Desorption tower kettle liquid waste heat utilization system based on absorption heat pump principle

Through the waste heat utilization system based on the principle of absorption heat pump, the low-grade heat source of the desorption tower kettle liquid is recovered, and the problem of low heat utilization efficiency in the existing technology is solved, efficient heat recovery and utilization is achieved, and steam consumption is reduced.

CN223299783UActive Publication Date: 2025-09-05SHUANGLIANG ECO ENERGY SYST CO LTD
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Patent Information

Application Number
CN202422417280.8
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-10-08
Publication Date
2025-09-05
Estimated Expiration
2034-10-08

AI Technical Summary

Technical Problem

In the prior art, the low-grade heat source of the desorption tower kettle liquid is not effectively utilized, resulting in low heat utilization efficiency during carbon capture, and latent heat is required for the evaporation of the liquid phase at the bottom of the desorption tower. The prior art fails to effectively recover and utilize this part of the heat.

Method used

The waste heat utilization system based on the principle of absorption heat pump is adopted, including a desorption tower, waste heat utilization device, tower kettle liquid circulation circuit and amine-lean liquid circulation circuit. The waste heat of the amine-lean liquid is recovered through the absorption heat pump device, and the tower kettle material is heated using a low-grade heat source to replace the high-temperature heat source of the tower bottom reboiler to reduce steam consumption.

Benefits of technology

The recycling and utilization of waste heat of amine-depleted liquid is achieved, the consumption of circulating water is reduced, the process steam consumption of the reboiler at the bottom of the desorption tower is reduced, and the heat utilization efficiency is improved.

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Abstract

The utility model discloses a desorption tower kettle liquid waste heat utilization system based on an absorption heat pump principle, which is characterized in that a tower kettle liquid circulation loop comprises a first material pipe led out from a desorption tower kettle, and the first material pipe is used as a heated high-grade heat source and is connected to a waste heat utilization device; the waste heat flows out of the waste heat utilization device and is connected to the tower kettle through a second material pipe to form a closed loop; the barren amine liquid circulation loop comprises a barren liquid pipeline for pumping materials from the tower kettle of the desorption tower to the tower top of the absorption tower, and the barren liquid pipeline comprises a third material pipe entering the waste heat utilization device and a fourth material pipe flowing out of the waste heat utilization device. According to the desorption tower kettle liquid waste heat utilization system, on one hand, waste heat of lean amine liquid is recycled, the use amount of circulating water is reduced, on the other hand, low-grade heat sources in the lean amine liquid are recycled, materials in a desorption tower kettle are heated, low-grade waste heat is used for replacing a high-temperature heat source of a tower bottom reboiler through the waste heat recovery device, and the desorption tower kettle liquid waste heat utilization efficiency is improved. The process steam consumption of the reboiler at the bottom of the desorption tower is reduced, and a large amount of steam is saved.
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Description

Technical Field

[0001] The utility model relates to the technical field of waste heat utilization, in particular to a desorption tower kettle liquid waste heat utilization system based on the absorption heat pump principle. Background Art

[0002] CCUS (Carbon Capture, Utilization and Storage) refers to a combination of technologies used to reduce carbon dioxide emissions from the atmosphere. These technologies can be divided into several stages:

[0003] Carbon Capture: In this phase, carbon dioxide is captured from industrial processes or directly from the air. Typically, this is achieved through methods such as chemical absorption, physical adsorption, or membrane separation.

[0004] Carbon Utilization: The captured CO2 can be used as a feedstock to make chemicals, fuels, or other products. It can also be used for enhanced oil recovery (EOR), which is to increase oil production by injecting CO2 into underground reservoirs.

[0005] Carbon Storage: Unused CO2 can be stored long-term in suitable geological formations, such as depleted oil and gas fields or deep saline aquifers, to ensure it is not released back into the atmosphere.

[0006] For the carbon capture stage, an absorption tower and a desorption tower are usually used, such as Figure 1 As shown, CO2-rich gas enters the bottom of the absorption tower, and lean amine liquid is sprayed from top to bottom as the absorption liquid, absorbing the CO2 and converting it into rich amine liquid. This is then transported to the desorption tower for desorption and circulation. After the lean amine liquid at the bottom of the desorption tower undergoes heat exchange in the lean-rich amine heat exchanger, it still retains low-grade heat at approximately 60°C before entering the lean amine cooler. In existing technology, this heat is directly cooled to approximately 40°C in the lean liquid cooler before being fed into the absorption tower. This heat is then carried into the circulating water, preventing further recycling and resulting in very low heat utilization efficiency during the carbon capture process. Research on energy-saving technologies in carbon capture processes should be given priority. During carbon capture, the lean liquid cooler removes low-grade heat, while the evaporation of the liquid phase at the bottom of the desorption tower requires latent heat. Combined with the working principle of heat pumps, heat pump technology is clearly a very suitable energy-saving technology for this process, significantly improving energy utilization and economic efficiency during carbon capture.

[0007] In view of the above, it is necessary to propose a waste heat utilization system for the intermediate liquid at the top of the desorption tower to solve the above problems. Utility Model Content

[0008] The purpose of the utility model is to overcome the defects in the prior art and provide a desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle.

[0009] To achieve the above-mentioned purpose, the technical solution of the present invention is as follows: a desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle, comprising a desorption tower, a waste heat utilization device, a tower bottom liquid circulation loop, and a lean amine liquid circulation loop;

[0010] The tower bottom liquid circulation loop includes a first material pipe drawn from the desorption tower bottom as a high-grade heat source to be heated and connected to the waste heat utilization device, and flows out from the waste heat utilization device and is connected to the tower bottom through a second material pipe to form a closed loop;

[0011] The lean amine liquid circulation loop includes a lean liquid pipeline that pumps material from the bottom of the desorption tower to the top of the absorption tower. The lean liquid pipeline includes a third material pipe entering the waste heat utilization device and a fourth material pipe flowing out of the waste heat utilization device.

[0012] Furthermore, the waste heat utilization device is an absorption heat pump device, which includes an absorber, a generator, a condenser, and an evaporator; a solvent circulation loop is formed between the absorber and the generator, and a solution pump is provided on the solvent circulation loop; the generator is connected to the condenser and is provided with a first gas pipeline; the condenser is connected to the evaporator and is provided with a throttling pipeline, and a throttling valve is provided on the throttling pipeline; the evaporator is connected to the absorber and is provided with a second gas pipeline; the generator is connected to a driving heat source pipeline.

[0013] Furthermore, the waste heat utilization device includes multiple groups of absorption heat pump devices arranged in parallel, the first material pipeline forms multiple branches and is respectively connected to the W1 pipeline of the absorption heat pump device to introduce into the absorber, connected to the condenser through the W2 pipeline, and connected to the second material pipe through the W3 pipeline; the third material pipe enters the evaporator through the W4 pipeline and flows out through the W5 pipeline.

[0014] Furthermore, the waste heat utilization device includes two groups of absorption heat pump devices, which are divided into a primary heat pump and a secondary heat pump, and an intermediate heat medium circulation loop is provided between the primary heat pump and the secondary heat pump.

[0015] Furthermore, the first material pipe is provided with a first branch pipe and a second branch pipe, the first branch pipe is connected to the absorber or condenser of the first-stage heat pump, the second branch pipe is connected to the second-stage heat pump and passes through the absorber and condenser in sequence, the two branch pipes converge and are connected to the second material pipe, and the third material pipe is connected to the evaporator of the first-stage heat pump.

[0016] Furthermore, the intermediate heat medium circulation loop is connected to the primary heat pump and the absorber or condenser different from the first branch pipe through the H1 pipeline. The intermediate heat medium circulation loop flows out of the primary heat pump through the H2 pipeline and is connected to the evaporator of the secondary heat pump, and flows back to the H1 pipeline from the secondary heat pump evaporator.

[0017] Furthermore, a heat medium circulation pump is provided on the H1 pipeline or the H2 pipeline.

[0018] Furthermore, a cross-line pipe is provided between the third material pipe and the fourth material pipe, and a cross-line regulating valve is provided on the cross-line pipe.

[0019] The advantages and beneficial effects of the utility model are as follows: the utility model is a desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle, which, on the one hand, recovers the waste heat of the lean amine liquid and reduces the amount of circulating water used; on the other hand, it recovers the low-grade heat source in the lean amine liquid to heat the desorption tower bottom material, and utilizes the low-grade waste heat through the waste heat recovery device to replace the high-temperature heat source of the bottom reboiler, thereby reducing the process steam consumption of the desorption tower bottom reboiler and saving a lot of steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the basic flow chart of carbon dioxide absorption and desorption in the prior art;

[0021] Figure 2 This is a simplified flow chart of waste heat utilization in the utility model;

[0022] Figure 3 This is a schematic diagram of the working medium flow direction of the waste heat utilization device of the utility model;

[0023] Figure 4 This is a detailed flow chart of waste heat utilization in the utility model;

[0024] Figure 5 This is a schematic diagram of the working medium flow of multiple absorption heat pumps in Example 2 of the present utility model;

[0025] Figure 6 This is a schematic diagram of the working medium flow of multiple absorption heat pumps in Example 3 of the present utility model;

[0026] Figure 1: Desorption tower; 2: Absorption tower; 3: Rich amine solution; 4: Lean amine solution; 5: Lean and rich amine solution heat exchanger; 6: Lean solution cooler; 7: Waste heat utilization device; 8: Tower bottom liquid circulation loop; 9: Lean amine solution circulation loop; 10: First material pipe; 11: Second material pipe; 12: Lean solution pipeline; 13: Third material pipe; 14: Fourth material pipe; 15: Absorber; 16: Generator; 17: Condenser; 18: Evaporator; 19: Solvent circulation loop; 20: Solution pump ; 21. First gas pipeline; 22. Throttle valve; 23. Second gas pipeline; 24. Driving heat source; 25. W1 pipeline; 26. W2 pipeline; 27. W3 pipeline; 28. W4 pipeline; 29. ​​W5 pipeline; 30. Primary heat pump; 31. Secondary heat pump; 32. Intermediate heat medium circulation loop; 33. First branch pipe; 34. Second branch pipe; 35. H1 pipeline; 36. H2 pipeline; 37. Heat medium circulation pump; 38. Cross-line pipe; 39. Cross-line regulating valve. DETAILED DESCRIPTION

[0027] The following embodiments are used to further describe the specific embodiments of the present invention in conjunction with the accompanying drawings and examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] The purpose of the carbon dioxide capture process is to recover the carbon dioxide in the exhaust gas of the self-owned power plant, realize the capture of carbon dioxide, realize the recovery value, and reduce carbon emissions. The basic process is as follows: Figure 1 As shown, it is carried out by chemical absorption method, which means that chemical solvent absorbs carbon dioxide by chemical reaction with CO2. When external conditions such as temperature or pressure change, the reaction is reversed, thereby achieving the purpose of carbon dioxide analysis and recycling of absorbent. Figure 1 As shown in the figure, after desulfurization and denitrification, the flue gas enters absorption tower 2 from the bottom through an induced draft fan. At the same time, absorption liquid is sprayed down from the top of absorption tower 2. The flue gas and absorption liquid come into contact in absorption tower 2 and react. The absorption liquid absorbs the CO2 in the flue gas and becomes a rich liquid containing a large amount of CO2. The rich liquid passes through a rich liquid pump and reaches desorption tower 1. In desorption tower 1, it is heated to 100 to 120°C by a reboiler, causing the rich liquid to decompose and release the CO2 absorbed in the flue gas, ultimately achieving the separation and recovery of carbon dioxide. As the lean amine liquid 4 flows from the bottom of desorption tower 1 to absorption tower 2, it passes through two heat exchangers: first, the lean-rich amine liquid heat exchanger 3, and then the lean liquid cooler 6. The lean-rich amine liquid heat exchanger 3 exchanges heat between low-temperature and high-temperature amine liquids, which is conducive to heat recovery. However, the lean liquid cooler 6 directly uses internal cooling water to cool the lean amine liquid 4 from approximately 60°C to approximately 40°C. In this process, a large amount of heat energy is not effectively utilized.

[0029] Example 1:

[0030] A desorption tower 1 kettle liquid waste heat utilization system based on the absorption heat pump principle, comprising a desorption tower 1, a waste heat utilization device 7, a tower kettle liquid circulation loop 8, and a lean amine liquid 4 circulation loop; Figure 2 、 3 As shown, the bottom liquid circulation loop 8 includes a first material pipe 10 drawn from the bottom of the desorption tower 1 as a high-grade heat source to be heated and connected to the waste heat utilization device 7, flowing out of the waste heat utilization device 7 and connected to the bottom of the tower through a second material pipe 11 to form a closed loop; in this embodiment, the bottom liquid temperature is about 110°C; the lean amine liquid 4 circulation loop includes a lean liquid pipeline 12 that pumps material from the bottom of the desorption tower 1 to the top of the absorption tower 2, and the lean liquid pipeline 12 includes a third material pipe 13 entering the waste heat utilization device 7 and a fourth material pipe 14 flowing out of the waste heat utilization device 7. It can be understood that, in combination with the attached Figure 1 In this embodiment, the third material pipe 13 is a pipeline leading out after the heat exchanger of the lean and rich amine liquid 3, wherein the material temperature is about 60°C. The lean amine liquid 4 is a low-grade heat source. The low-grade heat source enters the waste heat utilization device 7 and recovers the heat through the waste heat utilization device 7 to heat the high-grade heat source - the bottom liquid of the desorption tower 1, thereby realizing the effective utilization of the low-grade heat source and improving the thermal efficiency. A cross-line pipe 38 is provided between the third material pipe 13 and the fourth material pipe 14. The cross-line regulating valve 39 is provided on the cross-line pipe 38. The cross-line pipe 38 can adjust the flow of the low-grade heat source entering the waste heat utilization device 7, playing a fine adjustment role. It can also be used to isolate the waste heat utilization device 7 from the original carbon dioxide capture process, so that the system top condenser 17 can achieve its original function, which is conducive to meeting the requirements of the initial start-up of the system and the need for standby use in the later operation.

[0031] Specifically, such as Figure 3As shown, the waste heat utilization device 7 is an absorption heat pump device, which includes an absorber 15, a generator 16, a condenser 17, and an evaporator 18; a solvent circulation loop 19 is formed between the absorber 15 and the generator 16, and a solution pump 20 is provided on the solvent circulation loop 19; the working fluid used in the absorption heat pump device is a lithium bromide aqueous solution, the absorber 15 contains a dilute lithium bromide solution, the generator 16 contains a concentrated lithium bromide solution, and the lithium bromide solution is circulated between the absorber 15 and the generator 16 by the solution pump 20; the generator 16 is connected to the condenser 17 and is provided with a first gas pipeline 21; the generator 16 is connected to a driving heat source 24 pipeline, and the driving heat source 24 in this embodiment can be 1.0MPaG saturated steam is used as the drive, and 0.3MPaG saturated steam can also be used for driving. The steam heats the solution in the generator 16, causing the water therein to evaporate and enter the condenser 17 through the first gas pipeline 21. Water is used as the refrigerant, and condensation in the condenser 17 releases heat to heat the medium passing through the condenser 17; the condenser 17 is connected to the evaporator 18 and is provided with a throttling pipeline, and a throttle valve 22 is provided on the throttle pipeline. Water enters the evaporator 18 through the throttle valve 22 to evaporate and take away the heat of the passing medium; the evaporator 18 is connected to the absorber 15 and is provided with a second gas pipeline 23. The water vapor formed in the evaporator 18 returns to the absorber 15 through the second gas pipeline 23, forming a closed-loop absorption heat pump device.

[0032] In this embodiment, the waste heat utilization device 7 includes multiple groups of absorption heat pump devices arranged in parallel. Multiple groups of absorption heat pump devices can be set, such as Figure 2 Components 3-6 shown in the embodiment, this embodiment takes four groups of absorption heat pump devices arranged in parallel as an example, specifically, the first material pipe 10 forms multiple branches and is respectively connected to the W1 pipe 25 of the absorption heat pump device to introduce it into the absorber 15, specifically, the first material pipe 10 is divided into four branches, corresponding to the four groups of absorption heat pump devices, each device is introduced into the absorber 15 through the corresponding W1 pipe 25, as shown Figure 3 As shown, after flowing out of the absorber 15, it is connected to the condenser 17 through the W2 pipeline 26, and finally connected to the second material pipe 11 through the W3 pipeline 27. Therefore, it can be understood that the bottom liquid is forced to circulate and pumped into the four absorption heat pump devices by the bottom liquid circulation pump, and each group of devices is heated by the two stages of the absorber 15 and the condenser 17 to realize the utilization of low-grade thermal energy. Specifically, Figure 2As shown, the temperature of the liquid outlet from the bottom of the tower is 108°C. After heating, the temperature rises to 115°C and is sent back to the desorption tower 1, thereby reducing the heat load of the reboiler in the bottom of the desorption tower 1 and reducing steam usage. Furthermore, after the low-grade heat source passes through the heat exchanger for the lean and rich amine liquid 3, it enters the evaporator 18 through the third material pipe 13 via the W4 pipeline 28 and flows out through the W5 pipeline 29. The lean amine liquid 4 passes through the evaporator 18, and the water evaporates inside the evaporator, removing the heat of the low-grade heat source lean amine liquid 4, reducing the lean amine liquid 4 from 61°C to approximately 56°C. This can also simultaneously reduce the cooling load of the lean liquid cooler 6 and reduce the consumption of circulating water.

[0033] Energy-saving technical indicators:

[0034] Rated operating system parameters:

[0035] System heating capacity: 100.44MW - equivalent to 162t / h of 0.3MPaG saturated steam and 158.67t / h of 1.0MPaG saturated steam; waste heat recovery capacity is 30MW, approximately 47.39t / h of 1.0MPaG saturated steam.

[0036] Driving steam: 1.0MPaG saturated steam, consumption 111.28t / h, steam condensate temperature 120℃;

[0037] Intermediate liquid: flow rate 4000t / h, temperature 101→109.93℃;

[0038] Bottom liquid: temperature 108→115℃ (same as reboiler operating conditions), flow rate is about 7580t / h;

[0039] Desorption tower top steam: temperature 88→70℃, 17MW

[0040] Lean amine liquid: temperature 61→56℃, heat load 14.75MW, flow rate 2674t / h, flow rate share about 70.4%;

[0041] Reduce circulating water consumption: 3225t / h (according to 30→38℃), and reduce cooling tower water replenishment by an average of 45t / h;

[0042] System consumption: approximately 1600kW; (This is an estimated value. The selection parameters of the tower bottom liquid can only be determined after the physical properties are determined.)

[0043] Table 1 Main operating parameters before and after energy-saving transformation

[0044]

[0045] Economic benefit analysis:

[0046] Table 2 Economic Benefit Analysis Calculation Table (1 million tons / year CCUS)

[0047]

[0048] Example 2:

[0049] In Example 1, multiple groups of absorption heat pump devices are provided, and the lean amine liquid 4 needs to be divided into corresponding multiple branch pipes connected to each heat pump device. This results in the lean amine liquid 4 process medium coming out of the desorption tower 1 being divided into multiple fine branches, which can easily lead to an increase in the transportation resistance of the process medium to the top of the absorption tower 2; and at the same time, the process medium being divided into multiple fine branches will also increase the risk of pipeline leakage.

[0050] As an improvement, the waste heat utilization device 7 includes two groups of absorption heat pump devices, which are divided into a primary heat pump 30 and a secondary heat pump 31. An intermediate heat medium circulation loop 32 is provided between the primary heat pump 30 and the secondary heat pump 31. Figure 4 、 5 As shown, the first branch pipe 33 and the second branch pipe 34 branched from the first material pipe 10 are arranged in parallel, and the two branch pipes are connected to two heat pumps respectively.

[0051] The difference is that, Figure 5 As shown, the first branch pipe 33 is connected to the condenser 17 of the first-stage heat pump 30, the second branch pipe 34 is connected to the second-stage heat pump 31, and passes through the absorber 15 and the condenser 17 in sequence. Finally, the two branch pipes converge and are connected to the second material pipe 11, and flow back into the desorption tower 1; the third material pipe 13 is connected to the evaporator 18 of the first-stage heat pump 30. In this embodiment, the low-grade heat source is only connected to the first-stage heat pump 30 and is not connected to other absorption heat pump devices, so that the process medium of the lean amine liquid 4 can be concentrated to flow through the first-stage heat pump 30, so that the process pipeline of the desorption tower 1 kettle is simplified, and the load of the desorption tower 1 kettle pump can be reduced, so that the transportation resistance of the lean amine liquid 4 is reduced.

[0052] Specifically, the intermediate heat medium circulation loop 32 is connected to the absorber 15 of the primary heat pump 30 via the H1 pipeline 35. Since the condenser 17 in the primary heat pump 30 is connected to the first branch pipe 33, the H1 pipeline 35 is distributed to the absorber 15. The intermediate heat medium circulation loop 32 flows out of the primary heat pump 30 via the H2 pipeline 36 and is connected to the evaporator 18 of the secondary heat pump 31. From the evaporator 18 of the secondary heat pump 31, it flows back to the H1 pipeline 35, thus forming the intermediate heat medium circulation loop 32. The H1 pipeline 35 or the H2 pipeline 36 is provided with a heat medium circulation pump 37, which circulates the intermediate heat medium between the different heat pumps to transfer heat. In this way, the heat of the low-quality heat source of the lean amine liquid 4 is distributed to the secondary heat pump 31, and is used as the low-quality heat source in the secondary heat pump 31. This configuration avoids the disadvantages of high transportation resistance and leakage risk caused by the complicated separation of the lean amine liquid 4 pipeline in the bottom of the desorption tower 1.

[0053] Example 3:

[0054] As another embodiment, this embodiment is substantially the same as the second embodiment, except that: Figure 6 As shown, the first branch pipe 33 is connected to the absorber 15 of the primary heat pump 30, the second branch pipe 34 is connected to the secondary heat pump 31, and passes through the absorber 15 and the condenser 17 in sequence. Finally, the two branch pipes converge and are connected to the second material pipe 11, and flow back into the desorption tower 1; the third material pipe 13 is connected to the evaporator 18 of the primary heat pump 30, and the intermediate heat medium circulation loop 32 is connected to the condenser 17 of the primary heat pump 30 through the H1 pipeline 35. The intermediate heat medium circulation loop 32 flows out of the primary heat pump 30 through the H2 pipeline 36 and is connected to the evaporator 18 of the secondary heat pump 31, and flows back to the H1 pipeline 35 from the evaporator 18 of the secondary heat pump 31, thus forming the intermediate heat medium circulation loop 32.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle, characterized in that: It includes a desorption tower (1), a waste heat utilization device (7), a tower bottom liquid circulation loop (8), and a lean amine liquid (4) circulation loop; The tower bottom liquid circulation loop (8) includes a first material pipe (10) drawn from the tower bottom of the desorption tower (1) as a high-grade heat source to be heated and connected to the waste heat utilization device (7), and flows out of the waste heat utilization device (7) and is connected to the tower bottom through a second material pipe (11) to form a closed loop; The lean amine liquid (4) circulation loop comprises a lean liquid pipeline (12) for pumping material from the bottom of the desorption tower (1) to the top of the absorption tower (2), and the lean liquid pipeline (12) comprises a third material pipe (13) entering the waste heat utilization device (7) and a fourth material pipe (14) flowing out of the waste heat utilization device (7).

2. The desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle according to claim 1 is characterized in that: The waste heat utilization device (7) is an absorption heat pump device, which includes an absorber (15), a generator (16), a condenser (17), and an evaporator (18); a solvent circulation loop (19) is formed between the absorber (15) and the generator (16), and a solution pump (20) is provided on the solvent circulation loop (19); the generator (16) is connected to the condenser (17) and is provided with a first gas pipeline (21); the condenser (17) is connected to the evaporator (18) and is provided with a throttling pipeline, and a throttling valve (22) is provided on the throttling pipeline; the evaporator (18) is connected to the absorber (15) and is provided with a second gas pipeline (23); and the generator (16) is connected to a driving heat source (24) pipeline.

3. The desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle according to claim 2 is characterized in that: The waste heat utilization device (7) includes a plurality of absorption heat pump devices arranged in parallel, wherein the first material pipe (10) forms a plurality of branches and is respectively connected to the W1 pipe (25) of the absorption heat pump device to be introduced into the absorber (15), connected to the condenser (17) through the W2 pipe (26), and connected to the second material pipe (11) through the W3 pipe (27); the third material pipe (13) enters the evaporator (18) through the W4 pipe (28) and flows out through the W5 pipe (29).

4. The desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle according to claim 2 is characterized in that: The waste heat utilization device (7) comprises two groups of absorption heat pump devices, which are divided into a primary heat pump (30) and a secondary heat pump (31). An intermediate heat medium circulation loop (32) is provided between the primary heat pump (30) and the secondary heat pump (31).

5. The desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle according to claim 4 is characterized in that: The first material pipe (10) is provided with a first branch pipe (33) and a second branch pipe (34). The first branch pipe (33) is connected to the absorber (15) or the condenser (17) of the primary heat pump (30). The second branch pipe (34) is connected to the secondary heat pump (31) and passes through the absorber (15) and the condenser (17) in sequence. The two branch pipes converge and are connected to the second material pipe (11). The third material pipe (13) is connected to the evaporator (18) of the primary heat pump (30).

6. The desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle according to claim 5 is characterized in that: The intermediate heat medium circulation loop (32) is connected to the primary heat pump (30) and the absorber (15) or condenser (17) different from the first branch pipe (33) through the H1 pipeline (35). The intermediate heat medium circulation loop (32) flows out of the primary heat pump (30) through the H2 pipeline (36) and is connected to the evaporator (18) of the secondary heat pump (31), and flows back to the H1 pipeline (35) from the evaporator (18) of the secondary heat pump (31).

7. The desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle according to claim 6 is characterized in that: A heat medium circulation pump (37) is provided on the H1 pipeline (35) or the H2 pipeline (36).

8. The desorption tower bottom liquid waste heat utilization system based on the absorption heat pump principle according to claim 1 is characterized in that: A cross-line pipe (38) is provided between the third material pipe (13) and the fourth material pipe (14), and a cross-line regulating valve (39) is provided on the cross-line pipe (38).