A crystallization-preventing and step-by-step deep cooling unit and process

Abstract

The application discloses an absorption refrigeration technology field and relates to a crystallization-preventing and step-by-step deep cooling unit and process, which comprises a generation-condensation assembly, an evaporation-absorption assembly and an ejector; the generation-condensation assembly comprises a high-pressure evaporator, a high-pressure generator, a sub-high-pressure generator and a condenser; the evaporation-absorption assembly comprises a medium-pressure absorber, a low-pressure absorber, a medium-pressure evaporator and a low-pressure evaporator; the absorption refrigeration unit is optimized and designed in the application, part of heat in a high-temperature heat source is converted into pressure energy of high-pressure gaseous refrigerant, and the pressure energy of the high-pressure gaseous refrigerant is converted into pressure energy of the absorber through injection, so that the heat source temperature can be reduced, crystallization can be prevented, the absorption efficiency of the absorber can be improved, and therefore the deep cooling efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of absorption refrigeration, specifically to a unit and process for preventing crystallization and producing cryogenic products in stages. Background Technology

[0002] Absorption chillers utilize low-grade waste heat to drive a thermodynamic working fluid, achieving refrigeration through the phase change of the working fluid (such as ammonia). The main equipment includes a generator, condenser, evaporator, absorber, and solution pump. The low-grade waste heat used in these chillers is usually below 200℃. When the temperature exceeds this value, crystallization easily occurs in the unit. The conventional approach is to add a de-cooling and pressure-reducing device or a cooler to lower the heat source temperature to a suitable value before it enters the unit, resulting in a waste of heat source heat.

[0003] When producing cryogenic refrigerant, the main factor limiting the evaporator evaporation temperature is the absorption efficiency of the absorber. The absorption efficiency of the absorber is limited by the absorption pressure and the temperature of the cold source used for heat absorption during the absorption process. The higher the absorption pressure and the lower the temperature of the cold source used for heat absorption during the absorption process, the higher the absorption efficiency of the absorber. However, the absorption pressure of the absorber depends on the evaporation pressure of the evaporator. The lower the refrigeration temperature, the lower the evaporation pressure. Generally, a gas compressor is added between the evaporator and the absorber to extract the low-pressure gaseous refrigerant in the evaporator, pressurize it, and send it to the absorber. This can solve the absorption pressure problem. However, the gas compressor consumes a lot of energy, which also violates the goal of replacing electric compressor refrigeration machines with low-grade waste heat refrigeration machines to save energy, reduce emissions, and protect the environment.

[0004] Furthermore, the circulating water serves as the cold source for heat absorption during the absorber process, and its temperature directly affects the unit's cooling efficiency. The circulating water temperature is also affected by the wet-bulb temperature. In summer, the high wet-bulb temperature limits the maximum temperature of the cooling circulating water in the air-cooled tower, resulting in a higher circulating water temperature. This higher circulating water temperature leads to low efficiency when the unit is producing cryogenic fluid. Moreover, cryogenic fluid production typically uses single-stage refrigeration. To increase the cooling effect, the heat exchange area of ​​a single refrigeration unit is large, resulting in an excessively large size of the individual refrigeration equipment, which causes difficulties in manufacturing, processing, and installation. Summary of the Invention

[0005] The purpose of this invention is to provide a unit and process for preventing crystallization and producing cryogenic products in stages, which solves the problem of crystallization that easily occurs in existing units.

[0006] The present invention achieves the above objectives through the following technical solution: a unit for preventing crystallization and producing cryogenic products in stages, comprising: a condensation generation component, an evaporation absorption component, and an ejector;

[0007] The condensation assembly includes a high-pressure evaporator, a high-pressure generator, a sub-high-pressure generator, and a condenser; the evaporation absorption assembly includes a medium-pressure absorber, a low-pressure absorber, a medium-pressure evaporator, and a low-pressure evaporator.

[0008] The high-pressure evaporator uses the high-pressure liquid refrigerant discharged from the sub-high-pressure generator to absorb the heat from the heat source and use it as the ejector source to eject the gaseous refrigerant discharged from the low-pressure evaporator, thereby increasing the pressure of the gaseous refrigerant entering the low-pressure absorber.

[0009] The condenser uses the sub-high pressure gaseous refrigerant produced by the sub-high pressure generator to generate a cold source. The medium-pressure evaporator uses part of the generated cold source to initially cool the refrigerant and cool the low-pressure absorber. The low-pressure evaporator uses the remaining cold source discharged from the medium-pressure evaporator to cool the refrigerant again.

[0010] Preferably, the unit further includes a third solution pump, a second solution pump, a first expansion valve, a first solution pump, and a pressure reducing valve;

[0011] The third solution pump is used to pressurize the rich liquid input from the sub-high pressure generator to the high pressure generator; the second solution pump is used to pressurize the rich liquid input from the medium pressure absorber to the sub-high pressure generator; the first expansion valve is used to depressurize the liquid refrigerant introduced from the condenser to the medium pressure evaporator; the first solution pump is used to pressurize the rich liquid input from the low pressure absorber to the medium pressure absorber; and the pressure reducing valve is used to depressurize the lean liquid introduced from the high pressure generator to the low pressure absorber.

[0012] Preferably, the evaporation absorption assembly further includes a second expansion valve for reducing the pressure of the liquid refrigerant introduced from the medium-pressure evaporator into the low-pressure evaporator.

[0013] Preferably, the high-pressure generator is used to produce high-pressure gaseous refrigerant using the heat from a heat source, and the sub-high-pressure generator is used to produce sub-high-pressure gaseous refrigerant using the high-pressure gaseous refrigerant produced by the high-pressure generator as a heat source.

[0014] Preferably, a composite generator-condenser is used to replace the high-pressure evaporator, high-pressure generator, sub-high-pressure generator, and condenser, and a composite evaporator-absorber is used to replace the medium-pressure absorber, low-pressure absorber, medium-pressure evaporator, and low-pressure evaporator. Both the composite generator-condenser and the composite evaporator-absorber are fixed tube sheet heat exchangers whose main structure consists of end caps, tube box sections, tube sheets, heat exchange tubes, and shells. The composite generator-condenser is divided into a sub-high-pressure generating chamber, a condensing chamber, a high-pressure evaporating chamber, and a high-pressure generating chamber. The composite evaporator-absorber is divided into a low-pressure evaporating chamber, a low-pressure absorption chamber, a medium-pressure absorption chamber, and a medium-pressure evaporating chamber.

[0015] Preferably, the sub-high pressure generating chamber, condensing chamber, high pressure evaporating chamber and high pressure generating chamber are separated by a first partition, and the low pressure evaporating chamber, low pressure absorption chamber, medium pressure absorption chamber and medium pressure evaporating chamber are separated by a second partition.

[0016] Preferably, the inner cavity of the medium-pressure absorption chamber and the inner cavity of the medium-pressure evaporation chamber are connected by an opening, and the inner cavity of the secondary high-pressure generating chamber and the inner cavity of the condensation chamber are connected by an opening, with baffles provided in both openings.

[0017] Preferably, the composite evaporator absorber is mounted on top of the composite generator condenser via a support plate.

[0018] Preferably, a process for preventing crystallization and producing cryogenic material in stages, utilizing the aforementioned unit for preventing crystallization and producing cryogenic material in stages, includes the following steps:

[0019] The heat source cooled from the high-pressure evaporation chamber heats the high-pressure secondary rich liquid in the high-pressure generating chamber to produce high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant enters the secondary high-pressure generating chamber as a heat source to heat the secondary high-pressure rich liquid to produce secondary high-pressure gaseous refrigerant, which is then introduced into the condensing chamber and condensed into secondary high-pressure liquid refrigerant by circulating water.

[0020] The high-pressure liquid refrigerant enters the medium-pressure evaporation chamber. Part of it serves as a cold source for the initial cooling of the refrigerant and the cooling of the low-pressure absorption chamber, while the other part enters the low-pressure evaporation chamber to further cool the refrigerant that has undergone initial cooling.

[0021] The high-pressure gaseous refrigerant is absorbed and condensed into a high-pressure cold refrigerant in the sub-high-pressure generating chamber. It then enters the high-pressure evaporating chamber, where it absorbs heat from the heat source and vaporizes into a high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant acts as an ejector source, entering the ejector to eject the low-pressure gaseous refrigerant from the low-pressure evaporating chamber. The gaseous refrigerant mixes with the low-pressure gaseous refrigerant to form a medium-pressure gaseous refrigerant, which then circulates in the low-pressure absorption chamber.

[0022] A process for preventing crystallization and producing cryogenic material in stages, utilizing the aforementioned unit for preventing crystallization and producing cryogenic material in stages, includes the following steps:

[0023] The heat source cooled from the high-pressure evaporator heats the high-pressure secondary rich liquid in the high-pressure generator to produce high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant enters the secondary high-pressure generator as a heat source to heat the secondary high-pressure rich liquid to produce secondary high-pressure gaseous refrigerant, which is then introduced into the condenser and condensed into secondary high-pressure liquid refrigerant by circulating water.

[0024] The high-pressure liquid refrigerant enters the medium-pressure evaporator, part of which serves as a cold source for initial cooling of the refrigerant and cooling of the low-pressure absorber, while the other part enters the low-pressure evaporator to further cool the refrigerant that has undergone initial cooling.

[0025] The high-pressure gaseous refrigerant is absorbed and condensed into a high-pressure cold refrigerant in the sub-high-pressure generator. It then enters the high-pressure evaporator, where it absorbs heat from the heat source and vaporizes into a high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant acts as an ejector source, entering the ejector to eject the low-pressure gaseous refrigerant from the low-pressure evaporator. The mixture then becomes a medium-pressure gaseous refrigerant, which circulates in the low-pressure absorber.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. By optimizing the design of the absorption chiller, part of the heat in the high-temperature heat source is converted into the pressure energy of the high-pressure gaseous refrigerant, and then converted into the pressure energy of the absorber through the injection of the high-pressure gaseous refrigerant. This can reduce the temperature of the heat source and prevent crystallization, and also improve the absorption efficiency of the absorber, thus improving the efficiency of producing cryogenic products.

[0028] 2. When producing cryogenic fluid, a step-by-step refrigeration method is used instead of a single-stage refrigeration method. Part of the cooling capacity in the first-stage refrigeration is used as the cold source for the absorber in the second-stage refrigeration to replace the circulating water. This solves the problem of excessively high circulating water temperature and its susceptibility to climate change, improves the absorption efficiency of the absorber, and thus improves the efficiency of producing cryogenic fluid.

[0029] 3. When producing cryogenic products, the refrigeration efficiency of step-by-step refrigeration is higher than that of single-stage refrigeration. Step-by-step refrigeration can also reduce the heat exchange area of ​​individual equipment, solving the difficulties in manufacturing, processing and hoisting due to the large size of individual equipment.

[0030] 4. The heat of the high-pressure gaseous refrigerant desorbed from the generator is recovered, realizing the deep utilization of energy inside the unit, which can reduce the unit's energy consumption and improve the unit's COP. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the unit for preventing crystallization and producing cryogenic products in stages according to the present invention;

[0032] Figure 2 This is a schematic diagram showing the connection between the composite generator condenser and the composite evaporator absorber of the present invention;

[0033] Figure 3 This is a schematic cross-sectional view of the connection between the composite generator-condenser and the composite evaporator-absorber of the present invention.

[0034] Figure 4 For the present invention Figure 3 Schematic diagram of the AA direction.

[0035] In the diagram: 1. High-pressure evaporator; 2. High-pressure generator; 3. Third solution pump; 4. Secondary high-pressure generator; 5. Condenser; 6. Secondary solution pump; 7. First expansion valve; 8. Medium-pressure absorber; 9. First solution pump; 10. Low-pressure absorber; 11. Medium-pressure evaporator; 12. Secondary expansion valve; 13. Low-pressure evaporator; 14. Ejector; 15. Pressure reducing valve; 16. Composite generator condenser; 161. Secondary high-pressure generating chamber; 162. Condensing chamber; 163. High-pressure evaporation chamber; 164. High-pressure generating chamber; 165. First baffle; 17. Composite evaporator absorber; 171. Low-pressure evaporation chamber; 172. Low-pressure absorption chamber; 173. Medium-pressure absorption chamber; 174. Medium-pressure evaporation chamber; 175. Second baffle. Detailed Implementation

[0036] 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.

[0037] Example 1

[0038] Please see Figure 1 A unit that prevents crystallization and produces cryogenic products in stages includes: a condensation generation assembly, an evaporation absorption assembly, an ejector 14, a third solution pump 3, a second solution pump 6, a first expansion valve 7, a first solution pump 9, and a pressure reducing valve 15.

[0039] The condensation assembly includes a high-pressure evaporator 1, a high-pressure generator 2, a sub-high-pressure generator 4, and a condenser 5. The evaporation absorption assembly includes a medium-pressure absorber 8, a low-pressure absorber 10, a medium-pressure evaporator 11, a low-pressure evaporator 13, and a second expansion valve 12.

[0040] The high-pressure evaporator 1 has its heat source outlet connected to the high-pressure generator 2's heat source inlet. The rich liquid inlet of the high-pressure generator 2 is connected to the rich liquid outlet of the secondary high-pressure generator 4 via a third solution pump 3. The high-pressure gaseous refrigerant outlet of the high-pressure generator 2 is connected to the heat source inlet of the secondary high-pressure generator 4. The lean liquid outlet of the high-pressure generator 2 is connected to the lean liquid inlet of the low-pressure absorber 10 via a pressure reducing valve 15. The heat source outlet of the secondary high-pressure generator 4 is connected to the high-pressure evaporator 1. The high-pressure gaseous refrigerant outlet of the high-pressure evaporator 1 is connected to the ejector 14. The secondary high-pressure gaseous refrigerant outlet of the secondary high-pressure generator 4 is connected to the secondary high-pressure gaseous refrigerant inlet of the condenser 5. The rich liquid inlet of the secondary high-pressure generator 4 is connected to the rich liquid outlet of the intermediate-pressure absorber 8 via a second solution pump 6. The circulating water inlet of condenser 5 is connected to the circulating water outlet of medium-pressure absorber 8. The liquid refrigerant outlet of condenser 5 is connected to the liquid refrigerant inlet of medium-pressure evaporator 11 through the first expansion valve 7. The refrigerant outlet of medium-pressure evaporator 11 is connected to the refrigerant inlet of low-pressure evaporator 13. The gaseous refrigerant outlet of medium-pressure evaporator 11 is connected to the gaseous refrigerant inlet of medium-pressure absorber 8. The cooling water inlet and outlet of medium-pressure evaporator 11 are connected to the cooling water inlet and outlet of low-pressure absorber 10. The liquid refrigerant outlet of medium-pressure evaporator 11 is connected to the liquid refrigerant inlet of low-pressure evaporator 13 through the second expansion valve 12. The gaseous refrigerant outlet of low-pressure evaporator 13 is connected to ejector 14. The outlet of ejector 14 is connected to the gaseous refrigerant inlet of low-pressure absorber 10.

[0041] A process for preventing crystallization and producing cryogenic products in stages includes the following steps:

[0042] The heat source cooled from the high-pressure evaporator 1 heats the high-pressure secondary rich liquid delivered from the secondary high-pressure generator 4 by the third solution pump 3 in the high-pressure generator 2, causing most of the low-boiling-point refrigerant in the high-pressure secondary rich liquid to desorb, becoming high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant enters the secondary high-pressure generator 4 as a heat source, heating the secondary high-pressure rich liquid delivered from the medium-pressure absorber 8 by the second solution pump 6, causing some of the low-boiling-point refrigerant in the secondary high-pressure rich liquid to desorb, becoming secondary high-pressure gaseous refrigerant. The secondary high-pressure gaseous refrigerant enters the condenser 5 and is condensed into secondary high-pressure liquid refrigerant by circulating water.

[0043] The sub-high pressure liquid refrigerant flowing out of condenser 5 is reduced to medium pressure liquid refrigerant through the first expansion valve 7 and then enters the medium pressure evaporator 11. Part of it serves as the cold source for primary refrigeration and the cold source for the low pressure absorber 10, absorbing heat from the refrigerant and cooling water and vaporizing into medium pressure gaseous refrigerant, which then enters the medium pressure absorber 8. The other part of the medium pressure liquid refrigerant entering the medium pressure evaporator 11 is reduced to low pressure liquid refrigerant through the second expansion valve 12 and enters the low pressure evaporator 13. It serves as the cold source for deep refrigeration, absorbing heat from the refrigerant coming out of the medium pressure evaporator 11 and vaporizing into low pressure gaseous refrigerant, which is then ejected into the ejector 14.

[0044] The high-pressure gaseous refrigerant desorbed from the high-pressure generator 2 is used as a heat source in the secondary high-pressure generator 4. It is absorbed and condensed into a high-pressure cold refrigerant, which enters the high-pressure evaporator 1. It absorbs heat from the heat source and vaporizes into a high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant acts as an ejector source and enters the ejector 14 to eject the low-pressure gaseous refrigerant from the low-pressure evaporator 13. The gaseous refrigerant mixes with the low-pressure gaseous refrigerant to form a medium-pressure gaseous refrigerant, which then enters the low-pressure absorber 10.

[0045] The high-pressure lean liquid remaining after the generation process in the high-pressure generator 2 is reduced to low-pressure lean liquid by the pressure reducing valve 15 and then enters the low-pressure absorber 10. It mixes and absorbs with the medium-pressure gaseous refrigerant coming out of the ejector 14 to become low-pressure secondary rich liquid. The heat released during the absorption process is carried away by the entering cooling water. After absorbing heat, the cooling water enters the medium-pressure evaporator 11 and is cooled again (cooled by the medium-pressure liquid refrigerant in the medium-pressure evaporator 11). The cooling water circulates between the low-pressure absorber 10 and the medium-pressure evaporator 11.

[0046] The low-pressure secondary rich liquid formed in the low-pressure absorber 10 is pressurized into a medium-pressure secondary rich liquid by the first solution pump 9. The medium-pressure secondary rich liquid enters the medium-pressure absorber 8 and mixes with the medium-pressure gaseous refrigerant coming out of the medium-pressure evaporator 11 to absorb it, becoming a medium-pressure rich liquid. The heat released during the absorption process is carried away by the circulating water. The medium-pressure rich liquid formed in the medium-pressure absorber 8 is pressurized into a secondary high-pressure rich liquid by the second solution pump 6. The secondary high-pressure rich liquid enters the secondary high-pressure generator 4 to continue the subsequent cycle.

[0047] It should be noted that the refrigerant is absorbed by heat in the medium-pressure evaporator 11 and the low-pressure evaporator 13 in sequence, completing the primary cooling and deep cooling respectively, thereby completing the deep cooling process.

[0048] Example 2

[0049] As a further optimization of Example 1, please refer to Figure 2 , Figure 3 and Figure 4A composite generator-condenser 16 is used to replace the high-pressure evaporator 1, high-pressure generator 2, sub-high-pressure generator 4 and condenser 5. A composite evaporator-absorber 17 is used to replace the medium-pressure absorber 8, low-pressure absorber 10, medium-pressure evaporator 11 and low-pressure evaporator 13. Both the composite generator-condenser 16 and the composite evaporator-absorber 17 are fixed tube sheet heat exchangers whose main structure consists of end caps, tube box sections, tube sheets, heat exchange tubes and shells. The inner cavity of the composite generator-condenser 16 is provided with a first partition 165, which is used to divide the inner cavity of the composite generator-condenser 16 into a sub-high-pressure generating chamber 161, a condensing chamber 162, a high-pressure evaporating chamber 163 and a high-pressure generating chamber 164. The inner cavity of the composite evaporator-absorber 17 is provided with a second partition 175, which is used to divide the inner cavity of the composite evaporator-absorber 17 into a low-pressure evaporating chamber 171, a low-pressure absorption chamber 172, a medium-pressure absorption chamber 173 and a medium-pressure evaporating chamber 174.

[0050] The low-pressure evaporator chamber 171 is equipped with a spray assembly (including a spray pipe and a nozzle) inside its shell. The low-pressure evaporator chamber 171 is equipped with a low-pressure liquid refrigerant inlet. The low-pressure liquid refrigerant inlet is connected to the spray pipe and the second expansion valve 12 through a pipe. The left and right pipe boxes of the low-pressure evaporator chamber 171 are respectively equipped with a refrigerant outlet and inlet.

[0051] The low-pressure absorption chamber 172 is equipped with a spray assembly (including a spray pipe and a nozzle) inside its shell. The low-pressure absorption chamber 172 is equipped with a low-pressure lean liquid inlet, a medium-pressure gaseous refrigerant inlet, and a low-pressure sub-rich liquid outlet. The low-pressure lean liquid inlet is connected to the spray pipe and the pressure reducing valve 15 through a pipe. The low-pressure sub-rich liquid outlet is connected to the first solution pump 9 through a pipe. The left and right pipe boxes of the low-pressure absorption chamber 172 are respectively equipped with cooling water inlet and outlet.

[0052] The shell of the medium-pressure absorption chamber 173 is equipped with a spray assembly (including a spray pipe and a nozzle). The shell of the medium-pressure absorption chamber 173 is equipped with a medium-pressure secondary rich liquid inlet and a medium-pressure rich liquid outlet. The medium-pressure secondary rich liquid inlet is connected to the spray pipe and the first solution pump 9 through a pipe. The medium-pressure rich liquid outlet is connected to the second solution pump 6 through a pipe. The left and right pipe boxes of the medium-pressure absorption chamber 173 are respectively equipped with a circulating water inlet and a circulating water outlet.

[0053] The shell of the medium-pressure evaporator 174 is equipped with a spray assembly (including a spray pipe and a nozzle). The shell of the medium-pressure evaporator 174 is provided with a medium-pressure liquid refrigerant inlet and a medium-pressure liquid refrigerant outlet. The medium-pressure liquid refrigerant inlet is connected to the spray pipe and the first expansion valve 7 via a pipe, and the medium-pressure liquid refrigerant outlet is connected to the second expansion valve 12 via a pipe. The left pipe box of the medium-pressure evaporator 174 is provided with a refrigerant inlet and a cooling water inlet (the left pipe box is equipped with a baffle plate, which blocks the refrigerant inlet). The cooling water inlet is connected to the cooling water outlet on the left tube box of the low-pressure absorption chamber 172 via a pipe. The right tube box of the medium-pressure evaporation chamber 174 is provided with a refrigerant outlet and a cooling water outlet (a baffle plate is provided in the left tube box, which separates the refrigerant outlet and the cooling water outlet). The refrigerant outlet is connected to the refrigerant inlet on the right tube box of the low-pressure evaporation chamber 171 via a pipe. The cooling water outlet is connected to the cooling water inlet on the right tube box of the low-pressure absorption chamber 172 via a pipe.

[0054] The shell of the secondary high-pressure generating chamber 161 is equipped with a spray assembly (including a spray pipe and a nozzle). The shell of the secondary high-pressure generating chamber 161 is equipped with a secondary high-pressure rich liquid inlet and a secondary high-pressure secondary rich liquid outlet. The secondary high-pressure rich liquid inlet is connected to the spray pipe and the second solution pump 6 through a pipe. The secondary high-pressure secondary rich liquid outlet is connected to the inlet of the third solution pump 3 through a pipe. The left and right pipe boxes of the secondary high-pressure generating chamber 161 are respectively equipped with a high-pressure gaseous refrigerant inlet and a high-pressure liquid refrigerant outlet.

[0055] The condenser 162 has a sub-high pressure liquid refrigerant outlet on its shell. The left and right tube boxes of the condenser 162 are respectively equipped with circulating water inlet and outlet. The circulating water inlet is connected to the circulating water outlet on the right tube box of the medium pressure absorption chamber 173 through a pipe.

[0056] The high-pressure evaporator chamber 163 is equipped with a spray assembly (including a spray pipe and a nozzle) inside its shell. The high-pressure evaporator chamber 163 is equipped 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 high-pressure liquid refrigerant outlet on the right tube box of the secondary high-pressure generating chamber 161 through a pipe. The high-pressure gaseous refrigerant outlet is connected to the inlet of the ejector 14 through a pipe. The left and right tube boxes of the high-pressure evaporator chamber 163 are respectively equipped with heat source inlets and outlets.

[0057] The high-pressure generating chamber 164 is equipped with a spray assembly (including a spray pipe and a nozzle) inside its shell. The high-pressure generating chamber 164 is equipped with a high-pressure sub-rich liquid inlet, a high-pressure lean liquid outlet, and a high-pressure gaseous refrigerant outlet. The high-pressure sub-rich liquid inlet is connected to the spray pipe and the outlet of the third solution pump 3 through a pipe. The high-pressure lean liquid outlet is connected to the pressure reducing valve 15 through a pipe. The high-pressure gaseous refrigerant outlet is connected to the high-pressure gaseous refrigerant inlet on the left tube box of the sub-high-pressure generating chamber 161 through a pipe. The left and right tube boxes of the high-pressure generating chamber 164 are respectively equipped with a heat source inlet and outlet. The heat source inlet is connected to the heat source outlet on the right tube box of the high-pressure evaporating chamber 163 through a pipe.

[0058] Please see Figure 4 The inner cavity of the medium-pressure absorption chamber 173 is connected to the inner cavity of the medium-pressure evaporation chamber 174 through an opening (located on the second partition 175), allowing the medium-pressure gaseous refrigerant generated in the medium-pressure evaporation chamber 174 to directly enter the interior of the medium-pressure absorption chamber 173 without the need for piping. The inner cavity of the secondary high-pressure generating chamber 161 is connected to the inner cavity of the condensing chamber 162 through an opening (located on the first partition 165), allowing the secondary high-pressure gaseous refrigerant generated in the secondary high-pressure generating chamber 161 to directly enter the interior of the condensing chamber 162. Both openings are equipped with baffles to prevent liquid from passing through the openings.

[0059] In this embodiment, as a further optimization, please refer to... Figure 3 and Figure 4 The composite evaporator absorber 17 is mounted on top of the composite generator condenser 16 via a support plate.

[0060] A process for preventing crystallization and producing cryogenic products in stages includes the following steps:

[0061] The heat source, cooled in the tube side of the high-pressure evaporator 163, heats the high-pressure secondary rich liquid delivered from the secondary high-pressure generating chamber 161 by the third solution pump 3 in the tube side of the high-pressure generating chamber 164. This causes most of the low-boiling-point refrigerant in the shell side of the high-pressure secondary rich liquid to desorb, becoming high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant enters the tube side of the secondary high-pressure generating chamber 161 as a heat source, heating the secondary high-pressure rich liquid delivered from the medium-pressure absorption chamber 173 by the second solution pump 6. This causes some of the low-boiling-point refrigerant in the shell side of the secondary high-pressure rich liquid to desorb, becoming secondary high-pressure gaseous refrigerant. The secondary high-pressure gaseous refrigerant enters the shell side of the condensing chamber 162 and is condensed into secondary high-pressure liquid refrigerant by circulating water.

[0062] The sub-high pressure liquid refrigerant flowing out of the shell side of the condenser 162 is reduced to medium pressure liquid refrigerant by the first expansion valve 7 and then enters the shell side of the medium pressure evaporator 174. Part of it serves as the cold source for primary refrigeration and the cold source for the low pressure absorption chamber 172, absorbing heat from the refrigerant and cooling water and vaporizing into medium pressure gaseous refrigerant, which then enters the shell side of the medium pressure absorption chamber 173. The other part of the medium pressure liquid refrigerant entering the shell side of the medium pressure evaporator 174 is reduced to low pressure liquid refrigerant by the second expansion valve 12 and enters the shell side of the low pressure evaporator 171. It serves as the cold source for deep refrigeration, absorbing heat from the refrigerant coming out of the shell side of the medium pressure evaporator 174 and vaporizing into low pressure gaseous refrigerant, which is then ejected into the ejector 14.

[0063] The high-pressure gaseous refrigerant desorbed from the shell side of the high-pressure generating chamber 164 is used as a heat source for the secondary high-pressure generating chamber 161. It is then condensed into a high-pressure cold refrigerant and enters the shell side of the high-pressure evaporating chamber 163. There, it absorbs heat from the heat source and vaporizes into a high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant acts as an ejector source and enters the ejector 14 to eject the low-pressure gaseous refrigerant from the shell side of the low-pressure evaporating chamber 171. The gaseous refrigerant mixes with the low-pressure gaseous refrigerant and enters the shell side of the low-pressure absorption chamber 172.

[0064] In the shell side of the high-pressure generating chamber 164, the high-pressure lean liquid remaining after the generation process is reduced to low-pressure lean liquid by the pressure reducing valve 15 and then enters the shell side of the low-pressure absorption chamber 172, where it mixes and absorbs with the medium-pressure gaseous refrigerant coming out of the ejector 14 to become low-pressure secondary rich liquid. The heat released during the absorption process is carried away by the cooling water entering the tube side. After absorbing heat, the cooling water enters the tube side of the medium-pressure evaporating chamber 174 and is cooled again. The cooling water circulates between the low-pressure absorption chamber 172 and the medium-pressure evaporating chamber 174.

[0065] The low-pressure secondary rich liquid formed in the shell side of the low-pressure absorption chamber 172 is pressurized into a medium-pressure secondary rich liquid by the first solution pump 9, and then enters the shell side of the medium-pressure absorption chamber 173. It mixes and absorbs with the medium-pressure gaseous refrigerant coming out of the medium-pressure evaporation chamber 174 to become a medium-pressure rich liquid. The heat released during the absorption process is carried away by the circulating water. The medium-pressure rich liquid formed in the shell side of the medium-pressure absorption chamber 173 is pressurized into a secondary high-pressure rich liquid by the second solution pump 6. The secondary high-pressure rich liquid enters the shell side of the secondary high-pressure generating chamber 161 to continue the subsequent circulation.

[0066] It should be noted that the refrigerant is absorbed by heat in the medium-pressure evaporation chamber 174 and the low-pressure evaporation chamber 171 in sequence, completing the primary cooling and deep cooling respectively, thereby completing the deep cooling process.

[0067] 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. A unit for preventing crystallization and producing cryogenic products in stages, characterized in that, include: The condensation assembly, the evaporation absorption assembly and the ejector (14) are generated. The condensation assembly includes a high-pressure evaporator (1), a high-pressure generator (2), a sub-high-pressure generator (4), and a condenser (5). The evaporation absorption assembly includes a medium-pressure absorber (8), a low-pressure absorber (10), a medium-pressure evaporator (11), and a low-pressure evaporator (13). The high-pressure evaporator (1) uses the high-pressure liquid refrigerant discharged from the sub-high-pressure generator (4) to absorb the heat from the heat source and as the ejector source of the ejector (14) to eject the gaseous refrigerant discharged from the low-pressure evaporator (13) to increase the pressure of the gaseous refrigerant entering the low-pressure absorber (10). The condenser (5) uses the sub-high pressure gaseous refrigerant produced by the sub-high pressure generator (4) to produce a cold source. The medium pressure evaporator (11) uses part of the produced cold source to initially cool the refrigerant and cool the low pressure absorber (10). The low pressure evaporator (13) uses the remaining cold source discharged from the medium pressure evaporator (11) to cool the refrigerant again. The unit also includes a third solution pump (3), a second solution pump (6), a first expansion valve (7), a first solution pump (9), and a pressure reducing valve (15). The third solution pump (3) is used to pressurize the rich liquid input from the sub-high pressure generator (4) to the high pressure generator (2), the second solution pump (6) is used to pressurize the rich liquid input from the medium pressure absorber (8) to the sub-high pressure generator (4), the first expansion valve (7) is used to depressurize the liquid refrigerant introduced from the condenser (5) to the medium pressure evaporator (11), the first solution pump (9) is used to pressurize the rich liquid input from the low pressure absorber (10) to the medium pressure absorber (8), and the pressure reducing valve (15) is used to depressurize the lean liquid introduced from the high pressure generator (2) to the low pressure absorber (10).

2. The unit for preventing crystallization and producing cryogenic products in stages according to claim 1, characterized in that, The evaporation absorption assembly also includes a second expansion valve (12) for reducing the pressure of the liquid refrigerant introduced from the medium-pressure evaporator (11) into the low-pressure evaporator (13).

3. The unit for preventing crystallization and producing cryogenic products in stages according to claim 1, characterized in that, The high-pressure generator (2) is used to produce high-pressure gaseous refrigerant using the heat of the heat source, and the sub-high-pressure generator (4) is used to produce sub-high-pressure gaseous refrigerant using the high-pressure gaseous refrigerant produced by the high-pressure generator (2) as a heat source.

4. The unit for preventing crystallization and producing cryogenic products in stages according to claim 3, characterized in that, A composite generator condenser (16) is used to replace the high-pressure evaporator (1), high-pressure generator (2), sub-high-pressure generator (4) and condenser (5). A composite evaporator absorber (17) is used to replace the medium-pressure absorber (8), low-pressure absorber (10), medium-pressure evaporator (11) and low-pressure evaporator (13). Both the composite generator condenser (16) and the composite evaporator absorber (17) are fixed tube sheet heat exchangers whose main structure consists of end caps, tube box sections, tube sheets, heat exchange tubes and shell. The composite generator condenser (16) is divided into a sub-high-pressure generating chamber (161), a condensing chamber (162), a high-pressure evaporating chamber (163) and a high-pressure generating chamber (164). The composite evaporator absorber (17) is divided into a low-pressure evaporating chamber (171), a low-pressure absorbing chamber (172), a medium-pressure absorbing chamber (173) and a medium-pressure evaporating chamber (174).

5. The unit for preventing crystallization and producing cryogenic products in stages according to claim 4, characterized in that, The high-pressure generating chamber (161), condensing chamber (162), high-pressure evaporating chamber (163) and high-pressure generating chamber (164) are separated by a first partition (165), and the low-pressure evaporating chamber (171), low-pressure absorption chamber (172), medium-pressure absorption chamber (173) and medium-pressure evaporating chamber (174) are separated by a second partition (175).

6. The unit for preventing crystallization and producing cryogenic products in stages according to claim 5, characterized in that, The inner cavity of the medium-pressure absorption chamber (173) and the inner cavity of the medium-pressure evaporation chamber (174) are connected by an opening, and the inner cavity of the secondary high-pressure generating chamber (161) and the inner cavity of the condensation chamber (162) are connected by an opening. A baffle plate is provided in both openings.

7. The unit for preventing crystallization and producing cryogenic products in stages according to claim 4, characterized in that, The composite evaporator (17) is mounted on top of the composite generator condenser (16) via a support plate.

8. A process for preventing crystallization and producing cryogenic fluid in stages, utilizing a unit for preventing crystallization and producing cryogenic fluid in stages as described in any one of claims 1-3, characterized in that, Includes the following steps: The heat source cooled from the high-pressure evaporator (1) heats the high-pressure secondary rich liquid in the high-pressure generator (2) to produce high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant enters the secondary high-pressure generator (4) as a heat source to heat the secondary high-pressure rich liquid to produce secondary high-pressure gaseous refrigerant, and introduces it into the condenser (5) to be condensed into secondary high-pressure liquid refrigerant by circulating water. The high-pressure liquid refrigerant enters the medium-pressure evaporator (11), part of which serves as a cold source for the initial cooling of the refrigerant and the cooling of the low-pressure absorber (10), while the other part enters the low-pressure evaporator (13) to cool the refrigerant that has undergone initial cooling again. The high-pressure gaseous refrigerant is absorbed and condensed into a high-pressure cold refrigerant in the sub-high-pressure generator (4), and enters the high-pressure evaporator (1). It absorbs heat from the heat source and vaporizes into a high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant acts as an ejector source and enters the ejector (14) to eject the low-pressure gaseous refrigerant from the low-pressure evaporator (13) and mixes it into a medium-pressure gaseous refrigerant, which then enters the low-pressure absorber (10) for circulation.

9. A process for preventing crystallization and producing cryogenic fluid in stages, utilizing a unit for preventing crystallization and producing cryogenic fluid in stages as described in any one of claims 4-7, characterized in that, Includes the following steps: The heat source cooled from the high-pressure evaporation chamber (163) heats the high-pressure secondary rich liquid in the high-pressure generating chamber (164) to produce high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant enters the secondary high-pressure generating chamber (161) as a heat source to heat the secondary high-pressure rich liquid to produce secondary high-pressure gaseous refrigerant, and is introduced into the condensing chamber (162) and condensed into secondary high-pressure liquid refrigerant by circulating water. The high-pressure liquid refrigerant enters the medium-pressure evaporation chamber (174), part of which serves as a cold source for the initial cooling of the refrigerant and the cooling of the low-pressure absorption chamber (172), while the other part enters the low-pressure evaporation chamber (171) to cool the refrigerant that has undergone initial cooling again. The high-pressure gaseous refrigerant is absorbed and condensed into a high-pressure cold refrigerant in the sub-high-pressure generating chamber (161), and enters the high-pressure evaporating chamber (163). It absorbs heat from the heat source and vaporizes into a high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant acts as an ejector source and enters the ejector (14) to eject the low-pressure gaseous refrigerant coming out of the low-pressure evaporating chamber (171) and mixes with it to become a medium-pressure gaseous refrigerant, which then enters the low-pressure absorption chamber (172) for circulation.

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