Pressure-reducing and temperature-increasing second-class ammonia water two-stage synergistic absorption-reabsorption heat pump system

Abstract

The invention relates to a pressure-reducing and temperature-increasing second-class ammonia water two-stage synergistic absorption-re-absorption heat pump system which comprises a re-absorber (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 re-absorber are connected through a steam pipeline (17); the first-stage absorber is connected with the second-stage generator and the second-stage resolver through a middle heat exchange pipeline (12); absorbed heat released by the first-stage absorber is provided for the resolver and the generator of the second-stage circulation at the same time through the middle heat exchange pipeline, the larger temperature rise range is achieved, and meanwhile the operation pressure of the ammonia water two-stage heat pump system is effectively reduced through reabsorption circulation.

Description

Technical Field

[0001] The invention relates to a second-type ammonia water two-stage coordinated absorption-reabsorption heat pump system with pressure reduction and temperature increase, belonging to the technical field of heat pumps. Background Art

[0002] Energy is an important cornerstone of economic development and social progress. my country is a major energy consumer. Nearly half of the energy consumed by high-energy-consuming industries such as electricity, steel, cement, glass, nonferrous metals, and petrochemicals is discharged into the environment in the form of waste gas, waste water, waste residue liquid and other waste heat. These industrial waste heat, especially low-grade waste heat at 100°C, is difficult to use effectively and has huge energy-saving potential. Using absorption heat pumps to recover waste heat is an effective means to significantly improve energy utilization and reduce primary energy consumption, which is of great significance for energy conservation and emission reduction.

[0003] However, in the actual application of traditional second-class ammonia absorption heat pumps, due to the non-fixed external parameter conditions, sometimes the temperature of the waste heat is relatively low, or the user's demand for the heat temperature is relatively high, which requires the system to have a large temperature rise. Ordinary single-stage second-class ammonia absorption heat pumps cannot meet the requirements, so a two-stage heat pump is required to increase the temperature to the user's needs. At the same time, higher absorption temperatures bring higher absorption pressures, and high-pressure operation requires stronger and more complex components, which increases the system cost. How to reduce the operating pressure while keeping the primary goal of increasing the absorption temperature and simplify the heat pump system structure as much as possible is one of the important research topics at present. Summary of the invention

[0004] Technical problem: The purpose of the present invention is to solve the technical problems of the above-mentioned traditional second-type ammonia absorption heat pump, and to provide a second-type ammonia two-stage collaborative absorption-reabsorption heat pump system with pressure reduction and temperature increase, which utilizes waste heat to drive the system cycle and raises it to a higher temperature level, and utilizes the reabsorption cycle to reduce the operating pressure, thereby reducing the strength requirements for system components.

[0005] Technical solution: To achieve the above purpose, the present invention solves the problem of a second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase as follows:

[0006] The heat pump system comprises a reabsorber, a primary resolver, a primary absorber, a primary generator, a secondary resolver, a secondary absorber, a secondary generator and a solution heat exchanger; the output end of the reabsorber is respectively connected to the input ends of the primary resolver and the secondary resolver through a liquid discharge pipeline, and the output ends of the primary resolver and the secondary resolver are respectively connected to the input end of the reabsorber through a liquid discharge pipeline; the output end of the primary generator is connected to the input end of the primary absorber through a liquid discharge pipeline, and the output end of the primary absorber is connected to the input end of the primary generator through a liquid feed pipeline; the output end of the secondary generator is connected to the input end of the secondary absorber through a liquid discharge pipeline; and the output end of the secondary absorber is connected to the input end of the secondary generator through a liquid feed pipeline.

[0007] The steam port of the primary analyzer is connected to the steam port of the primary absorber through a steam pipe; the steam port of the secondary analyzer is connected to the steam port of the secondary absorber through a steam pipe; the steam ports of the primary generator and the secondary generator are connected to the steam port of the reabsorber through a steam pipe.

[0008] The heat pump system also includes an intermediate heat exchange pipeline, which has three intermediate heat exchange pipelines. The first intermediate heat exchange pipeline connects the heat exchange end outlet of the first-stage absorber and the heat exchange end inlet of the second-stage generator; the second intermediate heat exchange pipeline connects the heat exchange end outlet of the second-stage generator and the heat exchange end inlet of the second-stage analyzer; and the third intermediate heat exchange pipeline connects the heat exchange end outlet of the second-stage analyzer and the heat exchange end inlet of the first-stage absorber.

[0009] The liquid discharge pipeline is provided with a solution pump.

[0010] The liquid feed pipeline is provided with a throttle valve.

[0011] A third solution heat exchanger is provided between the reabsorber and the secondary analyzer, a first solution heat exchanger is provided between the reabsorber and the primary analyzer, a second solution heat exchanger is provided between the primary absorber and the primary generator, and a fourth solution heat exchanger is provided between the secondary absorber and the secondary generator.

[0012] The operation method of the ammonia solution and the refrigerant steam pipeline is as follows: the ammonia solution in the low-pressure reabsorber absorbs ammonia gas from the primary generator and the secondary generator, and releases heat to the environment of 8-12°C. A part of the ammonia solution with increased concentration is pressurized by the solution pump and preheated by the solution heat exchanger and then sent to the medium-pressure primary resolver for resolution; the ammonia solution absorbs industrial waste heat or other low-grade heat of 70-110°C in the primary resolver, and the generated ammonia and water mixed steam is condensed through the condensation section of the primary resolver to generate high-purity ammonia gas that enters the primary absorber; the ammonia solution in the primary absorber absorbs the medium-pressure ammonia gas from the primary resolver, and releases heat to the intermediate heat exchange pipeline, and the generated ammonia solution with increased concentration is sent to the low-pressure primary generator after being depressurized by the solution heat exchanger and the throttle valve; the ammonia solution absorbs industrial waste heat or other low-grade heat of 70-110°C in the primary generator, and the generated ammonia and water mixed steam is condensed through the condensation section of the primary resolver to generate high-purity ammonia gas that enters the primary absorber The condensation section of the generator is condensed to produce high-purity ammonia gas, which enters the reabsorber and is absorbed by the ammonia water in the reabsorber; the other part of the ammonia water with increased concentration produced by the low-pressure reabsorber is pressurized by the solution pump and preheated by the solution heat exchanger, and then sent to the high-pressure secondary resolver for analysis; the ammonia solution absorbs the heat of the intermediate heat exchange pipeline in the secondary resolver, and the generated ammonia and water mixed steam is condensed through the condensation section of the secondary resolver to produce high-purity ammonia gas and enter the secondary absorber; the ammonia water in the secondary absorber absorbs the high-pressure ammonia from the secondary resolver and releases high-temperature useful heat of 130-170°C, and the generated ammonia water with increased concentration is sent to the low-pressure secondary generator after being reduced in pressure by the solution heat exchanger and the throttle valve; the ammonia solution absorbs the heat of the intermediate heat exchange pipeline in the secondary generator, and the generated ammonia and water mixed steam is condensed through the condensation section of the secondary generator to produce high-purity ammonia gas, which enters the reabsorber and is absorbed by the ammonia water in the reabsorber.

[0013] Beneficial effects: Due to the adoption of the above technology, the present invention has the following advantages compared with the prior art:

[0014] The present invention discloses a second-class ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase. The present invention provides the absorption heat released by the primary absorber to the analyzer and generator of the secondary cycle at the same time, thereby increasing the driving heat source temperature of the secondary cycle, thereby achieving a higher waste heat temperature increase. In addition, by adopting the reabsorption cycle, the reabsorber replaces the condenser of the traditional system, and the analyzer replaces the evaporator of the traditional system, the operating pressure of the ammonia water two-stage absorption heat pump system is reduced, thereby improving the safety of the system operation and reducing the strength requirements for system components. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1It is a structural schematic diagram of a second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system for reducing pressure and increasing temperature according to the present invention;

[0017] The figure includes: reabsorber 1, primary analyzer 2, primary absorber 3, primary generator 4, secondary analyzer 5, secondary absorber 6, secondary generator 7, first solution heat exchanger 8, second solution heat exchanger 9, third solution heat exchanger 10, fourth solution heat exchanger 11, intermediate heat exchange pipeline 12, liquid discharge pipeline 13, solution pump 14, liquid feed pipeline 15, throttle valve 16, steam pipeline 17.

[0018] Among them, the black solid line represents the solution pipeline in the solution and refrigerant vapor pipeline, the dotted line represents the refrigerant vapor pipeline, and the dot-dash line represents the intermediate heat exchange pipeline. DETAILED DESCRIPTION

[0019] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments.

[0020] Embodiment 1:

[0021] A second-class ammonia water two-stage synergistic absorption-reabsorption heat pump system for reducing pressure and increasing temperature of the present invention comprises a reabsorber 1, a primary analyzer 2, a primary absorber 3, a primary generator 4, a secondary analyzer 5, a secondary absorber 6, a secondary generator 7 and a solution heat exchanger; the output end of the reabsorber 1 is connected to the input ends of the primary analyzer 2 and the secondary analyzer 5 respectively through a liquid discharge pipe 13, and the output ends of the primary analyzer 2 and the secondary analyzer 5 are connected to the input end of the reabsorber 1 through a liquid discharge pipe 15 respectively; the output end of the primary generator 4 is connected to the input end of the primary absorber 3 through a liquid discharge pipe 13, and the output end of the primary absorber 3 is connected to the input end of the primary generator 4 through a liquid feed pipe 15; the output end of the secondary generator 7 is connected to the input end of the secondary absorber 6 through a liquid discharge pipe 13; the output end of the secondary absorber 6 is connected to the input end of the secondary generator 7 through a liquid feed pipe 15.

[0022] Embodiment 2:

[0023] As an improvement of the present invention, the primary analyzer 2 is connected to the primary absorber 3 through a steam pipe 17; the secondary analyzer 5 is connected to the secondary absorber 6 through a steam pipe 17; the primary generator 4 and the secondary generator 7 are connected to the reabsorber 1 through a steam pipe 17.

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

[0025] Embodiment 3:

[0026] As an improvement of the present invention, it also includes an intermediate heat exchange pipeline 12, one end of which is connected to the primary absorber 3 and the secondary analyzer 5 in sequence; the other end of the intermediate heat exchange pipeline is connected to the primary absorber 3 and the secondary generator 7 in sequence.

[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 invention, a solution pump 14 is provided on each of the liquid discharge pipes 13 .

[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 invention, a throttle valve 16 is provided on each of the liquid feed pipelines 15 .

[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 invention, a third solution heat exchanger 10 is provided between the reabsorber 1 and the secondary analyzer 5, a first solution heat exchanger 8 is provided between the reabsorber 1 and the primary analyzer 2, a second solution heat exchanger 9 is provided between the primary absorber 3 and the primary generator 4, and a fourth solution heat exchanger 11 is provided between the secondary absorber 6 and the secondary 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 invention provides a second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system for reducing pressure and increasing temperature. The operating medium of the solution and refrigerant steam pipeline of the second type of ammonia water two-stage absorption-reabsorption heat pump system is ammonia-water refrigerant; the operating medium in the intermediate heat exchange pipeline 12 is water.

[0038] The solution and refrigerant vapor pipeline includes a reabsorber 1 (low-pressure absorption), a primary analyzer 2 (medium-pressure analysis), a primary absorber 3 (medium-pressure absorption), a primary generator 4 (low-pressure generation), a secondary analyzer 5 (high-pressure analysis), a secondary absorber 6 (high-pressure absorption), a secondary generator 7 (low-pressure generation), a first solution heat exchanger 8, a second solution heat exchanger 9, a third solution heat exchanger 10, and a fourth solution heat exchanger 11. A solution pump 14 is provided on the liquid discharge pipeline 13, and a throttle valve 16 is provided on the liquid feed pipeline 15.

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

[0040] The ammonia solution in the primary resolver 2 comes from the reabsorber 1. The high-concentration ammonia solution absorbs industrial waste heat or other low-grade heat at about 70-110°C in the primary resolver 2 to produce medium-pressure ammonia-water mixed steam and low-concentration ammonia solution. The ammonia-water mixed steam is condensed through the condensation section of the primary resolver 2 to produce high-purity ammonia gas, which is sent to the primary absorber 3. The low-concentration ammonia solution produced by the primary resolver 2 first passes through the first solution heat exchanger 8 to release waste heat, then passes through the throttle valve 16 to reduce the pressure, and then is sent to the reabsorber 1.

[0041] The ammonia solution in the primary absorber 3 comes from the primary generator 4, and the absorbed medium-pressure ammonia gas comes from the primary resolver 2. The ammonia solution absorbs ammonia gas in the primary absorber 3 and releases heat to the intermediate heat exchange pipeline. The generated ammonia solution with a higher concentration first releases waste heat through the solution heat exchanger 9, then passes through the throttle valve 16 to reduce the pressure, and then is sent to the primary generator 4.

[0042] The ammonia solution in the primary generator 4 comes from the primary absorber 3. The ammonia solution with a higher concentration absorbs industrial waste heat or other low-grade heat at about 70-110°C in the primary generator 4 to produce low-pressure ammonia-water mixed steam and low-concentration ammonia solution. The ammonia-water mixed steam is condensed through the condensation section of the primary generator 4 to produce high-purity ammonia gas, which is sent to the reabsorber 1. The low-concentration ammonia solution produced 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 to the primary absorber 3.

[0043] The ammonia solution in the secondary resolver 5 comes from the reabsorber 1. The high-concentration ammonia solution absorbs the heat of the intermediate heat exchange pipeline in the secondary resolver 5 to produce high-pressure ammonia-water mixed steam and low-concentration ammonia solution. The ammonia-water mixed steam is condensed through the condensation section of the secondary resolver 5 to produce high-purity ammonia gas, which is sent to the secondary absorber 6. The low-concentration ammonia solution produced by the secondary resolver 5 first passes through the third solution heat exchanger 10 to release the waste heat, then passes through the throttle valve 16 to reduce the pressure, and then is sent to the reabsorber 1.

[0044] The ammonia solution in the secondary absorber 6 comes from the secondary generator 7, and the absorbed high-pressure ammonia gas comes from the secondary analyzer 5. The ammonia solution absorbs ammonia gas in the secondary absorber 6 and releases high-temperature useful heat energy of about 130-170°C to the user. The generated ammonia solution with a higher concentration first releases waste heat through the solution heat exchanger 11, then passes through the throttle valve 16 to reduce the pressure, and then is sent to the secondary generator 7.

[0045] The ammonia solution in the secondary generator 7 comes from the secondary absorber 6. The ammonia solution with a higher concentration absorbs the heat of the intermediate heat exchange pipeline in the secondary generator 7 to produce low-pressure ammonia-water mixed steam and low-concentration ammonia solution. The ammonia-water mixed steam is condensed through the condensation section of the secondary generator 7 to produce high-purity ammonia gas, which is sent to the reabsorber 1. The low-concentration ammonia solution produced by the secondary generator 7 is first pressurized by the solution pump 14, then preheated by the fourth solution heat exchanger 11, and then sent to the secondary absorber 6.

[0046] From the perspective of the coupling mode of the two-stage system, the present invention provides the absorption heat released by the primary absorber 3 to the secondary analyzer 5 and the secondary generator 7 of the secondary cycle at the same time, thereby increasing the temperature of the driving heat source of the secondary cycle and increasing the exhaust range of the secondary generator 7, thereby achieving a higher waste heat temperature increase. In addition, the reabsorption cycle is adopted, the reabsorber replaces the condenser of the traditional system, and the analyzer replaces the evaporator of the traditional system, which reduces the operating pressure of the ammonia two-stage absorption heat pump system, thereby improving the safety of the system operation and reducing the strength requirements for the system components, which is conducive to reducing costs.

[0047] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The protection scope of the present invention should be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims, that is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A second-type ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase, Features: The invention comprises a reabsorber (1), a primary resolver (2), a primary absorber (3), a primary generator (4), a secondary resolver (5), a secondary absorber (6), a secondary generator (7) and a solution heat exchanger; the output end of the reabsorber (1) is respectively connected to the input ends of the primary resolver (2) and the secondary resolver (5) through a liquid discharge pipe (13); the output ends of the primary resolver (2) and the secondary resolver (5) are respectively connected to the input end of the reabsorber (1) through a liquid discharge pipe (15); the output end of the primary generator (4) is connected to the input end of the primary absorber (3) through a liquid discharge pipe (13); the output end of the primary absorber (3) is connected to the input end of the primary generator (4) through a liquid feed pipe (15); the output end of the secondary generator (7) is connected to the input end of the secondary absorber (6) through a liquid discharge pipe (13); the output end of the secondary absorber (6) is connected to the input end of the secondary generator (7) through a liquid feed pipe (15).

2. A second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase according to claim 1, Features: The steam port of the primary analyzer (2) is connected to the steam port of the primary absorber (3) via a steam pipe (17); the steam port of the secondary analyzer (5) is connected to the steam port of the secondary absorber (6) via a steam pipe (17); and the steam ports of the primary generator (4) and the secondary generator (7) are connected to the steam port of the reabsorber (1) via a steam pipe (17).

3. A second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase according to claim 1, Features: The heat pump system further comprises an intermediate heat exchange pipeline (12), wherein the intermediate heat exchange pipeline (12) comprises three pipelines, wherein the first pipeline connects the heat exchange end outlet of the primary absorber (3) and the heat exchange end inlet of the secondary generator (7); the second pipeline connects the heat exchange end outlet of the secondary generator (7) and the heat exchange end inlet of the secondary analyzer (5); and the third pipeline connects the heat exchange end outlet of the secondary analyzer (5) and the heat exchange end inlet of the primary absorber (3).

4. The second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase according to claim 1, Features: The liquid discharge pipe (13) is provided with a solution pump (14).

5. The second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase according to claim 1, Features: The liquid feed pipeline (15) is provided with a throttle valve (16).

6. A second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system with pressure reduction and temperature increase according to claim 1, Features: A third solution heat exchanger (10) is provided between the reabsorber (1) and the secondary analyzer (5), a first solution heat exchanger (8) is provided between the reabsorber (1) and the primary analyzer (2), a second solution heat exchanger (9) is provided between the primary absorber (3) and the primary generator (4), and a fourth solution heat exchanger (11) is provided between the secondary absorber (6) and the secondary generator (7).

7. A second type of ammonia water two-stage synergistic absorption-reabsorption heat pump system for reducing pressure and increasing temperature according to any one of claims 1 to 6, Features: The operation method of the ammonia solution and the refrigerant steam pipeline is as follows: the ammonia solution in the low-pressure reabsorber absorbs ammonia gas from the primary generator and the secondary generator, and releases heat to the environment of 8-12°C. A part of the ammonia solution with increased concentration is pressurized by the solution pump and preheated by the solution heat exchanger and then sent to the medium-pressure primary resolver for resolution; the ammonia solution absorbs industrial waste heat or other low-grade heat of 70-110°C in the primary resolver, and the generated ammonia and water mixed steam is condensed through the condensation section of the primary resolver to generate high-purity ammonia gas that enters the primary absorber; the ammonia solution in the primary absorber absorbs the medium-pressure ammonia gas from the primary resolver, and releases heat to the intermediate heat exchange pipeline, and the generated ammonia solution with increased concentration is sent to the low-pressure primary generator after being depressurized by the solution heat exchanger and the throttle valve; the ammonia solution absorbs industrial waste heat or other low-grade heat of 70-110°C in the primary generator, and the generated ammonia and water mixed steam is condensed through the condensation section of the primary resolver to generate high-purity ammonia gas that enters the primary absorber The condensation section of the generator is condensed to produce high-purity ammonia gas, which enters the reabsorber and is absorbed by the ammonia water in the reabsorber; the other part of the ammonia water with increased concentration produced by the low-pressure reabsorber is pressurized by the solution pump and preheated by the solution heat exchanger, and then sent to the high-pressure secondary resolver for analysis; the ammonia solution absorbs the heat of the intermediate heat exchange pipeline in the secondary resolver, and the generated ammonia and water mixed steam is condensed through the condensation section of the secondary resolver to produce high-purity ammonia gas and enter the secondary absorber; the ammonia water in the secondary absorber absorbs the high-pressure ammonia from the secondary resolver and releases high-temperature useful heat of 130-170°C, and the generated ammonia water with increased concentration is sent to the low-pressure secondary generator after being reduced in pressure by the solution heat exchanger and the throttle valve; the ammonia solution absorbs the heat of the intermediate heat exchange pipeline in the secondary generator, and the generated ammonia and water mixed steam is condensed through the condensation section of the secondary generator to produce high-purity ammonia gas, which enters the reabsorber and is absorbed by the ammonia water in the reabsorber.

Images