise existing in the single heating method using the rich-lean liquid heat exchanger, reducing the steam consumption during the regeneration process, and thus reducing the regeneration heat consumption. At the same time, since the reboiler gas exchanges heat with the rich liquid in the inter-stage heat exchanger, the heat of the reboiler gas is fully utilized, improving the energy utilization rate, saving the consumption of cooling water, and reducing the operating cost.

[0008] Therefore, the inter-stage waste heat utilization device of the decarbonization system compressor provided by the embodiment of the present invention reduces the heat consumption in the regeneration link, reduces the system loss, and reduces the carbon dioxide capture cost.

[0009] In some embodiments, the inter-stage waste heat utilization device of the decarbonization system compressor further includes a first regulating valve, which is arranged at the inlet ends of the first rich liquid pipeline and the second rich liquid pipeline for regulating the proportion of the rich liquid entering the first rich liquid pipeline and the second rich liquid pipeline from the rich liquid outlet.

[0010] In some embodiments, the compressor includes a first-stage compressor and a second-stage compressor. The first-stage compressor is in communication with the outlet of the regeneration gas. An inter-stage heat exchanger is connected between the first-stage compressor and the second-stage compressor. The first-stage compressor compresses and heats the regeneration gas to 120°C - 140°C.

[0011] In some embodiments, 70% - 95% of the rich liquid flowing out from the rich liquid outlet enters the first rich liquid pipeline, and 5% - 30% enters the second rich liquid pipeline.

[0012] In some embodiments, the inter-stage waste heat utilization device of the decarbonization system compressor includes: a first lean liquid pipeline, a second lean liquid pipeline, and a third rich liquid pipeline. The first lean liquid pipeline communicates with the lean liquid outlet and the hot-side inlet of the rich-lean liquid heat exchanger. The second lean liquid pipeline communicates with the hot-side outlet of the rich-lean liquid heat exchanger and the lean liquid inlet. The third rich liquid pipeline communicates with the cold-side outlet of the rich-lean liquid heat exchanger and the rich liquid inlet; a fourth rich liquid pipeline and a second regulating valve. The fourth rich liquid pipeline communicates with the cold-side outlet of the rich-lean liquid heat exchanger and the cold-side inlet of the inter-stage heat exchanger. The second regulating valve is provided at the inlet ends of the third rich liquid pipeline and the fourth rich liquid pipeline for adjusting the proportion of the rich liquid entering the third rich liquid pipeline and the fourth rich liquid pipeline from the cold-side outlet of the rich-lean liquid heat exchanger.

[0013] In some embodiments, the inter-stage waste heat utilization device of the decarbonization system compressor further includes a first temperature measuring component for measuring the temperature at the hot-side outlet of the inter-stage heat exchanger; and / or, further includes a second temperature measuring component for measuring the temperature at the lean liquid inlet.

[0014] In some embodiments, in the vertical direction, the second rich liquid inlet is located below the first rich liquid inlet.

[0015] On the other hand, an embodiment of the present invention provides an inter-stage waste heat utilization method for a decarbonization system compressor, including:

[0016] Making the rich liquid at the rich liquid outlet enter the first rich liquid pipeline and the second rich liquid pipeline according to an initial proportion;

[0017] Real-time detecting the temperature at the hot-side outlet of the inter-stage heat exchanger;

[0018] When the detected temperature at the hot-side outlet of the inter-stage heat exchanger is greater than a first preset threshold, increasing the proportion of the rich liquid entering the second rich liquid pipeline;

[0019] Real-time detecting the temperature at the lean liquid inlet;

[0020] When the detected temperature at the lean liquid inlet is greater than the second preset threshold, reduce the proportion of rich liquid entering the second rich liquid pipeline.

[0021] In some embodiments, the waste heat utilization method further includes:

[0022] Adjust the second regulating valve so that the rich liquid at the cold side outlet of the rich and lean liquid heat exchanger enters the third rich liquid pipeline and the fourth rich liquid pipeline according to the initial proportion;

[0023] When the detected temperature at the hot side outlet of the inter-stage heat exchanger is greater than the third preset threshold, adjust the second regulating valve to increase the proportion of rich liquid entering the fourth rich liquid pipeline.

[0024] In some embodiments, the waste heat utilization method further includes:

[0025] When the detected temperature at the hot side outlet of the inter-stage heat exchanger is greater than the fourth preset threshold, use cooling water to cool down the regenerated gas. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of the inter-stage waste heat utilization device of the decarbonization system compressor in Embodiment 1 of the present invention.

[0027] Figure 2 is a schematic structural diagram of the inter-stage waste heat utilization device of the decarbonization system compressor in Embodiment 2 of the present invention.

[0028] Reference Signs:

[0029] Absorption tower 100, lean liquid inlet 101, rich liquid outlet 102,

[0030] Regeneration tower 200, first rich liquid inlet 201-1, second rich liquid inlet 201-2, lean liquid outlet 202, regenerated gas outlet 203,

[0031] Rich and lean liquid heat exchanger 300,

[0032] First-stage compressor 401, second-stage compressor 402, inter-stage heat exchanger 403,

[0033] First rich liquid pipeline 501, second rich liquid pipeline 502, third rich liquid pipeline 503, fourth rich liquid pipeline 504, fifth rich liquid pipeline 505,

[0034] First lean liquid pipeline 601, second lean liquid pipeline 602,

[0035] First regulating valve 701, second regulating valve 702, Detailed Embodiments

[0036] Embodiments of the present invention will be described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] The following will be based on Figure 1 - Figure 2 Describe the inter-stage waste heat utilization device of the decarbonization system compressor provided by the embodiments of the present invention. The waste heat utilization device includes an absorption tower 100, a regeneration tower 200, a rich and lean liquid heat exchanger 300, a multi-stage series compressor, a first rich liquid pipeline 501, and a second rich liquid pipeline 502.

[0038] The absorption tower 100 has a lean liquid inlet 101 and a rich liquid outlet 102. The regeneration tower 200 has a first rich liquid inlet 201-1, a second rich liquid inlet 202-2, and a lean liquid outlet 202. A reboiler gas outlet 203 is provided at the top of the regeneration tower 200. The rich and lean liquid heat exchanger 300 is arranged between the absorption tower 100 and the regeneration tower 200 to exchange heat between the lean liquid and the rich liquid. Among them, the lean liquid is located on the hot side, and the rich liquid is located on the cold side. The rich liquid on the cold side absorbs the heat of the lean liquid on the hot side and is heated up. Specifically, the hot side of the rich and lean liquid heat exchanger 300 is communicated with the lean liquid outlet 202 and the lean liquid inlet 101, and the cold side is communicated with the rich liquid outlet 102 and the first rich liquid inlet 201-1. The compressor is communicated with the reboiler gas outlet 203 of the regeneration tower 200 to compress and liquefy the reboiler gas. An inter-stage heat exchanger 403 for cooling the compressed reboiler gas is connected between the compressors.

[0039] The inlet ends of the first rich liquid pipeline 501 and the second rich liquid pipeline 502 are both communicated with the rich liquid outlet 102 of the absorption tower 100. The outlet end of the first rich liquid pipeline 501 is communicated with the cold side inlet of the rich and lean liquid heat exchanger 300 to convey rich liquid to the cold side of the rich and lean liquid heat exchanger 300. This part of the rich liquid is heated up by absorbing the heat of the lean liquid in the rich and lean liquid heat exchanger 300 and then enters the regeneration tower 200. The outlet end of the second rich liquid pipeline 502 is communicated with the cold side inlet of the inter-stage heat exchanger 403 to convey rich liquid to the cold side inlet of the inter-stage heat exchanger 403. The cold side outlet of the inter-stage heat exchanger 403 is communicated with the second rich liquid inlet 201-2 of the regeneration tower 200. In the inter-stage heat exchanger 403, the hot side is the high-temperature compressed reboiler gas, and the cold side is the rich liquid. The rich liquid absorbs the heat of the cold side compressed reboiler gas and is heated up, while cooling the reboiler gas. The cooled reboiler gas is sent to the next-stage compressor for further pressurization to reach the target pressure of the product gas. The heated-up rich liquid enters the regeneration tower 200.

[0040] The waste heat utilization device provided by the embodiment of the present invention divides the rich liquid discharged from the rich liquid outlet of the absorption tower into two paths. One path of the rich liquid enters the cold side of the rich and lean liquid heat exchanger to absorb the heat of the lean liquid on the hot side, and the remaining rich liquid enters the inter-stage heat exchanger. After absorbing the waste heat of the regenerated gas and rising in temperature, it enters the regeneration tower, and at the same time, the temperature of the regenerated gas is reduced. By dividing the rich liquid into two paths and heating the two paths of rich liquid respectively, the flow rate of the rich liquid entering the rich and lean liquid heat exchanger is reduced, and the temperature rising space of the rich liquid is increased. The temperature of the rich liquid after heat exchange can be increased to a greater extent, so as to increase the inlet temperature of the rich liquid into the tower, improve the problems of low heating efficiency and slow temperature rise existing in the single heating method using the rich and lean liquid heat exchanger, reduce the steam consumption during the regeneration process, and thus reduce the regeneration heat consumption. At the same time, since the regenerated gas exchanges heat with the rich liquid in the inter-stage heat exchanger, the heat of the regenerated gas is fully utilized, the energy utilization rate is improved, the consumption of cooling water is saved, and the operation cost is reduced.

[0041] Therefore, the decarbonization system compressor inter-stage waste heat utilization device provided by the embodiment of the present invention reduces the heat consumption in the regeneration link, reduces the system loss, and reduces the carbon dioxide capture cost.

[0042] In some embodiments, the cold side outlet of the rich and lean liquid heat exchanger 300 is divided into two paths. One path enters the regeneration tower 200 through the first rich liquid inlet 201-1, and the other path converges with the second rich liquid pipeline 502 and enters the cold side of the inter-stage heat exchanger 403. After absorbing the heat of the compressed regenerated gas, it enters the regeneration tower 200 through the second rich liquid inlet 201-2. That is to say, a part of the rich liquid absorbs the heat of the lean liquid on the hot side in the rich and lean liquid heat exchanger 300, then enters the inter-stage heat exchanger 403 to continue absorbing heat, and after the temperature rises, it enters the regeneration tower 200. Without affecting the cooling of the lean liquid, the waste heat utilization device provided by this embodiment further increases the temperature rising space of the rich liquid, increases the inlet temperature of the rich liquid into the tower, improves the utilization rate of waste heat, saves the consumption of cooling water, and reduces the operation cost of the system.

[0043] In some preferred embodiments, in the vertical direction, the second rich liquid inlet 201-2 is located below the first rich liquid inlet 201-1. This is because, generally, the temperature of the rich liquid heated by the rich and lean liquid heat exchanger 300 is lower than the temperature of the rich liquid heated by the inter-stage heat exchanger 403. In the regeneration tower 200, the temperature gradually increases from top to bottom. In order to better match the temperature gradient in the regeneration tower 200, the second rich liquid inlet 201-2 is located below the first rich liquid inlet 201-1.

[0044] In some embodiments, the waste heat utilization device further includes a first temperature measuring component, and the first temperature measuring component is used to measure the temperature at the hot side outlet of the inter-stage heat exchanger 403.

[0045] In some embodiments, the waste heat utilization device further includes a second temperature measuring component for measuring the temperature at the lean liquid inlet 101.

[0046] The following will Figure 1 and Figure 2 describe in detail two specific embodiments of the inter-stage waste heat utilization device of the decarbonization system compressor provided by the present invention.

[0047] Embodiment 1:

[0048] As Figure 1 shown, the inter-stage waste heat utilization device of the decarbonization system compressor includes an absorption tower 100, a regeneration tower 200, a rich-lean liquid heat exchanger 300, a first-stage compressor 401, a second-stage compressor 402, an inter-stage heat exchanger 403, a first rich liquid pipeline 501, a second rich liquid pipeline 502, a third rich liquid pipeline 503, a fifth rich liquid pipeline 505, a first lean liquid pipeline 601 and a second lean liquid pipeline 602.

[0049] The first-stage compressor 401 is communicated with the reboiler gas outlet 203 of the regeneration tower 200, and an inter-stage heat exchanger 403 is connected between the first-stage compressor 401 and the second-stage compressor 402. The compressor outlet of the first-stage compressor 402 is communicated with the hot side inlet of the inter-stage heat exchanger 403, and the hot side outlet of the inter-stage heat exchanger 403 is communicated with the inlet of the second-stage compressor 403.

[0050] The first lean liquid pipeline 601 communicates the lean liquid outlet 202 at the bottom of the regeneration tower 200 and the hot side inlet of the rich-lean liquid heat exchanger 300, and the second lean liquid pipeline 602 communicates the hot side outlet of the rich-lean liquid heat exchanger 300 and the lean liquid inlet 101 of the absorption tower 100. The first rich liquid pipeline 501 communicates the rich liquid outlet 102 at the bottom of the absorption tower 100 and the cold side inlet of the rich liquid heat exchanger 300, and the second rich liquid pipeline 502 communicates the rich liquid outlet 102 and the cold side inlet of the inter-stage heat exchanger 403. The third rich liquid pipeline 503 communicates the cold side outlet of the rich-lean liquid heat exchanger 300 with the first rich liquid inlet 201-1, and the fifth rich liquid pipeline 505 communicates the cold side outlet of the inter-stage heat exchanger 403 with the second rich liquid inlet 201-2.

[0051] The reboiler gas regenerated in the regeneration tower 200 is discharged from the regeneration tower outlet 202 at the top, enters the inlet of the first-stage compressor 401 for compression. The temperature of the compressed reboiler gas rises. The high-temperature compressed gas enters the hot side of the inter-stage heat exchanger 403 and exchanges heat with the rich liquid on the cold side to heat the rich liquid, while realizing its own cooling. The cooled reboiler gas is sent to the second-stage compressor 402 through a pipeline for further pressurization to reach the target pressure of the product gas.

[0052] Optionally, the first-stage compressor 401 compresses and raises the temperature of the reboiler gas to 120°C - 140°C. This temperature range is relatively matched with the regeneration temperature of the rich liquid and will not cause solvent degradation.

[0053] In this embodiment, the proportion of rich liquid entering the first rich liquid pipeline 501 and the second rich liquid pipeline is adjustable. As Figure 1 shown, the waste heat utilization device further includes a first regulating valve 701. The first regulating valve 701 is arranged at the inlet ends of the first rich liquid pipeline 501 and the second rich liquid pipeline 502, and is used to adjust the proportion of rich liquid entering the first rich liquid pipeline 501 and the second rich liquid pipeline 502 from the rich liquid outlet 102 of the absorption tower 100.

[0054] Specifically, the first regulating valve 701 is a three-way valve, which has one inlet and two outlets. The inlet is connected to the rich liquid outlet 102 through a pipeline. One of the outlets is connected to the inlet end of the first rich liquid pipeline 501, and the other outlet is connected to the inlet end of the second rich liquid pipeline 502.

[0055] In this embodiment, according to the temperature at the hot side outlet of the inter-stage heat exchanger 403 and the temperature at the lean liquid inlet 101, the first regulating valve 701 is used to adjust the proportion of rich liquid entering the first rich liquid pipeline 501 and the second rich liquid pipeline 502.

[0056] The decarbonization system compressor inter-stage waste heat utilization device provided in this embodiment further includes a first temperature measuring component for measuring the temperature at the hot side outlet of the inter-stage heat exchanger 403, and a second temperature measuring component for measuring the temperature at the lean liquid inlet 101.

[0057] The present invention also proposes a decarbonization system compressor inter-stage waste heat utilization method. The waste heat utilization method based on the above embodiment includes:

[0058] Making the rich liquid at the rich liquid outlet 102 enter the first rich liquid pipeline 501 and the second rich liquid pipeline 502 according to the initial proportion;

[0059] The first temperature measuring component detects the temperature at the hot side outlet of the inter-stage heat exchanger 403 in real time;

[0060] When the detected temperature at the hot side outlet of the inter-stage heat exchanger 403 is greater than the first preset threshold, it indicates that the cooling demand of the inter-stage heat exchanger 403 is large at this time. Therefore, the first regulating valve 701 is used to increase the proportion of rich liquid entering the second rich liquid pipeline 502;

[0061] The second temperature measuring component detects the temperature at the lean liquid inlet 101 in real time;

[0062] When the detected temperature at the lean liquid inlet 101 is greater than the second preset threshold, it indicates that the lean liquid needs to be cooled at this time. Therefore, the first regulating valve 701 is used to reduce the proportion of rich liquid entering the second rich liquid pipeline 502, so that more rich liquid enters the rich-lean liquid heat exchanger 300 to cool the lean liquid.

[0063] Optionally, to ensure the cooling of the lean liquid, 70%-95% of the rich liquid flowing out of the rich liquid outlet 102 enters the first rich liquid pipeline 501, and 5%-30% enters the second rich liquid pipeline 502.

[0064] Optionally, the preset temperature range at the lean liquid inlet 101 is 40°C - 50°C. When the second temperature measuring component detects that the temperature of the lean liquid at the lean liquid inlet 101 exceeds 50°C, the proportion of the rich liquid entering the second rich liquid pipeline 502 is reduced to accelerate the cooling of the lean liquid.

[0065] Furthermore, when, while ensuring that the temperature of the lean liquid does not exceed the second preset threshold, the proportion of the rich liquid entering the second rich liquid pipeline 502 reaches the maximum, and at this time the detected temperature at the hot side outlet of the inter-stage heat exchanger 403 is greater than the first preset threshold, cooling water can be used to cool the regeneration gas on the hot side of the inter-stage heat exchanger 403 to ensure the normal operation of the compression gas process.

[0066] Optionally, the temperature of the rich liquid flowing out of the cold side outlet of the inter-stage heat exchanger 403 is 70°C - 80°C.

[0067] Embodiment 2:

[0068] As Figure 2 shown, the decarbonization system compressor inter-stage waste heat utilization device provided in this embodiment includes an absorption tower 100, a regeneration tower 200, a rich and lean liquid heat exchanger 300, a first-stage compressor 401, a second-stage compressor 402, an inter-stage heat exchanger 403, a first rich liquid pipeline 501, a second rich liquid pipeline 502, a third rich liquid pipeline 503, a fourth rich liquid pipeline 504, a fifth rich liquid pipeline 505, a first lean liquid pipeline 601, and a second lean liquid pipeline 602. Only the differences from Embodiment 1 will be described below.

[0069] The fourth rich liquid pipeline 504 connects the cold side outlet of the rich and lean liquid heat exchanger 300 to the cold side inlet of the inter-stage heat exchanger 403. A part of the rich liquid discharged from the cold side outlet of the rich and lean liquid heat exchanger 300 enters the first rich liquid inlet 202-1 through the third rich liquid pipeline 503, and another part enters the cold side inlet of the inter-stage heat exchanger 403 through the fourth rich liquid pipeline 504. After heat exchange in the inter-stage heat exchanger 403, it enters the regeneration tower 200 through the second rich liquid inlet 201-2.

[0070] In this embodiment, a second regulating valve 702 is further included. The second regulating valve 702 is provided at the inlet ends of the third rich liquid pipeline 503 and the fourth rich liquid pipeline 505 for regulating the proportion of the rich liquid entering the third rich liquid pipeline 503 and the fourth rich liquid pipeline 505 from the cold side outlet of the rich and lean liquid heat exchanger 300. Specifically, the second regulating valve 702 is a three-way valve.

[0071] In this embodiment, the ratio of the rich liquid entering the third rich liquid pipeline 503 and the fourth rich liquid pipeline 504 is adjusted by using the second regulating valve 702 according to the temperature at the hot side outlet of the inter-stage heat exchanger 403.

[0072] The waste heat utilization method based on this embodiment further includes:

[0073] Adjust the second regulating valve 702 so that the rich liquid at the cold side outlet of the rich and lean liquid heat exchanger 300 enters the third rich liquid pipeline 503 and the fourth rich liquid pipeline 504 according to the initial ratio.

[0074] When the detected temperature at the hot side outlet of the inter-stage heat exchanger 4 is greater than the third preset threshold, adjust the second regulating valve 702 to increase the ratio of the rich liquid entering the fourth rich liquid pipeline 404, so as to further absorb waste heat and reduce the temperature at the hot side outlet of the inter-stage heat exchanger 4.

[0075] The purpose of this step is that when ensuring the cooling of the lean liquid, the ratio of the rich liquid entering the second rich liquid pipeline 502 reaches the maximum. At this time, when the detected temperature at the hot side outlet of the inter-stage heat exchanger 403 is greater than the third preset threshold, the ratio of the rich liquid entering the fourth rich liquid pipeline 404 can be increased to make the rich liquid further absorb heat and cool the regenerated gas.

[0076] Optionally, the third preset threshold is greater than or equal to the first preset threshold.

[0077] Furthermore, the waste heat utilization method further includes: when the detected temperature at the hot side outlet of the inter-stage heat exchanger 4 is greater than the fourth preset threshold, use cooling water to cool the regenerated gas.

[0078] That is to say, when ensuring the cooling of the lean liquid, the ratio of the rich liquid entering the second rich liquid pipeline 502 reaches the maximum, and the ratio of the rich liquid entering the fourth rich liquid pipeline 404 reaches the maximum. At this time, when the detected temperature at the hot side outlet of the inter-stage heat exchanger 403 is greater than the fourth preset threshold, cooling water can be used to cool the regenerated gas on the hot side of the inter-stage heat exchanger 403 to ensure the normal progress of the compression gas process.

[0079] Optionally, the fourth preset threshold is greater than or equal to the third preset threshold.

[0080] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0081] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0082] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention may be understood according to specific circumstances.

[0083] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0084] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0085] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A device for utilizing the waste heat between stages of a decarbonization system compressor, characterized in that, Including: An absorption tower and a regeneration tower. The absorption tower has a lean liquid inlet and a rich liquid outlet. The regeneration tower has a first rich liquid inlet, a second rich liquid inlet, and a lean liquid outlet. A regenerated gas outlet is provided at the top of the regeneration tower. A lean-rich liquid heat exchanger is arranged between the absorption tower and the regeneration tower for heat exchange between the lean liquid and the rich liquid. The hot side is communicated with the lean liquid outlet and the lean liquid inlet, and the cold side is communicated with the rich liquid outlet and the first rich liquid inlet. A multi-stage series-connected compressor is communicated with the regenerated gas outlet for compressing and liquefying the regenerated gas. An inter-stage heat exchanger for cooling is connected between the compressors. A first rich liquid pipeline and a second rich liquid pipeline. The inlet ends of the first rich liquid pipeline and the second rich liquid pipeline are both communicated with the rich liquid outlet. The outlet end of the first rich liquid pipeline is communicated with the cold side inlet of the lean-rich liquid heat exchanger. The outlet end of the second rich liquid pipeline is communicated with the cold side inlet of the inter-stage heat exchanger. The cold side outlet of the inter-stage heat exchanger is communicated with the second rich liquid inlet. A first lean liquid pipeline, a second lean liquid pipeline, and a third rich liquid pipeline. The first lean liquid pipeline communicates the lean liquid outlet and the hot side inlet of the lean-rich liquid heat exchanger. The second lean liquid pipeline communicates the hot side outlet of the lean-rich liquid heat exchanger and the lean liquid inlet. The third rich liquid pipeline communicates the cold side outlet of the lean-rich liquid heat exchanger and the rich liquid inlet. A fourth rich liquid pipeline and a second regulating valve. The fourth rich liquid pipeline communicates the cold side outlet of the lean-rich liquid heat exchanger and the cold side inlet of the inter-stage heat exchanger. The second regulating valve is arranged at the inlet ends of the third rich liquid pipeline and the fourth rich liquid pipeline for adjusting the rich liquid ratio entering the third rich liquid pipeline and the fourth rich liquid pipeline from the cold side outlet of the lean-rich liquid heat exchanger.

2. The inter-stage waste heat utilization device of the decarbonization system compressor according to claim 1, characterized in that, It further includes a first regulating valve. The first regulating valve is arranged at the inlet ends of the first rich liquid pipeline and the second rich liquid pipeline for adjusting the rich liquid ratio entering the first rich liquid pipeline and the second rich liquid pipeline from the rich liquid outlet.

3. The inter-stage waste heat utilization device of the decarbonization system compressor according to claim 1, characterized in that The compressor includes a first-stage compressor and a second-stage compressor. The first-stage compressor is communicated with the regenerated gas outlet. An inter-stage heat exchanger is connected between the first-stage compressor and the second-stage compressor. The first-stage compressor compresses the regenerated gas to a temperature of 120°C - 140°C.

4. The decarbonization system compressor inter-stage waste heat utilization device according to any one of claims 1-3, characterized in that, 70% - 95% of the rich liquid flowing out from the rich liquid outlet enters the first rich liquid pipeline, and 5% - 30% enters the second rich liquid pipeline.

5. The decarbonization system compressor inter-stage waste heat utilization device according to any one of claims 1-3, characterized in that, It further includes a first temperature measuring component for measuring the temperature at the hot side outlet of the inter-stage heat exchanger. And / or, it further includes a second temperature measuring component for measuring the temperature at the lean liquid inlet.

6. The decarbonization system compressor inter-stage waste heat utilization device according to any one of claims 1-3, characterized in that, In the vertical direction, the second rich liquid inlet is located below the first rich liquid inlet.

7. A method for utilizing the waste heat between stages of a compressor in a decarbonization system, characterized in that, The waste heat utilization method is based on the decarbonization system compressor inter-stage waste heat utilization device according to any one of claims 1 - 6. And the rich liquid ratio entering the first rich liquid pipeline and the second rich liquid pipeline is adjustable. The waste heat utilization method includes: Make the rich liquid at the rich liquid outlet enter the first rich liquid pipeline and the second rich liquid pipeline according to the initial ratio; Detect the temperature at the hot side outlet of the inter-stage heat exchanger in real time; When the detected temperature at the hot side outlet of the inter-stage heat exchanger is greater than the first preset threshold, increase the proportion of the rich liquid entering the second rich liquid pipeline; Detect the temperature at the lean liquid inlet in real time; When the detected temperature at the lean liquid inlet is greater than the second preset threshold, reduce the proportion of the rich liquid entering the second rich liquid pipeline.

8. The method for utilizing the inter-stage waste heat of the compressor in the decarbonization system according to claim 7, characterized in that, The decarbonization system compressor inter-stage waste heat utilization device is the decarbonization system compressor inter-stage waste heat utilization device according to claim 5, and the waste heat utilization method further includes: Adjust the second regulating valve to make the rich liquid at the cold side outlet of the rich-lean liquid heat exchanger enter the third rich liquid pipeline and the fourth rich liquid pipeline according to the initial ratio; When the detected temperature at the hot side outlet of the inter-stage heat exchanger is greater than the third preset threshold, adjust the second regulating valve to increase the proportion of the rich liquid entering the fourth rich liquid pipeline.

9. The method for utilizing the inter-stage waste heat of the compressor in the decarbonization system according to claim 8, wherein It further includes: When the detected temperature at the hot side outlet of the inter-stage heat exchanger is greater than the fourth preset threshold, use cooling water to cool down the regenerated gas.

Images