Absorption type refrigeration system and process for increasing pressure of steam turbine solution

Abstract

The invention discloses a steam turbine solution pressure increasing absorption type refrigeration system and process in the technical field of absorption type refrigeration, and the system comprises a generator, an absorber, a condenser and an evaporator, and further comprises a pressure increasing assembly; the pressure increasing assembly is used for increasing the pressure of the rich solution in the absorber and conveying the rich solution into the generator by using the pressure energy of the refrigerant steam prepared by the generator; the pressure energy in the ammonia vapor expansion process is converted into mechanical energy through the turbine structure, the solution pump is directly driven to increase the pressure, dependence on external power supply is thoroughly eliminated, the absorption refrigeration system can be used in the scene with unstable electric power or even no power, a motor of the solution pump is replaced, and the cost is reduced. The absorption refrigeration system does not need to be driven by electric energy and is suitable for photo-thermal direct-drive refrigeration scenes, small-sized non-electric refrigeration houses and the like.

Description

Technical Field

[0001] This invention relates to the field of absorption refrigeration, and more specifically to an absorption refrigeration system and process for vapor turbine solution pressurization. Background Technology

[0002] Absorption refrigeration systems have been developed for over two hundred years. Compared to compression refrigeration systems, absorption refrigeration systems can use thermal energy as the driving energy to complete the refrigeration cycle, which can significantly reduce the power consumption of the refrigeration system; therefore, in scenarios with waste heat, absorption refrigeration systems have obvious economic advantages.

[0003] In absorption refrigeration systems, the solution pump, as a pipe component that boosts the pressure in the low-pressure system and sends it into the high-pressure system to complete the refrigeration cycle, has been extensively studied. Although absorption refrigeration systems can significantly reduce power consumption, the solution pump itself is still a power-consuming component. Therefore, in areas without electricity or with unstable power systems, the application of absorption refrigeration systems is greatly limited.

[0004] One proposed diffusion absorption refrigeration system uses a bubble pump to circulate the solution. However, the bubble pump has a low head and requires a large amount of hydrogen or helium to be filled into the low-pressure system as a balance gas to increase the system pressure. While this method allows the absorption refrigeration system to operate without consuming electricity, it has two major drawbacks: 1. In the low-pressure system, hydrogen or helium acts as a balance gas, but as a non-condensable gas, it severely affects absorption efficiency and reduces the performance of the refrigeration system; 2. The bubble pump utilizes the buoyancy generated by the steam during heating to reduce the average density of the overall high-temperature solution, completing the circulation through density difference. However, the bubble pump has limited power and cannot be scaled up, therefore it is only suitable for small refrigeration devices such as household refrigerators. Some have proposed a combined cooling and power absorption refrigeration system that uses high-pressure refrigerant vapor generated by a generator to power a turbine, thereby adjusting and switching between cooling and power supply modes. Although this refrigeration system can make full use of low-grade heat by increasing power output when the cooling load is insufficient, the unit itself still consumes electricity, and the overall power generation efficiency is relatively low. Summary of the Invention

[0005] The purpose of this invention is to provide an absorption refrigeration system and process for vapor turbine solution pressurization, which solves the problem of existing absorption refrigeration systems in areas without electricity or with unstable power systems.

[0006] The present invention achieves the above-mentioned objective through the following technical solution: an absorption refrigeration system for vapor turbine solution pressurization, comprising: a generator, an absorber, a condenser and an evaporator, wherein the absorption refrigeration system further comprises a pressurization component; The pressurization assembly includes a solution pump, a turbine expander, and a linkage shaft for connecting the solution pump and the turbine expander. The turbine expander is used to drive the solution pump to work by utilizing the pressure energy of the refrigerant vapor generated by the generator, so as to pressurize and deliver the rich solution in the absorber to the generator.

[0007] Preferably, the inlet and outlet of the solution pump are connected to the absorber and the generator, respectively, and the inlet and outlet of the turbine expander are connected to the generator and the absorber, respectively.

[0008] Preferably, the absorption refrigeration system further includes a heat exchanger for exchanging heat between the lean solution input from the generator to the absorber and the rich solution input from the solution pump to the generator.

[0009] Preferably, the absorption refrigeration system further includes an ejector, which is used to use the lean liquid discharged from the generator to eject and absorb the refrigerant vapor discharged from the turbine expander and input it into the absorber.

[0010] Preferably, the solution pump is a centrifugal pump or a positive displacement pump.

[0011] Preferably, a buffer tank and a refrigerant pressure reducing valve are sequentially provided between the liquid refrigerant outlet of the condenser and the liquid refrigerant inlet of the evaporator, and a working fluid pressure reducing valve is provided between the lean liquid outlet of the heat exchanger and the lean liquid inlet of the absorber.

[0012] Preferably, the absorber is provided with a liquid distribution assembly for communication with the lean liquid inlet.

[0013] Preferably, the condenser and absorber are water-cooled or air-cooled.

[0014] Preferably, the generator, absorber, evaporator, buffer tank, and solution pump are equipped with detectors.

[0015] Preferably, an absorption refrigeration process for vapor turbine solution pressurization, utilizing the aforementioned absorption refrigeration system for vapor turbine solution pressurization, includes the following steps: A heat source enters the generator to heat the rich solution working fluid and produce refrigerant vapor. One stream of refrigerant vapor enters the condenser, and the other stream enters the pressure boosting assembly. After the refrigerant vapor is condensed by the condenser, it enters the evaporator to generate cooling capacity, and then is introduced into the absorber to be absorbed by the lean liquid discharged from the generator to form a rich solution. A turboexpander uses the pressure energy of refrigerant vapor to drive a solution pump, pressurizes the rich solution, and inputs it into the generator. The used refrigerant vapor is mixed with the lean solution discharged from the generator.

[0016] The beneficial effects of this invention are as follows: 1. By converting the pressure energy of the ammonia vapor expansion process into mechanical energy through a turbine structure, the solution pump is directly driven to pressurize, completely eliminating the dependence on external power supply. This allows the absorption refrigeration system to be used in scenarios where the power supply is unstable or even non-existent. It replaces the motor of the solution pump, so that the absorption refrigeration system does not require electric power to drive it. It is suitable for solar thermal direct-drive refrigeration scenarios and small non-electric cold storage applications. 2. Since the high-temperature refrigerant vapor at the generator outlet is superheated vapor, it contains higher energy density. Directly entering the condenser would waste energy. After entering the turbine to do work, it has higher efficiency. After losing energy, the refrigerant vapor will not condense directly, so it will not affect the work efficiency and avoid the corrosion of the impeller by the droplets generated after condensation. 3. The ejector uses the high-pressure lean liquid discharged from the generator to eject and absorb the low-pressure refrigerant vapor after it has done work, thereby recovering the energy of the high-pressure lean liquid and increasing the efficiency of the booster assembly. 4. This absorption refrigeration system is highly adaptable to different operating conditions. When the system load is low, the high-pressure system pressure is low, the pressure difference between the high and low pressure systems is small, the turbine mechanical work is low, and the circulation volume is reduced, which helps to maintain the high efficiency of the system. When the unit load increases, the pressure difference between the high and low pressure systems increases, the work done increases, and the solution circulation volume increases, which helps to increase the system load. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the absorption refrigeration system for vapor turbine solution pressurization according to the present invention; Figure 2 This is a schematic diagram of the pressure-lifting component structure of the present invention; Figure 3 This is a schematic diagram showing the work done by the pressure-boosting component of the present invention under different loads; Figure 4 This is a diagram showing the condensing pressure-load relationship of the refrigeration system of the present invention.

[0018] In the diagram: 1. Generator; 2. Heat exchanger; 3. Absorber; 4. Condenser; 5. Buffer tank; 6. Evaporator; 7. Pressure boosting assembly; 701. Solution pump; 702. Turbine expander; 703. Linkage shaft; 8. Refrigerant pressure reducing valve; 9. Ejector; 10. Working fluid pressure reducing valve; 11. Liquid distribution assembly. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] Example 1

[0021] Please see Figure 1 An absorption refrigeration system for vapor turbine solution pressure boosting includes: a generator 1, an absorber 3, a condenser 4, an evaporator 6, and a pressure boosting assembly 7; the absorption refrigeration system also includes a buffer tank 5, a refrigerant pressure reducing valve 8, and a working liquid pressure reducing valve 10; the pressure boosting assembly 7 includes a solution pump 701, a turbine expander 702, and a linkage shaft 703, with both ends of the linkage shaft 703 connected to the shafts of the solution pump 701 and the turbine expander 702, respectively; The generator 1 has a gaseous refrigerant outlet, a lean liquid outlet, and a rich liquid inlet on its casing; the condenser 4 has a gaseous refrigerant inlet and a liquid refrigerant outlet on its casing; the evaporator 6 has a liquid refrigerant inlet and a gaseous refrigerant outlet on its casing; and the absorber 3 has a gaseous refrigerant inlet, a lean liquid inlet, and a rich liquid outlet on its casing. The gaseous refrigerant outlet of the generator 1 is connected to the gaseous refrigerant inlet of the condenser 4 and the turbine expander 702, respectively. The lean liquid outlet of the generator 1 is connected to the lean liquid inlet of the absorber 3 through the working fluid pressure reducing valve 10. The rich liquid inlet of the generator 1 is connected to the solution pump 701. The liquid refrigerant outlet of the condenser 4 is connected to the buffer tank 5. The outlet of the buffer tank 5 is connected to the liquid refrigerant inlet of the evaporator 6 through the refrigerant pressure reducing valve 8. The gaseous refrigerant outlet of the evaporator 6 is connected to the gaseous refrigerant inlet of the absorber 3. The rich liquid outlet of the absorber 3 is connected to the solution pump 701. The gaseous refrigerant outlet of the turbine expander 702 is connected to the absorber 3.

[0022] An absorption refrigeration process for vapor turbine solution pressurization includes the following steps: A heat source enters generator 1 to heat the rich solution, causing the refrigerant in it to be released and form a high-pressure gaseous refrigerant (ammonia vapor). The lean solution after release enters absorber 3. The high-pressure gaseous refrigerant from generator 1 is divided into two paths. One path enters condenser 4, where it exchanges heat with the cooling medium and condenses into high-pressure liquid refrigerant. It then enters buffer tank 5, and after being depressurized by refrigerant pressure reducing valve 8, it enters evaporator 6, where it exchanges heat with the heat transfer fluid and evaporates (the heat transfer fluid temperature decreases to provide cooling to the outside). It then becomes low-pressure gaseous refrigerant vapor, which enters absorber 3 and is absorbed by lean solution (from generator 1). The high-pressure gaseous refrigerant from generator 1 enters the booster assembly 7 to do work. After doing work, it becomes a low-pressure gaseous refrigerant and enters the absorber 3 to be absorbed. The booster assembly 7 generates power after doing work, which boosts the pressure of the rich solution discharged from the absorber 3 and inputs it into generator 1 for circulation.

[0023] In this embodiment, as a further optimization, please refer to... Figure 1 and Figure 2The inlet and outlet of the solution pump 701 are connected to the rich liquid outlet of the absorber 3 and the rich liquid inlet of the generator 1, respectively. The inlet and outlet of the turbine expander 702 are connected to the gaseous refrigerant outlet of the generator 1 and the gaseous refrigerant inlet of the absorber 3, respectively. Part of the high-pressure gaseous refrigerant produced by the generator 1 enters the turbine expander 702, which uses its own pressure energy to drive the turbine expander 702 to work and rotate the linkage shaft 703. As the linkage shaft 703 rotates, the impeller in the solution pump 701 rotates, which is used to pressurize the rich solution discharged from the absorber 3 and transport the rich solution to the generator 1.

[0024] Example 2

[0025] As a further optimization of Example 1, please refer to Figure 1 The absorption refrigeration system also includes a heat exchanger 2. The tube side inlet and outlet of the heat exchanger 2 are connected to the lean liquid outlet of the generator 1 and the lean liquid inlet of the absorber 3, respectively. The shell side inlet and outlet of the heat exchanger 2 are connected to the outlet of the solution pump 701 and the rich liquid inlet of the generator 1, respectively. The heat exchanger 2 is used to exchange heat between the lean liquid input from the generator 1 to the absorber 3 and the rich liquid input from the solution pump 701 to the generator 1, thereby raising the temperature of the rich liquid and lowering the temperature of the lean liquid.

[0026] In this embodiment, as a further optimization, please refer to... Figure 1 The absorption refrigeration system also includes an ejector 9. The outlet of the ejector 9 is connected to the lean liquid inlet of the absorber 3. One inlet of the ejector 9 is connected to the outlet of the turbine expander 702, and the other inlet of the ejector 9 is connected to the tube-side outlet of the heat exchanger 2. The ejector 9 is used to use the lean liquid discharged from the generator 1 to eject and absorb the refrigerant vapor discharged from the turbine expander 702, recover the energy of the high-pressure lean liquid, and increase the efficiency of the pressure boosting component 7.

[0027] In this embodiment, as a further optimization, please refer to... Figure 1 The solution pump 701 is a centrifugal pump or a positive displacement pump.

[0028] In this embodiment, as a further optimization, please refer to... Figure 1 The absorber 3 has a liquid distribution assembly 11 (including pipes and nozzles on the pipes) at the top of its inner cavity. The liquid distribution assembly 11 is connected to the lean liquid inlet. The liquid distribution assembly 11 is used to atomize the lean liquid input into the absorber 3 so that it can fully contact the heat exchange tube inside the absorber 3.

[0029] In this embodiment, as a further optimization, please refer to... Figure 1Gas or liquid flows through the heat exchange pipes of condenser 4 and absorber 3. Condenser 4 and absorber 3 are water-cooled or air-cooled. The heat exchange medium used to cool condenser 4 and absorber 3 can be gas or liquid (gas can be air, and liquid can be water).

[0030] In this embodiment, as a further optimization, please refer to... Figure 1 The generator 1, absorber 3, evaporator 6, buffer tank 5, and solution pump 701 are equipped with detectors, which are pressure, temperature, liquid level, and flow rate instruments (P refers to pressure, T refers to temperature, L refers to liquid level, and Q refers to flow rate). The generator 1 is equipped with a pressure instrument, the lean liquid outlet pipe of the generator 1 is equipped with a temperature instrument, the rich liquid discharge pipe of the solution pump 701 is equipped with a flow rate instrument, the gaseous refrigerant outlet pipe of the evaporator 6 is equipped with a pressure instrument, the heat transfer refrigerant pipe of the evaporator 6 is equipped with a temperature instrument, the buffer tank 5 is equipped with a liquid level instrument, and the outlet pipe of the buffer tank 5 is equipped with a flow rate instrument.

[0031] It should be noted that the startup method for an absorption refrigeration system is as follows: 1. In the initial state, the pressure of generator 1 and absorber 3 are basically balanced, and the solution in the system is distributed in generator 1 and absorber 3; 2. The cooling systems of absorber 3 and condenser 4 are turned on, and the cooling system of evaporator 6 is turned on; 3. A heat source is introduced into generator 1, and the pressure in generator 1 increases; 4. After the pressure of generator 1 rises to the set value, the working fluid pressure reducing valve 10 from generator 1 to absorber 3 opens, the pressure boosting component 7 opens, and the solution in the system begins to circulate. 5. After the heat source is continuously added and the pressure of generator 1 reaches the set value, the high-pressure gaseous refrigerant in condenser 4 begins to condense, and the condensed liquid refrigerant enters buffer tank 5. 6. After the liquid level in the buffer tank 5 reaches the set value, the refrigerant pressure reducing valve 8 opens, and the liquid refrigerant is depressurized and enters the evaporator 6 to evaporate, and the system begins to cool.

[0032] It should also be noted that the load adjustment method for the absorption refrigeration system is as follows: When the refrigeration system needs to increase its load, the heat source input increases; the lean liquid temperature at the generator 1 outlet increases, the amount of gaseous refrigerant released increases, and the pressure of generator 1 increases; the increased pressure of generator 1 increases the work done by the turbine expander 702 and the solution pump 701; the solution circulation rate increases, the amount of ammonia absorbed by absorber 3 increases, the lean liquid temperature at the generator 1 outlet decreases, and the system reaches a new equilibrium; at this time, the amount of gaseous refrigerant released increases, the amount of ammonia evaporated by evaporator 6 increases, and the system's cooling capacity increases; the opposite is true when the system needs to reduce its refrigeration load. Among them, the work done by the pressure boosting component 7 under different loads (under the rated conditions of using ammonia as refrigerant, refrigeration temperature -15℃, and steam expander internal efficiency 70%), such as Figure 3 As shown), the condensing pressure-load relationship (using ammonia as refrigerant, with an ambient temperature of 20℃ as the rated condition, such as...) Figure 4 (As shown).

[0033] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An absorption refrigeration system for vapor turbine solution pressurization, comprising: The generator (1), absorber (3), condenser (4) and evaporator (6) are characterized in that the absorption refrigeration system further includes a pressure boosting component (7). The pressurization assembly (7) includes a solution pump (701), a turbine expander (702), and a linkage shaft (703) for connecting the solution pump (701) and the turbine expander (702). The turbine expander (702) is used to drive the solution pump (701) to work by utilizing the pressure energy of the refrigerant vapor generated by the generator (1) to pressurize and deliver the rich solution in the absorber (3) to the generator (1).

2. The absorption refrigeration system for vapor turbine solution pressurization according to claim 1, characterized in that, The inlet and outlet of the solution pump (701) are connected to the absorber (3) and the generator (1) respectively, and the inlet and outlet of the turbine expander (702) are connected to the generator (1) and the absorber (3) respectively.

3. The absorption refrigeration system for vapor turbine solution pressurization according to claim 2, characterized in that, The absorption refrigeration system also includes a heat exchanger (2), which is used to exchange heat between the lean solution input from the generator (1) to the absorber (3) and the rich solution input from the solution pump (701) to the generator (1).

4. The absorption refrigeration system for vapor turbine solution pressurization according to claim 2, characterized in that, The absorption refrigeration system also includes an ejector (9), which is used to use the lean liquid discharged from the generator (1) to eject the refrigerant vapor discharged from the turbine expander (702) and input it into the absorber (3).

5. The absorption refrigeration system for vapor turbine solution pressurization according to claim 2, characterized in that, The solution pump (701) is a centrifugal pump or a positive displacement pump.

6. The absorption refrigeration system for vapor turbine solution pressurization according to claim 3, characterized in that, A buffer tank (5) and a refrigerant pressure reducing valve (8) are sequentially provided between the liquid refrigerant outlet of the condenser (4) and the liquid refrigerant inlet of the evaporator (6), and a working liquid pressure reducing valve (10) is provided between the lean liquid outlet of the heat exchanger (2) and the lean liquid inlet of the absorber (3).

7. The absorption refrigeration system for vapor turbine solution pressurization according to claim 1, characterized in that, The absorber (3) is provided with a liquid distribution assembly (11) for communication with the lean liquid inlet.

8. The absorption refrigeration system for vapor turbine solution pressurization according to claim 1, characterized in that, The condenser (4) and absorber (3) are water-cooled or air-cooled.

9. The absorption refrigeration system for vapor turbine solution pressurization according to claim 6, characterized in that, The generator (1), absorber (3), evaporator (6), buffer tank (5), and solution pump (701) are equipped with detectors.

10. An absorption refrigeration process for vapor turbine solution pressurization, utilizing an absorption refrigeration system for vapor turbine solution pressurization as described in any one of claims 1-9, characterized in that, Includes the following steps: A heat source enters the generator (1) to heat the rich solution working fluid and produce refrigerant vapor. One stream of refrigerant vapor enters the condenser (4), and the other stream of refrigerant vapor enters the pressure boosting assembly (7). After the refrigerant vapor is condensed by the condenser (4), it enters the evaporator (6) to generate cooling capacity, and then is introduced into the absorber (3) to be absorbed by the lean liquid discharged from the generator (1) to form a rich solution. The turbo expander (702) uses the pressure energy of refrigerant vapor to drive the solution pump (701) to work, pressurize the rich solution and input it into the generator (1), and the used refrigerant vapor is mixed with the lean solution discharged from the generator (1).

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