Second-type ammonia-water two-stage synergic absorption-reabsorption heat pump system with pressure reduction and temperature increase

Abstract

The application relates to a second type of pressure-reducing and temperature-increasing ammonia water two-stage synergic absorption-reabsorption type heat pump system, which comprises a reabsorber (1), a first-stage resolver (2), a first-stage absorber (3), a first-stage generator (4), a second-stage resolver (5), a second-stage absorber (6), a second-stage generator (7) and a solution heat exchanger; the first-stage resolver and the first-stage absorber, the second-stage resolver and the second-stage absorber, the first-stage generator and the second-stage generator and the reabsorber are connected through steam pipelines (17); the first-stage absorber and the second-stage generator and the second-stage resolver are connected through intermediate heat exchange pipelines (12); the absorption heat released by the first-stage absorber is simultaneously provided to the resolver and the generator of the second-stage cycle through the intermediate heat exchange pipelines, a greater temperature rising range is realized, and the operation pressure of the ammonia water two-stage heat pump system is effectively reduced through the reabsorption cycle.

Description

TECHNICAL FIELD

[0001] The application relates to a second-type ammonia water two-stage synergic absorption-reabsorption type heat pump system with pressure reduction and temperature increase, and belongs to the technical field of heat pumps. BACKGROUND

[0002] Energy is an important cornerstone of economic development and social progress, China is a big energy consumer, and nearly half of the energy consumed by high-energy-consuming industries such as electric power, steel, cement, glass, non-ferrous metal, petroleum chemical industry is discharged into the environment in the form of waste heat, waste water and waste residue liquid. These industrial waste heat, especially low-grade waste heat at 100 DEG C, is difficult to effectively utilize, and has great energy-saving potential. Using an absorption heat pump to recover waste heat is an effective means, which can significantly improve energy utilization and reduce primary energy consumption, and is of great significance for energy saving and emission reduction.

[0003] However, in the actual application of the traditional second-type ammonia water absorption heat pump, since the external provided parameter conditions are not fixed, sometimes the temperature of waste heat is relatively low, or the user end has a relatively high demand for the heat temperature, which requires the system to have a large temperature rise range. The ordinary single-stage second-type ammonia water absorption heat pump cannot meet the requirements, and therefore a two-stage heat pump is needed to increase the temperature to the user demand. At the same time, a higher absorption temperature brings a higher absorption pressure, and high-pressure operation requires more solid and complex components, which increases the system cost. How to reduce the operating pressure under the primary goal of increasing the absorption temperature and simplify the structure of the heat pump system as much as possible is one of the important research topics at present. SUMMARY

[0004] Technical problem: The purpose of the application is to solve the technical problem of the traditional second-type ammonia water absorption heat pump, and provide a second-type ammonia water two-stage synergic absorption-reabsorption type heat pump system with pressure reduction and temperature increase. The system is driven by waste heat to circulate and increase the temperature to a higher level, and the reabsorption cycle is used to reduce the operating pressure, thereby reducing the strength requirement of the system components.

[0005] Technical scheme: In order to achieve the above purpose, the application solves a second-type ammonia water two-stage synergic absorption-reabsorption type heat pump system with pressure reduction and temperature increase, which is as follows:

[0006] The heat pump system comprises a resorber, a first desorber, a first absorber, a first generator, a second desorber, a second absorber, a second generator and a solution heat exchanger; the output end of the resorber is connected with the input end of the first desorber and the second desorber through liquid discharge pipelines respectively, and the output end of the first desorber and the second desorber is connected with the input end of the resorber through liquid discharge pipelines respectively; the output end of the first generator is connected with the input end of the first absorber through a liquid discharge pipeline, and the output end of the first absorber is connected with the input end of the first generator through a liquid feed pipeline; the output end of the second generator is connected with the input end of the second absorber through a liquid discharge pipeline; and the output end of the second absorber is connected with the input end of the second generator through a liquid feed pipeline.

[0007] The steam port of the first desorber is connected with the steam port of the first absorber through a steam pipeline; the steam port of the second desorber is connected with the steam port of the second absorber through a steam pipeline; and the steam port of the first generator and the second generator is connected with the steam port of the resorber through a steam pipeline.

[0008] The heat pump system further comprises three intermediate heat exchange pipelines, the first pipeline connecting the heat exchange end outlet of the first absorber with the heat exchange end inlet of the second generator, the second pipeline connecting the heat exchange end outlet of the second generator with the heat exchange end inlet of the second desorber, and the third pipeline connecting the heat exchange end outlet of the second desorber with the heat exchange end inlet of the first absorber.

[0009] The liquid discharge pipelines are each provided with a solution pump.

[0010] The liquid feed pipelines are each provided with a throttle valve.

[0011] The third solution heat exchanger is arranged between the resorber and the second desorber, the first solution heat exchanger is arranged between the resorber and the first desorber, the second solution heat exchanger is arranged between the first absorber and the first generator, and the fourth solution heat exchanger is arranged between the second absorber and the second generator.

[0012] The operation method of the ammonia water solution and the refrigerant vapor pipeline is as follows: the ammonia water in the low-pressure reabsorber absorbs the ammonia gas from the primary generator and the secondary generator, releases heat to the environment at 8-12 DEG C, a part of the ammonia water with increased concentration generated is pressurized by a solution pump and preheated by a solution heat exchanger, and then is sent to the medium-pressure primary desorber for desorption; the ammonia water solution absorbs the industrial waste heat or other low-grade heat at 70-110 DEG C in the primary desorber, the ammonia and water mixed vapor generated is separated by the separation section of the primary desorber, the high-purity ammonia gas enters the primary absorber; the ammonia water in the primary absorber absorbs the medium-pressure ammonia gas from the primary desorber, releases heat to the intermediate heat exchange pipeline, the ammonia water with increased concentration generated is reduced in pressure by a solution heat exchanger and a throttle valve, and then is sent to the low-pressure primary generator; the ammonia water solution absorbs the industrial waste heat or other low-grade heat at 70-110 DEG C in the primary generator, the ammonia and water mixed vapor generated is separated by the separation section of the primary generator, the high-purity ammonia gas enters the reabsorber and is absorbed by the ammonia water in the reabsorber; another part of the ammonia water with increased concentration generated by the low-pressure reabsorber is pressurized by a solution pump and preheated by a solution heat exchanger, and then is sent to the high-pressure secondary desorber for desorption; the ammonia water solution absorbs the heat of the intermediate heat exchange pipeline in the secondary desorber, the ammonia and water mixed vapor generated is separated by the separation section of the secondary desorber, the high-purity ammonia gas enters the secondary absorber; the ammonia water in the secondary absorber absorbs the high-pressure ammonia gas from the secondary desorber, and releases the high-temperature useful heat at 130-170 DEG C, the ammonia water with increased concentration generated is reduced in pressure by a solution heat exchanger and a throttle valve, and then is sent to the low-pressure secondary generator; the ammonia water solution absorbs the heat of the intermediate heat exchange pipeline in the secondary generator, the ammonia and water mixed vapor generated is separated by the separation section of the secondary generator, the high-purity ammonia gas enters the reabsorber and is absorbed by the ammonia water in the reabsorber.

[0013] Advantages: compared with the prior art, the application has the following advantages:

[0014] The application discloses a second-type ammonia water two-stage collaborative absorption-reabsorption type heat pump system with pressure reduction and temperature increase, which simultaneously provides the desorber and the generator of the secondary cycle with the absorption heat released by the primary absorber, improves the driving heat source temperature of the secondary cycle, and further realizes higher waste heat temperature increase. In addition, the reabsorption cycle is adopted, the reabsorber is used to replace the condenser of the traditional system, and the desorber is used to replace the evaporator of the traditional system, so that the operation pressure of the ammonia water two-stage absorption type heat pump system is reduced, the safety of system operation is improved, and the strength requirement of the system components is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application is further explained below in combination with the drawings and examples.

[0016] Figure 1is a structural schematic diagram of a second type of ammonia water two-stage synergic absorption-reabsorption heat pump system for pressure reduction and temperature increase according to the present application;

[0017] In the figure, there are: a reabsorber 1, a first-stage desorber 2, a first-stage absorber 3, a first-stage generator 4, a second-stage desorber 5, a second-stage absorber 6, a second-stage generator 7, a first solution heat exchanger 8, a second solution heat exchanger 9, a third solution heat exchanger 10, a fourth solution heat exchanger 11, an intermediate heat exchange pipeline 12, a liquid discharge pipeline 13, a solution pump 14, a liquid feed pipeline 15, a throttle valve 16, and a steam pipeline 17.

[0018] In the figure, a black solid line represents a solution pipeline in a solution and refrigerant vapor pipeline, a dashed line represents a refrigerant vapor pipeline, and a dot-dashed line represents an intermediate heat exchange pipeline. DETAILED DESCRIPTION

[0019] The present application will be further illustrated below in combination with the accompanying drawings and specific examples.

[0020] Example 1

[0021] A second type of ammonia water two-stage synergic absorption-reabsorption heat pump system for pressure reduction and temperature increase according to the present application includes a reabsorber 1, a first-stage desorber 2, a first-stage absorber 3, a first-stage generator 4, a second-stage desorber 5, a second-stage absorber 6, a second-stage generator 7, and solution heat exchangers; an output end of the reabsorber 1 is connected to input ends of the first-stage desorber 2 and the second-stage desorber 5 through a liquid discharge pipeline 13, output ends of the first-stage desorber 2 and the second-stage desorber 5 are connected to an input end of the reabsorber 1 through a liquid discharge pipeline 15; an output end of the first-stage generator 4 is connected to an input end of the first-stage absorber 3 through a liquid discharge pipeline 13, and an output end of the first-stage absorber 3 is connected to an input end of the first-stage generator 4 through a liquid feed pipeline 15; an output end of the second-stage generator 7 is connected to an input end of the second-stage absorber 6 through a liquid discharge pipeline 13; and an output end of the second-stage absorber 6 is connected to an input end of the second-stage generator 7 through a liquid feed pipeline 15.

[0022] Example 2

[0023] As an improvement of the present application, the first-stage desorber 2 is connected to the first-stage absorber 3 through a steam pipeline 17, the second-stage desorber 5 is connected to the second-stage absorber 6 through a steam pipeline 17, and the first-stage generator 4 and the second-stage generator 7 are connected to the reabsorber 1 through a steam pipeline 17.

[0024] The remaining structural features and advantages are completely the same as those of Example 1.

[0025] Example 3

[0026] As an improvement of the present application, the intermediate heat exchange pipeline 12 is connected with the first stage absorber 3 and the second stage desorber 5 in sequence at one end; and the intermediate heat exchange pipeline is connected with the first stage absorber 3 and the first stage generator 4 in sequence at the other end.

[0027] The remaining structural features and advantages are the same as those of Embodiment 1 or 2.

[0028] Embodiment 4:

[0029] As an improvement of the present application, the liquid discharge pipeline 13 is provided with the solution pump 14.

[0030] The remaining structural features and advantages are the same as those of Embodiment 1, 2 or 3.

[0031] Embodiment 5:

[0032] As an improvement of the present application, the liquid feed pipeline 15 is provided with the throttle valve 16.

[0033] The remaining structural features and advantages are the same as those of Embodiment 1, 2, 3 or 4.

[0034] Embodiment 6:

[0035] As an improvement of the present application, the third solution heat exchanger 10 is arranged between the resorber 1 and the second stage desorber 5, the first solution heat exchanger 8 is arranged between the resorber 1 and the first stage desorber 2, the second solution heat exchanger 9 is arranged between the first stage absorber 3 and the first stage generator 4, and the fourth solution heat exchanger 11 is arranged between the second stage absorber 6 and the second stage generator 7.

[0036] The remaining structural features and advantages are the same as those of Embodiment 1, 2, 3, 4 or 5.

[0037] The present application provides a second type of ammonia water two-stage collaborative absorption-resorption heat pump system with pressure reduction and temperature increase. The operating working medium of the solution and refrigerant vapor pipeline of the second type of ammonia water two-stage absorption-resorption heat pump system is ammonia-water refrigeration working medium; and the operating working medium in the intermediate heat exchange pipeline 12 is water.

[0038] The solution and refrigerant vapor pipeline comprises the resorber 1 (low-pressure absorption), the first stage desorber 2 (medium-pressure desorption), the first stage absorber 3 (medium-pressure absorption), the first stage generator 4 (low-pressure generation), the second stage desorber 5 (high-pressure desorption), the second stage absorber 6 (high-pressure absorption), the second stage generator 7 (low-pressure generation), the first solution heat exchanger 8, the second solution heat exchanger 9, the third solution heat exchanger 10, and the fourth solution heat exchanger 11; the liquid discharge pipeline 13 is provided with the solution pump 14; and the liquid feed pipeline 15 is provided with the throttle valve 16.

[0039] The ammonia water solution in the reabsorber 1 comes from the primary absorber 2 and the secondary absorber 5, and the absorbed low-pressure ammonia gas comes from the primary generator 4 and the secondary generator 7. The ammonia water solution absorbs the ammonia gas in the reabsorber 1 and releases heat to the low-temperature environment of about 10℃, and the generated high-concentration ammonia water is divided into two paths, one of which is finally sent into the primary absorber 2 after being pressurized by the solution pump 14 and preheated by the solution heat exchanger 8, and the other of which is finally sent into the secondary absorber 5 after being pressurized by the solution pump 14 and preheated by the solution heat exchanger 10.

[0040] The ammonia water solution in the primary absorber 2 comes from the reabsorber 1. The high-concentration ammonia water absorbs the industrial waste heat or other low-grade heat of about 70-110℃ in the primary absorber 2, and generates medium-pressure ammonia-water mixed steam and low-concentration ammonia water. The ammonia-water mixed steam is condensed in the condensing section of the primary absorber 2, and high-purity ammonia gas is generated and sent into the primary absorber 3. The low-concentration ammonia water generated by the primary absorber 2 is first released of waste heat by the first solution heat exchanger 8, then depressurized by the throttle valve 16, and then sent into the reabsorber 1.

[0041] The ammonia water solution in the primary absorber 3 comes from the primary generator 4, and the absorbed medium-pressure ammonia gas comes from the primary absorber 2. The ammonia water solution absorbs the ammonia gas in the primary absorber 3 and releases heat to the intermediate heat exchange pipeline, and the generated high-concentration ammonia water is first released of waste heat by the solution heat exchanger 9, then depressurized by the throttle valve 16, and then sent into the primary generator 4.

[0042] The ammonia water solution in the primary generator 4 comes from the primary absorber 3. The high-concentration ammonia water absorbs the industrial waste heat or other low-grade heat of about 70-110℃ in the primary generator 4, and generates low-pressure ammonia-water mixed steam and low-concentration ammonia water. The ammonia-water mixed steam is condensed in the condensing section of the primary generator 4, and high-purity ammonia gas is generated and sent into the reabsorber 1. The low-concentration ammonia water generated by the primary generator 4 is first pressurized by the solution pump 14, then preheated by the second solution heat exchanger 9, and then sent into the primary absorber 3.

[0043] The ammonia water solution in the secondary absorber 5 comes from the reabsorber 1. The high-concentration ammonia water absorbs the heat of the intermediate heat exchange pipeline in the secondary absorber 5, and generates high-pressure ammonia-water mixed steam and low-concentration ammonia water. The ammonia-water mixed steam is condensed in the condensing section of the secondary absorber 5, and high-purity ammonia gas is generated and sent into the secondary absorber 6. The low-concentration ammonia water generated by the secondary absorber 5 is first released of waste heat by the third solution heat exchanger 10, then depressurized by the throttle valve 16, and then sent into the reabsorber 1.

[0044] The ammonia water solution in the secondary absorber 6 comes from the secondary generator 7, and the absorbed high-pressure ammonia gas comes from the secondary desorber 5. The ammonia water solution absorbs the ammonia gas in the secondary absorber 6 and releases high-temperature useful heat energy of about 130-170 DEG C to the user, and the generated high-concentration ammonia water releases waste heat through the fourth solution heat exchanger 11 and then is depressurized through the throttle valve 16 and then is sent into the secondary generator 7.

[0045] The ammonia water solution in the secondary generator 7 comes from the secondary absorber 6. The high-concentration ammonia water absorbs the heat of the intermediate heat exchange pipeline in the secondary generator 7, and generates low-pressure ammonia and water mixed steam and low-concentration ammonia water. The ammonia and water mixed steam is condensed through the condensing section of the secondary generator 7, and high-purity ammonia gas is sent into the resorber 1. The low-concentration ammonia water generated by the secondary generator 7 is first pressurized through the solution pump 14, then preheated through the fourth solution heat exchanger 11, and then is sent into the secondary absorber 6.

[0046] From the coupling mode of the two-stage system, the present application simultaneously provides the absorption heat released by the primary absorber 3 to the secondary desorber 5 and the secondary generator 7 of the secondary cycle, improves the driving heat source temperature of the secondary cycle, increases the gas release range of the secondary generator 7, and thus can realize higher waste heat temperature increase. In addition, the resorber is used to replace the condenser of the traditional system, and the desorber is used to replace the evaporator of the traditional system, which reduces the operating pressure of the ammonia water two-stage absorption heat pump system, thereby improving the safety of the system operation and reducing the strength requirement of the system components, which is conducive to reducing the cost.

[0047] The above embodiments are only preferred technical solutions of the present application, and should not be regarded as limitations of the present application. The protection scope of the present application should be based on the technical solutions recited in the claims, including equivalent replacement solutions of the technical features recited in the claims, i.e. within the scope of equivalent replacement improvement, which is also within the protection scope of the present application.

Claims

1. A second-stage synergistic absorption-reabsorption heat pump system for ammonia water with pressure reduction and temperature increase, characterized in that: The heat pump system comprises a reabsorber (1), a first desorber (2), a first absorber (3), a first generator (4), a second desorber (5), a second absorber (6), a second generator (7) and solution heat exchangers; the output end of the reabsorber (1) is connected with the input end of the first desorber (2) and the second desorber (5) through liquid discharge pipelines (13), and the output end of the first desorber (2) and the second desorber (5) is connected with the input end of the reabsorber (1) through liquid feeding pipelines (15); the output end of the first generator (4) is connected with the input end of the first absorber (3) through a liquid discharge pipeline (13), and the output end of the first absorber (3) is connected with the input end of the first generator (4) through a liquid feeding pipeline (15); the output end of the second generator (7) is connected with the input end of the second absorber (6) through a liquid discharge pipeline (13); and the output end of the second absorber (6) is connected with the input end of the second generator (7) through a liquid feeding pipeline (15). The steam port of the first desorber (2) is connected with the steam port of the first absorber (3) through a steam pipeline (17); the steam port of the second desorber (5) is connected with the steam port of the second absorber (6) through a steam pipeline (17); and the steam port of the first generator (4) and the second generator (7) is connected with the steam port of the reabsorber (1) through a steam pipeline (17). The heat pump system further comprises three intermediate heat exchange pipelines (12), the first pipeline connects the heat exchange end outlet of the first absorber (3) with the heat exchange end inlet of the second generator (7); the second pipeline connects the heat exchange end outlet of the second generator (7) with the heat exchange end inlet of the second desorber (5); and the third pipeline connects the heat exchange end outlet of the second desorber (5) with the heat exchange end inlet of the first absorber (3). The third solution heat exchanger (10) is arranged between the reabsorber (1) and the second desorber (5), the first solution heat exchanger (8) is arranged between the reabsorber (1) and the first desorber (2), the second solution heat exchanger (9) is arranged between the first absorber (3) and the first generator (4), and the fourth solution heat exchanger (11) is arranged between the second absorber (6) and the second generator (7).

2. The pressure-reducing and temperature-increasing second-type ammonia-water two-stage synergic absorption-reabsorption heat pump system according to claim 1, characterized in that: Solution pumps (14) are arranged on the liquid discharge pipelines (13).

3. The pressure-lowering and temperature-increasing second-type ammonia-water two-stage synergic absorption-reabsorption heat pump system according to claim 1, characterized in that: Throttling valves (16) are arranged on the liquid feeding pipelines (15).

4. The pressure-lowering and temperature-increasing second-type ammonia-water two-stage synergic absorption-reabsorption heat pump system according to any one of claims 1 to 3, characterized in that: The operation method of the ammonia solution and the refrigerant vapor pipeline is as follows: the ammonia water in the low-pressure reabsorber absorbs the ammonia gas from the primary generator and the secondary generator, releases heat to the environment of 8-1210 DEG C, and a part of the generated ammonia water with increased concentration is sent to the medium-pressure primary desorber after being pressurized by a solution pump and preheated by a solution heat exchanger; the ammonia water solution absorbs the industrial waste heat or other low-grade heat at 70-110 DEG C in the primary desorber, the generated ammonia and water mixed vapor is condensed by the condensing section of the primary desorber, the high-purity ammonia gas enters the primary absorber; the ammonia water in the primary absorber absorbs the medium-pressure ammonia gas from the primary desorber, releases heat to the intermediate heat exchange pipeline, the generated ammonia water with increased concentration is sent to the low-pressure primary generator after being pressurized by a solution pump and preheated by a solution heat exchanger and a pressure reducing valve; the ammonia water solution absorbs the industrial waste heat or other low-grade heat at 70-110 DEG C in the primary generator, the generated ammonia and water mixed vapor is condensed by the condensing section of the primary generator, the high-purity ammonia gas enters the reabsorber and is absorbed by the ammonia water in the reabsorber; another part of the ammonia water with increased concentration generated by the low-pressure reabsorber is sent to the high-pressure secondary desorber after being pressurized by a solution pump and preheated by a solution heat exchanger; the ammonia water solution absorbs the heat of the intermediate heat exchange pipeline in the secondary desorber, the generated ammonia and water mixed vapor is condensed by the condensing section of the secondary desorber, the high-purity ammonia gas enters the secondary absorber; the ammonia water in the secondary absorber absorbs the high-pressure ammonia gas from the secondary desorber, releases the high-temperature useful heat of 130-170 DEG C, and the generated ammonia water with increased concentration is sent to the low-pressure secondary generator after being pressurized by a solution heat exchanger and a pressure reducing valve; the ammonia water solution absorbs the heat of the intermediate heat exchange pipeline in the secondary generator, the generated ammonia and water mixed vapor is condensed by the condensing section of the secondary generator, the high-purity ammonia gas enters the reabsorber and is absorbed by the ammonia water in the reabsorber.

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