A double absorption-reabsorption parallel heat recovery utilization collaborative temperature increasing heat pump system

Abstract

The present application relates to a kind of double absorption-reabsorption parallel waste heat utilization collaborative temperature-increasing heat pump systems, including reabsorber, resolver, primary absorber, primary generator, secondary absorber, secondary generator and solution heat exchanger.Reabsorber is sequentially connected with solution heat exchanger, resolver by liquid discharge pipeline;Resolver is sequentially connected with solution heat exchanger, reabsorber by liquid feed pipeline;Primary generator is sequentially connected with solution heat exchanger, primary absorber by liquid discharge pipeline;Primary absorber is sequentially connected with solution heat exchanger, primary generator by liquid feed pipeline;Secondary generator is connected with solution heat exchanger, secondary absorber by liquid discharge pipeline;Secondary absorber is sequentially connected with solution heat exchanger, secondary generator by liquid feed pipeline.The present application can realize larger temperature rise amplitude and performance coefficient, further reduce the operating pressure of absorption heat pump system, improve the operating stability of system.

Description

TECHNICAL FIELD

[0001] The present application relates to a double absorption-reabsorption parallel waste heat utilization collaborative temperature-increasing heat pump system, 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 power, steel, cement, glass, non-ferrous metal, petroleum chemical industry is in the form of waste heat such as waste gas, waste water and waste residue liquid discharged into the environment. These industrial waste heat, especially low-grade waste heat at 100℃, is difficult to effectively utilize, and has great energy-saving potential. Using absorption heat pumps 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 absorption heat pump, due to the non-fixed parameter conditions provided externally, 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, and the ordinary single-stage absorption heat pump cannot meet the requirements, so a multi-stage cycle heat pump is needed to increase the temperature to the user's 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 present application is to solve the technical problems of the above-mentioned traditional absorption heat pump, and to provide a double absorption-reabsorption parallel waste heat utilization collaborative temperature-increasing heat pump system, which utilizes waste heat to drive the system cycle and raises it to a higher temperature level, and utilizes reabsorption cycle to reduce the operating pressure, thereby reducing the strength requirement of the system components.

[0005] Technical scheme: In order to achieve the above-mentioned purpose, the present application adopts the following scheme:

[0006] The heat pump system comprises a resorber, a resolver, a first-stage absorber, a first-stage generator, a second-stage absorber, a second-stage generator and a solution heat exchanger; the discharge end of the resorber is connected to the feed end of the resolver through a liquid discharge pipeline, and the discharge end of the resolver is connected to the feed end of the resorber through a liquid feed pipeline; the discharge end of the first-stage absorber is connected to the feed end of the first-stage generator through a liquid discharge pipeline, and the discharge end of the first-stage generator is connected to the feed end of the first-stage absorber through a liquid feed pipeline; the discharge end of the second-stage generator is connected to the feed end of the second-stage absorber through a liquid discharge pipeline, and the discharge end of the second-stage absorber is connected to the feed end of the second-stage generator through a liquid feed pipeline.

[0007] The steam discharge end of the resolver is connected to the steam feed end of the first-stage absorber and the steam feed end of the second-stage absorber through steam pipelines respectively; the steam discharge end of the first-stage generator is connected to the steam feed end of the resorber and the steam feed end of the second-stage generator through steam pipelines respectively.

[0008] The heat exchange discharge end of the first-stage absorber is connected to the heat exchange feed end of the second-stage generator through an intermediate heat exchange pipeline, and the heat exchange discharge end of the second-stage generator is connected to the heat exchange feed end of the first-stage absorber through an intermediate heat exchange pipeline, forming a heat exchange loop.

[0009] Solution pumps are arranged on the liquid discharge pipelines.

[0010] Throttling valves are arranged on the liquid feed pipelines.

[0011] The first solution heat exchanger is arranged between the resorber and the resolver, the second solution heat exchanger is arranged between the first-stage absorber and the first-stage generator, and the third solution heat exchanger is arranged between the second-stage absorber and the second-stage 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 ammonia gas from the primary generator and the secondary generator, releases heat to the environment at 8-12 DEG C, the generated ammonia water with increased concentration is sent to the high-pressure desorber for desorption after being pressurized by a solution pump and preheated by a solution heat exchanger; the ammonia water solution absorbs 70-110 DEG C industrial waste heat or other low-grade heat in the desorber, the generated ammonia and water mixed vapor is separated by the desorption section of the desorber, part of the generated high-purity ammonia gas enters the primary absorber; the ammonia water in the primary absorber absorbs high-pressure ammonia gas from the 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 depressurized by a solution heat exchanger and a throttle valve; the ammonia water solution absorbs 70-110 DEG C industrial waste heat or other low-grade heat in the primary generator, the generated ammonia and water mixed vapor is separated by the desorption section of the primary generator, the generated high-purity ammonia gas enters the reabsorber and is absorbed by the ammonia water in the reabsorber; the other part of the high-purity ammonia gas generated by the high-pressure desorber enters the secondary absorber; the ammonia water in the secondary absorber absorbs high-pressure ammonia gas from the desorber and releases 120-160 DEG C high-temperature useful heat, the generated ammonia water with increased concentration is sent to the low-pressure secondary generator after being depressurized by a solution heat exchanger and a throttle valve; the ammonia water solution absorbs heat from the intermediate heat exchange pipeline in the secondary generator, the generated ammonia and water mixed vapor is separated by the desorption section of the secondary generator, the generated high-purity ammonia gas enters the reabsorber and is absorbed by the ammonia water in the reabsorber.

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

[0014] The application discloses a double-absorption-reabsorption parallel waste heat utilization and temperature-increasing heat pump system, which provides the absorption heat released by a primary absorber to a generator of a secondary cycle, improves the generation 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 a traditional system, and the desorber is used to replace the evaporator of the traditional system, so that the operation pressure of the absorption heat pump system is reduced, the safety of system operation is improved, and the strength requirement of system components is reduced. In addition, the desorbers and the reabsorbers of the two-stage cycle are combined, the system works under the optimal high-low pressure ratio of two pressure stages, has a better performance coefficient, and has a simplified structure. BRIEF DESCRIPTION OF DRAWINGS

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

[0016] Figure 1is a structure diagram of a double-absorption-reabsorption parallel waste heat utilization synergic temperature-increasing heat pump system according to the present application; the solid line represents the solution pipeline in the solution and refrigerant vapor pipeline, the dotted line represents the refrigerant vapor pipeline, and the dash-dot line represents the intermediate heat exchange pipeline.

[0017] In the figure, there are: a reabsorber 1, a resolver 2, a primary absorber 3, a primary generator 4, a secondary absorber 5, a secondary generator 6, a first solution heat exchanger 7, a second solution heat exchanger 8, a third solution heat exchanger 9, an intermediate heat exchange pipeline 10, a liquid discharge pipeline 11, a solution pump 12, a liquid feed pipeline 13, a throttle valve 14, and a vapor pipeline 15. DETAILED DESCRIPTION

[0018] The present application will be further illustrated below in combination with the accompanying drawings and specific examples.

[0019] Example 1

[0020] The heat pump system comprises a reabsorber 1, a resolver 2, a primary absorber 3, a primary generator 4, a secondary absorber 5, a secondary generator 6, and a solution heat exchanger; the discharge end of the reabsorber 1 is connected to the feed end of the resolver 2 through the liquid discharge pipeline 11, and the discharge end of the resolver 2 is connected to the feed end of the reabsorber 1 through the liquid feed pipeline 13; the discharge end of the primary generator 4 is connected to the feed end of the primary absorber 3 through the liquid discharge pipeline 11, and the discharge end of the primary absorber 3 is connected to the feed end of the primary generator 4 through the liquid feed pipeline 13; the discharge end of the secondary generator 6 is connected to the feed end of the secondary absorber 5 through the liquid discharge pipeline 11, and the discharge end of the secondary absorber 5 is connected to the feed end of the secondary generator 6 through the liquid feed pipeline 13.

[0021] Example 2

[0022] As an improvement of the present application, the vapor discharge end of the resolver 2 is connected to the vapor feed end of the primary absorber 3 and the secondary absorber 5 through the vapor pipeline 15 respectively; and the vapor discharge end of the primary generator 4 is connected to the vapor feed end of the reabsorber 1 and the secondary generator 6 through the vapor pipeline 15 respectively.

[0023] The remaining structural features and advantages are the same as those of Example 1.

[0024] Example 3

[0025] As an improvement of the present application, the heat exchange discharge end of the primary absorber 3 is connected to the heat exchange feed end of the secondary generator 6 through the intermediate heat exchange pipeline 10, and the heat exchange discharge end of the secondary generator 6 is connected to the heat exchange feed end of the primary absorber 3 through the intermediate heat exchange pipeline 10, forming a heat exchange loop.

[0026] The remaining structural features and advantages are the same as those of Embodiment 1 or 2.

[0027] Embodiment 4:

[0028] As an improvement of the present application, the liquid discharge pipe 11 is provided with a solution pump 12.

[0029] The remaining structural features and advantages are the same as those of Embodiment 1, 2 or 3.

[0030] Embodiment 5:

[0031] As an improvement of the present application, the liquid feed pipe 13 is provided with a throttle valve 14.

[0032] The remaining structural features and advantages are the same as those of Embodiment 1, 2, 3 or 4.

[0033] Embodiment 6:

[0034] As an improvement of the present application, the first solution heat exchanger 7 is arranged between the resorber 1 and the desorber 2, the second solution heat exchanger 8 is arranged between the primary absorber 3 and the primary generator 4, and the third solution heat exchanger 9 is arranged between the secondary absorber 5 and the secondary generator 6.

[0035] The remaining structural features and advantages are the same as those of Embodiment 1, 2, 3, 4 or 5.

[0036] The present application provides a double-absorption-resorption parallel waste heat utilization and temperature-increasing heat pump system. The working medium of the solution and refrigerant vapor pipeline of the double-absorption-resorption parallel waste heat utilization and temperature-increasing heat pump system is ammonia-water refrigeration working medium; and the working medium running in the intermediate heat exchange pipeline 10 is water.

[0037] The solution and refrigerant vapor pipeline comprises a resorber 1 (low-pressure absorption), a desorber 2 (high-pressure desorption), a primary absorber 3 (high-pressure absorption), a primary generator 4 (low-pressure generation), a secondary absorber 5 (high-pressure absorption), a secondary generator 6 (low-pressure generation), a first solution heat exchanger 7, a second solution heat exchanger 8, and a third solution heat exchanger 9; the liquid discharge pipe 11 is provided with a solution pump 12; and the liquid feed pipe 13 is provided with a throttle valve 14.

[0038] The ammonia-water solution in the resorber 1 comes from the desorber 2, and the absorbed low-pressure ammonia gas comes from the primary generator 4 and the secondary generator 6. The ammonia-water solution absorbs the ammonia gas in the resorber 1 and releases heat to a low-temperature environment of about 10℃, and the ammonia water with a higher concentration generated is finally sent into the desorber 2 after being pressurized by the solution pump 12 and preheated by the solution heat exchanger 7.

[0039] The ammonia water solution in the resolver 2 comes from the reabsorber 1. The high concentration ammonia water absorbs the industrial waste heat or other low grade heat around 70-110℃ in the resolver 2, and generates high pressure ammonia and water mixed steam and low concentration ammonia water. The ammonia and water mixed steam is condensed in the condensing section of the resolver 2, and the generated high purity ammonia gas is divided into two routes, one of which is sent into the first absorber 3, and the other is sent into the second absorber 5. The low concentration ammonia water generated by the resolver 2 is first released waste heat through the solution heat exchanger 7, then is depressurized through the throttle valve 14, and then is sent into the reabsorber 1.

[0040] The ammonia water solution in the first absorber 3 comes from the first generator 4, and the absorbed high pressure ammonia gas comes from the resolver 2. The ammonia water solution absorbs the ammonia gas in the first absorber 3, and releases heat to the intermediate heat exchange pipeline, and generates higher concentration ammonia water which is first released waste heat through the solution heat exchanger 8, then is depressurized through the throttle valve 14, and then is sent into the first generator 4.

[0041] The ammonia water solution in the first generator 4 comes from the first absorber 3. The higher concentration ammonia water absorbs the industrial waste heat or other low grade heat around 70-110℃ in the first generator 4, and generates low pressure ammonia and water mixed steam and low concentration ammonia water. The ammonia and water mixed steam is condensed in the condensing section of the first generator 4, and the generated high purity ammonia gas is sent into the reabsorber 1. The low concentration ammonia water generated by the first generator 4 is first pressurized through the solution pump 12, then is preheated through the solution heat exchanger 8, and then is sent into the first absorber 3.

[0042] The ammonia water solution in the second absorber 5 comes from the second generator 6, and the absorbed high pressure ammonia gas comes from the resolver 2. The ammonia water solution absorbs the ammonia gas in the second absorber 5, and releases high temperature useful heat energy around 120-160℃ to the user, and generates higher concentration ammonia water which is first released waste heat through the solution heat exchanger 9, then is depressurized through the throttle valve 14, and then is sent into the second generator 6.

[0043] The ammonia water solution in the second generator 6 comes from the second absorber 5. The higher concentration ammonia water absorbs the heat of the intermediate heat exchange pipeline in the second generator 6, and generates low pressure ammonia and water mixed steam and low concentration ammonia water. The ammonia and water mixed steam is condensed in the condensing section of the second generator 6, and the generated high purity ammonia gas is sent into the reabsorber 1. The low concentration ammonia water generated by the second generator 6 is first pressurized through the solution pump 12, then is preheated through the solution heat exchanger 9, and then is sent into the second absorber 5.

[0044] From the coupling mode of the two-stage system, the present application provides the absorption heat released by the first-stage absorber 3 to the generator 6 of the second-stage cycle, improves the generation temperature of the second-stage cycle, increases the air release range of the second-stage generator 6, and further can realize higher waste heat temperature promotion. In addition, the reabsorption cycle is adopted, the reabsorber is used to replace the traditional system condenser, and the resolver is used to replace the traditional system evaporator, so that the operation pressure of the absorption heat pump system is reduced, thereby improving the safety of the system operation and reducing the strength requirement of the system components, which is beneficial to reduce the cost. In addition, the resolver and the reabsorber of the two-stage cycle are combined, the system works at the optimal high-low pressure ratio of two pressure stages, has better performance coefficient and simpler structure, and is also beneficial to reduce the cost.

[0045] The above embodiments are only preferred technical solutions of the present application, and should not be regarded as a limitation of the present application. The protection scope of the present application should be the technical solutions recited in the claims, including the equivalent replacement solutions of the technical features recited in the claims, i.e. the equivalent replacement improvements within this range are also within the protection scope of the present application.

Claims

1. A dual-absorption-reabsorption parallel waste heat utilization and synergistic heating heat pump system, characterized in that: The heat pump system includes a reabsorber (1), a desorber (2), a primary absorber (3), a primary generator (4), a secondary absorber (5), a secondary generator (6), and a solution heat exchanger. The outlet of the reabsorber (1) is connected to the inlet of the desorber (2) via a liquid outlet pipe (11), and the outlet of the desorber (2) is connected to the inlet of the reabsorber (1) via a liquid inlet pipe (13). The outlet of the primary generator (4) is connected to the inlet of the primary absorber (3) via a liquid outlet pipe (11), and the outlet of the primary absorber (3) is connected to the inlet of the primary generator (4) via a liquid inlet pipe (13). The outlet of the secondary generator (6) is connected to the inlet of the secondary absorber (5) via a liquid outlet pipe (11), and the outlet of the secondary absorber (5) is connected to the inlet of the secondary generator (6) via a liquid inlet pipe (13). The steam outlet of the analyzer (2) is connected to the steam inlet of the first-stage absorber (3) and the second-stage absorber (5) respectively through the steam pipe (15); the steam outlet of the first-stage generator (4) is connected to the steam inlet of the reabsorber (1) and the second-stage generator (6) respectively through the steam pipe (15). The heat exchange outlet of the primary absorber (3) is connected to the heat exchange inlet of the secondary generator (6) through an intermediate heat exchange pipeline (10), and the heat exchange outlet of the secondary generator (6) is connected to the heat exchange inlet of the primary absorber (3) through an intermediate heat exchange pipeline (10), forming a heat exchange loop. A first solution heat exchanger (7) is provided between the reabsorber (1) and the resolver (2), a second solution heat exchanger (8) is provided between the first-stage absorber (3) and the first-stage generator (4), and a third solution heat exchanger (9) is provided between the second-stage absorber (5) and the second-stage generator (6).

2. The dual-absorption-reabsorption parallel waste heat utilization synergistic heating heat pump system according to claim 1, characterized in that: Each of the liquid discharge pipes (11) is equipped with a solution pump (12).

3. The dual-absorption-reabsorption parallel waste heat utilization synergistic heating heat pump system according to claim 1, characterized in that: Each of the liquid feed pipes (13) is equipped with a throttle valve (14).

4. The dual-absorption-reabsorption parallel waste heat utilization synergistic heating heat pump system according to claim 1, characterized in that: The heat pump system uses an environmentally friendly ammonia-water working fluid pair. The operation of the ammonia solution and refrigerant vapor pipeline is as follows: In the low-pressure reabsorber, the ammonia solution absorbs ammonia gas from the primary and secondary generators and releases heat to the environment at 8-12°C. The resulting ammonia solution, after being pressurized by a solution pump and preheated by a solution heat exchanger, is sent to the high-pressure desorber for desorption. In the desorber, the ammonia solution absorbs industrial waste heat or other low-grade heat at 70-110°C. The resulting ammonia-water mixed vapor is condensed in the decondensation section of the desorber, and a portion of the high-purity ammonia gas enters the primary absorber. In the primary absorber, the ammonia solution absorbs high-pressure ammonia gas from the desorber and releases heat to the intermediate heat exchange pipeline. The resulting ammonia solution, after being depressurized by a solution heat exchanger and a throttling valve, is sent to the low-pressure primary absorber. The generator consists of an ammonia solution that absorbs industrial waste heat or other low-grade heat at 70-110℃ in the primary generator. The resulting ammonia-water mixture vapor is condensed in the condensation section of the primary generator, producing high-purity ammonia gas which enters the reabsorber and is absorbed by the ammonia solution there. Another portion of the high-purity ammonia gas produced by the high-pressure desorber enters the secondary absorber. The ammonia solution in the secondary absorber absorbs the high-pressure ammonia gas from the desorber and releases high-temperature useful heat at 120-160℃. The resulting ammonia solution with increased concentration is depressurized by a solution heat exchanger and a throttling valve and then sent to the low-pressure secondary generator. The ammonia solution absorbs heat from the intermediate heat exchange pipeline in the secondary generator, and the resulting ammonia-water mixture vapor is condensed in the condensation section of the secondary generator, producing high-purity ammonia gas which enters the reabsorber and is absorbed by the ammonia solution there.

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