Waste heat recovery system for carbon dioxide capture

Abstract

The utility model discloses a waste heat recovery system for carbon dioxide capture, which is characterized in that a feed gas multi-stage compressor comprises a first-stage compression cavity, a second-stage compression cavity, a third-stage compression cavity and a fourth-stage compression cavity, the first-stage compression cavity comprises a first-stage gas inlet and a first-stage gas outlet, the second-stage compression cavity comprises a second-stage gas inlet and a second-stage gas outlet, and the third-stage compression cavity comprises a third-stage gas inlet and a fourth-stage gas outlet. The third-stage compression cavity comprises a third-stage air inlet and a third-stage air outlet; the first-stage gas inlet is used for externally connecting an upstream device carbon dioxide tail gas pipeline; the first-stage gas outlet, the first cooler, the pre-desulfurization tower and the second-stage gas inlet are communicated in sequence; the second-stage gas outlet, the second cooler, the hydrolysis desulfurization tower, the third cooler, the fine desulfurization tower and the third-stage gas inlet are communicated in sequence; the third-stage gas outlet, the food-grade refined removal tower and the fourth cooler are communicated in sequence; the feed gas multistage compressor is used for being externally connected with a compression heat dryer. The system is simple in process, stable in operation, reliable and high in compression heat utilization rate, and the energy consumption of the waste heat recovery system for carbon dioxide capture is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of carbon dioxide capture, in particular to a waste heat recovery system for carbon dioxide capture. Background Art

[0002] Among high-concentration carbon dioxide capture technologies, medium-pressure carbon dioxide compression, liquefaction, and distillation capture technology is the main technology for large-scale industrial applications. In this type of technology, reducing the cost of carbon dioxide capture and reducing energy consumption per ton of product will save a lot of resources, and it will become the main research content in the future. Utility Model Content

[0003] In order to reasonably and effectively utilize the compression heat energy between various stages of the raw gas compressor in the carbon capture process, provide the required heat for the desulfurization section, purification section, drying section, etc., and achieve the purpose of reducing the energy consumption of the overall device operation, the utility model proposes a waste heat recovery system for carbon dioxide capture.

[0004] In a first aspect, the embodiment of the utility model provides a waste heat recovery system for carbon dioxide capture, which may include: a raw gas multi-stage compressor, a first cooler, a pre-desulfurization tower, a second cooler, a hydrolysis desulfurization tower, a third cooler, a fine desulfurization tower, a food-grade fine desulfurization tower and a fourth cooler;

[0005] Wherein, the raw gas multi-stage compressor includes a primary compression chamber, a secondary compression chamber, a tertiary compression chamber and a quaternary compression chamber, the primary compression chamber includes a primary air inlet and a primary air outlet, the secondary compression chamber includes a secondary air inlet and a secondary air outlet, the tertiary compression chamber includes a tertiary air inlet and a tertiary air outlet, and the quaternary compression chamber includes a quaternary air inlet and a quaternary air outlet;

[0006] The primary air inlet is used for external connection to the carbon dioxide tail gas pipeline of the upstream device; the primary air outlet, the first cooler, the pre-desulfurization tower, and the secondary air inlet are connected in sequence, and the pre-desulfurization tower is used to remove hydrogen sulfide in the raw gas; the secondary air outlet, the second cooler, the hydrolysis desulfurization tower, the third cooler, the fine desulfurization tower and the tertiary air inlet are connected in sequence, the hydrolysis desulfurization tower is used to convert the organic sulfur in the raw gas into hydrogen sulfide, and the fine desulfurization tower is used to remove the hydrogen sulfide converted from the organic sulfur in the raw gas; the tertiary air outlet, the food-grade fine desulfurization tower, the fourth cooler and the fourth-stage air inlet are connected in sequence, and the fourth-stage air outlet of the food-grade fine desulfurization tower is used to remove impurities in the raw gas; the raw gas multi-stage compressor is used for external connection to a compression heat dryer.

[0007] In an optional embodiment, the raw gas multi-stage compressor is a reciprocating compressor or a centrifugal compressor;

[0008] When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa-4MPa, the raw gas multi-stage compressor is a reciprocating compressor, the raw gas multi-stage compressor is a three-stage compression, and the fourth cooler is externally connected to the compression heat dryer;

[0009] When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa-4MPa and the raw gas multi-stage compressor is a centrifugal compressor, the raw gas multi-stage compressor is a four-stage compression, and the four-stage gas outlet is externally connected to the compression heat dryer;

[0010] When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a reciprocating compressor, the raw gas multi-stage compressor is a four-stage compression, the fourth cooler is externally connected to the compression heat dryer, or the fourth-stage air outlet is externally connected to the compression heat dryer;

[0011] When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa~8MPa, and the raw gas multi-stage compressor is a centrifugal compressor, the raw gas multi-stage compressor is a five-stage compression, and the raw gas multi-stage compressor includes a five-stage compression chamber, and the five-stage compression chamber includes a five-stage air inlet and a five-stage air outlet, and the system also includes a fifth cooler; the fourth-stage air outlet is externally connected to the compression heat dryer, or the fourth-stage air outlet, the fifth cooler and the fifth-stage air inlet are connected in sequence, and the fifth-stage air outlet is externally connected to the compression heat dryer.

[0012] In another optional embodiment, the system may further include: a first regulating valve, a second regulating valve and a third regulating valve;

[0013] The first regulating valve is located on the cold-side fluid pipeline of the second cooler, the second regulating valve is located on the cold-side fluid pipeline of the third cooler, and the third regulating valve is located on the cold-side fluid pipeline of the fourth cooler.

[0014] In another optional embodiment, the system may further include: a first pressure gauge and a first thermometer, wherein the first pressure gauge and the first thermometer are located on the pipeline between the first-stage air inlet of the raw gas multi-stage compressor and the carbon dioxide tail gas pipeline of the external upstream device.

[0015] In another optional embodiment, the system may further include: a second thermometer and a third thermometer, wherein the second thermometer and the third thermometer are respectively located on pipelines on both sides of the first cooler.

[0016] In another optional embodiment, the system may further include: a fourth thermometer and a fifth thermometer, wherein the fourth thermometer and the fifth thermometer are respectively located on pipelines on both sides of the second cooler.

[0017] In another optional embodiment, the system may also include: a sixth thermometer, a seventh thermometer and an eighth thermometer, the sixth thermometer is located on the pipeline between the third cooler and the fine desulfurization tower, the seventh thermometer is located on the pipeline between the third-level air outlet and the food-grade fine desulfurization tower, and the eighth thermometer is located on the pipeline between the food-grade fine desulfurization tower and the fourth-level air inlet.

[0018] In another optional embodiment, when the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a reciprocating compressor, the system further includes: a ninth thermometer, a tenth thermometer, an eleventh thermometer and a second pressure gauge;

[0019] The ninth thermometer is located on the pipeline between the fourth-stage air outlet and the fifth cooler, the tenth thermometer is located on the pipeline between the fifth cooler and the fifth-stage air inlet, and the eleventh thermometer and the second pressure gauge are located on the pipeline between the fifth-stage air outlet and the external compression heat dryer.

[0020] In another optional embodiment, the system may further include: a heat of compression dryer;

[0021] When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5 MPa to 4 MPa and the raw gas multi-stage compressor is a reciprocating compressor, the compression heat dryer is connected to the fourth cooler;

[0022] When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5 MPa to 4 MPa and the raw gas multi-stage compressor is a centrifugal compressor, the compression heat dryer is connected to the fourth-stage gas outlet;

[0023] When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a reciprocating compressor, the compression heat dryer is connected to the fourth cooler or the fourth-stage gas outlet;

[0024] When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a centrifugal compressor, the compression heat dryer is connected to the fourth-stage air outlet or the fifth-stage air outlet.

[0025] In another optional embodiment, the compression heat dryer is a double-tower dryer, including two drying towers, two heat exchangers, a heater, and a ducted booster fan; the compression heat dryer is used to dry the raw gas.

[0026] The beneficial effects of the above technical solution provided by the embodiment of the utility model include at least:

[0027] The embodiment of the utility model provides a waste heat recovery system for carbon dioxide capture, which can effectively reduce the operating energy consumption of each section in the system by reasonably and effectively utilizing the compression heat between each stage of the raw gas multi-stage compressor to meet the heat required by the desulfurization section, the purification section and the drying section. The waste heat recovery system for carbon dioxide capture has a streamlined process, stable operation, a reliable system and a high compression heat utilization rate, which reduces the energy consumption of the waste heat recovery system for carbon dioxide capture.

[0028] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by implementing the utility model. The purpose and other advantages of the utility model can be realized and obtained by the structures particularly pointed out in the written description and the drawings.

[0029] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 It is a structural diagram of a waste heat recovery system for carbon dioxide capture in an embodiment of the utility model;

[0032] Among them, 1-raw gas multi-stage compressor; 2-first cooler; 3-pre-desulfurization tower; 4-second cooler; 5-hydrolysis desulfurization tower; 6-third cooler; 7-fine desulfurization tower; 8-food grade fine desulfurization tower; 9-fourth cooler; 20-compression heat dryer; 21-fifth cooler; 22-first regulating valve; 23-second regulating valve; 24-third regulating valve; 31-first pressure gauge; 32-second pressure gauge; 41-first thermometer; 42-second thermometer; 43-third thermometer; 44-fourth thermometer; 45-fifth thermometer; 46-sixth thermometer; 47-seventh thermometer; 48-eighth thermometer; 49-ninth thermometer; 50-tenth thermometer; 51-eleventh thermometer;

[0033] 11-first-stage compression chamber; 12-second-stage compression chamber; 13-third-stage compression chamber; 14-fourth-stage compression chamber; 15-fifth-stage compression chamber; 111-first-stage air inlet; 112-first-stage air outlet; 121-second-stage air inlet; 122-second-stage air outlet; 131-third-stage air inlet; 132-third-stage air outlet; 141-fourth-stage air inlet; 142-fourth-stage air outlet; 151-fifth-stage air inlet; 152-fifth-stage air outlet; 201-drying tower; 202-heat exchanger; 203-heater; 204-ducted booster fan. DETAILED DESCRIPTION

[0034] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0035] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "far", "near", "front", "rear" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] The utility model provides a waste heat recovery system for carbon dioxide capture, referring to Figure 1As shown, the system may include: a raw gas multi-stage compressor 1, a first cooler 2, a pre-desulfurization tower 3, a second cooler 4, a hydrolysis desulfurization tower 5, a third cooler 6, a fine desulfurization tower 7, a food-grade fine desulfurization tower 8 and a fourth cooler 9; wherein the raw gas multi-stage compressor 1 includes a primary compression chamber 11, a secondary compression chamber 12, a tertiary compression chamber 13 and a quaternary compression chamber 14, the primary compression chamber 11 includes a primary air inlet 111 and a primary air outlet 112, the secondary compression chamber 12 includes a secondary air inlet 121 and a secondary air outlet 122, the tertiary compression chamber 13 includes a tertiary air inlet 131 and a tertiary air outlet 132, the quaternary compression chamber 14 includes a quaternary air inlet 141 and a quaternary air outlet 142; the primary air inlet 111 is used to connect to the upstream The device has a carbon dioxide tail gas pipeline; the first-level air outlet 112, the first cooler 2, the pre-desulfurization tower 3, and the second-level air inlet 121 are connected in sequence, and the pre-desulfurization tower 3 is used to remove hydrogen sulfide in the raw gas; the second-level air outlet 122, the second cooler 4, the hydrolysis desulfurization tower 5, the third cooler 6, the fine desulfurization tower 7 and the third-level air inlet 131 are connected in sequence, the hydrolysis desulfurization tower 5 is used to convert the organic sulfur in the raw gas into hydrogen sulfide, and the fine desulfurization tower 7 is used to remove the hydrogen sulfide converted from the organic sulfur in the raw gas; the third-level air outlet 132, the food-grade fine desulfurization tower 8, the fourth cooler 9 and the fourth-level air inlet 141 are connected in sequence, and the food-grade fine desulfurization tower 8 is used to remove impurities in the raw gas; the fourth-level air outlet 142 of the raw gas multi-stage compressor 1 is used for an external compression heat dryer 20.

[0038] In the embodiment of the utility model, the air inlet (first-level air inlet) of the raw gas compressor is externally connected to the carbon dioxide tail gas pipeline of the upstream device, the first-level air outlet of the first-level compression chamber is connected to the first cooler after the first-level compression chamber, and the raw gas enters the pre-desulfurization tower after cooling; the raw gas after the pre-desulfurization treatment of the pre-desulfurization tower enters the second-level air inlet of the second-level compression chamber through the pipeline, and the second-level air outlet is connected to the second cooler after the second-level compression chamber, and enters the hydrolysis desulfurization tower after cooling; the raw gas is hydrolyzed and desulfurized in the hydrolysis desulfurization tower, and then further cooled by the third cooler after the hydrolysis desulfurization tower and enters the fine desulfurization tower; the outlet of the fine desulfurization tower is connected to the third-level air inlet of the third-level compression chamber, and the third-level air outlet of the third-level compression chamber is connected to the food-grade fine desulfurization tower, and after desulfurization in the food-grade fine desulfurization tower, it reaches food-grade carbon dioxide gas; the outlet of the food-grade fine desulfurization tower is connected to the fourth cooler, and the raw gas after cooling or further compression enters the external compression heat dryer, that is, the low dew point carbon dioxide raw gas required for carbon dioxide liquefaction is obtained.

[0039] It should be noted that the second cooler after the above-mentioned secondary compression chamber is used to control the temperature of the raw gas entering the hydrolysis desulfurization tower. The purpose of the third cooler is to reduce the temperature of the raw gas after hydrolysis to below 40°C. The food-grade fine desulfurization tower is composed of multiple fine desulfurization towers, and its purpose is to remove the remaining impurities in the raw gas to meet the food-grade carbon dioxide purity requirements. The system is calculated on the basis that the raw gas is pure carbon dioxide. The use of compression heat alone can save about 30kWh / t.CO2 power consumption, which can achieve the purpose of energy conservation and emission reduction.

[0040] The waste heat recovery system in the embodiment of the utility model can effectively reduce the operating energy consumption of each section in the system by reasonably and effectively utilizing the compression heat between each stage of the raw gas multi-stage compressor to meet the heat required by the desulfurization section, purification section and drying section. The waste heat recovery system for carbon dioxide capture has a streamlined process, stable operation, reliable system and high compression heat utilization rate, which reduces the energy consumption of the waste heat recovery system for carbon dioxide capture.

[0041] In an alternative embodiment, referring to Figure 1 As shown, the raw gas multistage compressor 1 is a reciprocating compressor or a centrifugal compressor; when the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa~4MPa, the raw gas multistage compressor 1 is a reciprocating compressor, the raw gas multistage compressor 1 is a three-stage compression, and the fourth cooler 9 is externally connected to the compression heat dryer 20; when the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa~4MPa, the raw gas multistage compressor 1 is a centrifugal compressor, the raw gas multistage compressor 1 is a four-stage compression, and the fourth-stage air outlet 142 is externally connected to the compression heat dryer 20; when the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa~8MPa, the raw gas multistage compressor 1 is a reciprocating compressor, The feed gas multi-stage compressor 1 is a four-stage compression, the fourth cooler 9 is externally connected to the compression heat dryer 20, or the fourth-stage air outlet 142 is externally connected to the compression heat dryer 20; when the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa~8MPa, and the feed gas multi-stage compressor 1 is a centrifugal compressor, the feed gas multi-stage compressor 1 is a five-stage compression, and the feed gas multi-stage compressor 1 includes a five-stage compression chamber 15, and the five-stage compression chamber 15 includes a five-stage air inlet 151 and a five-stage air outlet 152, and the system can also include a fifth cooler 21; the fourth-stage air outlet 142 is externally connected to the compression heat dryer 20, or the fourth-stage air outlet 142, the fifth cooler 21 and the fifth-stage air inlet 151 are connected in sequence, and the fifth-stage air outlet 152 is externally connected to the compression heat dryer 20.

[0042] It should be noted that, when the fourth cooler 9 is connected to the compression heat dryer 20, the fourth-stage compression chamber 14 can be connected to other heat exchangers or cold circulating water to lower the temperature. At this time, the unused heat can be utilized by connecting other devices in the embodiment of the utility model. Similarly, when the fourth cooler 9 is connected to the fourth-stage air inlet 141 and the fourth-stage air outlet 142 is connected to the compression heat dryer 20, the fifth-stage compression chamber 15 can also be connected to other devices to realize waste heat recovery and utilization, which is not specifically limited in the embodiment of the utility model.

[0043] In another alternative embodiment, referring to Figure 1 As shown, the above system may also include: a first regulating valve 22, a second regulating valve 23 and a third regulating valve 24; the first regulating valve 22 is located on the cold side fluid pipeline of the second cooler 4, the second regulating valve 23 is located on the cold side fluid pipeline of the third cooler 6, and the third regulating valve 24 is located on the cold side fluid pipeline of the fourth cooler 9.

[0044] In this embodiment, the second cooler after the above-mentioned secondary compression chamber is used to control the temperature of the raw gas entering the hydrolysis desulfurization tower. In this embodiment, a first regulating valve is set on the cold side fluid pipeline of the second cooler, and the temperature range required for hydrolysis desulfurization in the hydrolysis desulfurization tower is met by adjusting the first regulating valve. The purpose of the third cooler after the hydrolysis desulfurization tower is to reduce the temperature of the raw gas after hydrolysis to below 40°C. In this embodiment, a second regulating valve is set on the cold side fluid pipeline of the third cooler, and the outlet temperature is stabilized by the second regulating valve. The purpose of the fourth cooler after the food-grade fine desulfurization tower is to reduce the temperature of the raw gas after purification by the food-grade fine desulfurization tower to below 40°C. In this embodiment, a third regulating valve is set on the cold side fluid pipeline of the fourth condenser, and the outlet temperature is stabilized by the third regulating valve.

[0045] In another alternative embodiment, referring to Figure 1 As shown, the system may further include: a first pressure gauge 31 and a first thermometer 41, the first pressure gauge 31 and the first thermometer 41 are located on the pipeline between the primary air inlet 111 of the raw gas multi-stage compressor 1 and the carbon dioxide tail gas pipeline of the external upstream device. The first pressure gauge and the first thermometer in this embodiment are used to monitor the temperature and pressure of the raw gas entering the waste heat recovery system of the carbon dioxide capture.

[0046] In another alternative embodiment, referring to Figure 1 As shown, the system may further include: a second thermometer 42 and a third thermometer 43, which are respectively located on the pipelines on both sides of the first cooler 2. The second thermometer and the third thermometer in this embodiment are respectively used to monitor the raw gas temperature on the pipelines on both sides of the first cooler.

[0047] In another alternative embodiment, referring to Figure 1 As shown, the system may further include: a fourth thermometer 44 and a fifth thermometer 45, which are respectively located on the pipelines on both sides of the second cooler 4. The fourth thermometer and the fifth thermometer in this embodiment are respectively used to monitor the temperature of the raw gas on the pipelines on both sides of the second cooler, and adjust the first regulating valve on the fluid pipeline on the cold side of the second cooler based on the monitored temperature.

[0048] In another alternative embodiment, referring to Figure 1 As shown, the system may further include: a sixth thermometer 46, a seventh thermometer 47 and an eighth thermometer 48, the sixth thermometer 46 is located on the pipeline between the third cooler 6 and the fine desulfurization tower 7, the seventh thermometer 47 is located on the pipeline between the third-stage gas outlet 132 and the food-grade fine desulfurization tower 8, and the eighth thermometer 48 is located on the pipeline between the food-grade fine desulfurization tower 8 and the fourth-stage gas inlet 141. The sixth thermometer, the seventh thermometer and the eighth thermometer are respectively used to monitor the temperature of the raw gas on their pipelines, and can adjust the second regulating valve set on the cold side fluid pipeline of the third condenser according to the monitoring result of the sixth thermometer, and adjust the third regulating valve set on the cold side fluid pipeline of the fourth condenser according to the monitoring result of the eighth thermometer.

[0049] In another alternative embodiment, referring to Figure 1 As shown, when the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor 1 is a reciprocating compressor, the system may further include: a ninth thermometer 49, a tenth thermometer 50, an eleventh thermometer 51 and a second pressure gauge 32;

[0050] The ninth thermometer 49 is located on the pipeline between the fourth-stage air outlet 142 and the fifth cooler 21, the tenth thermometer 50 is located on the pipeline between the fifth cooler 21 and the fifth-stage air inlet 151, and the eleventh thermometer 51 and the second pressure gauge 32 are located on the pipeline between the fifth-stage air outlet 152 and the external compression heat dryer 20. The eleventh thermometer and the second pressure gauge are used to monitor the outlet temperature and pressure of the raw gas multi-stage compressor for adjustment of subsequent processes.

[0051] In another alternative embodiment, referring to Figure 1As shown, the system may further include: a compression heat dryer 20; when the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa~4MPa, and the raw gas multistage compressor 1 is a reciprocating compressor, the compression heat dryer 20 is connected to the fourth cooler 9; when the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa~4MPa, and the raw gas multistage compressor 1 is a centrifugal compressor, the compression heat dryer 20 is connected to the fourth cooler 9 or the fourth-stage air outlet 142; when the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa~8MPa, and the raw gas multistage compressor 1 is a reciprocating compressor, the compression heat dryer 20 is connected to the fourth cooler 9 or the fourth-stage air outlet 142; when the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa~8MPa, and the raw gas multistage compressor 1 is a centrifugal compressor, the compression heat dryer 20 is connected to the fourth-stage air outlet 142 or the fifth-stage air outlet 152. The purpose of the compression heat dryer in this embodiment is to dry the raw gas to a low dew point that meets the requirement for liquefaction of carbon dioxide.

[0052] In another alternative embodiment, referring to Figure 1 As shown, the compression heat dryer 20 is a double-tower dryer, including two drying towers 201, two heat exchangers 202, a heater 203, and a duct-type booster fan 204; the compression heat dryer 20 is used to dry the raw gas. In the drying process of this embodiment, the addition of a duct-type booster fan and an electric heater can make the system have no carbon dioxide emissions and no reflux, and improve the system carbon dioxide capture rate and the stability of the compression system.

[0053] The waste heat recovery system for carbon dioxide capture provided in the embodiment of the utility model has a streamlined process, stable operation, reliable system and high compression heat utilization rate, which reduces the energy consumption of the waste heat recovery system for carbon dioxide capture. The system is calculated on the basis of 100% carbon dioxide as the raw gas, and can save about 30kWh / t.CO2 power consumption by using compression heat alone, which can achieve the purpose of energy saving and emission reduction.

[0054] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. The present disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from its scope. The scope of the present disclosure is limited only by the appended claims. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A waste heat recovery system for carbon dioxide capture, characterized in that: include: Raw gas multi-stage compressor, first cooler, pre-desulfurization tower, second cooler, hydrolysis desulfurization tower, third cooler, fine desulfurization tower, food grade fine desulfurization tower and fourth cooler; Wherein, the raw gas multi-stage compressor includes a primary compression chamber, a secondary compression chamber, a tertiary compression chamber and a quaternary compression chamber, the primary compression chamber includes a primary air inlet and a primary air outlet, the secondary compression chamber includes a secondary air inlet and a secondary air outlet, the tertiary compression chamber includes a tertiary air inlet and a tertiary air outlet, and the quaternary compression chamber includes a quaternary air inlet and a quaternary air outlet; The primary air inlet is used for external connection to the carbon dioxide tail gas pipeline of the upstream device; the primary air outlet, the first cooler, the pre-desulfurization tower, and the secondary air inlet are connected in sequence, and the pre-desulfurization tower is used to remove hydrogen sulfide in the raw gas; the secondary air outlet, the second cooler, the hydrolysis desulfurization tower, the third cooler, the fine desulfurization tower and the tertiary air inlet are connected in sequence, the hydrolysis desulfurization tower is used to convert the organic sulfur in the raw gas into hydrogen sulfide, and the fine desulfurization tower is used to remove the hydrogen sulfide converted from the organic sulfur in the raw gas; the tertiary air outlet, the food-grade fine desulfurization tower, the fourth cooler and the fourth-stage air inlet are connected in sequence, and the food-grade fine desulfurization tower is used to remove impurities in the raw gas; the fourth-stage air outlet of the raw gas multi-stage compressor is used for external connection to a compression heat dryer.

2. The waste heat recovery system for carbon dioxide capture according to claim 1, characterized in that: The raw gas multi-stage compressor is a reciprocating compressor or a centrifugal compressor; When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa-4MPa, the raw gas multi-stage compressor is a reciprocating compressor, the raw gas multi-stage compressor is a three-stage compression, and the fourth cooler is externally connected to the compression heat dryer; When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5MPa-4MPa and the raw gas multi-stage compressor is a centrifugal compressor, the raw gas multi-stage compressor is a four-stage compression, and the four-stage gas outlet is externally connected to the compression heat dryer; When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a reciprocating compressor, the raw gas multi-stage compressor is a four-stage compression, the fourth cooler is externally connected to the compression heat dryer, or the fourth-stage air outlet is externally connected to the compression heat dryer; When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa~8MPa, and the raw gas multi-stage compressor is a centrifugal compressor, the raw gas multi-stage compressor is a five-stage compression, and the raw gas multi-stage compressor includes a five-stage compression chamber, and the five-stage compression chamber includes a five-stage air inlet and a five-stage air outlet, and the system also includes a fifth cooler; the fourth-stage air outlet is externally connected to the compression heat dryer, or the fourth-stage air outlet, the fifth cooler and the fifth-stage air inlet are connected in sequence, and the fifth-stage air outlet is externally connected to the compression heat dryer.

3. The waste heat recovery system for carbon dioxide capture according to claim 2, characterized in that: The system further comprises: a first regulating valve, a second regulating valve and a third regulating valve; The first regulating valve is located on the cold-side fluid pipeline of the second cooler, the second regulating valve is located on the cold-side fluid pipeline of the third cooler, and the third regulating valve is located on the cold-side fluid pipeline of the fourth cooler.

4. The waste heat recovery system for carbon dioxide capture according to claim 2, characterized in that: The system further comprises: a first pressure gauge and a first thermometer, wherein the first pressure gauge and the first thermometer are located on a pipeline between a first-stage air inlet of the raw gas multi-stage compressor and a carbon dioxide tail gas pipeline of an external upstream device.

5. The waste heat recovery system for carbon dioxide capture according to claim 2, characterized in that: The system further includes: a second thermometer and a third thermometer, wherein the second thermometer and the third thermometer are respectively located on pipelines on both sides of the first cooler.

6. The waste heat recovery system for carbon dioxide capture according to claim 2, characterized in that: The system further includes: a fourth thermometer and a fifth thermometer, wherein the fourth thermometer and the fifth thermometer are respectively located on pipelines on both sides of the second cooler.

7. The waste heat recovery system for carbon dioxide capture according to claim 2, characterized in that: The system also includes: a sixth thermometer, a seventh thermometer and an eighth thermometer, the sixth thermometer is located on the pipeline between the third cooler and the fine desulfurization tower, the seventh thermometer is located on the pipeline between the third-level air outlet and the food-grade fine desulfurization tower, and the eighth thermometer is located on the pipeline between the food-grade fine desulfurization tower and the fourth-level air inlet.

8. The waste heat recovery system for carbon dioxide capture according to claim 2, characterized in that: When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a reciprocating compressor, the system further includes: a ninth thermometer, a tenth thermometer, an eleventh thermometer and a second pressure gauge; The ninth thermometer is located on the pipeline between the fourth-stage air outlet and the fifth cooler, the tenth thermometer is located on the pipeline between the fifth cooler and the fifth-stage air inlet, and the eleventh thermometer and the second pressure gauge are located on the pipeline between the fifth-stage air outlet and the external compression heat dryer.

9. The waste heat recovery system for carbon dioxide capture according to any one of claims 2 to 8, characterized in that: The system also includes: a heat of compression dryer; When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5 MPa to 4 MPa and the raw gas multi-stage compressor is a reciprocating compressor, the compression heat dryer is connected to the fourth cooler; When the working pressure of the waste heat recovery system for carbon dioxide capture is 2.5 MPa to 4 MPa and the raw gas multi-stage compressor is a centrifugal compressor, the compression heat dryer is connected to the fourth-stage gas outlet; When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a reciprocating compressor, the compression heat dryer is connected to the fourth cooler or the fourth-stage gas outlet; When the working pressure of the waste heat recovery system for carbon dioxide capture is 4MPa-8MPa and the raw gas multi-stage compressor is a centrifugal compressor, the compression heat dryer is connected to the fourth-stage air outlet or the fifth-stage air outlet.

10. The waste heat recovery system for carbon dioxide capture according to claim 9, characterized in that: The compression heat dryer is a double-tower dryer, comprising two drying towers, two heat exchangers, a heater, and a ducted booster fan; The compression heat dryer is used to dry the raw gas.

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