CN115597245A - Optimized single-cycle mixed refrigerant refrigerating system and refrigerating method - Google Patents

Optimized single-cycle mixed refrigerant refrigerating system and refrigerating method Download PDF

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Publication number
CN115597245A
CN115597245A CN202110778316.3A CN202110778316A CN115597245A CN 115597245 A CN115597245 A CN 115597245A CN 202110778316 A CN202110778316 A CN 202110778316A CN 115597245 A CN115597245 A CN 115597245A
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China
Prior art keywords
interstage
stage
inlet
separation tank
cooler
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CN202110778316.3A
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Chinese (zh)
Inventor
李简
张欢
张朝阳
窦维敏
孟令然
曹炎
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China National Petroleum Corp
China Petroleum Engineering and Construction Corp
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China National Petroleum Corp
China Petroleum Engineering and Construction Corp
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Priority to CN202110778316.3A priority Critical patent/CN115597245A/en
Publication of CN115597245A publication Critical patent/CN115597245A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/40—Fluid line arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat

Abstract

The invention discloses an optimized single-cycle mixed refrigerant refrigerating system and a refrigerating method.A mixed refrigerant in a cold box is conveyed to an inlet separating tank from an outlet in the refrigerating system, the inlet separating tank is communicated with a first-stage inlet of a compressor, a first-stage outlet of the compressor is communicated with an interstage cooler, and the interstage cooler is communicated with the interstage separating tank; the liquid phase outlet of the interstage separation tank is communicated with the cold box, the gas phase outlet of the interstage separation tank is communicated with the second-stage inlet of the compressor, the second-stage outlet of the compressor is communicated with the final-stage cooler, and the final-stage cooler is communicated with the final-stage separation tank; the liquid phase outlet of the last stage separating tank is communicated with the interstage separating tank, and the gas phase outlet of the last stage separating tank is communicated with the cold box. By adopting the technical scheme of the invention, the flow entering the refrigerant of the cold box is reduced, the complexity of the design of the cold box is reduced, the energy consumption of the compressor is reduced, the number of movable equipment is reduced, the equipment investment is reduced, and the safety operability and the stability of the device are improved.

Description

Optimized single-cycle mixed refrigerant refrigerating system and refrigerating method
Technical Field
The invention relates to the technical field of refrigeration, in particular to an Optimized Single-cycle Mixed refrigerant refrigeration system and an Optimized Single-cycle Mixed refrigerant refrigeration method (OSMR process: optimized Single-cycle Mixed refrigeration Technology).
Background
As a clean, environment-friendly and high-quality energy source, the demand of natural gas is increasing along with the change of energy structures in China and the improvement of environmental protection requirements. However, as gas, there are many limitations in storage and transportation, and Liquefied Natural Gas (LNG) exhibits great advantages in storage and transportation, and liquefaction of natural gas is gradually becoming a trend.
The traditional single-cycle mixed refrigerant refrigeration process comprises the following two steps:
the first method comprises the following steps: conventional single cycle mixed refrigerant refrigeration process a (see fig. 1): liquid at the bottom of the interstage separation tank 15 is mixed with gas from the top of the interstage separation tank 15 through a high-pressure pump 18, the mixture is cooled through a final stage cooler 16 and then enters a final stage separation tank 17, and finally the final stage separation tank 17 is divided into two streams which enter a cold box 11, wherein one stream is a top high-pressure gas-phase refrigerant and the other stream is a bottom high-pressure liquid-phase refrigerant.
In the conventional single-cycle mixed refrigerant refrigeration process a, the liquid-phase refrigerant at the bottom of the interstage separation tank 15 is sent to the final cooler 16 through the high-pressure pump 18, and the following problems exist in the process:
1. the liquid-phase refrigerant passes through the high-pressure pump 18 again, so that the operation energy consumption of the pump is increased;
2. the introduction of the high-pressure pump 18 increases the number of devices in the device, thereby increasing the workload of equipment maintenance and increasing the investment;
3. because the saturated vapor pressure of the mixed refrigerant is lower, the high-pressure pump 18 is easy to generate cavitation in the using process, thereby generating vibration, damaging the mechanical sealing property of the pump and bringing great potential safety hazards to the safe production and stable operation of the device.
And the second method comprises the following steps: conventional single cycle mixed refrigerant refrigeration process B (see fig. 2): liquid at the bottom of the interstage separation tank 15 is used as low-pressure refrigerant and enters the cold box 11; the gas at the top of the interstage separation tank 15 is continuously pressurized and cooled, and enters a final stage separator for separation; the gas phase separated by the last separator enters the cold box 11 as a high-pressure gas-phase refrigerant, and the liquid phase enters the cold box 11 as a high-pressure liquid-phase refrigerant.
In the traditional single-cycle mixed refrigerant refrigeration process B, the refrigerant flow entering the cold box 11 is three, and compared with the traditional single-cycle mixed refrigerant refrigeration process B, the high-pressure liquid-phase refrigerant is added, so that the following problems exist in the process:
1. the number of refrigerant streams entering the cold box 11 is large, so that the design difficulty of the cold box 11 is increased;
2. more light components are dissolved in the high-pressure liquid-phase refrigerant, bias flow is easily formed in the cold box, the difficulty in arrangement and design of all layers of the cold box is increased, the work load of the light components at the supercooling section of the cold box 11 is reduced, and the processing capacity and energy consumption of the compressor 13 for compressing the light components are increased.
Disclosure of Invention
In order to solve the problems, the invention provides an optimized single-cycle mixed refrigerant refrigerating system and an optimized single-cycle mixed refrigerant refrigerating method (OSMR process), high-pressure liquid-phase refrigerant at the bottom of a last-stage separation tank is throttled and returned to the interstage separation tank, and is mixed with low-pressure liquid at the bottom of the interstage separation tank to enter a cold box for refrigeration of a precooling section of the cold box.
To achieve the above object, the present invention provides an optimized single-cycle mixed refrigerant refrigeration system, comprising: a cold box, an inlet knockout drum, a compressor, an inter-stage cooler, an inter-stage knockout drum, a final stage cooler, and a final stage knockout drum; the mixed refrigerant in the cold box is conveyed from an outlet to an inlet of the inlet separation tank, an outlet of the inlet separation tank is communicated with a primary inlet of the compressor, a primary outlet of the compressor is communicated with an inlet of the interstage cooler, and an outlet of the interstage cooler is communicated with an inlet of the interstage separation tank; a liquid phase outlet of the interstage separation tank communicates with an inlet of the cold box, a gas phase outlet of the interstage separation tank communicates with a secondary inlet of the compressor, a secondary outlet of the compressor communicates with an inlet of the final stage cooler, and an outlet of the final stage cooler communicates with an inlet of the final stage separation tank; the liquid phase outlet of the last stage knockout drum is communicated with the inlet of the interstage knockout drum, and the gas phase outlet of the last stage knockout drum is communicated with the inlet of the cold box.
In the above technical solution, preferably, the interstage cooler includes an interstage air cooler and an interstage water cooler, a first stage outlet of the compressor is communicated with an inlet of the interstage air cooler, an outlet of the interstage air cooler is communicated with an inlet of the interstage water cooler, and an outlet of the interstage water cooler is communicated with an inlet of the interstage separation tank.
In the above technical solution, preferably, the final stage cooler includes a final stage air cooler and a final stage water cooler, a secondary outlet of the compressor is communicated with an inlet of the final stage air cooler, an outlet of the final stage air cooler is communicated with an inlet of the final stage water cooler, and an outlet of the final stage water cooler is communicated with an inlet of the final stage separation tank.
In the above technical solution, preferably, the cold box uses an aluminum plate-fin heat exchanger.
In the above technical solution, preferably, the compressor is a screw compressor or a centrifugal compressor.
In the above technical solution, preferably, the mixed refrigerant includes nitrogen, methane, ethylene, propane, and isopentane.
In the above technical solution, preferably, the inlet separation tank, the interstage separation tank and the final stage separation tank include centrifugal force type separation internals, and the centrifugal force type separation internals adopt blade type separation internals of horizontal flow, vertical flow, single band structure or double band structure type.
The invention also provides an optimized single-cycle mixed refrigerant refrigerating method, which is applied to the optimized single-cycle mixed refrigerant refrigerating system in any one of the technical schemes and comprises the following steps: conveying the mixed refrigerant in the cold box to an inlet separation tank for gas-liquid separation, and conveying the gas-phase refrigerant separated by the inlet separation tank to a compressor for primary compression; conveying the mixed refrigerant after the first-stage pressurization to an interstage cooler for cooling, and conveying the mixed refrigerant after the interstage cooling to an interstage separation tank for gas-liquid separation; the liquid-phase refrigerant separated from the interstage separation tank is conveyed back to the cold box, and the separated gas-phase refrigerant is conveyed to the compressor for secondary compression; conveying the mixed refrigerant after the two-stage pressurization to a final-stage cooler for cooling, and conveying the mixed refrigerant after the final-stage cooling to a final-stage separation tank for gas-liquid separation; the liquid-phase refrigerant separated by the last-stage separation tank is sent back to the inter-stage separation tank, and the separated gas-phase refrigerant is sent back to the cold box.
In the above technical solution, preferably, the feeding the mixed refrigerant after the first-stage pressurization to the inter-stage cooler for cooling specifically includes: the mixed refrigerant after the first-stage pressurization sequentially enters an interstage air cooler and an interstage water cooler for cooling; the step of conveying the two-stage supercharged mixed refrigerant to the final cooler for cooling specifically comprises: and the mixed refrigerant after the two-stage pressurization sequentially enters a final-stage air cooler and a final-stage water cooler for cooling.
In the above technical solution, preferably, heat exchange is performed in the cold box by a mixed refrigerant composed of nitrogen, methane, ethylene, propane and isopentane.
Compared with the prior art, the invention has the beneficial effects that: compared with the traditional single-cycle mixed refrigerant refrigeration process, the high-pressure pump at the liquid-phase refrigerant outlet at the bottom of the interstage separation tank is omitted, and the steam pressure in the interstage separation tank is used as driving force to be conveyed to the cold tank, so that the flow entering the cold tank refrigerant is reduced, the complexity of the design of the cold tank is reduced, the energy consumption of a compressor is reduced, the number of movable equipment is reduced, the equipment investment is reduced, and the safety operability and the stability of the device are improved.
Drawings
FIG. 1 is a schematic flow diagram of a conventional single cycle mixed refrigerant refrigeration process disclosed in the prior art;
FIG. 2 is a schematic view of a conventional single cycle mixed refrigerant refrigeration process flow disclosed in yet another prior art;
FIG. 3 is a schematic process flow diagram of an optimized single cycle mixed refrigerant refrigeration system according to one embodiment of the present disclosure;
fig. 4 is a schematic flow chart of an optimized single-cycle mixed refrigerant refrigeration method according to an embodiment of the disclosure.
In the drawings, the correspondence between each component and the reference numeral is:
11. cooling the box; 12. an inlet separation tank; 13. a compressor; 14. an interstage cooler; 141. an interstage air cooler; 142. an interstage water cooler; 15. an interstage separation tank; 16. a final stage cooler; 161. a final stage air cooler; 162. a final stage water cooler; 17. a last stage knockout drum; 18. high-pressure pump, 19 flow control valve.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The invention is described in further detail below with reference to the following drawings:
as shown in fig. 3, the present invention provides an optimized single-cycle mixed refrigerant refrigeration system, which comprises: a cold box 11, an inlet separation tank 12, a compressor 13, an interstage cooler 14, an interstage separation tank 15, a final stage cooler 16, and a final stage separation tank 17; the mixed refrigerant in the cold box 11 is conveyed from an outlet to an inlet of an inlet separation tank 12, an outlet of the inlet separation tank 12 is communicated with a primary inlet of a compressor 13, a primary outlet of the compressor 13 is communicated with an inlet of an interstage cooler 14, and an outlet of the interstage cooler 14 is communicated with an inlet of an interstage separation tank 15; a liquid phase outlet of the interstage separation tank 15 is communicated with an inlet of the cold box 11, a gas phase outlet of the interstage separation tank 15 is communicated with a secondary inlet of the compressor 13, a secondary outlet of the compressor 13 is communicated with an inlet of the final stage cooler 16, and an outlet of the final stage cooler 16 is communicated with an inlet of the final stage separation tank 17; the liquid phase outlet of the last stage separation tank 17 communicates with the inlet of the inter-stage separation tank 15, and the gas phase outlet of the last stage separation tank 17 communicates with the inlet of the cold box 11.
In the embodiment, the high-pressure liquid-phase refrigerant at the bottom of the final-stage separation tank 17 is throttled and returned to the interstage separation tank 15, and is mixed with the low-pressure liquid at the bottom of the interstage separation tank 15 to enter the cold box 11 for refrigeration of the pre-cooling section of the cold box 11, compared with the traditional single-cycle mixed refrigerant refrigeration process, the high-pressure pump 18 at the liquid-phase refrigerant outlet at the bottom of the interstage separation tank 15 is omitted, and is conveyed to the cold box 11 by using the steam pressure in the interstage separation tank 15 as driving force, so that the flow of the refrigerant entering the cold box 11 is reduced, the complexity of the design of the cold box 11 is reduced, the energy consumption of the compressor 13 is reduced, the number of movable equipment is reduced, the equipment investment is reduced, and the safety operation performance and the stability of the device are improved.
Specifically, the inlet separation tank 12 is disposed in front of the primary inlet of the compressor 13 for separating the mixed refrigerant liquid phase, buffering the inlet air flow of the compressor 13, and preventing liquid droplets from hitting the impeller of the compressor 13; the compressor 13 is used for compressing the mixed refrigerant; the inter-cooler 14 is used for cooling the mixed refrigerant at the outlet of the first stage of the compressor 13; the interstage separation tank 15 is used for separating gas-liquid two phases in the mixed refrigerant at the outlet of the interstage cooler 14, and sending the liquid phase into the cold box 11 for refrigeration of a precooling section of the cold box 11; the final cooler 16 is used for cooling the mixed refrigerant at the secondary outlet of the compressor 13; the final separating tank 17 is used for separating gas phase and liquid phase in the mixed refrigerant at the outlet of the final cooler 16, regulating the pressure of the liquid phase, sending the liquid phase into the inter-stage separating tank 15, mixing the liquid phase with the liquid phase at the bottom of the inter-stage separating tank 15, and sending the mixed liquid phase and the liquid phase into the cold box 11 for refrigeration of a pre-cooling section of the cold box 11; the cold box 11 is used for heat exchange between a refrigerant and natural gas, and is used for liquefying the natural gas to generate a qualified LNG product.
In the above embodiment, preferably, the interstage cooler 14 includes an interstage air cooler 141 and an interstage water cooler 142, a first stage outlet of the compressor 13 communicates with an inlet of the interstage air cooler 141, an outlet of the interstage air cooler 141 communicates with an inlet of the interstage water cooler 142, and an outlet of the interstage water cooler 142 communicates with an inlet of the interstage separation tank 15.
In the above embodiment, preferably, the final stage cooler 16 includes a final stage air cooler 161 and a final stage water cooler 162, the second-stage outlet of the compressor 13 is communicated with the inlet of the final stage air cooler 161, the outlet of the final stage air cooler 161 is communicated with the inlet of the final stage water cooler 162, and the outlet of the final stage water cooler 162 is communicated with the inlet of the final stage separation tank 17.
Specifically, the inter-stage cooler 14 is a combination of an inter-stage air cooler 141 and an inter-stage water cooler 142, and the final stage cooler 16 is a combination of a final stage air cooler 161 and a final stage water cooler 162, so as to reduce the investment of a cooling water circulation system and save the consumption of cooling water.
In the above embodiment, preferably, the cold box 11 is an aluminum plate-fin heat exchanger, and has the characteristics of small pressure drop, high heat exchange efficiency, and the like.
In the above-described embodiment, it is preferable that the compressor 13 employs a screw type compressor, a reciprocating compressor, or a centrifugal compressor. Specifically, based on the processing flow rate of the compressor and the outlet pressure requirement of the liquefaction process, for a small-sized liquefaction plant, the refrigerant compressor 13 is a screw-type compressor, and for a large-sized or medium-sized liquefaction plant, the refrigerant compressor 13 is a centrifugal compressor.
In the above embodiment, preferably, the mixed refrigerant includes five-component refrigerants of nitrogen, methane, ethylene, propane and isopentane, and the mixture ratio of the five-component refrigerants is adjusted according to the pressure and the components of the liquefied natural gas and the cooling temperature of the liquefied natural gas, so as to cool the natural gas in stages. Specifically, in the staged cooling process, two or three of the five refrigerants are combined, and refrigeration is respectively carried out in different stages according to the temperature level and the properties of the combined refrigerant.
In the above embodiment, the inlet separation tank 12, the interstage separation tank 15 and the final stage separation tank 17 preferably include centrifugal force type separation internals, which adopt horizontal flow, vertical flow, single-belt structure or double-belt structure type blade type separation internals, and the specific model is selected according to the specific implementation process, and will not be described herein again.
As shown in fig. 4, the present invention further provides an optimized single-cycle mixed refrigerant refrigeration method, which is applied to the optimized single-cycle mixed refrigerant refrigeration system in any one of the above embodiments, and includes: the mixed refrigerant in the cold box 11 is conveyed to an inlet separation tank 12 for gas-liquid separation, and the gas-phase refrigerant separated from the inlet separation tank 12 is conveyed to a compressor 13 for primary compression; the mixed refrigerant after the first-stage pressurization is conveyed to an interstage cooler 14 for cooling, and the mixed refrigerant after the interstage cooling is conveyed to an interstage separation tank 15 for gas-liquid separation; the liquid-phase refrigerant separated from the interstage separation tank 15 is conveyed back to the cold box 11, and the separated gas-phase refrigerant is conveyed to the compressor 13 for secondary compression; the mixed refrigerant after the two-stage pressurization is conveyed to a final-stage cooler 16 for cooling, and the mixed refrigerant after the final-stage cooling is conveyed to a final-stage separation tank 17 for gas-liquid separation; the liquid-phase refrigerant separated by the final-stage separation tank 17 is sent back to the interstage separation tank 15, and the separated gas-phase refrigerant is sent back to the cold box 11.
In the embodiment, the high-pressure liquid-phase refrigerant at the bottom of the final-stage separation tank 17 is throttled and returned to the interstage separation tank 15, and is mixed with the low-pressure liquid at the bottom of the interstage separation tank 15 to enter the cold box 11 for refrigeration of the pre-cooling section of the cold box 11, compared with the traditional single-cycle mixed refrigerant refrigeration process, the high-pressure pump 18 at the liquid-phase refrigerant outlet at the bottom of the interstage separation tank 15 is omitted, and the high-pressure liquid-phase refrigerant is conveyed to the cold box 11 by using the steam pressure in the interstage separation tank 15 as driving force, so that the flow of the refrigerant entering the cold box 11 is reduced, the complexity of the design of the cold box 11 is reduced, the energy consumption of the compressor 13 is reduced, the number of movable equipment is reduced, the equipment investment is reduced, and the safety operation performance and the stability of the device are improved.
Specifically, in the refrigeration process, a mixed refrigerant is output from an inlet separation tank 12, a gas-phase refrigerant enters a first-stage compression of a compressor 13 through a pipeline, the mixed refrigerant after first-stage pressurization sequentially enters an interstage cooler 14 through a pipeline to be cooled, the cooled mixed refrigerant enters an interstage separation tank 15 through a pipeline to be subjected to two-phase separation, a liquid-phase refrigerant separated from the interstage separation tank 15 enters a cold box 11 (a plate-fin heat exchanger) through a pipeline to be subjected to first-stage heat exchange with natural gas, the gas-phase refrigerant separated from the interstage separation tank 15 enters a second-stage compression of the compressor 13 through a pipeline, the mixed refrigerant after second-stage pressurization sequentially enters a last-stage cooler 16 through a pipeline to be cooled, the cooled mixed refrigerant enters a last-stage separation tank 17 through a pipeline to be subjected to two-phase separation, and the liquid-phase refrigerant separated from the last-stage separation tank 17 passes through a pipeline and a flow regulating valve 19, is conveyed to an inlet pipeline of the interstage separation tank 15, and then enters the interstage separation tank 15 again to be subjected to two-phase separation. The gas-phase refrigerant separated by the last-stage separation tank 17 enters the cold box 11 (plate-fin heat exchanger) to exchange heat with natural gas and low-pressure refrigerant. The mixed refrigerant after heat exchange comes out from the top of a cold box 11 (a plate-fin heat exchanger) and enters an inlet separation tank 12 through a pipeline to form a closed single-cycle refrigeration system.
The liquid-phase refrigerant at the bottom of the final-stage separation tank 17 is throttled and then mixed with the liquid-phase refrigerant at the bottom of the interstage separation tank 15, and the mixture is used for refrigerating the precooling section of the cold box 11, so that on one hand, the air quantity entering the secondary compressor 13 is reduced, and the energy consumption of the compressor 13 is reduced; on the other hand, compared with the traditional process, the use of a high-pressure pump 18 is eliminated, the steam pressure in the interstage separation tank 15 is used as driving force to send the steam to the cold box 11, the process flow reduces the number of movable equipment, reduces the flow of refrigerant entering the cold box 11, reduces the complexity of the design of the cold box 11, and therefore improves the safe operation and stability of the device.
In the above embodiment, preferably, the feeding the one-stage pressurized mixed refrigerant to the inter-stage cooler 14 for cooling specifically includes: the mixed refrigerant after the first-stage pressurization sequentially enters an interstage air cooler 141 and an interstage water cooler 142 for cooling; the step of delivering the two-stage pressurized mixed refrigerant to the final stage cooler 16 for cooling specifically includes: and the mixed refrigerant after the two-stage pressurization sequentially enters a final-stage air cooler 161 and a final-stage water cooler 162 for cooling.
In the above embodiment, preferably, the heat exchange is performed in the cold box 11 by a mixed refrigerant composed of nitrogen, methane, ethylene, propane and isopentane.
The present invention has been described in terms of the preferred embodiment, and it is not intended to be limited to the embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. An optimized single cycle mixed refrigerant refrigeration system, comprising: a cold box (11), an inlet knockout drum (12), a compressor (13), an interstage cooler (14), an interstage knockout drum (15), a final stage cooler (16), and a final stage knockout drum (17);
the mixed refrigerant in the cold box (11) is conveyed from an outlet to an inlet of the inlet separation tank (12), an outlet of the inlet separation tank (12) is communicated with a first-stage inlet of the compressor (13), a first-stage outlet of the compressor (13) is communicated with an inlet of the interstage cooler (14), and an outlet of the interstage cooler (14) is communicated with an inlet of the interstage separation tank (15);
a liquid phase outlet of the interstage separation tank (15) is communicated with an inlet of the cold box (11), a gas phase outlet of the interstage separation tank (15) is communicated with a secondary inlet of the compressor (13), a secondary outlet of the compressor (13) is communicated with an inlet of the final stage cooler (16), and an outlet of the final stage cooler (16) is communicated with an inlet of the final stage separation tank (17);
the liquid phase outlet of the last stage separation tank (17) is communicated with the inlet of the interstage separation tank (15), and the gas phase outlet of the last stage separation tank (17) is communicated with the inlet of the cold box (11).
2. The optimized single-cycle mixed refrigerant refrigeration system according to claim 1, wherein the interstage cooler (14) comprises an interstage air cooler (141) and an interstage water cooler (142), a first stage outlet of the compressor (13) communicates with an inlet of the interstage air cooler (141), an outlet of the interstage air cooler (141) communicates with an inlet of the interstage water cooler (142), and an outlet of the interstage water cooler (142) communicates with an inlet of the interstage separation tank (15).
3. The optimized single-cycle mixed-refrigerant refrigeration system according to claim 1 or 2, wherein the final stage cooler (16) comprises a final stage air cooler (161) and a final stage water cooler (162), a secondary outlet of the compressor (13) is communicated with an inlet of the final stage air cooler (161), an outlet of the final stage air cooler (161) is communicated with an inlet of the final stage water cooler (162), and an outlet of the final stage water cooler (162) is communicated with an inlet of the final stage separation tank (17).
4. The optimized single-cycle mixed refrigerant refrigeration system as claimed in claim 3, wherein the cold box (11) employs an aluminum plate-fin heat exchanger.
5. The optimized single-cycle mixed refrigerant refrigeration system according to claim 3, wherein the compressor (13) is a screw-type compressor or a centrifugal compressor.
6. The optimized single-cycle mixed refrigerant refrigeration system as claimed in claim 3, wherein the mixed refrigerant comprises nitrogen, methane, ethylene, propane and isopentane.
7. The optimized single-cycle mixed refrigerant refrigeration system according to claim 3, wherein the inlet separation tank (12), the interstage separation tank (15) and the final stage separation tank (17) comprise centrifugal force type separation internals which employ blade type separation internals of horizontal flow, vertical flow, single-band structure or double-band structure type.
8. An optimized single-cycle mixed refrigerant refrigeration method applied to the optimized single-cycle mixed refrigerant refrigeration system as claimed in any one of claims 1 to 7, and characterized by comprising the following steps of:
the mixed refrigerant in the cold box (11) is conveyed to an inlet separation tank (12) for gas-liquid separation, and the gas-phase refrigerant separated from the inlet separation tank (12) is conveyed to a compressor (13) for primary compression;
the mixed refrigerant after the first-stage pressurization is conveyed to an interstage cooler (14) for cooling, and the mixed refrigerant after the interstage cooling is conveyed to an interstage separation tank (15) for gas-liquid separation;
the liquid-phase refrigerant separated from the interstage separation tank (15) is conveyed back to the cold box (11), and the separated gas-phase refrigerant is conveyed to the compressor (13) for secondary compression;
the mixed refrigerant after the two-stage pressurization is conveyed to a final-stage cooler (16) for cooling, and the mixed refrigerant after the final-stage cooling is conveyed to a final-stage separation tank (17) for gas-liquid separation;
the liquid-phase refrigerant separated by the final stage separation tank (17) is sent back to the interstage separation tank (15), and the separated gas-phase refrigerant is sent back to the cold box (11).
9. The optimized single-cycle mixed-refrigerant refrigeration method as claimed in claim 8, wherein the feeding the one-stage pressurized mixed refrigerant to the inter-stage cooler (14) for cooling specifically comprises:
the mixed refrigerant after the first-stage pressurization sequentially enters an interstage air cooler (141) and an interstage water cooler (142) for cooling;
the step of conveying the two-stage supercharged mixed refrigerant to the final cooler (16) for cooling specifically comprises the following steps:
and the mixed refrigerant after the two-stage pressurization sequentially enters a final-stage air cooler (161) and a final-stage water cooler (162) for cooling.
10. The optimized single-cycle mixed refrigerant refrigeration method as claimed in claim 8, wherein the heat exchange is performed in the cold box (11) by a mixed refrigerant composed of nitrogen, methane, ethylene, propane and isopentane.
CN202110778316.3A 2021-07-09 2021-07-09 Optimized single-cycle mixed refrigerant refrigerating system and refrigerating method Pending CN115597245A (en)

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CN202110778316.3A CN115597245A (en) 2021-07-09 2021-07-09 Optimized single-cycle mixed refrigerant refrigerating system and refrigerating method

Applications Claiming Priority (1)

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