A multi-demand coupled distillation refrigeration system

Abstract

The present invention is applicable to the technical field of low-temperature refrigeration, and discloses a multi-demand coupled distillation refrigeration system, including a compressor, a primary heat exchanger, a secondary heat exchanger, an expander, a cooling heat exchanger, and a rewarming heat exchanger. A cold flow is drawn out between the primary and secondary heat exchangers, and heat exchange is performed in the cooling heat exchanger to achieve a cooling demand, that is, the temperature required at the cold screen. The cold flow is then divided into two fluids, one of which provides cooling capacity for the cold screen, and the other flows into the reboiler to realize the function of a low-temperature heater, providing heating capacity for the reboiled liquid in the distillation tower. Subsequently, the fluid that has provided the heating capacity flows back to the low-pressure side of the secondary heat exchanger, and finally flows back to the compressor. The high-pressure flow flowing out from the high-pressure side of the secondary heat exchanger flows through the expander to reduce the pressure and temperature, and then flows into the condenser to provide cooling capacity. The refrigeration system can simultaneously meet the cooling capacity demands of multiple temperature zones.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature refrigeration, and in particular to a multi-demand coupled distillation refrigeration system. Background Art

[0002] Cryogenic refrigeration systems have important applications in many fields such as aerospace, nuclear energy utilization, medical diagnosis and treatment, high-energy physics, etc. Among them, cryogenic distillation is an important way to obtain pure gas in industry and is widely used in the field of gas acquisition and purification. Hydrogen, as a clean energy, has important application prospects in the future.

[0003] There are condensers and reboilers inside the distillation tower, and there is a cold screen outside the distillation tower to block the heat radiation and heat conduction between the inside and the outside. The condenser inside the distillation tower provides cold capacity for the gas phase mixed working fluid in the tower, liquefies the high boiling point working fluid, and realizes the gas-liquid separation of different working fluids. The reboiler inside the distillation tower heats the liquid phase mixed working fluid in the tower, vaporizes the low boiling point working fluid, and realizes separation. The existing condenser and cold screen use refrigerators to provide cold capacity, and the reboiler uses heaters to achieve heating. Using a heater at low temperature is equivalent to losing cold capacity at low temperature, which is less efficient from the perspective of energy utilization efficiency. At the same time, the existing distillation system is often used in air separation fields such as nitrogen and oxygen separation, and there are fewer distillation systems with lower temperatures such as 20K temperature zone. The 20K temperature zone distillation system has a wide range of uses, so it is necessary to use a low-temperature refrigerator in the liquid hydrogen temperature zone to provide cold capacity, and it is crucial to realize the cold capacity supply of the condenser and cold screen. Summary of the invention

[0004] The object of the present invention is to provide a multi-demand coupled distillation refrigeration system, which aims to solve the technical problem that the existing refrigeration system cannot simultaneously meet the cooling demand of multiple temperature zones.

[0005] To achieve the above object, the solution provided by the present invention is:

[0006] A multi-demand coupled distillation refrigeration system, comprising a compressor, a primary heat exchanger, a secondary heat exchanger, an expander, a cooling heat exchanger, a rewarming heat exchanger, a first branch pipe, a second branch pipe, a third branch pipe, a fourth branch pipe, a fifth branch pipe, and a sixth branch pipe; the high-pressure side inlet of the primary heat exchanger is connected to the outlet of the compressor, the high-pressure side outlet of the primary heat exchanger is connected to the high-pressure side inlet of the secondary heat exchanger through the first branch pipe, the high-pressure side outlet of the secondary heat exchanger is connected to the inlet of the expander, the outlet of the expander is configured to be connected to the inlet of a condenser, the low-pressure side inlet of the cooling heat exchanger is configured to be connected to the outlet of the condenser through the third branch pipe, the low-pressure side outlet of the cooling heat exchanger is connected to the cold side inlet of the rewarming heat exchanger, and the cold side outlet of the rewarming heat exchanger is connected to the pressure compressor; the low-pressure side inlet of the secondary heat exchanger is configured to be connected to the outlet of the condenser through the fourth branch pipe, the low-pressure side outlet of the secondary heat exchanger is connected to the low-pressure side inlet of the primary heat exchanger, and the low-pressure side outlet of the primary heat exchanger is connected to the inlet of the compressor; the high-pressure side outlet of the primary heat exchanger is connected to the high-pressure side inlet of the cooling heat exchanger through the second branch pipe, the high-pressure side outlet of the cooling heat exchanger is configured to be connected to the inlet of the cold screen through the fifth branch pipe, the hot side inlet of the recuperation heat exchanger is configured to be connected to the outlet of the cold screen, and the hot side outlet of the recuperation heat exchanger is connected to the compressor; the high-pressure side outlet of the cooling heat exchanger is configured to be connected to the inlet of the reboiler through the sixth branch pipe, and the outlet of the reboiler is connected to the fourth branch pipe.

[0007] Preferably, a first low-temperature valve and a second low-temperature valve are sequentially arranged between the primary heat exchanger and the cooling heat exchanger.

[0008] Preferably, a sixth cryogenic valve is provided between the cooling heat exchanger and the reboiler.

[0009] Preferably, a third low-temperature valve is provided between the cold-side outlet of the recuperation heat exchanger and the compressor, and a normal-temperature valve is provided between the hot-side outlet of the recuperation heat exchanger and the compressor.

[0010] Preferably, a fourth cryogenic valve is provided between the secondary heat exchanger and the expander.

[0011] Preferably, a fifth cryogenic valve is provided between the expander and the condenser.

[0012] Preferably, a seventh cryogenic valve is provided between the secondary heat exchanger and the condenser.

[0013] Preferably, a first heater is provided between the secondary heat exchanger and the reboiler.

[0014] Preferably, a second heater is provided between the rewarming heat exchanger and the cold shield.

[0015] Preferably, a third heater is provided between the hot-side outlet of the rewarming heat exchanger and the compressor.

[0016] The multi-demand coupled distillation refrigeration system provided by the present invention can provide cooling capacity for the condenser inside the distillation tower, heat for the reboiler inside the distillation tower, and cooling capacity for the cold screen outside the distillation tower, and can realize gas distillation and fractionation and condensation separation from 4K to 120K, that is, it can meet the cooling capacity requirements of multiple temperature zones at the same time. Moreover, under the premise of meeting multiple demands, the refrigeration system integrates multiple temperature zones into a set of refrigeration systems, ensuring high integration and high stability, while avoiding the complexity of the refrigeration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of a multi-demand coupled distillation refrigeration system provided in an embodiment of the present invention.

[0019] Description of Figure Numbers:

[0020] 101. compressor; 201. primary heat exchanger; 202. secondary heat exchanger; 203. reheating heat exchanger; 204. cooling heat exchanger; 300. first cryogenic valve; 301. second cryogenic valve; 302. third cryogenic valve; 303. fourth cryogenic valve; 304. fifth cryogenic valve; 305. sixth cryogenic valve; 306. seventh cryogenic valve; 307. normal temperature valve; 401. expander; 501. cold screen; 502. condenser; 503. reboiler; 601. first heater; 602. second heater; 603. third heater. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0024] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] like Figure 1 As shown, it is a multi-demand coupled distillation refrigeration system of an embodiment of the present invention, which can be applied to distillation refrigeration cycles such as helium-neon distillation and hydrogen-neon distillation. The refrigeration system is used to provide cooling for the condenser inside the distillation tower, provide heat for the reboiler inside the distillation tower, and provide cooling for the cold screen outside the distillation tower, and can realize gas distillation and condensation separation from 4K to 120K.

[0026] See also Figure 1The multi-demand coupled distillation refrigeration system of the embodiment of the present invention comprises a compressor 101, a primary heat exchanger 201, a secondary heat exchanger 202, an expander 401, a cooling heat exchanger 204, a rewarming heat exchanger 203, a first branch pipe, a second branch pipe, a third branch pipe, a fourth branch pipe, a fifth branch pipe, and a sixth branch pipe. The high-pressure side inlet of the primary heat exchanger 201 is connected to the inlet of the compressor 101, the high-pressure side outlet of the primary heat exchanger 201 is connected to the high-pressure side inlet of the secondary heat exchanger 202 through the first branch pipe, the high-pressure side outlet of the secondary heat exchanger 202 is connected to the inlet of the expander 401, the outlet of the expander 401 is connected to the inlet of the condenser 502, the outlet of the condenser 502 is connected to the low-pressure side inlet of the cooling heat exchanger 204 through the third branch pipe, the low-pressure side outlet of the cooling heat exchanger 204 is connected to the cold side inlet of the rewarming heat exchanger 203, and the rewarming heat exchanger 203 is connected to the cooling side inlet of the cooling heat exchanger 204. The cold side outlet of the heat exchanger 203 is connected to the inlet of the compressor 101; the outlet of the condenser 502 is connected to the low-pressure side inlet of the secondary heat exchanger 202 through the fourth branch pipe, the low-pressure side outlet of the secondary heat exchanger 202 is connected to the low-pressure side inlet of the primary heat exchanger 201, and the low-pressure side outlet of the primary heat exchanger 201 is connected to the inlet of the compressor 101; the high-pressure side outlet of the primary heat exchanger 201 is connected to the high-pressure side inlet of the cooling heat exchanger 204 through the second branch pipe, the high-pressure side outlet of the cooling heat exchanger 204 is connected to the inlet of the cold shield 501 through the fifth branch pipe, the outlet of the cold shield 501 is connected to the hot side inlet of the reheating heat exchanger 203, and the hot side outlet of the reheating heat exchanger 203 is connected to the inlet of the compressor 101; the high-pressure side outlet of the cooling heat exchanger 204 is connected to the inlet of the reboiler 503 through the sixth branch pipe, and the outlet of the reboiler 503 is connected to the fourth branch pipe.

[0027] Preferably, the heat exchange medium of the primary heat exchanger 201 is liquid nitrogen. Using liquid nitrogen as the heat exchange medium can improve the heat exchange effect.

[0028] The compressor 101 compresses the refrigerant and flows into the primary heat exchanger 201, and then flows out from the high-pressure side outlet after reflux and pre-cooling with liquid nitrogen. The pre-cooled high-pressure refrigerant is divided into two streams at the high-pressure side outlet of the primary heat exchanger 201. Most of the high-pressure refrigerant flows from the first branch pipe through the secondary heat exchanger 202 and the expander 401 to achieve cooling. After cooling, the refrigerant flows into the condenser 502 to provide cooling capacity. The remaining high-pressure refrigerant flows from the second branch pipe into the cooling heat exchanger 204 to achieve cooling. At the high-pressure side outlet of the cooling heat exchanger 204, it is divided into two streams. One fluid flows from the fifth branch pipe into the cold screen 501 to provide cooling capacity for the system, and then flows through the reheating heat exchanger 203 to achieve reheating and then flows back to the compressor 101. Another fluid separated at the high-pressure side outlet of the cooling heat exchanger 204 flows from the sixth branch pipe into the reboiler 503 to achieve reboiling heating of the distillation medium. The high-pressure refrigerant flowing through the condenser 502 is divided into two fluids at the outlet of the condenser 502. One fluid flows from the third branch pipe through the cooling heat exchanger 204 for heat exchange, then flows into the reheating heat exchanger 203 for reheating, and then flows back to the compressor 101. The other fluid flows out from the fourth branch pipe and mixes with the refrigerant flowing out of the outlet of the reboiler 503. After mixing, it exchanges heat in the secondary heat exchanger 202 and the primary heat exchanger 201 and then flows back to the compressor 101.

[0029] The multi-demand coupled distillation refrigeration system of the embodiment of the present invention can simultaneously meet the cooling demand of multiple temperature zones. Moreover, the refrigeration system integrates multiple temperature zones into a set of refrigeration systems under the premise of meeting multiple demands, thereby ensuring high integration and high stability, while avoiding the complexity of the refrigeration system.

[0030] Preferably, a first cryogenic valve 300 and a second cryogenic valve 301 are sequentially arranged between the primary heat exchanger 201 and the cooling heat exchanger 204. The refrigeration system independently controls the flow of the pre-cooled high-pressure refrigerant entering the cooling heat exchanger 204 by arranging the first cryogenic valve 300 and the second cryogenic valve 301, thereby controlling the refrigeration capacity entering the cold screen 501. The first cryogenic valve 300 is a switch valve, and the second cryogenic valve 301 is a regulating valve. The two valves are used together to effectively isolate the cold box part of the refrigerator and ensure accurate flow regulation.

[0031] Furthermore, a sixth cryogenic valve 305 is provided between the cooling heat exchanger 204 and the reboiler 503. The refrigeration system independently controls the amount of heating entering the reboiler 503 by providing the sixth cryogenic valve 305. The amount of heating can be adjusted according to the temperature and flow before and after the reboiler 503.

[0032] Preferably, a fourth cryogenic valve 303 is provided between the secondary heat exchanger 202 and the expander 401 , and the refrigeration system independently controls the flow of the refrigerant entering the expander 401 by providing the fourth cryogenic valve 303 .

[0033] Preferably, a fifth cryogenic valve 304 is provided between the expander 401 and the condenser 502. The refrigeration system independently controls the refrigeration capacity entering the condenser 502 by providing the fifth cryogenic valve 304. The refrigeration capacity can be adjusted according to the temperature and flow rate of the refrigerant.

[0034] Preferably, a seventh cryogenic valve 306 is provided between the condenser 502 and the secondary heat exchanger 202 , and the refrigeration system independently controls the reflux flow entering the secondary heat exchanger 202 by providing the seventh cryogenic valve 306 .

[0035] Preferably, a third low-temperature valve 302 is provided between the cold side outlet of the recuperation heat exchanger 203 and the compressor 101, and a normal temperature valve 307 is provided between the hot side outlet of the recuperation heat exchanger 203 and the compressor 101. The refrigeration system independently controls the reflux flow rate entering the compressor 101 from the cold side outlet of the recuperation heat exchanger 203 by providing the third low-temperature valve 302, and independently controls the reflux flow rate entering the compressor 101 from the hot side outlet of the recuperation heat exchanger 203 by providing the normal temperature valve 307.

[0036] The refrigeration system independently adjusts the cooling capacity of different equipment by installing low-temperature valves at multiple locations inside the system, avoiding interference between multiple cooling demands.

[0037] Preferably, a first heater 601 is provided between the reboiler 503 and the secondary heat exchanger 202 to heat the refrigerant flowing back to the secondary heat exchanger 202 to meet the system fixed frequency regulation requirements.

[0038] It should be noted that the first heater 601 can also be arranged at the low-pressure side inlet of the secondary heat exchanger 202, that is, the refrigerant flowing out of the reboiler 503 can be reheated by the first heater 601 and then merged with the refrigerant flowing out of the condenser 502, and then flow into the secondary heat exchanger 202. The refrigerant flowing out of the reboiler 503 can also merge with the refrigerant flowing out of the condenser 502, then flow through the first heater 601 for reheating, and then flow into the secondary heat exchanger 202 after reheating.

[0039] Preferably, a second heater 602 is provided between the cold shield 501 and the rewarming heat exchanger 203 for heating the refrigerant entering the cold side inlet of the rewarming heat exchanger 203 to achieve a cold flow rewarming effect.

[0040] Furthermore, a third heater 603 is provided between the hot side outlet of the rewarming heat exchanger 203 and the compressor 101 for heating the refrigerant flowing back to the compressor 101 to achieve a cold flow rewarming effect.

[0041] Preferably, a heater is provided between the expander 401 and the condenser 502 to realize a fixed frequency regulation function of the system.

[0042] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A multi-demand coupled distillation refrigeration system, characterized in that: It includes a compressor, a primary heat exchanger, a secondary heat exchanger, an expander, a cooling heat exchanger, a rewarming heat exchanger, a first branch pipe, a second branch pipe, a third branch pipe, a fourth branch pipe, a fifth branch pipe, and a sixth branch pipe; the high-pressure side inlet of the primary heat exchanger is connected to the outlet of the compressor, the high-pressure side outlet of the primary heat exchanger is connected to the high-pressure side inlet of the secondary heat exchanger through the first branch pipe, the high-pressure side outlet of the secondary heat exchanger is connected to the inlet of the expander, the outlet of the expander is configured to be connected to the inlet of the condenser, the low-pressure side inlet of the cooling heat exchanger is configured to be connected to the outlet of the condenser through the third branch pipe, the low-pressure side outlet of the cooling heat exchanger is connected to the cold side inlet of the rewarming heat exchanger, and the cold side outlet of the rewarming heat exchanger is connected to the compressor; The low-pressure side inlet of the secondary heat exchanger is configured to be connected to the outlet of the condenser through the fourth branch pipe, the low-pressure side outlet of the secondary heat exchanger is connected to the low-pressure side inlet of the primary heat exchanger, and the low-pressure side outlet of the primary heat exchanger is connected to the inlet of the compressor; the high-pressure side outlet of the primary heat exchanger is connected to the high-pressure side inlet of the cooling heat exchanger through the second branch pipe, the high-pressure side outlet of the cooling heat exchanger is configured to be connected to the inlet of the cold screen through the fifth branch pipe, the hot side inlet of the recuperation heat exchanger is configured to be connected to the outlet of the cold screen, and the hot side outlet of the recuperation heat exchanger is connected to the compressor; the high-pressure side outlet of the cooling heat exchanger is configured to be connected to the inlet of the reboiler through the sixth branch pipe, and the outlet of the reboiler is connected to the fourth branch pipe; A fourth cryogenic valve is provided between the secondary heat exchanger and the expander; A fifth cryogenic valve is provided between the expander and the condenser.

2. The multi-demand coupled distillation refrigeration system according to claim 1, characterized in that: A first low-temperature valve and a second low-temperature valve are sequentially arranged between the primary heat exchanger and the cooling heat exchanger.

3. The multi-demand coupled distillation refrigeration system according to claim 2, characterized in that: A sixth low-temperature valve is provided between the cooling heat exchanger and the reboiler.

4. The multi-demand coupled distillation refrigeration system according to claim 1, characterized in that: A third low-temperature valve is provided between the cold-side outlet of the retemperature heat exchanger and the compressor, and a normal-temperature valve is provided between the hot-side outlet of the retemperature heat exchanger and the compressor.

5. The multi-demand coupled distillation refrigeration system according to claim 1, characterized in that: A seventh low-temperature valve is provided between the secondary heat exchanger and the condenser.

6. The multi-demand coupled distillation refrigeration system according to claim 1, characterized in that: A first heater is provided between the secondary heat exchanger and the reboiler.

7. The multi-demand coupled distillation refrigeration system according to claim 1, characterized in that: A second heater is arranged between the rewarming heat exchanger and the cold shield.

8. The multi-demand coupled distillation refrigeration system according to claim 7, characterized in that: A third heater is provided between the hot side outlet of the rewarming heat exchanger and the compressor.

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