Multi-stage waste heat recovery heat exchange system

Abstract

The present application relates to the technical field of waste heat gas heat source heating or refrigeration, and particularly relates to a multi-stage waste heat recovery heat exchange system, which comprises an evaporator, an absorber, a condenser, a low-pressure generator, a first generator, a second generator and a heat source heat exchanger; a driving source sequentially passes through heat exchange pipes of the first generator, heat exchange pipes of the second generator and the heat source heat exchanger; the heat source heat exchanger is provided with a circulating water inlet and a circulating water outlet, and a circulating water pipeline is formed by connection between the circulating water inlet and the circulating water outlet; a gas outlet of the first generator is connected with an inlet of heat exchange pipes of the low-pressure generator, and an outlet of the heat exchange pipes of the low-pressure generator is connected with a liquid inlet of the condenser; a gas outlet of the second generator is connected with a gas inlet of the condenser. Through multi-stage recovery of the high-temperature waste heat gas heat source, the multi-stage waste heat recovery heat exchange system realizes deep recovery and utilization of waste flue gas heat, and improves energy utilization.

Description

Technical Field

[0001] This invention relates to the technical field of using waste heat gas as a heat source for heating or cooling, and in particular to a multi-stage waste heat recovery and heat exchange system. Background Technology

[0002] Currently, during the operation of thermal power plant systems, high-temperature waste heat gases are generated simultaneously. To fully utilize the heat from these waste heat gases, they are typically used for heating or cooling applications.

[0003] During refrigeration, waste heat gas is used as a heat source to exchange heat with a plate heat exchanger to produce hot water, which is then used to drive the refrigeration unit for cooling; or the waste heat gas is used directly as a heat source to drive the refrigeration unit for cooling.

[0004] During heating, hot water is directly produced by exchanging heat between the high-temperature exhaust gas from the generator and the heating water.

[0005] The drawback of using high-temperature waste heat gas as a heat source for cooling and heating is that the recovery temperature of the recovered gas heat source is limited by the temperature of the heated fluid, making it impossible to fully utilize the high-temperature waste heat gas heat source, resulting in low energy utilization and low energy-saving effect. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects in the existing technology and propose a waste heat recovery and heat exchange system, which realizes the deep recovery and utilization of heat from waste flue gas through multi-stage recovery of high-temperature waste heat gas heat source, thereby improving energy utilization efficiency.

[0007] The technical solution of the present invention is: a waste heat recovery heat exchange system, comprising an evaporator, an absorber, a condenser, a low-pressure generator, a first generator, a second generator, and a heat source absorber;

[0008] The driving source passes sequentially through the heat exchange tubes of the first generator, the heat exchange tubes of the second generator, and the heat source absorber. The heat source absorber is equipped with a circulating water inlet and a circulating water outlet, and the circulating water inlet and the circulating water outlet are connected to form a circulating water pipeline.

[0009] The gas outlet of the first generator is connected to the heat exchange tube inlet of the low-pressure generator, and the heat exchange tube outlet of the low-pressure generator is connected to the liquid inlet of the condenser.

[0010] The gas outlet of the second generator is connected to the gas inlet of the condenser.

[0011] In this invention, the absorber and condenser are respectively provided with a heating water inlet and a heating water outlet, and the heat exchange tubes in the absorber and condenser are respectively connected to the heating water inlet and the heating water outlet, and the heat exchange tubes in the absorber and condenser are connected in series.

[0012] The evaporator is equipped with two heat exchange tubes. The two ends of the first heat exchange tube are connected to the waste heat source inlet and the waste heat source outlet, respectively, and the second heat exchange tube is connected in series with the circulating water pipeline.

[0013] The absorber and condenser are respectively provided with a cooling water inlet and a cooling water outlet. The heat exchange tubes in the absorber and condenser are respectively connected to the cooling water inlet and the cooling water outlet. The heat exchange tubes in the absorber and condenser are connected in series.

[0014] The heat exchange tubes of the evaporator are connected at both ends to the cold water inlet and the cold water outlet, respectively.

[0015] A heat exchanger is provided between the pipeline connected to the liquid outlet of the generator and the circulating water pipeline. The heat absorbed by the circulating water from the driving source is transferred to the dilute solution flowing out of the generator in the heat exchanger.

[0016] The liquid outlet of the absorber is connected to the liquid inlet at the top of the second generator, the liquid outlet of the second generator is connected to the liquid inlet at the top of the first generator, the liquid outlet of the first generator is connected to the liquid inlet at the top of the low-pressure generator, and the liquid outlet of the low-pressure generator is connected to the liquid inlet at the top of the absorber.

[0017] A low-temperature heat exchanger is provided between the connecting pipe between the liquid outlet of the absorber and the liquid inlet of the second generator and the connecting pipe between the liquid outlet of the low-pressure generator and the liquid inlet of the absorber.

[0018] A high-temperature heat exchanger is provided between the connecting pipe between the liquid outlet of the second generator and the liquid inlet of the first generator, and between the connecting pipe between the liquid outlet of the first connecting pipe and the liquid inlet of the low-pressure generator.

[0019] The liquid outlet of the absorber is connected to the liquid inlet at the top of the low-pressure generator, the liquid outlet of the low-pressure generator is connected to the liquid inlet at the top of the first generator, the liquid outlet of the first generator is connected to the liquid inlet at the top of the second generator, and the liquid outlet of the second generator is connected to the liquid inlet at the top of the absorber.

[0020] A low-pressure heat exchanger is provided between the connecting pipeline between the liquid outlet of the absorber and the liquid inlet of the low-pressure generator and the connecting pipeline between the liquid outlet of the second generator and the liquid inlet of the absorber.

[0021] A high-temperature heat exchanger is provided between the connecting pipe between the liquid outlet of the low-pressure generator and the liquid inlet of the first generator, and between the connecting pipe between the liquid outlet of the first generator and the liquid inlet of the second generator.

[0022] The gas outlet of the evaporator and the gas inlet of the absorber are connected by a steam channel;

[0023] The gas outlet of the low-pressure generator and the gas inlet of the condenser are connected by a steam channel.

[0024] The liquid outlet of the condenser is connected to the liquid inlet of the evaporator.

[0025] The beneficial effects of this invention are:

[0026] (1) When using this system for heating, the heating water is heated in stages, thereby raising the temperature of the heating water above that of conventional heating technology.

[0027] (2) By performing triple heat recovery on waste heat source water, the goal of maximizing the heat recovery of heat source water can be achieved;

[0028] (3) By applying the heat of the driving source three times, the solution is generated twice and recovered once, which realizes the deep recovery and utilization of the heat of the waste flue gas. This breaks the limitation of the existing refrigeration unit that the heat recovery of the high temperature waste heat gas heat source cannot be too low. It can reduce the temperature of the high temperature waste heat gas heat source to close to the normal temperature under the refrigeration condition, reduce the equipment operating cost, improve the energy utilization rate, and thus realize the maximum application of energy. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention in Embodiment 1;

[0030] Figure 2 This is a schematic diagram of the structure of the present invention in Embodiment 2;

[0031] Figure 3 This is a schematic diagram of the structure of the present invention in Embodiment 3;

[0032] Figure 4 This is a schematic diagram of the structure of the present invention in Embodiment 4.

[0033] In the diagram: 1. Evaporator; 2. Absorber; 3. Condenser; 4. Low-pressure generator; 5. First generator; 6. Second generator; 7. Heat source absorber; 8. Low-temperature heat exchanger; 9. High-temperature heat exchanger; 10. Heat source heat exchanger; 11. Dilute solution pump; 12. Intermediate solution pump; 13. Concentrated solution pump; 14. Refrigerant pump; 15. Baffle plate; 16. Drip device; 17. First connecting pipe; 18. Second connecting pipe; 19. Third connecting pipe; 20. Fourth connecting pipe; 20'. Circulating water pump; 21. Circulating water pipe; 22. Fifth connecting pipe; 23. Sixth connecting pipe; 24. Seventh connecting pipe; 25. Eighth connecting pipe. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] Specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Example

[0036] like Figure 1 As shown, this embodiment of a multi-stage waste heat recovery heat exchange system achieves a refrigeration function. The system includes an evaporator 1, an absorber 2, a condenser 3, a low-pressure generator 4, a first generator 5, and a second generator 6. A steam passage connects the evaporator 1 and the absorber 2, and a baffle plate 15 is installed within the steam passage. A steam passage also connects the condenser 3 and the low-pressure generator 4, and a baffle plate 15 is installed within the steam passage.

[0037] Both the absorber 2 and the condenser 3 are equipped with cooling water inlets and outlets. One end of the heat exchange tube in the absorber 2 is connected to the cooling water inlet, and the other end is connected to the cooling water outlet. Similarly, one end of the heat exchange tube in the condenser 3 is connected to the cooling water inlet, and the other end is connected to the cooling water outlet. In this embodiment, the cooling water inlets and outlets on the absorber 2 and condenser 3 are connected in series; that is, the cooling water outlet on the absorber 2 is connected to the cooling water inlet on the condenser 3 via a connecting pipe, or vice versa. Cooling water flows sequentially through the absorber 2 and condenser 3. Within the absorber 2 and condenser 3, the cooling water in the heat exchange tubes absorbs heat from the refrigerant, carrying away heat from the absorber 2 and condenser 3, causing the cooling water temperature to gradually increase.

[0038] In this embodiment, the driving source is a high-temperature waste heat gas heat source. The first generator 5, the second generator 6, and the heat source absorber 7 are all equipped with a heat source inlet and a heat source outlet. The heat exchange tubes in the first generator 5, the second generator 6, and the heat source absorber 7 are connected to the heat source inlet and the heat source outlet, respectively. In this embodiment, the heat source inlets and outlets on the first generator 5, the second generator 6, and the heat source absorber 7 are connected in series; that is, the heat source outlet of the first generator 5 is connected to the heat source inlet of the second generator 6 via a connecting pipe, and the heat source outlet of the second generator 6 is connected to the heat source inlet of the heat source absorber 7 via a connecting pipe. As the high-temperature waste heat gas flows sequentially through the heat exchange tubes of the first generator 5, the second generator 6, and the heat source absorber 7, the heat from the high-temperature waste heat gas heat source is absorbed sequentially, achieving full utilization of the heat from the high-temperature waste heat gas heat source.

[0039] Evaporator 1 is equipped with a cold water inlet and a cold water outlet. One end of the heat exchange tube inside the evaporator is connected to the cold water inlet, and the other end of the heat exchange tube is connected to the cold water outlet, thus realizing the flow of cold water in the heat exchange tube of the evaporator.

[0040] The liquid outlet at the bottom of the absorber 2 is connected to the liquid inlet at the top of the second generator 6 via a first connecting pipe 17. A dripping device 16 is provided at the liquid inlet at the top of the second generator 6. A dilute solution pump 11 is provided on the first connecting pipe 17. Under the power of the dilute solution pump, the dilute solution in the absorber 2 enters the second generator 6 through the first connecting pipe 17 and is dripped onto the outer surface of the heat exchange tubes in the second generator 6 by the dripping device 16.

[0041] Inside the second generator 6, the dilute solution absorbs heat from the high-temperature waste heat gas in the heat exchange tubes, generating low-temperature refrigerant vapor. Simultaneously, the dilute solution is concentrated into a first intermediate solution. A vapor channel is provided between the top of the second generator 6 and the top of the condenser 3, and a baffle plate 15 is installed within the vapor channel. The low-temperature refrigerant vapor enters the condenser 3 through the outlet at the top of the second generator 6. The outlet of the second generator 6 is connected to the inlet at the top of the first generator 5 via a second connecting pipe 18. An intermediate solution pump 12 is installed on the second connecting pipe, pumping the intermediate solution from the second generator 6 into the first generator 5.

[0042] A dripping device 16 is provided at the liquid inlet of the first generator 5. The first intermediate solution is dripped onto the surface of the heat exchange tube of the first generator 5 by the dripping device 16. The first intermediate solution absorbs heat from the high-temperature waste heat gas in the heat exchange tube, generating high-temperature refrigerant vapor, while the first intermediate solution is concentrated into a second intermediate solution. The gas outlet at the top of the first generator 5 is connected to the heat exchange tube of the low-pressure generator 4 through a steam channel, and a baffle plate 15 is provided in the steam channel. The liquid outlet of the first generator 5 is connected to the liquid inlet at the top of the low-pressure generator 4 through a third connecting pipe 19.

[0043] A dripping device 16 is provided at the liquid inlet at the top of the low-pressure generator 4. High-temperature refrigerant vapor enters the heat exchange tube of the low-pressure generator 4 along the vapor channel. At the same time, the second intermediate solution generated by the first generator 5 enters the low-pressure generator 4 along the third connecting pipe 19 under the action of pressure difference, and drips onto the outer surface of the heat exchange tube of the low-pressure generator through the dripping device 16.

[0044] A high-temperature heat exchanger 9 is provided between the second connecting pipe 18 and the third connecting pipe 19. Inside the high-temperature heat exchanger 9, the first intermediate solution flowing out from the second generator 6 absorbs the heat from the second intermediate solution flowing out from the first generator, thus forming internal heat recovery.

[0045] Inside the low-pressure generator 4, the second intermediate solution absorbs heat from the high-temperature refrigerant vapor in the heat exchange tubes. After heating, the solution absorbs heat to generate low-temperature refrigerant vapor, which enters the condenser 3 through the vapor channel between the low-pressure generator 4 and the condenser 3, where the second intermediate solution is concentrated into a concentrated solution. Simultaneously, the high-temperature refrigerant vapor in the heat exchange tubes releases heat to form refrigerant water. The outlet of the low-pressure generator 4 is connected to the inlet at the top of the absorber 2 via a fourth connecting pipe 20. A concentrated solution pump 13 is installed on the fourth connecting pipe 20, which pumps the concentrated solution generated in the low-pressure generator 4 into the absorber 2.

[0046] A low-temperature heat exchanger 8 is provided between the fourth connecting pipe 20 and the first connecting pipe 17. Inside the low-temperature heat exchanger 8, the dilute solution flowing out from the absorber 2 absorbs heat from the concentrated solution from the low-pressure generator 4, forming an internal heat recovery.

[0047] Inside the condenser 3, the cooling water in its heat exchange tubes absorbs the low-temperature refrigerant vapor from the second generator 6 and the low-temperature refrigerant vapor from the low-pressure generator 4, and merges with the refrigerant water from the heat exchange tubes of the low-pressure generator 4 in the condenser 3, and flows into the evaporator 1 through the U-shaped tube.

[0048] The liquid outlet at the bottom of evaporator 1 is connected to a dripping device at the top of the evaporator via a connecting pipe. A refrigerant pump 14 is installed at the liquid outlet of the evaporator. Powered by the refrigerant pump, the refrigerant in evaporator 1 is pumped into the dripping device 16 at the top of the evaporator and drips onto the surface of the heat exchange tubes. Cold water flows inside the heat exchange tubes of evaporator 1. The refrigerant water absorbs heat from the cold water in the heat exchange tubes and evaporates to form refrigerant vapor. The refrigerant vapor enters the absorber 2 through the vapor channel between evaporator 1 and absorber 2. Inside the evaporator, the temperature of the cold water is lowered.

[0049] A dripping device 16 is provided at the liquid inlet at the top of the absorber 2. The concentrated solution from the low-pressure generator 4 is dripped onto the outer surface of the heat exchange tube. The refrigerant vapor from the evaporator 1 is absorbed by the concentrated solution dripped onto the outer surface of the heat exchange tube. At the same time, the absorption heat is released. This absorption heat is absorbed by the circulating cooling water in the heat exchange tube of the absorber. At the same time, the concentrated solution becomes a dilute solution, realizing the solution circulation in the system.

[0050] The aforementioned high-temperature waste heat gas heat source passes sequentially through the first generator 5 and the second generator 6 before entering the heat source absorber 7. There, it exchanges heat with circulating water on the other side of the heat source absorber 7, with the circulating water absorbing the heat from the high-temperature waste heat gas heat source. The heat source absorber 7 has a circulating water outlet at its bottom and a circulating water inlet at its top. A circulating water pipeline 21 connects the circulating water inlet and outlet. A circulating water pump 20' is located at the circulating water outlet, enabling the circulating water to circulate within the circulating water pipeline 21. A heat source heat exchanger 10 connects the circulating water pipeline 21 and the first connecting pipeline 17. Within the heat source heat exchanger 10, a dilute solution from the absorber absorbs heat from the circulating water in the circulating water pipeline. The residual heat from the high-temperature waste heat gas heat source that was not fully recovered by the second generator 6 is absorbed by the circulating water and transferred to the dilute solution through heat transfer between the circulating water and the dilute solution. This not only achieves full recovery and utilization of the heat from the high-temperature waste heat gas heat source, but also enables the temperature of the high-temperature waste heat gas heat source to be reduced to normal temperature, thereby reducing the amount of heat source used, reducing energy waste and environmental thermal pollution, and improving the performance of the entire unit.

[0051] The working principle of this invention is as follows: The dilute solution in absorber 2, driven by the dilute solution pump, flows into the second generator 6 through the first connecting pipe 17. During its flow within the first connecting pipe 17, it absorbs heat from the high-temperature waste heat gas in the heat source heat exchanger 10 and heat from the concentrated solution in the low-temperature heat exchanger 8. After entering the second generator 6, the dilute solution is heated by the high-temperature waste heat gas in the heat exchange tubes, causing the refrigerant water in the dilute solution to evaporate and generate low-temperature refrigerant vapor. The dilute solution is then concentrated into the first intermediate solution. The low-temperature refrigerant vapor is transported to the condenser 3 under pressure difference. The first intermediate solution, driven by the intermediate solution pump 12, flows into the first generator 5 through the second connecting pipe 18. During its flow within the second connecting pipe 18, it absorbs heat from the second intermediate solution in the high-temperature heat exchanger 9.

[0052] After the first intermediate solution enters the first generator 5, it is heated by the high-temperature waste heat gas in the heat exchange tube. The refrigerant water in the first intermediate solution evaporates to generate high-temperature refrigerant vapor, and the first intermediate solution is concentrated into the second intermediate solution. The high-temperature refrigerant vapor is transported to the low-pressure generator 4 under the action of pressure difference, and the second intermediate solution is transported to the heat exchange tube of the low-pressure generator 4 under the action of pressure difference.

[0053] After the second intermediate solution enters the low-pressure generator 4, it is heated by the high-temperature refrigerant vapor in the heat exchange tube. The refrigerant water in the second intermediate solution evaporates to produce low-temperature refrigerant vapor, and the second intermediate solution is concentrated into a concentrated solution. The low-temperature refrigerant vapor is transported to the condenser 3 under the action of the pressure difference, and the concentrated solution is transported to the absorber 2 by the action of the concentrated solution pump 13.

[0054] Inside condenser 3, the low-temperature refrigerant vapor from the second generator 6 and the low-pressure generator 4 absorb heat from the cooling water in the condenser heat exchange tubes and condense into refrigerant water. At the same time, the high-temperature refrigerant vapor in the heat exchange tubes of the low-pressure generator 4 releases heat and condenses into refrigerant water, which also flows into condenser 3. After merging in condenser 3, the refrigerant water flows into the evaporator, realizing the circulation of refrigerant water throughout the system.

[0055] Inside absorber 2, the concentrated solution absorbs refrigerant vapor from evaporator 1, turning the concentrated solution into a dilute solution, thus realizing the circulation of the solution throughout the system. Example

[0056] like Figure 2 As shown, the multi-stage waste heat recovery heat exchange system in this embodiment is also used for refrigeration. The difference from Embodiment 1 is that in this embodiment, the liquid outlet at the bottom of the absorber 2 is connected to the liquid inlet at the top of the low-pressure generator 4 via a fifth connecting pipe 22. A dripping device 16 is provided at the liquid inlet at the top of the low-pressure generator 4. A dilute solution pump 11 is provided at the liquid outlet at the bottom of the absorber 2 to pump the dilute solution in the absorber 2 into the low-pressure generator 4.

[0057] After the dilute solution enters the low-pressure generator 4, it is dripped onto the surface of the heat exchange tubes by the dripping device 16. This dripping absorbs heat from the high-temperature refrigerant vapor inside the heat exchange tubes, causing the refrigerant water in the dilute solution to evaporate into refrigerant vapor. The refrigerant vapor then enters the condenser 3 through the vapor passage between the low-pressure generator 4 and the condenser 3. The dilute solution is then concentrated into a third intermediate solution. The outlet at the bottom of the low-pressure generator 4 is connected to the inlet at the top of the first generator 5 via a sixth connecting pipe 23. An intermediate solution pump 12 is installed on the sixth connecting pipe 23, which pumps the third intermediate solution into the first generator 5.

[0058] A dripping device 16 is provided at the liquid inlet at the top of the first generator 5. After the third intermediate solution enters the first generator 5, it is dripped onto the surface of the heat exchange tubes and absorbs heat from the high-temperature waste heat gas heat source inside the heat exchange tubes. The refrigerant water in the third intermediate solution is evaporated into high-temperature refrigerant vapor, which flows into the heat exchange tubes of the low-pressure generator 4 through the vapor channel. At the same time, the third intermediate solution is concentrated into a fourth intermediate solution.

[0059] The outlet of the first generator 5 is connected to the inlet at the top of the second generator 6 via a seventh connecting pipe 24. A dripping device 16 is installed at the inlet at the top of the second generator 6. Under the action of a pressure difference, the fourth intermediate solution generated by the first generator 5 flows into the second generator 6. After entering the second generator 6, the fourth intermediate solution is dripped onto the surface of the heat exchange tubes and absorbs heat from the high-temperature waste heat gas inside the heat exchange tubes. The refrigerant water in the fourth intermediate solution is evaporated into low-temperature refrigerant vapor, which flows into the condenser 3 through the vapor channel under the action of a pressure difference. The fourth intermediate solution is then concentrated into a concentrated solution.

[0060] The outlet of the second generator 6 is connected to the inlet at the top of the absorber 2 via the eighth connecting pipe 25. A dripping device 16 is provided at the inlet at the top of the absorber 2. A concentrated solution pump 13 is provided on the eighth connecting pipe 25, and the concentrated solution in the second generator is pumped into the absorber 2.

[0061] A heat source heat exchanger 10 is installed between the fifth connecting pipe 22 and the circulating water pipe 21 of the heat source heat exchanger. Through the heat source heat exchanger 10, the heat from the high-temperature waste heat gas heat source absorbed by the circulating water is transferred to the dilute solution, realizing the full utilization of the heat from the high-temperature waste heat gas heat source. A low-temperature heat exchanger 8 is installed between the fifth connecting pipe 22 and the eighth connecting pipe 25. In the low-temperature heat exchanger, the dilute solution in the fifth connecting pipe 22 absorbs the heat from the concentrated solution in the eighth connecting pipe 25, realizing internal heat recovery. A high-temperature heat exchanger 9 is installed between the sixth connecting pipe 23 and the seventh connecting pipe 24. The third intermediate solution in the sixth connecting pipe 23 absorbs the heat from the fourth intermediate solution in the seventh connecting pipe 24, realizing internal heat recovery.

[0062] Unlike Example 1, in this example, the solution gradually flows from the low-pressure generator 4 to the first generator 5 and the second generator 6. Therefore, the pressure of the generator is relatively low. However, since the solution concentration in the first generator is high, crystallization is likely to occur in the pipeline of the unit, which is not conducive to the flow of the solution in the pipeline.

[0063] In Example 1, the solution gradually flows from the second generator to the first generator and the low-pressure generator. Therefore, the generator requires a higher pressure. However, the solution concentration in the first generator is relatively low, so crystallization is not likely to occur in the pipeline. Example

[0064] Unlike Example 1, the multi-stage waste heat recovery heat exchange system in this example is mainly used to achieve the heating function.

[0065] The condenser 3 and absorber 2 are respectively provided with heating water inlet and heating water outlet. The two ends of the heat exchange tubes of the condenser 3 and absorber 2 are connected to the heating water inlet and heating water outlet respectively. The heat exchange tubes of the condenser 3 and absorber 2 are connected in series. In this embodiment, the heating water inlet and heating water outlet on the condenser 3 and absorber 2 are arranged in series, and the heating water outlet of the condenser 3 is connected to the heating water inlet of the absorber 2, that is, the heating water flows sequentially in the heat exchange tubes of the condenser 3 and the heat exchange tubes of the absorber 2.

[0066] Evaporator 1 includes two sets of heat exchange tubes. Evaporator 1 is equipped with a waste heat source inlet, a waste heat source outlet, a circulating water inlet, and a circulating water outlet. One set of heat exchange tubes is connected to the waste heat source inlet and the waste heat source outlet at both ends, and waste hot water flows through this heat exchange tube. The other set of heat exchange tubes is connected in series at both ends to the circulating water pipeline 21, and circulating water flows through this heat exchange tube.

[0067] Inside evaporator 1, the heat absorbed during the evaporation of refrigerant water into refrigerant vapor mainly comes from two sources: one is the heat from the waste hot water, and the other is the heat absorbed by the circulating water from the high-temperature waste heat gas heat source.

[0068] The circulation process in this embodiment includes internal circulation and external circulation. The external circulation includes waste heat source circulation, high-temperature waste heat gas heat source circulation, and heating water circulation. The internal circulation includes solution circulation and refrigerant circulation.

[0069] The waste heat source circulation occurs within the evaporator 1. The waste heat source enters the heat exchange tube of the evaporator 1 and exchanges heat with the refrigerant in the evaporator 1, transferring the heat from the waste heat source to the heating water in the absorber 2 through the refrigerant.

[0070] The high-temperature waste heat gas heat source circulation mainly takes place in the low-pressure generator 4, the first generator 5, the second generator 6, and the heat source heat exchanger. In the first generator 5, the high-temperature waste heat gas heat source heats the generator 5, generating heat from the solution within it, separating the solution from the refrigerant, achieving regeneration and recovery of the refrigerant and the concentrated solution. In the second generator 6, the high-temperature waste heat gas heat source heats the generator 6, generating heat from the solution within it, separating the solution from the refrigerant, achieving regeneration and recovery of the refrigerant and the concentrated solution. The refrigerant vapor generated in the first generator 5 further enters the low-pressure generator 4 for secondary heating of the solution. Simultaneously, the high-temperature waste heat gas heat source emitted from the second generator 6 enters the heat source absorber 7, where the circulating water further recovers the heat from the high-temperature waste heat gas heat source, and then transports it to the evaporator 1 through the circulating water pipeline.

[0071] The heating water circulation occurs within absorber 2 and condenser 3. In absorber 2, the latent heat of liquefaction generated by the solution absorbing refrigerant vapor is absorbed by the heating water. In condenser 3, heat from the refrigerant vapor in the first generator 5 and the refrigerant water in the second generator 6 is absorbed by the heating water. The absorbed heat originates from waste heat sources and high-temperature waste heat gas sources, respectively, and the heating water undergoes staged temperature increase and heat exchange within the absorber and condenser, raising its temperature to the desired level.

[0072] During the solution circulation process, the concentrated solution from the low-pressure generator 4 in absorber 2 is dripped onto the surface of the heat exchange tubes of the absorber through a dripping device, absorbing refrigerant vapor from evaporator 1, thus diluting the solution concentration and producing a dilute solution. The heat generated by the concentrated solution absorbing the refrigerant vapor is transferred to the heating water through the heat exchange tubes.

[0073] The dilute solution from absorber 2 is pumped to the second generator 6 via dilute solution pump 11. During this process, heat from the concentrated solution in the low-temperature generator is absorbed in the low-temperature heat exchanger 8. Inside the second generator 6, high-temperature waste heat gas in its heat exchange tubes heats the dilute solution, generating low-temperature refrigerant vapor. This vapor is then transported to the condenser 3 via a vapor channel. The dilute solution is then concentrated into a fifth intermediate solution.

[0074] The fifth intermediate solution in the second generator 6 is transported to the first generator 5 via the intermediate solution pump 12. During the transport process, the fifth intermediate solution absorbs heat from the sixth intermediate solution in the first generator within the high-temperature heat exchanger 9. In the first generator 5, the fifth intermediate solution is heated by a high-temperature waste heat gas source within its heat exchange tubes, generating high-temperature refrigerant vapor. This high-temperature refrigerant vapor enters the heat exchange tubes of the low-temperature generator 4 through a vapor channel. The fifth intermediate solution is then concentrated into the sixth intermediate solution. Due to the pressure difference between the first generator 5 and the low-pressure generator 4, the sixth intermediate solution passes through the high-temperature heat exchanger 9 and enters the low-pressure generator 4.

[0075] Inside the low-pressure generator 4, the sixth intermediate solution is heated and regenerated by the high-temperature refrigerant vapor in the heat exchange tube. The refrigerant in the sixth intermediate solution absorbs heat and evaporates into low-temperature refrigerant vapor, which enters the condenser 3 along the vapor channel. The sixth intermediate solution is concentrated into a concentrated solution, and after passing through the low-temperature heat exchanger 8 via the concentrated solution pump 13, it enters the absorber 2.

[0076] During the refrigerant circulation process, the refrigerant water in evaporator 1 is transported to the top of evaporator 1 by refrigerant pump 14, and drips onto the surface of heat exchange tubes through dripping device 16. After absorbing the heat from the waste heat source in the heat exchange tubes and the heat from the high-temperature waste heat gas source, the refrigerant water evaporates into gas. The refrigerant vapor enters the absorber 2 through the vapor channel and is absorbed by the concentrated solution.

[0077] As the solution circulates, the refrigerant is generated in the second generator 6, and a portion is recovered and returned to the condenser 3. There, it exchanges heat with the heating water in the condenser's heat exchange tubes, condensing into refrigerant water and transferring heat to the heating water. The remaining refrigerant circulates back to the first generator 5, where a portion is condensed by the low-pressure generator 4 and returned to the condenser 3. The remaining refrigerant circulates through the intermediate solution back to the low-pressure generator 4, where it is heated by the high-temperature refrigerant steam generated in the first generator. After being heated, it is returned to the condenser 3 through the steam channel, where it exchanges heat with the heating water in the condenser's heat exchange tubes, condensing into refrigerant water and transferring heat to the heating water. The refrigerant water in the condenser 3 is then transported by gravity to the evaporator 1 to replenish the consumed refrigerant water.

[0078] Everything else is the same as in Example 1. Example

[0079] like Figure 4 As shown, the multi-stage waste heat recovery heat exchange system in this embodiment is used to achieve heating function. Unlike embodiment 3, the liquid outlet at the bottom of the absorber 2 is connected to the liquid inlet at the top of the low-pressure generator 4, and a dripping device 16 is provided at the liquid inlet at the top of the low-pressure generator 4. A dilute solution pump 11 is provided at the liquid outlet at the bottom of the absorber 2 to pump the dilute solution in the absorber 2 into the low-pressure generator 4.

[0080] After the dilute solution enters the low-pressure generator 4, it is dripped onto the surface of the heat exchange tubes by the dripping device 16. This dripping absorbs heat from the high-temperature refrigerant vapor inside the heat exchange tubes, causing the refrigerant water in the dilute solution to evaporate into refrigerant vapor. The refrigerant vapor then enters the condenser 3 through the vapor channel between the low-pressure generator 4 and the condenser 3. The dilute solution is then concentrated into the seventh intermediate solution. The outlet at the bottom of the low-pressure generator 4 is connected to the inlet at the top of the first generator 5. An intermediate solution pump 12 is installed at the outlet at the bottom of the low-pressure generator 4, pumping the seventh intermediate solution into the first generator 5.

[0081] A dripping device 16 is installed at the liquid inlet at the top of the first generator 5. After the seventh intermediate solution enters the first generator 5, it is dripped onto the surface of the heat exchange tubes and absorbs heat from the high-temperature waste heat gas inside the heat exchange tubes. The refrigerant water in the third intermediate solution is evaporated into high-temperature refrigerant vapor, which flows into the heat exchange tubes of the low-pressure generator 4 through the vapor channel. At the same time, the seventh intermediate solution is concentrated into the eighth intermediate solution.

[0082] The outlet at the bottom of the first generator 5 is connected to the inlet at the top of the second generator 6. A dripping device 16 is installed at the inlet at the top of the second generator 6. Under the pressure difference between the first generator 5 and the second generator 6, the eighth intermediate solution in the first generator 5 flows into the second generator 6. After entering the second generator 6, the eighth intermediate solution is dripped onto the surface of the heat exchange tubes and absorbs heat from the high-temperature waste heat gas in the heat exchange tubes. The refrigerant water in the eighth intermediate solution is evaporated into low-temperature refrigerant vapor. Under the pressure difference between the second generator 6 and the condenser 3, the low-temperature refrigerant vapor flows into the condenser 3 through the vapor channel. The eighth intermediate solution is concentrated into a concentrated solution.

[0083] The outlet at the bottom of the second generator 6 is connected to the inlet at the top of the absorber 2. A dripping device 16 is provided at the inlet at the top of the absorber 2. A concentrated solution pump 13 is provided at the outlet at the bottom of the second generator 6, and the concentrated solution in the second generator is pumped into the absorber 2.

[0084] A low-temperature heat exchanger 8 is installed between the connecting pipes of absorber 2 and low-pressure generator 4 and the connecting pipes of second generator 6 and absorber 2. Inside the low-temperature heat exchanger, the dilute solution flowing out of the absorber absorbs heat from the concentrated solution flowing out of the second generator, achieving internal heat recovery. A high-temperature heat exchanger 9 is installed between the connecting pipes of low-pressure generator 4 and first generator 5 and the connecting pipes of first generator 5 and second generator 6. The eighth intermediate solution flowing out of the first generator absorbs heat from the seventh intermediate solution flowing out of the low-temperature generator, achieving internal heat recovery.

[0085] The following are the differences between Example 3 and Example 4.

[0086] The heating water flowing out of the heating water outlet in this embodiment has a relatively high temperature and a relatively high solution concentration. When a high-temperature heat source heats a high-concentration solution, the solution is prone to crystallization. The precipitated crystals adhere to the inner wall of the pipe, affecting the flow of the solution within the pipe.

[0087] In Example 3, the temperature of the heating water flowing out of the heating water outlet is relatively low, and its solution concentration is also relatively low. At this time, the solution is not easy to crystallize and precipitate, ensuring the normal flow of the solution in the pipe.

[0088] Everything else is the same as in Example 3.

[0089] The multi-stage recovery heating and cooling system provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention. The above description of the disclosed embodiments enables those skilled in the art to implement or use this invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this invention. Therefore, this invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-stage waste heat recovery heat exchange system, characterized in that, It includes an evaporator, absorber, condenser, low-pressure generator, first generator, second generator, and heat source absorber; The driving source passes sequentially through the heat exchange tubes of the first generator, the heat exchange tubes of the second generator, and the heat exchange tubes of the heat source absorber. The heat source absorber is provided with a circulating water inlet and a circulating water outlet, and the circulating water inlet and the circulating water outlet are connected to form a circulating water pipeline. The gas outlet of the first generator is connected to the heat exchange tube inlet of the low-pressure generator, and the heat exchange tube outlet of the low-pressure generator is connected to the liquid inlet of the condenser. The gas outlet of the second generator is connected to the gas inlet of the condenser; The liquid outlet of the absorber is connected to the liquid inlet at the top of the second generator, the liquid outlet of the second generator is connected to the liquid inlet at the top of the first generator, the liquid outlet of the first generator is connected to the liquid inlet at the top of the low-pressure generator, and the liquid outlet of the low-pressure generator is connected to the liquid inlet at the top of the absorber. A low-temperature heat exchanger is provided between the connecting pipe between the liquid outlet of the absorber and the liquid inlet of the second generator and the connecting pipe between the liquid outlet of the low-pressure generator and the liquid inlet of the absorber. At this time, a high-temperature heat exchanger is provided between the connecting pipe between the liquid outlet of the second generator and the liquid inlet of the first generator and the connecting pipe between the liquid outlet of the first connecting pipe and the liquid inlet of the low-pressure generator. or, The liquid outlet of the absorber is connected to the liquid inlet at the top of the low-pressure generator, the liquid outlet of the low-pressure generator is connected to the liquid inlet at the top of the first generator, the liquid outlet of the first generator is connected to the liquid inlet at the top of the second generator, and the liquid outlet of the second generator is connected to the liquid inlet at the top of the absorber. A low-temperature heat exchanger is installed between the connecting pipe between the liquid outlet of the absorber and the liquid inlet of the low-pressure generator, and between the connecting pipe between the liquid outlet of the second generator and the liquid inlet of the absorber. A high-temperature heat exchanger is installed between the connecting pipe between the liquid outlet of the low-pressure generator and the liquid inlet of the first generator, and between the connecting pipe between the liquid outlet of the first generator and the liquid inlet of the second generator.

2. The multi-stage waste heat recovery heat exchange system according to claim 1, characterized in that, The condenser and absorber are respectively provided with heating water inlet and heating water outlet, and the heat exchange tubes in the condenser and absorber are respectively connected to the heating water inlet and heating water outlet, and the heat exchange tubes of the condenser and absorber are connected in series. The evaporator is equipped with two sets of heat exchange tubes. The two ends of the first set of heat exchange tubes are connected to the waste heat source inlet and the waste heat source outlet, respectively, and the second set of heat exchange tubes is connected in series with the circulating water pipeline.

3. The multi-stage waste heat recovery heat exchange system according to claim 1, characterized in that, The absorber and condenser are respectively provided with a cooling water inlet and a cooling water outlet. The heat exchange tubes in the absorber and condenser are respectively connected to the cooling water inlet and the cooling water outlet. The cooling water outlet of the absorber is connected to the cooling water inlet of the condenser. The heat exchange tubes of the evaporator are connected at both ends to the cold water inlet and the cold water outlet, respectively. A heat exchanger is provided between the pipe connected to the liquid outlet of the absorber and the circulating water pipe. The heat absorbed by the circulating water from the driving source is transferred to the liquid flowing out of the absorber in the heat exchanger.

4. The waste heat recovery heat exchange system according to claim 1, characterized in that, The gas outlet of the evaporator and the gas inlet of the absorber are connected by a steam channel; The gas outlet of the low-pressure generator and the gas inlet of the condenser are connected by a steam channel. The liquid outlet of the condenser is connected to the liquid inlet of the evaporator.

Images