Absorption refrigeration system and process with vapor turbine solution pressure boosting

Abstract

The application discloses the technical field of absorption refrigeration technology and relates to an absorption refrigeration system and process with a steam turbine solution pressure-raising function, which comprises a generator, an absorber, a condenser and an evaporator, and further comprises a pressure-raising assembly; the pressure-raising assembly is used for raising the pressure of a rich solution in the absorber by using the pressure energy of refrigerant vapor prepared by the generator and then conveying the pressure-raising rich solution into the generator; the application converts the pressure energy of an ammonia vapor expansion process into mechanical energy through a turbine structure, directly drives a solution pump to raise the pressure, completely gets rid of the dependence on external power supply, enables the absorption refrigeration system to be used in a scene where power is unstable or even no power is supplied, replaces the motor of the solution pump, and enables the absorption refrigeration system to be driven by no electric energy, so that the absorption refrigeration system is suitable for a photothermal direct-drive refrigeration scene and small no-power cold storage and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of absorption refrigeration, in particular to a vapor turbine solution pressure boosting absorption refrigeration system and process. BACKGROUND

[0002] Absorption refrigeration system has a history of more than two hundred years. Compared with compression refrigeration system, absorption refrigeration system can complete refrigeration cycle with heat energy as driving energy, which can greatly reduce the power consumption of refrigeration system; therefore, in the scene with waste heat, absorption refrigeration system has obvious economic efficiency.

[0003] In the absorption refrigeration system, the solution pump is a pipe component for boosting the pressure in the low-pressure system to the high-pressure system to complete the refrigeration cycle, which has been widely studied; although the absorption refrigeration system can greatly reduce the power consumption, the solution pump itself still belongs to the power consumption component; therefore, in the area without electricity or unstable power system, the application of absorption refrigeration system is greatly limited.

[0004] Some people propose a diffusion absorption refrigeration system, which completes solution circulation through a bubble pump, but the bubble pump has low lift, and needs to fill a large amount of hydrogen or helium as balancing gas in the low-pressure system to increase the pressure of the low-pressure system; this method can make the absorption refrigeration system run without consuming electric energy, but has two major disadvantages: 1. In the low-pressure system, hydrogen or helium as balancing gas, but also as non-condensable gas, which will seriously affect the absorption efficiency and reduce the performance of the refrigeration system; 2. The bubble pump uses the buoyancy of steam generated by heating to reduce the average density of the overall high-temperature solution, and completes circulation through the density difference, but the power of the bubble pump is limited and cannot be large, so it is only suitable for small refrigeration devices such as household refrigerators;

[0005] Some people also propose a cold and power cogeneration absorption refrigeration system, which generates high-pressure refrigerant vapor in the generator to generate electricity through turbine, to complete the adjustment and switching of refrigeration and power supply in two working conditions; this refrigeration system can fully utilize low-grade heat by increasing power output when the cooling load is insufficient, but the unit still consumes electric energy, and the overall power generation efficiency is low. SUMMARY

[0006] The present application aims to provide a vapor turbine solution pressure boosting absorption refrigeration system and process, which solves the problem of existing absorption refrigeration system in the area without electricity or unstable power system.

[0007] The present application achieves the above-mentioned purpose through the following technical scheme: a vapor turbine solution pressure boosting absorption refrigeration system, comprising a generator, an absorber, a condenser and an evaporator, the absorption refrigeration system further comprising a pressure boosting assembly.

[0008] The pressure boosting assembly comprises a solution pump, a turbo-expander, and a connecting shaft for connecting the solution pump and the turbo-expander, wherein the turbo-expander is used to drive the solution pump to work by the pressure energy of the refrigerant vapor generated by the generator, so as to boost the rich solution in the absorber and deliver it into the generator.

[0009] Preferably, the inlet and outlet of the solution pump are respectively communicated with the absorber and the generator, and the inlet and outlet of the turbo-expander are respectively communicated with the generator and the absorber.

[0010] Preferably, the absorption refrigeration system further comprises a heat exchanger, which is used to exchange heat between the lean solution input from the generator into the absorber and the rich solution input from the solution pump into the generator.

[0011] Preferably, the absorption refrigeration system further comprises an ejector, which is used to inject the refrigerant vapor discharged from the absorption turbo-expander into the absorber by using the lean solution discharged from the generator.

[0012] Preferably, the solution pump is a centrifugal pump or a positive displacement pump.

[0013] Preferably, a buffer tank and a refrigerant pressure reducing valve are sequentially arranged between the liquid refrigerant outlet of the condenser and the liquid refrigerant inlet of the evaporator, and a working fluid liquid pressure reducing valve is arranged between the lean solution outlet of the heat exchanger and the lean solution inlet of the absorber.

[0014] Preferably, a liquid distribution assembly for communicating with the lean solution inlet is arranged in the absorber.

[0015] Preferably, the condenser and the absorber are water-cooled or air-cooled.

[0016] Preferably, detectors are arranged on the generator, the absorber, the evaporator, the buffer tank, and the solution pump.

[0017] Preferably, a vapor turbo-solution boosting absorption refrigeration process is provided, which utilizes the above-mentioned vapor turbo-solution boosting absorption refrigeration system and comprises the following steps:

[0018] The heat source enters the generator to heat the rich solution working fluid, generate refrigerant vapor, one of which enters the condenser, and the other of which enters the pressure boosting assembly;

[0019] The refrigerant vapor condensed by the condenser enters the evaporator to generate cold energy, and then is introduced into the absorber to be absorbed by the lean solution discharged from the generator to form the rich solution;

[0020] The turbo-expander drives the solution pump to work by the pressure energy of the refrigerant vapor, boosts the rich solution, and inputs it into the generator, and the used refrigerant vapor is mixed with the lean solution discharged from the generator.

[0021] The present application has the advantages of:

[0022] 1. The pressure energy of the ammonia vapor expansion process is converted into mechanical energy by the turbine structure, directly driving the solution pump to increase the pressure, completely eliminating the dependence on external power supply, making the absorption refrigeration system applicable in scenes where the power is unstable or even unavailable, replacing the motor of the solution pump, making the absorption refrigeration system not need to be driven by electricity, suitable for photothermal direct drive refrigeration scenes and small-scale electricity-free cold storage applications;

[0023] 2. Since the high-temperature refrigerant vapor at the outlet of the generator is superheated vapor, it contains higher energy density, which directly enters the condenser, causing energy waste. After working in the turbine, it has higher efficiency. After losing energy, the refrigerant vapor will not directly condense, so it will not affect the working efficiency, and the corrosion of the droplets produced after condensation to the impeller is avoided;

[0024] 3. The ejector uses the high-pressure lean liquid discharged from the generator to inject and absorb the low-pressure refrigerant vapor after working, recycles the energy of the high-pressure lean solution, and increases the efficiency of the pressure increasing assembly;

[0025] 4. The absorption refrigeration system has strong adaptability to different working conditions. When the system load is low, the high-pressure system pressure is low, the high-low pressure system pressure difference is small, the turbine works less, and the circulation amount decreases, which is beneficial to maintain the high efficiency of the system. When the unit load increases, the high-low pressure system pressure difference increases, the working capacity increases, and the solution circulation amount increases, which is beneficial to increase the system load. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is an absorption refrigeration system with steam turbine solution pressure increasing of the present application;

[0027] Figure 2 It is a pressure increasing assembly structure diagram of the present application;

[0028] Figure 3 It is a working capacity diagram of the pressure increasing assembly of the present application under different loads;

[0029] Figure 4 It is a condensing pressure-load relationship diagram of the refrigeration system of the present application.

[0030] In the figure: 1, generator; 2, heat exchanger; 3, absorber; 4, condenser; 5, buffer tank; 6, evaporator; 7, pressure increasing 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 DESCRIPTION

[0031] The application will be further described in detail below with reference to the drawings. It is necessary to point out here that the following specific embodiments are only used to further illustrate the application and cannot be understood as limiting the scope of protection of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above application content.

[0032] Embodiment 1

[0033] Please refer to Figure 1 An absorption refrigeration system with a steam turbine solution pressure boosting device, comprising a generator 1, an absorber 3, a condenser 4, an evaporator 6 and a pressure boosting assembly 7; the absorption refrigeration system further comprises a buffer tank 5, a refrigerant pressure reducing valve 8 and a working fluid liquid pressure reducing valve 10; the pressure boosting assembly 7 comprises a solution pump 701, a turbine expander 702 and a connecting shaft 703, the two ends of the connecting shaft 703 are connected with the shafts of the solution pump 701 and the turbine expander 702 respectively;

[0034] The shell of the generator 1 is provided with a gaseous refrigerant outlet, a lean liquid outlet and a rich liquid inlet, the shell of the condenser 4 is provided with a gaseous refrigerant inlet and a liquid refrigerant outlet, the shell of the evaporator 6 is provided with a liquid refrigerant inlet and a gaseous refrigerant outlet, and the shell of the absorber 3 is provided with a gaseous refrigerant inlet, a lean liquid inlet and a rich liquid outlet; the gaseous refrigerant outlet of the generator 1 is in communication with the gaseous refrigerant inlet of the condenser 4 and the turbine expander 702 respectively, the lean liquid outlet of the generator 1 is in communication with the lean liquid inlet of the absorber 3 through the working fluid liquid pressure reducing valve 10, the rich liquid inlet of the generator 1 is in communication with the solution pump 701, the liquid refrigerant outlet of the condenser 4 is in communication with the buffer tank 5, the outlet of the buffer tank 5 is in communication with the liquid refrigerant inlet of the evaporator 6 through the refrigerant pressure reducing valve 8, the gaseous refrigerant outlet of the evaporator 6 is in communication with the gaseous refrigerant inlet of the absorber 3, and the rich liquid outlet of the absorber 3 is in communication with the solution pump 701; the gaseous refrigerant outlet of the turbine expander 702 is in communication with the absorber 3.

[0035] An absorption refrigeration process with a steam turbine solution pressure boosting device, comprising the following steps:

[0036] The heat source enters the generator 1, heats the rich solution, and analyzes the refrigerant therein to form high-pressure gaseous refrigerant (ammonia vapor), and the analyzed lean solution enters the absorber 3;

[0037] The high-pressure gaseous refrigerant from the generator 1 is divided into two paths, one of which enters the condenser 4, exchanges heat with the cooling medium, and is condensed into high-pressure liquid refrigerant, and enters the buffer tank 5, and then enters the evaporator 6 through the refrigerant pressure reducing valve 8 after being reduced in pressure, exchanges heat with the cooling medium to evaporate (the temperature of the cooling medium is reduced to be used for external cooling), and becomes low-pressure gaseous refrigerant vapor, which enters the absorber 3 to be absorbed by the lean solution (from the generator 1);

[0038] The high-pressure gaseous refrigerant from the generator 1 enters the pressure boosting assembly 7 to do work, and becomes low-pressure gaseous refrigerant after doing work and enters the absorber 3 to be absorbed. The pressure boosting assembly 7 generates power after doing work, and boosts the pressure of the rich solution discharged from the absorber 3 and inputs the rich solution into the generator 1 to circulate.

[0039] In this embodiment, as a further optimized scheme, please refer to Figure 1 and Figure 2 The inlet and outlet of the solution pump 701 are respectively communicated with the rich solution outlet of the absorber 3 and the rich solution inlet of the generator 1, and the inlet and outlet of the turbo-expander 702 are respectively communicated with the gaseous refrigerant outlet of the generator 1 and the gaseous refrigerant inlet of the absorber 3. The high-pressure gaseous refrigerant produced by the generator 1 enters the turbo-expander 702, and drives the turbo-expander 702 to work by using the pressure energy of the high-pressure gaseous refrigerant, and drives the linkage shaft 703 to rotate. Due to the rotation of the linkage shaft 703, the impeller in the solution pump 701 rotates to boost the pressure of the rich solution discharged from the absorber 3, and to input the rich solution into the generator 1.

[0040] Embodiment 2

[0041] As a further optimized scheme of the embodiment 1, please refer to Figure 1 The absorption refrigeration system further comprises the heat exchanger 2. The inlet and outlet of the tube side of the heat exchanger 2 are respectively communicated with the lean solution outlet of the generator 1 and the lean solution inlet of the absorber 3, and the inlet and outlet of the shell side of the heat exchanger 2 are respectively communicated with the outlet of the solution pump 701 and the rich solution inlet of the generator 1. The heat exchanger 2 is used to exchange heat between the lean solution input into the absorber 3 from the generator 1 and the rich solution input into the generator 1 from the solution pump 701, to increase the temperature of the rich solution and to decrease the temperature of the lean solution.

[0042] In this embodiment, as a further optimized scheme, please refer to Figure 1 The absorption refrigeration system further comprises the ejector 9. The outlet of the ejector 9 is communicated with the lean solution inlet of the absorber 3, one inlet of the ejector 9 is communicated with the outlet of the turbo-expander 702, and the other inlet of the ejector 9 is communicated with the tube side outlet of the heat exchanger 2. The ejector 9 is used to use the lean solution discharged from the generator 1 to induce and absorb the refrigerant vapor discharged from the turbo-expander 702, to recover the energy of the high-pressure lean solution, and to increase the efficiency of the pressure boosting assembly 7.

[0043] In this embodiment, as a further optimized scheme, please refer to Figure 1 The solution pump 701 is a centrifugal pump or a positive displacement pump.

[0044] In this embodiment, as a further optimized scheme, please refer to Figure 1The inner cavity top of the absorber 3 is provided with a liquid distribution assembly 11 (including a pipeline and a spray head arranged on the pipeline), and the liquid distribution assembly 11 is communicated with the lean liquid inlet; the liquid distribution assembly 11 is used for atomizing the lean liquid input into the absorber 3, so that the lean liquid can fully contact with the heat exchange pipes in the absorber 3.

[0045] In the embodiment, as a further optimized scheme, refer to Figure 1 The condenser 4 and the heat exchange pipes in the absorber 3 are communicated with gas or liquid, the condenser 4 and the absorber 3 are water-cooled or air-cooled, and the heat exchange medium for cooling the condenser 4 and the absorber 3 can be gas or liquid (the gas can be air, and the liquid can be water).

[0046] In the embodiment, as a further optimized scheme, refer to Figure 1 The generator 1, the absorber 3, the evaporator 6, the buffer tank 5 and the solution pump 701 are provided with detectors, and the detectors are pressure, temperature, liquid level and flow meters (P represents pressure, T represents temperature, L represents liquid level, and Q represents flow rate); the generator 1 is provided with a pressure meter, the lean liquid outlet pipeline of the generator 1 is provided with a temperature meter, the rich liquid discharge pipeline of the solution pump 701 is provided with a flow meter, the gaseous refrigerant outlet pipeline of the evaporator 6 is provided with a pressure meter, the cold carrier pipeline of the evaporator 6 is provided with a temperature meter, the buffer tank 5 is provided with a liquid level meter, and the outlet pipeline of the buffer tank 5 is provided with a flow meter.

[0047] It should be noted that the starting method of the absorption refrigeration system is as follows:

[0048] 1. In the initial state, the pressures of the generator 1 and the absorber 3 are basically balanced, and the solution in the system is distributed in the generator 1 and the absorber 3.

[0049] 2. The cooling system of the absorber 3 and the condenser 4 is started, and the cold supply system of the evaporator 6 is started.

[0050] 3. The generator 1 is input with a heat source, and the pressure of the generator 1 is increased.

[0051] 4. After the pressure of the generator 1 is increased to a set value, the working fluid liquid pressure reducing valve 10 from the generator 1 to the absorber 3 is opened, the pressure increasing assembly 7 is opened, and the solution in the system starts to circulate.

[0052] 5. After the pressure of the generator 1 reaches the set value, the high-pressure gaseous refrigerant in the condenser 4 starts to condense, and the condensed liquid refrigerant enters the buffer tank 5.

[0053] 6. After the liquid level of the buffer tank 5 reaches a set value, the refrigerant pressure reducing valve 8 is opened, the liquid refrigerant is reduced in pressure and enters the evaporator 6 to evaporate, and the system starts to refrigerate.

[0054] It should be further explained that the load adjustment method of the absorption refrigeration system is as follows: when the refrigeration system needs to increase the load, the heat source input increases; the lean liquid temperature at the outlet of the generator 1 increases, the gaseous refrigerant desorption amount increases, and the pressure of the generator 1 increases; the pressure of the generator 1 increases, the work amount of the turbo expander 702 increases, and the work of the solution pump 701 increases; the solution circulation amount increases, the absorption of the ammonia gas in the absorber 3 increases, the lean liquid temperature at the outlet of the generator 1 decreases, and the system reaches a new balance; at this time, the gaseous refrigerant desorption amount increases, the ammonia gas evaporation amount in the evaporator 6 increases, and the system refrigeration capacity increases; when the system needs to reduce the refrigeration load, the above-mentioned process is reversed.

[0055] Wherein, the work amount of the pressure increasing assembly 7 under different loads (in the rated state of taking ammonia as the refrigerant, the refrigeration temperature being-15℃, and the internal efficiency of the steam expander being 70%, as shown in Figure 3 , the condensation pressure-load relationship (in the rated state of taking ammonia as the refrigerant and the ambient temperature being 20℃, as shown in Figure 4 ).

[0056] The above-mentioned embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as the limitation on the patent scope of the present application. It should be pointed out that, for the ordinary skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. An absorption refrigeration system of the vapor turbine solution pressure boosting absorption type, comprising: The generator (1), the absorber (3), the condenser (4) and the evaporator (6) are characterized in that the absorption refrigeration system further comprises a pressure boosting assembly (7); The pressure boosting assembly (7) comprises a solution pump (701), a turbo expander (702) and a linkage shaft (703) for connecting the solution pump (701) and the turbo expander (702), wherein the turbo expander (702) is used to drive the solution pump (701) to work by using the pressure energy of the refrigerant vapor produced by the generator (1) so as to boost the pressure of the rich solution in the absorber (3) and deliver it into the generator (1); The inlet and outlet of the solution pump (701) are respectively communicated with the absorber (3) and the generator (1), and the inlet and outlet of the turbo expander (702) are respectively communicated with the generator (1) and the absorber (3). The absorption refrigeration system further comprises an ejector (9) which is used to inject the refrigerant vapor discharged from the absorption turbo expander (702) into the absorber (3) by using the lean solution discharged from the generator (1).

2. An absorption refrigeration system of the type described in claim 1 wherein, The absorption refrigeration system further comprises a heat exchanger (2) which is used to exchange heat between the lean solution delivered from the generator (1) into the absorber (3) and the rich solution delivered from the solution pump (701) into the generator (1).

3. An absorption refrigeration system of claim 1 wherein, The solution pump (701) is a centrifugal pump or a positive displacement pump.

4. An absorption refrigeration system of the type described in claim 2 wherein, A buffer tank (5) and a refrigerant pressure reducing valve (8) are sequentially arranged between the liquid refrigerant outlet of the condenser (4) and the liquid refrigerant inlet of the evaporator (6), and a working fluid pressure reducing valve (10) is arranged between the lean solution outlet of the heat exchanger (2) and the lean solution inlet of the absorber (3).

5. An absorption refrigeration system of claim 1 wherein, The absorber (3) is provided with a liquid distribution assembly (11) which is communicated with the lean solution inlet.

6. An absorption refrigeration system of the type described in claim 1 wherein, The condenser (4) and the absorber (3) are water-cooled or air-cooled.

7. An absorption refrigeration system of the type described in claim 4 wherein, Detectors are arranged on the generator (1), the absorber (3), the evaporator (6), the buffer tank (5) and the solution pump (701).

8. A vapour-transpiration pressure-increasing absorption refrigeration process using a vapour-transpiration pressure-increasing absorption refrigeration system according to any one of claims 1 to 7, characterised in that, The method comprises the following steps: The heat source enters the generator (1) to heat the rich solution working fluid, produce refrigerant vapor, one of which enters the condenser (4) and the other of which enters the pressure boosting assembly (7); The refrigerant vapor condensed by the condenser (4) enters the evaporator (6) to produce cold energy, and then is introduced into the absorber (3) to be absorbed by the lean solution discharged from the generator (1) to form a rich solution; The turbo expander (702) drives the solution pump (701) to work by using the pressure energy of the refrigerant vapor, boosts the pressure of the rich solution and delivers 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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