Energy-saving efficient refrigerating unit and process capable of preventing cavitation of steam condensate pump

Abstract

The invention discloses an energy-saving efficient refrigerating unit and process for preventing cavitation of a steam condensate pump in the technical field of refrigeration. The energy-saving efficient refrigerating unit comprises a high-pressure generator, a medium-pressure generator, a high-pressure evaporator, the steam condensate pump, a composite power generation compressor and a refrigerating assembly. Heat of saturated steam condensate flowing out of the high-pressure generator is absorbed by the high-pressure liquid refrigerant through the high-pressure evaporator, and the saturated steam condensate is changed into supercooled steam condensate, so that cavitation cannot be generated when the supercooled steam condensate enters the steam condensate pump, an original mode of increasing the height difference between the generator and the steam condensate pump is replaced, and the production efficiency is improved. The cost of a unit pipeline is reduced, meanwhile, the cost of ultrahigh transportation is reduced, heat contained in saturated steam condensate is converted into pressure energy of a high-pressure gaseous refrigerant to be used for driving a composite power generation compressor to work, the pressure energy is converted into electric energy and pressure energy of a low-pressure gaseous refrigerant, and the electric energy is used for a solution pump. The deep utilization of the internal energy of the unit can be realized, and the COP of the unit is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration, in particular to an energy-saving and efficient refrigeration unit and process for preventing vapor condensate pump cavitation. BACKGROUND

[0002] The absorption refrigeration unit is driven by low-grade waste heat to drive the thermal working medium, and refrigeration is carried out through the phase change of the working medium (such as ammonia). The main equipment includes a generator, a condenser, an evaporator, an absorber, a solution pump, etc. When the above refrigeration unit uses low-grade waste heat as steam, the steam is condensed into vapor condensate by the generator, and the vapor condensate is mostly in a saturated state. The saturated vapor condensate is sent to the vapor condensate header of the user after being pressurized by the vapor condensate pump. The saturated vapor condensate entering the vapor condensate pump is prone to cavitation. The conventional method is to increase the height difference between the generator and the vapor condensate pump to increase the effective cavitation allowance. However, this will increase the overall height of the unit, increase the cost of the unit pipeline, and also increase the cost of super-high transportation. In addition, the temperature and heat absorption efficiency of the circulating water as the cold source of the absorber directly affect the refrigeration efficiency of the unit. The heat absorption of the circulating water belongs to sensible heat temperature rise without phase change, so the heat absorption efficiency is limited. The temperature of the circulating water is affected by the wet-bulb temperature. In summer, the wet-bulb temperature is high, which limits the maximum temperature of the air cooling tower to cool the circulating water. Therefore, the temperature of the circulating water is high, which will reduce the efficiency of the unit. SUMMARY

[0003] The present application provides an energy-saving and efficient refrigeration unit and process for preventing vapor condensate pump cavitation, which solves the problem of cavitation in existing refrigeration units.

[0004] The present application achieves the above-mentioned purpose through the following technical solutions: an energy-saving and efficient refrigeration unit and process for preventing vapor condensate pump cavitation, comprising: a high-pressure generator, a medium-pressure generator, a high-pressure evaporator, a vapor condensate pump, a combined power generation compressor, and a refrigeration assembly. The high-pressure generator uses the heat of the steam to produce high-pressure gaseous refrigerant. The medium-pressure generator is used to absorb the heat of the high-pressure gaseous refrigerant produced by the high-pressure generator to liquefy it into high-pressure liquid refrigerant. The high-pressure evaporator uses the high-pressure liquid refrigerant discharged by the medium-pressure generator to absorb the heat of the steam after being used by the high-pressure generator to vaporize, so as to drive the combined power generation compressor to generate power. The refrigeration assembly is used to produce cold energy by absorbing the heat of the medium-pressure generator.

[0005] Preferably, the refrigeration assembly comprises a second ejector, a condenser, an evaporator, a first ejector, an absorber, and a flash tank. The condenser is used for delivering liquid refrigerant to the evaporator and the absorber respectively, the flash tank is used for flashing the lean liquid discharged by the high-pressure generator to make the refrigerant in the lean liquid vaporize, the first ejector uses the gaseous refrigerant discharged by the compound power compressor as an injection source to introduce the gaseous refrigerant in the evaporator into the absorber, and the compound power compressor is also used for pressurizing the gaseous refrigerant discharged by the absorber and the flash tank to serve as an injection source of the second ejector to guide the gaseous refrigerant discharged by the medium-pressure generator into the condenser.

[0006] Preferably, the refrigeration assembly further comprises an expansion valve and a first solution pump, the expansion valve is used for depressurizing the liquid refrigerant discharged by the condenser, and the first solution pump is used for pressurizing the rich liquid in the absorber to input into the medium-pressure generator.

[0007] Preferably, the energy-saving and high-efficiency refrigeration unit further comprises a second solution pump, the second solution pump is used for pressurizing the rich liquid of the medium-pressure generator to input into the high-pressure generator.

[0008] Preferably, the compound power compressor comprises an impeller turbine assembly, an impeller turbine power generation assembly connected with an output shaft of the impeller turbine assembly, and an impeller turbine compression assembly.

[0009] Preferably, the unit B is used for replacing the high-pressure generator and the medium-pressure generator, and the unit A is used for replacing the high-pressure evaporator, the condenser, the evaporator and the absorber, the unit B and the unit A are both fixed tube sheet heat exchangers whose main structures are composed of a head, a tube box cylinder segment, a tube sheet, heat exchange tubes and a shell, the inner cavity of the unit B is divided into a medium-pressure generation cavity and a high-pressure generation cavity, and the inner cavity of the unit A is divided into a condensation cavity, a high-pressure evaporation cavity, an absorption cavity and an evaporation cavity.

[0010] Preferably, the medium-pressure generation cavity and the high-pressure generation cavity are separated by a first partition plate, and the condensation cavity, the high-pressure evaporation cavity, the absorption cavity and the evaporation cavity are separated by a second partition plate.

[0011] Preferably, the unit A is located above the unit B, and the shell inner cavities of the medium-pressure generation cavity, the high-pressure generation cavity, the high-pressure evaporation cavity, the absorption cavity and the evaporation cavity are all provided with spray assemblies.

[0012] Preferably, an energy-saving and high-efficiency refrigeration process for preventing steam condensate pump cavitation uses the above-mentioned energy-saving and high-efficiency refrigeration unit for preventing steam condensate pump cavitation, and comprises the following steps: Steam heats high-pressure lean liquid in the high-pressure generation cavity to produce high-pressure gaseous refrigerant, the high-pressure gaseous refrigerant enters the medium-pressure generation cavity as a heat source, is liquefied into high-pressure liquid refrigerant by absorbing heat, and enters the high-pressure evaporation cavity; The steam is condensed into saturated steam condensate by absorbing heat in the high-pressure generating cavity, and then enters the high-pressure evaporator to heat the high-pressure liquid refrigerant, so that the high-pressure liquid refrigerant is gasified into high-pressure gaseous refrigerant, and the steam is cooled into supercooled steam condensate and enters the steam condensate pump; The high-pressure gaseous refrigerant enters the combined power generator and compressor to drive the generator, and the refrigeration assembly uses the heat absorbed by the medium-pressure generating cavity to generate cold energy; An energy-saving and high-efficiency refrigeration process for preventing steam condensate pump cavitation, and a refrigeration unit for preventing steam condensate pump cavitation, comprising the following steps: The steam heats the high-pressure lean liquid in the high-pressure generator to produce high-pressure gaseous refrigerant, and the high-pressure gaseous refrigerant enters the medium-pressure generator as a heat source and is liquefied into high-pressure liquid refrigerant by absorbing heat, and then enters the high-pressure evaporator; The steam is condensed into saturated steam condensate by absorbing heat in the high-pressure generator, and then enters the high-pressure evaporator to heat the high-pressure liquid refrigerant, so that the high-pressure liquid refrigerant is gasified into high-pressure gaseous refrigerant, and the steam is cooled into supercooled steam condensate and enters the steam condensate pump; The high-pressure gaseous refrigerant enters the combined power generator and compressor to drive the generator, and the refrigeration assembly uses the heat absorbed by the medium-pressure generator to generate cold energy.

[0013] The beneficial effects of the present application are: 1. The high-pressure evaporator absorbs the heat of the saturated steam condensate flowing out of the high-pressure generator to change the saturated steam condensate into supercooled steam condensate, so that cavitation does not occur when the supercooled steam condensate enters the steam condensate pump, replacing the original method of increasing the height difference between the generator and the steam condensate pump, reducing the cost of the unit pipeline, and also reducing the cost of ultra-high transportation, and converting the heat contained in the saturated steam condensate into pressure energy of the high-pressure gaseous refrigerant, which is used to drive the combined power generator and compressor to work, converting into electrical energy and pressure energy of low-pressure gaseous refrigerant, the electrical energy is used for the solution pump, which realizes deep utilization of energy inside the unit, and improves the COP of the unit; 2. The low-pressure liquid refrigerant obtained by reducing the pressure of the secondary high-pressure liquid refrigerant condensed in the condenser through the expansion valve is used as the cold source of the absorber, replacing the circulating water, and the heat absorption in the absorber tube generates flow boiling and phase change, and the heat transfer efficiency is greatly improved, thereby improving the efficiency of the unit, and the temperature of the self-produced liquid refrigerant of the unit is stable and is hardly affected by high temperature in summer; 3. By replacing the original pressure reducing valve with a flash tank, the high-pressure lean liquid flowing from the high-pressure generator is flash-evaporated and depressurized, resulting in a lower concentration of refrigerant in the lean liquid before it enters the absorber, thus improving absorption efficiency. The low-pressure gaseous refrigerant flash-evaporated combines with the low-pressure gaseous refrigerant that has absorbed heat and vaporized in the absorber, and is then compressed into high-pressure gaseous refrigerant by a composite generator compressor. This high-pressure gaseous refrigerant is then ejected from the medium-pressure generator by a second ejector, and finally converted into a sub-high-pressure gaseous refrigerant that enters the condenser. This increases the condensing temperature of the condenser, reduces the condenser's requirement for low circulating water temperature, and thus improves condensing efficiency. 4. The medium-pressure exhaust gas from the combined generator compressor is ejected by the first ejector to the low-pressure gaseous refrigerant that has absorbed heat and vaporized in the evaporator, and is converted into a secondary medium-pressure gaseous refrigerant that enters the absorber, thereby improving the absorption efficiency of the absorber and thus improving the cooling efficiency of the unit. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the energy-saving and high-efficiency refrigeration unit of the present invention; Figure 2 This is a schematic diagram showing the connection between unit A and unit B of the present invention; Figure 3 This is a schematic cross-sectional view of the connection between unit A and unit B of the present invention; Figure 4 For the present invention Figure 3 Schematic diagram of EE direction; Figure 5 This is a schematic diagram of the composite power generation compressor structure of the present invention.

[0015] In the diagram: 1. High-pressure generator; 2. Second solution pump; 3. Medium-pressure generator; 4. High-pressure evaporator; 5. Steam condensate pump; 6. Combined power generation compressor; 601. Impeller turbine assembly; 602. Impeller turbine power generation assembly; 603. Impeller turbine compression assembly; 7. Second ejector; 8. Condenser; 9. Expansion valve; 10. Evaporator; 11. First ejector; 12. Absorber; 13. First solution pump; 14. Flash tank; 15. Unit B; 151. Medium-pressure generating chamber; 152. High-pressure generating chamber; 153. First baffle; 16. Unit A; 161. Condensation chamber; 162. High-pressure evaporation chamber; 163. Absorption chamber; 164. Evaporation chamber; 165. Second baffle. Detailed Implementation

[0016] 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.

[0017] Example 1 Please refer to Figure 1 The application discloses an energy-saving and high-efficiency refrigerating unit capable of preventing steam condensate pump cavitation, which comprises a high-pressure generator 1, a second solution pump 2, a medium-pressure generator 3, a high-pressure evaporator 4, a steam condensate pump 5, a compound power generation compressor 6 and a refrigerating assembly. The refrigerating assembly comprises a second ejector 7, a condenser 8, an expansion valve 9, an evaporator 10, a first ejector 11, an absorber 12, a first solution pump 13 and a flash tank 14. The rich liquid inlet of the high-pressure generator 1 is communicated with the rich liquid outlet of the medium-pressure generator 3 through the second solution pump 2, the high-pressure gaseous refrigerant outlet of the high-pressure generator 1 is communicated with the heat source inlet of the medium-pressure generator 3, the heat source outlet of the high-pressure generator 1 is communicated with the high-pressure evaporator 4, the high-pressure lean liquid outlet of the high-pressure generator 1 is communicated with the flash tank 14, the heat source outlet of the medium-pressure generator 3 is communicated with the high-pressure evaporator 4, the rich liquid inlet of the medium-pressure generator 3 is communicated with the rich liquid outlet of the absorber 12 through the first solution pump 13, the medium-pressure gaseous refrigerant outlet of the medium-pressure generator 3 is communicated with the second ejector 7, the steam condensate outlet of the high-pressure evaporator 4 is communicated with the steam condensate pump 5, the high-pressure gaseous refrigerant outlet of the high-pressure evaporator 4 is communicated with the compound power generation compressor 6, the medium-pressure exhaust gas outlet of the compound power generation compressor 6 is communicated with the first ejector 11, the gaseous refrigerant inlet of the compound power generation compressor 6 is communicated with the gaseous refrigerant outlet of the flash tank 14 and the cooling medium outlet (gaseous refrigerant outlet) of the absorber 12, the gaseous refrigerant outlet of the compound power generation compressor 6 is communicated with the second ejector 7, the outlet of the second ejector 7 is communicated with the gaseous refrigerant inlet of the condenser 8, the liquid refrigerant outlet of the condenser 8 is communicated with the expansion valve 9, the expansion valve 9 has two outlets, one of which is communicated with the liquid refrigerant inlet of the evaporator 10, and the other of which is communicated with the cooling medium inlet (liquid refrigerant inlet) of the absorber 12, the gaseous refrigerant outlet of the evaporator 10 is communicated with the first ejector 11, the outlet of the first ejector 11 is communicated with the gaseous refrigerant inlet of the absorber 12, and the lean liquid outlet of the flash tank 14 is communicated with the lean liquid inlet of the absorber 12.

[0018] Please refer to Figure 5The composite power compressor 6 comprises a turbine wheel assembly 601, a turbine wheel power generation assembly 602 connected with the output shaft of the turbine wheel assembly 601, and a turbine wheel compression assembly 603 (comprising a shell and turbine wheels arranged in the shell). The inlet of the turbine wheel assembly 601 is communicated with the high-pressure gaseous refrigerant outlet of the high-pressure evaporator 4. The outlet of the turbine wheel assembly 601 is communicated with the first ejector 11. The inlet of the turbine wheel compression assembly 603 is communicated with the gaseous refrigerant outlet of the flash tank 14 and the cooling medium outlet of the absorber 12. The outlet of the turbine wheel compression assembly 603 is communicated with the second ejector 7. The high-pressure gaseous refrigerant discharged from the high-pressure evaporator 4 enters the turbine wheel assembly 601 to drive the turbine wheel assembly 601 to rotate, thereby driving the turbine wheel power generation assembly 602 to rotate to generate power and driving the turbine wheel compression assembly 603 to rotate to compress gas.

[0019] An energy-saving and high-efficiency refrigeration process for preventing vapor condensate pump cavitation includes the following steps: Steam heats the high-pressure lean solution delivered from the medium-pressure generator 3 by the second solution pump 2 in the high-pressure generator 1 to desorb most of the low-boiling-point refrigerants in the high-pressure lean solution into high-pressure gaseous refrigerants. The high-pressure gaseous refrigerants enter the medium-pressure generator 3 as a heat source to heat the medium-pressure rich solution delivered from the absorber 12 by the first solution pump 13 to desorb part of the low-boiling-point refrigerants in the medium-pressure rich solution into medium-pressure gaseous refrigerants. The medium-pressure gaseous refrigerants are injected into the second ejector 7. Steam is condensed into saturated vapor condensate in the high-pressure generator 1 by heat absorption. The saturated vapor condensate enters the high-pressure evaporator 4. The high-pressure gaseous refrigerants entering the medium-pressure generator 3 are condensed into high-pressure liquid refrigerants by heat absorption and then enter the high-pressure evaporator 4 to absorb the heat of the saturated vapor condensate to be vaporized into high-pressure gaseous refrigerants. The high-pressure gaseous refrigerants enter the composite power compressor 6 to drive the composite power compressor 6 to work and then become medium-pressure exhaust gas. The medium-pressure exhaust gas enters the first ejector 11 as an injection source. The saturated vapor condensate is cooled into supercooled vapor condensate in the high-pressure evaporator 4 and then enters the vapor condensate pump 5 to be pressurized and sent to the vapor condensate main pipe of the user. The remaining high-pressure lean solution in the high-pressure generator 1 after the generation process enters the flash tank 14, from which low-pressure gaseous refrigerants are flashed out to become low-pressure lean solution. The low-pressure lean solution enters the absorber 12. The low-pressure gaseous refrigerants flowing out of the flash tank 14 are compressed into high-pressure gaseous refrigerants in the composite power compressor 6. The high-pressure gaseous refrigerants enter the second ejector 7 as an injection source to inject the medium-pressure gaseous refrigerants flowing out of the medium-pressure generator 3 to become secondary high-pressure gaseous refrigerants, which are condensed into secondary high-pressure liquid refrigerants in the condenser 8 by circulating water. The sub-high pressure liquid refrigerant is decompressed by the expansion valve 9 into low pressure liquid refrigerant, which is divided into two paths. One path of the low pressure liquid refrigerant is used as a cold source in the absorption process and enters the absorber 12. The other path of the low pressure liquid refrigerant enters the evaporator 10, absorbs the heat of the cooling medium, and becomes low pressure gaseous refrigerant. The low pressure gaseous refrigerant is injected into the first ejector 11 from the middle pressure exhaust gas flowing out of the combined power generation compressor 6, and becomes sub-middle pressure gaseous refrigerant. The sub-middle pressure gaseous refrigerant enters the absorber 12 and is mixed with the low pressure lean liquid flowing out of the flash tank 14 to be absorbed, and becomes low pressure rich liquid. The heat released in the absorption process is absorbed by the cold source (low pressure liquid refrigerant) entering the absorber 12. The cold source (low pressure liquid refrigerant) absorbs heat and gasifies into low pressure gaseous refrigerant. The low pressure gaseous refrigerant is combined with the low pressure gaseous refrigerant flashed out of the flash tank 14, and enters the combined power generation compressor 6 to be compressed into high pressure gaseous refrigerant, which enters the second ejector 7 as an injection source to continue the subsequent cycle. The low pressure rich liquid formed in the absorber 12 is pressurized by the first solution pump 13 into middle pressure rich liquid, which enters the middle pressure generator 3 to continue the subsequent cycle.

[0020] It should be noted that the high pressure gaseous refrigerant flowing out of the high pressure evaporator 4 enters the combined power generation compressor 6 to drive its operation. On the one hand, it generates power to supply the first solution pump 13 and the second solution pump 2. On the other hand, it compresses the incoming low pressure gaseous refrigerant into high pressure gaseous refrigerant.

[0021] Example 2 As a further optimized solution of Example 1, please refer to Figure 2 , Figure 3 and Figure 4 , the unit B 15 is used to replace the high pressure generator 1 and the middle pressure generator 3, and the unit A 16 is used to replace the high pressure evaporator 4, the condenser 8, the evaporator 10 and the absorber 12. Both the unit B 15 and the unit A 16 are fixed tube sheet heat exchangers, which are mainly composed of a head, a tube box cylinder, a tube sheet, heat exchange tubes and a shell. The unit B 15 is provided with a first partition plate 153, which is used to divide the inner cavity of the unit B 15 into a middle pressure generation cavity 151 and a high pressure generation cavity 152. The unit A 16 is provided with a second partition plate 165, which is used to divide the inner cavity of the unit A 16 into a condensation cavity 161, a high pressure evaporation cavity 162, an absorption cavity 163 and an evaporation cavity 164. Both the first partition plate 153 and the second partition plate 165 are externally coated with an insulating layer. The shell of the condensation cavity 161 is provided with a sub-high pressure gaseous refrigerant inlet and a sub-high pressure liquid refrigerant outlet. The sub-high pressure gaseous refrigerant inlet is connected to the outlet of the second ejector 7 through a pipeline. The sub-high pressure liquid refrigerant outlet is connected to the expansion valve 9 through a pipeline. The left and right tube boxes of the condensation cavity 161 are respectively provided with circulating water outlets and inlets. The shell of the high-pressure evaporation cavity 162 is provided with a spray assembly (including a spray pipe and a spray head), the shell of the high-pressure evaporation cavity 162 is provided with a high-pressure liquid refrigerant inlet and a high-pressure gaseous refrigerant outlet, the high-pressure liquid refrigerant inlet is connected to the spray pipe and the tube passage of the medium-pressure generation cavity 151 through a pipeline, the high-pressure gaseous refrigerant outlet is connected to the compound power generation compressor 6 through a pipeline, the left and right tube boxes of the high-pressure evaporation cavity 162 are respectively provided with a saturated steam condensate inlet and a supercooled steam condensate outlet, and the supercooled steam condensate outlet is connected to the steam condensate pump 5 through a pipeline; The shell of the absorption cavity 163 is provided with a spray assembly (including a spray pipe and a spray head), the shell of the absorption cavity 163 is provided with a low-pressure lean liquid inlet, a secondary medium-pressure gaseous refrigerant inlet and a low-pressure rich liquid outlet, the low-pressure lean liquid inlet is connected to the spray pipe and the flash tank 14 through a pipeline, the secondary medium-pressure gaseous refrigerant inlet is connected to the outlet of the first ejector 11 through a pipeline, and the low-pressure rich liquid outlet is connected to the inlet of the first solution pump 13 through a pipeline; the left and right tube boxes of the absorption cavity 163 are respectively provided with a low-pressure liquid refrigerant inlet and a low-pressure gaseous refrigerant outlet, the low-pressure liquid refrigerant inlet is connected to the expansion valve 9 through a pipeline, and the low-pressure gaseous refrigerant outlet is connected to the compound power generation compressor 6 through a pipeline; The shell of the evaporation cavity 164 is provided with a spray assembly (including a spray pipe and a spray head), the shell of the evaporation cavity 164 is provided with a low-pressure liquid refrigerant inlet and a low-pressure gaseous refrigerant outlet, the low-pressure liquid refrigerant inlet is connected to the spray pipe and the expansion valve 9 through a pipeline, and the low-pressure gaseous refrigerant outlet is connected to the first ejector 11 through a pipeline; the left and right tube boxes of the evaporation cavity 164 are respectively provided with a heat transfer medium inlet and an outlet; The shell of the medium-pressure generation cavity 151 is provided with a spray assembly (including a spray pipe and a spray head), the shell of the medium-pressure generation cavity 151 is provided with a medium-pressure rich liquid inlet, a medium-pressure gaseous refrigerant outlet and a medium-pressure secondary rich liquid outlet, the medium-pressure rich liquid inlet is connected to the spray pipe and the outlet of the first solution pump 13 through a pipeline, the medium-pressure gaseous refrigerant outlet is connected to the inlet of the second ejector 7 through a pipeline, and the medium-pressure secondary rich liquid outlet is connected to the inlet of the second solution pump 2 through a pipeline; the left and right tube boxes of the medium-pressure generation cavity 151 are respectively provided with a high-pressure gaseous refrigerant inlet and a high-pressure liquid refrigerant outlet, and the high-pressure liquid refrigerant outlet is connected to the shell passage of the high-pressure evaporation cavity 162 through a pipeline; A spray assembly (including a spray pipe and a spray head) is arranged in the shell of the high-pressure generating cavity 152. The shell of the high-pressure generating cavity 152 is provided with a high-pressure sub-rich liquid inlet, a high-pressure gaseous refrigerant outlet and a high-pressure lean liquid outlet. The high-pressure sub-rich liquid inlet is connected to the spray pipe and the outlet of the second solution pump 2 through a pipeline. The high-pressure gaseous refrigerant outlet is connected to the high-pressure gaseous refrigerant inlet on the left tube box of the medium-pressure generating cavity 151 through a pipeline. The high-pressure lean liquid outlet is connected to the flash tank 14 through a pipeline. The left and right tube boxes of the high-pressure generating cavity 152 are respectively provided with a saturated steam condensate outlet and a steam inlet. The saturated steam condensate outlet is connected to the saturated steam condensate inlet on the left tube box of the high-pressure evaporation cavity 162 through a pipeline.

[0022] In this embodiment, as a further optimized scheme, please refer to Figure 3 and Figure 4 The unit A 16 is located above the unit B 15. The medium-pressure generating cavity 151 is located above the high-pressure generating cavity 152. The condensation cavity 161, the high-pressure evaporation cavity 162, the absorption cavity 163 and the evaporation cavity 164 are respectively located in the first, second, third and fourth quadrants.

[0023] An energy-saving and high-efficiency type refrigeration process for preventing steam condensate pump cavitation includes the following steps: The steam heats the high-pressure sub-rich liquid transported from the shell side of the medium-pressure generating cavity 151 by the second solution pump 2 in the shell side of the high-pressure generating cavity 152, so that most of the low-boiling-point refrigerants in the high-pressure sub-rich liquid are desorbed to become high-pressure gaseous refrigerants. The high-pressure gaseous refrigerants enter the tube side of the medium-pressure generating cavity 151 as a heat source, heat the medium-pressure rich liquid transported from the shell side of the absorption cavity 163 by the first solution pump 13, so that part of the low-boiling-point refrigerants in the medium-pressure rich liquid are desorbed to become medium-pressure gaseous refrigerants, which are then injected into the second ejector 7. The steam is condensed into saturated steam condensate by heat absorption in the tube side of the high-pressure generating cavity 152, and then enters the tube side of the high-pressure evaporation cavity 162. The high-pressure gaseous refrigerants entering the tube side of the medium-pressure generating cavity 151 are condensed into high-pressure liquid refrigerants by heat absorption, and then enter the shell side of the high-pressure evaporation cavity 162. The high-pressure gaseous refrigerants are vaporized into high-pressure gaseous refrigerants by absorbing the heat of the saturated steam condensate entering the tube side, and then enter the impeller turbine assembly of the compound power compressor 6 to drive it to work and become medium-pressure exhaust gas, which enters the first ejector 11 as an injection source. The saturated steam condensate is cooled into supercooled steam condensate by heat absorption in the tube side of the high-pressure evaporation cavity 162, and then enters the steam condensate pump 5 to be pressurized and sent to the steam condensate main pipe of the user. The high-pressure lean liquid remaining in the shell side of the high-pressure generating cavity 152 after the generating process enters the flash tank 14, and the low-pressure gaseous refrigerant is flashed out, and then becomes low-pressure lean liquid and enters the shell side of the absorbing cavity 163; the low-pressure gaseous refrigerant flowing out of the flash tank 14 enters the impeller turbine compression assembly of the compound power generation compressor 6 and is compressed into high-pressure gaseous refrigerant, which enters the second ejector 7 as an injection source, injects the medium-pressure gaseous refrigerant flowing out of the shell side of the medium-pressure generating cavity 151, and then becomes low-pressure gaseous refrigerant and enters the shell side of the condensing cavity 161 and is condensed into low-pressure liquid refrigerant by circulating water; The low-pressure liquid refrigerant is decompressed by the expansion valve 9 into low-pressure liquid refrigerant, which is divided into two paths, one of which enters the tube side of the absorbing cavity 163 as a cold source in the absorbing process, and the other of which enters the shell side of the evaporating cavity 164, absorbs the heat of the heat carrier and becomes low-pressure gaseous refrigerant, which is injected into the first ejector 11 by the medium-pressure exhaust gas flowing out of the compound power generation compressor 6, becomes low-pressure gaseous refrigerant, and enters the shell side of the absorbing cavity 163 and is mixed with the low-pressure lean liquid flowing out of the flash tank 14 to become low-pressure rich liquid; the heat released in the absorbing process is absorbed by the cold source (low-pressure liquid refrigerant) entering the tube side of the absorbing cavity 163, and the cold source (low-pressure liquid refrigerant) absorbs heat and vaporizes into low-pressure gaseous refrigerant, which is combined with the low-pressure gaseous refrigerant flashed out of the flash tank 14 and enters the impeller turbine compression assembly of the compound power generation compressor 6 and is compressed into high-pressure gaseous refrigerant, which enters the second ejector 7 as an injection source and continues the subsequent cycle; The low-pressure rich liquid formed in the shell side of the absorbing cavity 163 is pressurized by the first solution pump 13 into medium-pressure rich liquid, which enters the shell side of the medium-pressure generating cavity 151 and continues the subsequent cycle.

[0024] It should be noted that the high-pressure evaporator 4, the condenser 8, the evaporator 10, and the absorber 12 are integrated into a device, i.e., the unit A 16, and the high-pressure generator 1 and the medium-pressure generator 3 are integrated into a device, i.e., the unit B 15; this can reduce the cost of equipment and pipelines and greatly reduce the floor area occupied by the unit, which is conducive to the skid packaging of the unit.

[0025] The above-described embodiments only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled persons 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 energy-saving and high-efficiency refrigeration unit capable of preventing vapor condensate from cavitation, characterized in that, It comprises a high-pressure generator (1), a medium-pressure generator (3), a high-pressure evaporator (4), a steam condensate pump (5), a combined power generation compressor (6) and a refrigeration assembly. The high-pressure generator (1) uses the heat of steam to produce high-pressure gaseous refrigerant, the medium-pressure generator (3) is used to absorb the heat of the high-pressure gaseous refrigerant produced by the high-pressure generator (1) to liquefy it into high-pressure liquid refrigerant, the high-pressure evaporator (4) uses the high-pressure liquid refrigerant discharged by the medium-pressure generator (3) to absorb the heat of the used steam of the high-pressure generator (1) to vaporize, so as to drive the combined power generation compressor (6) to generate power, and the refrigeration assembly is used to produce cold energy by using the heat absorbed by the medium-pressure generator (3). The refrigeration assembly comprises a second ejector (7), a condenser (8), an evaporator (10), a first ejector (11), an absorber (12) and a flash tank (14).

2. The energy-saving and high-efficiency refrigerating unit preventing vapor condensate pump cavitation according to claim 1, characterized in that, The condenser (8) is used to deliver liquid refrigerant to the evaporator (10) and the absorber (12) respectively, the flash tank (14) is used to flash the lean liquid discharged by the high-pressure generator (1) to vaporize the refrigerant in the lean liquid, the first ejector (11) uses the gaseous refrigerant discharged by the combined power generation compressor (6) as an injection source to introduce the gaseous refrigerant in the evaporator (10) into the absorber (12), and the combined power generation compressor (6) is also used to pressurize the gaseous refrigerant discharged by the absorber (12) and the flash tank (14) to serve as an injection source of the second ejector (7) to guide the gaseous refrigerant discharged by the medium-pressure generator (3) into the condenser (8). The refrigeration assembly further comprises an expansion valve (9) and a first solution pump (13), the expansion valve (9) is used to depressurize the liquid refrigerant discharged by the condenser (8), and the first solution pump (13) is used to pressurize the rich liquid in the absorber (12) and input it into the medium-pressure generator (3).

3. The energy-saving and high-efficiency refrigerating unit of claim 2, wherein the unit is characterized in that, The energy-saving and high-efficiency refrigeration unit further comprises a second solution pump (2), which is used to pressurize the rich liquid of the medium-pressure generator (3) and input it into the high-pressure generator (1).

4. The energy-saving and high-efficiency refrigerating unit preventing vapor condensate pump cavitation according to claim 1, characterized in that, The combined power generation compressor (6) comprises an impeller turbine assembly (601), an impeller turbine power generation assembly (602) connected with an output shaft of the impeller turbine assembly (601) and an impeller turbine compression assembly (603).

5. The energy-saving and high-efficiency refrigerating unit preventing vapor condensate pump cavitation according to claim 1, characterized in that, The unit B (15) is used to replace the high-pressure generator (1) and the medium-pressure generator (3), and the unit A (16) is used to replace the high-pressure evaporator (4), the condenser (8), the evaporator (10) and the absorber (12). The unit B (15) and the unit A (16) are both fixed tube sheet heat exchangers, the main structure of which comprises a head, a tube box cylinder segment, a tube sheet, heat exchange tubes and a shell. The inner cavity of the unit B (15) is divided into a medium-pressure generation cavity (151) and a high-pressure generation cavity (152), and the inner cavity of the unit A (16) is divided into a condensing cavity (161), a high-pressure evaporation cavity (162), an absorption cavity (163) and an evaporation cavity (164).

6. The energy-saving and high-efficiency refrigerating unit preventing vapor condensate pump cavitation according to claim 2, characterized in that, ​ 7. The energy-saving and high-efficiency refrigerating unit of claim 6, wherein the unit is characterized in that, The medium-pressure generating cavity (151) and the high-pressure generating cavity (152) are separated by a first partition (153), and the condensing cavity (161), the high-pressure evaporating cavity (162), the absorbing cavity (163) and the evaporating cavity (164) are separated by a second partition (165).

8. The energy-saving and high-efficiency refrigerating unit of claim 6, wherein the unit is characterized in that, The unit A (16) is located above the unit B (15), and the shell cavities of the medium-pressure generating cavity (151), the high-pressure generating cavity (152), the high-pressure evaporating cavity (162), the absorbing cavity (163) and the evaporating cavity (164) are each provided with a spraying assembly.

9. An energy-saving and high-efficiency refrigeration process for preventing vapor-condensate pump cavitation, characterized in that it uses an energy-saving and high-efficiency refrigeration unit for preventing vapor-condensate pump cavitation according to any one of claims 1-5. The method comprises the following steps: The steam heats the high-pressure sub-rich liquid in the high-pressure generator (1) to produce high-pressure gaseous refrigerant, which enters the medium-pressure generator (3) as a heat source and is liquefied into high-pressure liquid refrigerant by absorbing heat, and then enters the high-pressure evaporator (4); After the steam is condensed into saturated steam condensate by absorbing heat in the high-pressure generator (1), it enters the high-pressure evaporator (4) to heat the high-pressure liquid refrigerant, so that the high-pressure liquid refrigerant is vaporized into high-pressure gaseous refrigerant, and the steam itself is cooled into supercooled steam condensate and enters the steam condensate pump (5); The high-pressure gaseous refrigerant enters the combined power generator and compressor (6) to drive the generator, and the refrigeration assembly produces cold energy by absorbing heat in the medium-pressure generator (3).

10. An energy-saving and high-efficiency refrigeration process for preventing vapor-condensate pump cavitation, using the energy-saving and high-efficiency refrigeration unit for preventing vapor-condensate pump cavitation according to any one of claims 6-8, characterized in that, The method comprises the following steps: The steam heats the high-pressure sub-rich liquid in the high-pressure generating cavity (152) to produce high-pressure gaseous refrigerant, which enters the medium-pressure generating cavity (151) as a heat source and is liquefied into high-pressure liquid refrigerant by absorbing heat, and then enters the high-pressure evaporating cavity (162); After the steam is condensed into saturated steam condensate by absorbing heat in the high-pressure generating cavity (152), it enters the high-pressure evaporating cavity (162) to heat the high-pressure liquid refrigerant, so that the high-pressure liquid refrigerant is vaporized into high-pressure gaseous refrigerant, and the steam itself is cooled into supercooled steam condensate and enters the steam condensate pump (5); The high-pressure gaseous refrigerant enters the combined power generator and compressor (6) to drive the generator, and the refrigeration assembly produces cold energy by absorbing heat in the medium-pressure generating cavity (151).

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