CN115031431A - Ultralow-temperature efficient refrigerating device and refrigerating method thereof - Google Patents
Ultralow-temperature efficient refrigerating device and refrigerating method thereof Download PDFInfo
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- CN115031431A CN115031431A CN202210958133.4A CN202210958133A CN115031431A CN 115031431 A CN115031431 A CN 115031431A CN 202210958133 A CN202210958133 A CN 202210958133A CN 115031431 A CN115031431 A CN 115031431A
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- 238000000034 method Methods 0.000 title claims abstract description 14
- 239000007788 liquid Substances 0.000 claims abstract description 146
- 239000012071 phase Substances 0.000 claims abstract description 68
- 239000007791 liquid phase Substances 0.000 claims abstract description 48
- 238000005057 refrigeration Methods 0.000 claims abstract description 46
- 238000001704 evaporation Methods 0.000 claims abstract description 43
- 230000008020 evaporation Effects 0.000 claims abstract description 43
- 238000009833 condensation Methods 0.000 claims abstract description 29
- 230000005494 condensation Effects 0.000 claims abstract description 29
- 239000003507 refrigerant Substances 0.000 claims description 73
- 230000005484 gravity Effects 0.000 claims description 8
- 238000004781 supercooling Methods 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 3
- 230000008859 change Effects 0.000 claims description 2
- 239000007789 gas Substances 0.000 description 24
- 239000003921 oil Substances 0.000 description 6
- XPDWGBQVDMORPB-UHFFFAOYSA-N Fluoroform Chemical compound FC(F)F XPDWGBQVDMORPB-UHFFFAOYSA-N 0.000 description 5
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007792 gaseous phase Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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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
- F25B7/00—Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit
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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
- F25B39/00—Evaporators; Condensers
- F25B39/02—Evaporators
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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
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
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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
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
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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
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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Abstract
The invention discloses an ultralow-temperature high-efficiency refrigerating device and a refrigerating method thereof, belonging to the technical field of refrigeration. The ultra-low temperature high-efficiency refrigerating device and the refrigerating method thereof comprise a high-temperature refrigerating unit and a low-temperature refrigerating unit, wherein a gas-phase working medium inlet of a condensing evaporator/cold carrier is connected with a first gas-phase working medium outlet of an evaporator gas-liquid separator through a cold-carrying return gas pipeline; the liquid phase working medium outlet of the condensation evaporator/cold carrier is connected with the inlet of the cold carrier/cascade switching valve, the first outlet of the cold carrier/cascade switching valve is connected with the first working medium inlet of the evaporator gas-liquid separator through a cold carrier liquid dropping pipeline, and the working medium inlet of the low-temperature flash evaporation barrel is connected with the second outlet of the cold carrier/cascade switching valve. The ultralow-temperature high-efficiency refrigerating device and the refrigerating method thereof disclosed by the invention avoid the problems that the low-temperature stage compressor cannot be normally started or the compressor is damaged and the service life is shortened due to starting caused by different temperature areas of the high-pressure compressor and the low-temperature stage compressor when the high-temperature stage compressor and the low-temperature stage compressor are directly started.
Description
Technical Field
The invention relates to an ultra-low temperature high-efficiency refrigerating device and a refrigerating method thereof, belonging to the technical field of refrigeration.
Background
Cascade refrigeration is a special form of vapour compression refrigeration, usually consisting of two to three separate vapour compression refrigeration cycles with different working temperature zones. Taking a two-stage cascade refrigeration cycle as an example, the two-stage cascade refrigeration cycle consists of a high-temperature stage refrigeration unit and a low-temperature stage refrigeration unit, wherein a medium-temperature refrigerant is used in the high-temperature stage refrigeration unit, and a low-temperature refrigerant is used in the low-temperature stage refrigeration unit, so that a cycle of cascade operation of two single-stage compression refrigeration units is formed. The two refrigeration units are connected by a common condensation evaporator, so that medium-temperature refrigerants in the high-temperature refrigeration unit are evaporated and refrigerated in the condensation evaporator, and low-temperature refrigerants are condensed into a liquid phase by heat release in the condensation evaporator. The medium temperature refrigerant vapor from the condensing evaporator takes away the condensing heat of the low temperature refrigerant and transfers the heat to the environment medium through the condenser in the high temperature stage refrigeration cycle. The liquid-phase low-temperature refrigerant from the condensing evaporator is depressurized by the low-temperature stage throttle valve, enters the evaporator to absorb the heat of the cooled medium to be evaporated and refrigerated, so that the cooled medium obtains the required low temperature.
Along with the increasing year by year of the requirements on the specifications of pharmaceutical and chemical products, the requirements on the improvement of the production process are increased, and particularly the requirements on the stability and the energy efficiency of an ultralow-temperature refrigerating unit are particularly outstanding. For example, the high-end pharmaceutical and chemical industry has a very high requirement on the whole refrigeration process, and not only does the unit have to be cooled quickly, but also has to achieve high efficiency and be capable of running stably for a long time, so that the uninterrupted industrial production requirement can be met.
Most of the existing ultra-low temperature overlapping units adopt a conventional direct-expansion liquid supply mode to meet the heat exchange requirements of a condensation evaporation side and an evaporation side (evaporator), although the unit structure is simple under the form, the heat exchange efficiency is extremely low, and the high-temperature refrigeration unit and the low-temperature refrigeration unit are started simultaneously or at intervals in a short time to lead to the hard start of the low-temperature compressor (not started in an allowable operation interval), so that the severe abrasion and the service life reduction of the compressor are easily caused, and further, the phenomena of frequent equipment failure and poor operation stability are caused. Therefore, it is very important to develop a new ultra-low temperature refrigerator set.
The above description is included in the technical recognition scope of the inventors, and does not necessarily constitute the prior art.
Disclosure of Invention
The invention aims to solve the problems in the prior art, and provides an ultralow-temperature high-efficiency refrigerating device and a refrigerating method thereof, so that the refrigerating device is ensured to be stable and high-efficiency, and the limit operation capacity of the refrigerating device is greatly improved.
The invention adopts the following technical scheme to realize the purpose:
an ultra-low temperature high-efficiency refrigerating device comprises a high-temperature refrigerating unit and a low-temperature refrigerating unit which are coupled through a condensation evaporator/cold carrier and an evaporator gas-liquid separator, wherein the condensation evaporator/cold carrier is a flooded heat exchanger and is arranged above the evaporator gas-liquid separator;
the high-temperature refrigerating unit comprises a high-temperature stage compressor, a condenser, a high-temperature stage flash evaporation barrel throttling valve, a high-temperature stage flash evaporation barrel, a high-temperature stage gas-liquid separator throttling valve and a high-temperature stage gas-liquid separator, the high-temperature stage gas-liquid separator is arranged above the condensing evaporator/cold carrier, a working medium outlet of the high-temperature stage compressor is connected with a low-temperature working medium inlet of the high-temperature stage flash evaporation barrel through a condenser and a throttling valve of the high-temperature stage flash evaporation barrel, a first low-temperature working medium outlet of the high-temperature stage flash evaporation barrel is connected with a first working medium inlet of the high-temperature stage gas-liquid separator, a gas-phase working medium outlet of the high-temperature stage gas-liquid separator is connected with a working medium inlet of the high-temperature stage compressor, a liquid-phase working medium outlet of the high-temperature stage gas-liquid separator is connected with a liquid-phase working medium inlet of the condensing evaporator/cold carrier, and a gas-phase working medium outlet of the condensing evaporator/cold carrier is connected with the gas-phase working medium inlet of the high-temperature stage gas-liquid separator;
a gas-phase working medium inlet of the condensing evaporator/cold carrier is connected with a first gas-phase working medium outlet of the evaporator gas-liquid separator through a cold-carrying gas return pipeline, and a cold-carrying gas return electromagnetic valve is arranged on the cold-carrying gas return pipeline; a liquid phase working medium outlet of the condensation evaporator/cold carrier is connected with an inlet of the cold carrying/cascade switching valve, a first outlet of the cold carrying/cascade switching valve is connected with a first working medium inlet of the evaporator gas-liquid separator through a cold carrying liquid dropping pipeline, and the first working medium inlet and the first gas phase working medium outlet of the evaporator gas-liquid separator are both positioned at the upper part of the evaporator gas-liquid separator;
the low-temperature refrigerating unit comprises a low-temperature stage compressor, a precooler, a low-temperature stage flash evaporation barrel throttle valve, a low-temperature stage flash evaporation barrel, a heat regenerator, an evaporator throttle valve and an evaporator, wherein the evaporator is positioned below an evaporator gas-liquid separator, a working medium outlet of the low-temperature stage compressor is connected with a high-temperature working medium inlet of the high-temperature stage flash evaporation barrel through the precooler, a high-temperature working medium outlet of the high-temperature stage flash evaporation barrel is connected with a high-temperature working medium inlet of a condensing evaporator/cold carrier, a working medium inlet of the low-temperature stage flash evaporation barrel is connected with a second outlet of a cold carrier/cascade switching valve, a first working medium outlet of the low-temperature stage flash evaporation barrel is connected with a first working medium inlet of the heat regenerator, a first working medium outlet of the heat regenerator is connected with a second working medium inlet of the evaporator gas-liquid separator, a second gas-phase working medium outlet of the evaporator gas-liquid separator is connected with a second working medium inlet of the heat regenerator, a second working medium outlet of the heat regenerator is connected with a working medium inlet of the low-temperature stage compressor;
the liquid phase working medium outlet of the evaporator gas-liquid separator is connected with the liquid phase working medium inlet of the evaporator, and the gas phase working medium outlet of the evaporator is connected with the gas phase working medium inlet of the evaporator gas-liquid separator.
Optionally, the high-temperature refrigeration unit further includes a high-temperature stage oil separator disposed between the high-temperature stage compressor and the condenser.
Optionally, the low-temperature refrigeration unit further comprises a low-temperature stage oil separator arranged between the low-temperature stage compressor and the precooler.
Optionally, the high-temperature stage gas-liquid separator adopts a horizontal U-shaped tubular gas-liquid separator.
Optionally, the evaporator gas-liquid separator adopts a horizontal U-shaped tubular gas-liquid separator.
Optionally, the horizontal U-shaped tubular gas-liquid separator includes a U-shaped housing, and the housing working medium inlet is disposed at a first end of the housing; the shell gas phase working medium inlet is close to the first end of the shell, a bent pipe is inserted into the shell gas phase working medium inlet, and the upper port of the bent pipe extends into the shell; the shell gas-phase working medium outlet is arranged at the top of the shell and is close to the second end of the shell; the shell liquid phase working medium outlet is arranged at the bottom of the shell and close to the second end of the shell.
Optionally, the second low-temperature working medium outlet of the high-temperature flash barrel is connected with the working medium inlet of the high-temperature compressor, and the second working medium outlet of the low-temperature flash barrel is connected with the working medium inlet of the low-temperature compressor.
Optionally, the cold-carrying/overlapping switching valve adopts an electric three-way valve.
Optionally, the refrigeration method of the ultra-low temperature high-efficiency refrigeration device provided by the invention comprises a cold loading mode and a cascade refrigeration mode which are sequentially operated, wherein the cold loading mode comprises the following steps:
(1.1) opening a cold-carrying air return electromagnetic valve to conduct a cold-carrying liquid dropping pipeline, and adjusting a cold-carrying/overlapping switching valve to conduct the cold-carrying liquid dropping pipeline and close the connection between a condensation evaporator/cold carrier and a low-temperature flash evaporation barrel; meanwhile, a high-temperature-stage compressor is started, a high-temperature-side refrigerant is compressed by the high-temperature-stage compressor, condensed by a condenser, throttled and expanded by a throttle valve of the high-temperature-stage flash drum, enters the high-temperature-stage flash drum for supercooling, throttled and expanded by a throttle valve of a high-temperature-stage gas-liquid separator, enters the high-temperature-stage gas-liquid separator, a liquid-phase high-temperature-side refrigerant obtained by separation enters a condensation evaporator/cold carrier, absorbs heat in the liquid-phase high-temperature-side refrigerant in the condensation evaporator/cold carrier, evaporates into a gas phase, and then enters the high-temperature-stage gas-liquid separator again, and the gas-phase high-temperature-side refrigerant is sucked into the high-temperature-stage compressor for circulation;
gas-phase low-temperature side refrigerants in the evaporator gas-liquid separator enter the condensing evaporator/cold carrier through the cold carrier return pipeline to discharge heat and change into liquid phase, then enter the evaporator gas-liquid separator again through the cold carrier liquid falling pipeline, liquid-phase low-temperature side refrigerants in the evaporator gas-liquid separator enter the evaporator through gravity liquid supply, the liquid-phase low-temperature side refrigerants in the evaporator absorb the heat of a cooled medium to form a gas-liquid mixed phase, and the low-temperature side refrigerants of the gas-liquid mixed phase return to the evaporator gas-liquid separator through the evaporator;
(1.2) after the temperature of the cooled medium outlet in the evaporator is reduced to the condensation temperature of a low-temperature side refrigerant of the low-temperature refrigerating unit, starting the low-temperature stage compressor, closing the cold-carrying air return electromagnetic valve to stop the cold-carrying liquid dropping pipeline, adjusting the cold-carrying/cascade switching valve to stop the cold-carrying liquid dropping pipeline, conducting the connection between the condensing evaporator/cold carrier and the low-temperature stage flash evaporation barrel, ending the cold-carrying mode, and starting to operate the cascade refrigerating mode.
Further, the cascade refrigeration mode comprises the following steps:
the low-temperature side refrigerant is compressed by a low-temperature stage compressor, then is discharged partial sensible heat by a precooler, then enters a high-temperature stage flash barrel to exchange heat with the high-temperature side refrigerant and is cooled, then enters a condensation evaporator/cold carrier, the low-temperature side refrigerant in the condensation evaporator/cold carrier is changed into a liquid phase after being absorbed by the high-temperature side refrigerant, the low-temperature side refrigerant in the liquid phase is throttled and expanded by a low-temperature stage flash barrel throttle valve and then enters a low-temperature stage flash barrel to be subcooled again, then flows through a heat regenerator to exchange heat, and then is throttled and expanded by an evaporator throttle valve and then enters an evaporator gas-liquid separator, the low-temperature side refrigerant in the liquid phase in the evaporator gas-liquid separator is supplied to an evaporator by gravity, the low-temperature side refrigerant in the liquid phase in the evaporator absorbs the heat of a cooled medium to form a gas-liquid mixed phase, and the low-temperature side refrigerant in the gas-liquid mixed phase returns to the evaporator gas-liquid separator by the evaporator, and a gas-phase low-temperature side refrigerant in the gas-liquid separator of the evaporator is sucked into the low-temperature stage compressor through the heat regenerator to circulate.
Benefits of the present application include, but are not limited to:
the invention provides an ultra-low temperature high-efficiency refrigerating device and a refrigerating method thereof, which have a cold carrying mode and a cascade refrigerating mode, wherein the cold carrying mode is firstly operated at the start-up, at the moment, a condensing evaporator/cold carrier executes the function of a cold carrier, a high-temperature-stage compressor directly acts on an evaporator, and after the temperature of a cooled medium outlet in the evaporator is reduced to the condensing temperature of a low-temperature-side refrigerant of a low-temperature refrigerating unit, the operation interval of the low-temperature-stage compressor is reached, and the operation interval is switched to the cascade refrigerating mode. In the cascade refrigeration mode, the low-temperature stage compressor directly acts on the evaporator. By the means, the problems that the low-temperature stage compressor cannot be started normally when the high-temperature stage compressor and the low-temperature stage compressor are started directly due to different temperature areas are solved, or the low-temperature stage compressor is damaged and the service life of the low-temperature stage compressor is shortened due to starting. Furthermore, the condensing evaporator/cold carrier in the ultralow-temperature high-efficiency refrigerating device provided by the invention adopts a flooded condensing heat exchange and evaporation mode, so that the heat exchange efficiency is high, the stability and high efficiency of the refrigerating device can be ensured, and the limit operation capacity of the refrigerating device is greatly improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 is a schematic view of an ultra-low temperature high efficiency refrigeration apparatus according to the present invention;
fig. 2 is a schematic diagram of an ultra-low temperature high-efficiency refrigerating device according to the present invention (the solid line indicates the refrigerant direction in the cold carrying mode);
fig. 3 is a schematic view of the ultra-low temperature high-efficiency refrigerating apparatus according to the present invention (the solid line indicates the direction of refrigerant flow in the cascade refrigeration mode);
FIG. 4 is a perspective view of the horizontal U-shaped tubular gas-liquid separator at an angle;
FIG. 5 is a perspective view of the horizontal U-shaped tubular gas-liquid separator at another angle;
in the figure, 100, a high temperature refrigerating unit; 110. a high temperature stage compressor; 120. a condenser; 130. a high-temperature flash drum throttle valve; 140. a high temperature grade flash barrel; 150. a high temperature stage gas-liquid separator throttle valve; 160. a high temperature stage gas-liquid separator; 170. a high temperature grade oil separator;
200. a low temperature refrigeration unit; 210. a low temperature stage compressor; 220. a precooler; 230. a low temperature stage flash drum throttle valve; 240. a low temperature stage flash barrel; 250. a heat regenerator; 260. an evaporator throttle valve; 270. an evaporator gas-liquid separator; 280. an evaporator; 290. a low temperature grade oil separator;
300. a condenser evaporator/chiller; 310. a cold-carrying gas return line; 311. a cold-carrying air return electromagnetic valve; 320. a cold-carrying falling liquid pipeline; 321. a cold load/cascade switching valve.
400. A housing; 410. a shell working medium inlet; 420. a shell gas-phase working medium inlet; 430. and a shell gas-phase working medium outlet.
Detailed Description
The present invention will be described in further detail in the following. It should be noted, however, that the following detailed description merely gives specific operation examples of the present invention by way of example, and the scope of the present invention is not limited thereto. The scope of the invention is limited only by the claims. It will be obvious to those skilled in the art that various other modifications and substitutions can be made to the described embodiments of the invention within the scope of the invention as defined by the claims and still achieve the same technical result and achieve the final technical object of the invention.
As shown in fig. 1, the ultra-low temperature high-efficiency refrigeration apparatus provided by the present invention comprises a high temperature refrigeration unit 100 and a low temperature refrigeration unit 200 coupled by a condenser-evaporator/cold carrier 300 and an evaporator gas-liquid separator 270, wherein the condenser-evaporator/cold carrier 300 is a flooded heat exchanger, and the condenser-evaporator/cold carrier 300 is installed above the evaporator gas-liquid separator 270.
As shown in the dashed line frame at the upper part of fig. 1, the high-temperature refrigeration unit 100 includes a high-temperature stage compressor 110, a condenser 120, a high-temperature stage flash evaporation barrel throttle valve 130, a high-temperature stage flash evaporation barrel 140, a high-temperature stage gas-liquid separator throttle valve 150, and a high-temperature stage gas-liquid separator 160, wherein the high-temperature stage gas-liquid separator 160 is installed above the condensing evaporator/cold carrier 300, a working medium outlet of the high-temperature stage compressor 110 is connected with a low-temperature working medium inlet of the high-temperature stage flash evaporation barrel 140 through the condenser 120 and the high-temperature stage flash evaporation barrel throttle valve 130, a first low-temperature working medium outlet of the high-temperature stage flash evaporation barrel 140 is connected with a first working medium inlet of the high-temperature stage gas-liquid separator 160, a gas-phase working medium outlet of the high-temperature stage gas-liquid separator 160 is connected with a working medium inlet of the condensing evaporator/cold carrier 300, the gas phase working medium outlet of the condenser evaporator/chiller 300 is connected to the gas phase working medium inlet of the high temperature stage gas-liquid separator 160.
A gas-phase working medium inlet of the condensing evaporator/cold carrier 300 is connected with a first gas-phase working medium outlet of the evaporator gas-liquid separator through a cold-carrying gas return pipeline 310, and a cold-carrying gas return electromagnetic valve 311 is arranged on the cold-carrying gas return pipeline 310; the liquid phase working medium outlet of the condensing evaporator/cold carrier 300 is connected with the inlet of the cold carrying/cascade switching valve 321, the first outlet of the cold carrying/cascade switching valve 321 is connected with the first working medium inlet of the evaporator gas-liquid separator 270 through the cold carrying liquid falling pipeline 320, and the first working medium inlet and the first gas phase working medium outlet of the evaporator gas-liquid separator 270 are both positioned at the upper part of the evaporator gas-liquid separator 270.
As shown in the dashed line frame at the lower part of fig. 1, the low-temperature refrigeration unit 200 includes a low-temperature stage compressor 210, a precooler 220, a low-temperature stage flash drum throttle valve 230, a low-temperature stage flash drum 240, a heat regenerator 250, an evaporator throttle valve 260, and an evaporator 280, the evaporator 280 is located below an evaporator gas-liquid separator 270, a working medium outlet of the low-temperature stage compressor 210 is connected with a high-temperature working medium inlet of the high-temperature stage flash drum 140 through the precooler 220, a high-temperature working medium outlet of the high-temperature stage flash drum 140 is connected with a high-temperature working medium inlet of a condensing evaporator/cold carrier 300, a working medium inlet of the low-temperature stage flash drum 240 is connected with a second outlet of the cold carrier/cascade switching valve 321, a first working medium outlet of the low-temperature stage flash drum 240 is connected with a first working medium inlet of the heat regenerator 250, a first working medium outlet of the heat regenerator 250 is connected with a second working medium inlet of the evaporator gas-liquid separator, a second gas-phase working medium outlet of the evaporator gas-liquid separator is connected with a second working medium inlet of the heat regenerator 250, and a second working medium outlet of the heat regenerator 250 is connected with a working medium inlet of the low-temperature stage compressor 210;
the liquid phase working medium outlet of the evaporator gas-liquid separator 270 is connected with the liquid phase working medium inlet of the evaporator 280, and the gas phase working medium outlet of the evaporator 280 is connected with the gas phase working medium inlet of the evaporator gas-liquid separator.
The refrigeration method based on the ultralow-temperature high-efficiency refrigeration device comprises a cold carrying mode and a cascade refrigeration mode which are sequentially operated, wherein the cold carrying mode comprises the following steps as shown in figure 2:
(1.1) opening the cold-carrying air return electromagnetic valve 311 to conduct the cold-carrying liquid dropping pipeline 320, and adjusting the cold-carrying/cascade switching valve 321 to conduct the cold-carrying liquid dropping pipeline 320 to close the connection between the condensing evaporator/cold carrier 300 and the low-temperature stage flash evaporation barrel 240; meanwhile, the high-temperature-stage compressor 110 is started, the high-temperature-side refrigerant is compressed by the high-temperature-stage compressor 110, condensed by the condenser 120, throttled and expanded by the high-temperature-stage flash drum throttle valve 130, enters the high-temperature-stage flash drum 140 for supercooling, throttled and expanded by the high-temperature-stage gas-liquid separator throttle valve 150, enters the high-temperature-stage gas-liquid separator 160, the separated liquid-phase high-temperature-side refrigerant enters the condenser evaporator/cold carrier 300, the liquid-phase high-temperature-side refrigerant in the condenser evaporator/cold carrier 300 absorbs heat and evaporates to become a gas phase, and then enters the high-temperature-stage gas-liquid separator 160 again, and the gas-phase high-temperature-side refrigerant is sucked into the high-temperature-stage compressor 110 for circulation;
the gas-phase low-temperature side refrigerant in the evaporator gas-liquid separator 270 can enter the condensation evaporator/cold carrier 300 through the cold-carrying gas return pipe 310 due to low specific gravity, releases heat, changes into a liquid phase, and reenters the evaporator gas-liquid separator 270 through the cold-carrying liquid falling pipe 320 by gravity; in the cooling mode, the cooled medium enters the evaporator 280 to gradually cool the cooled medium, specifically, the liquid-phase low-temperature-side refrigerant in the evaporator gas-liquid separator 270 is fed into the evaporator 280 by gravity, the liquid-phase low-temperature-side refrigerant in the evaporator 280 absorbs heat of the cooled medium to form a gas-liquid mixed phase, and the gas-liquid mixed phase low-temperature-side refrigerant returns to the evaporator gas-liquid separator 270 from the evaporator 280.
(1.2) after the temperature of the outlet of the cooled medium in the evaporator is reduced to the condensation temperature of the refrigerant at the low-temperature side of the low-temperature refrigerating unit, closing the cold-carrying air return electromagnetic valve 311 to stop the cold-carrying liquid falling pipeline 320, adjusting the cold-carrying/cascade switching valve 321 to stop the cold-carrying liquid falling pipeline 320, and conducting the connection between the condensing evaporator/cold carrier 300 and the low-temperature stage flash evaporation barrel 240, thus ending the cold-carrying mode, and starting to operate the cascade refrigerating mode.
For example, when the low temperature refrigerator group 200 uses the R-23 refrigerant (freon 23) as the refrigerant, the cascade refrigeration mode is switched after the condensation temperature of R-23 is reached to-23 ℃.
As shown in fig. 3, the cascade refrigeration mode includes the steps of:
the low-temperature side refrigerant is compressed by the low-temperature stage compressor 210 and then partially discharged sensible heat by the precooler 220, then enters a high-temperature flash evaporation barrel 140 to exchange heat with a high-temperature side refrigerant and is cooled, and then enters a condensation evaporator/cold carrier 300, the refrigerant at the low temperature side in the condenser/chiller 300 is changed into a liquid phase after being absorbed by the refrigerant at the high temperature side, the refrigerant at the low temperature side of the liquid phase enters the low temperature grade flash barrel 240 for secondary supercooling after being throttled and expanded by the low temperature grade flash barrel throttle valve 230, then flows through a heat regenerator 250 for heat exchange, throttles and expands through an evaporator throttle valve 260, then enters an evaporator gas-liquid separator 270, the liquid-phase low-temperature side refrigerant in the evaporator gas-liquid separator 270 is fed into the evaporator 280 by gravity, the liquid-phase low-temperature-side refrigerant in the evaporator 280 absorbs heat of the refrigerant to be cooled to form a gas-liquid mixed phase, and the gas-liquid mixed-phase low-temperature-side refrigerant returns to the evaporator gas-liquid separator from the evaporator 280. The low-temperature side refrigerant of the gas phase in the evaporator gas-liquid separator 270 is sucked into the low-temperature stage compressor 210 through the heat regenerator 250 to circulate, and the evaporator 280 can achieve flooded evaporation.
The effect of regenerator is that the liquid phase low temperature side refrigerant that supplies liquid to evaporimeter vapour and liquid separator 270 is further supercooled, and the gaseous phase low temperature side refrigerant return gas of following evaporimeter vapour and liquid separator 270 exhaust is further overheated, promotes refrigerating plant's whole efficiency, and the effect is more obvious under the low temperature operating mode.
The low-temperature side refrigerant can further supercool the gas-phase low-temperature side refrigerant exhaust through the high-temperature stage flash evaporation barrel, so that the load of a condensation evaporator/cold carrier is reduced, and the power consumption of the high-temperature stage compressor is further reduced.
When the unit is shut down, the low-temperature stage compressor 210 is first shut down, and the high-temperature stage compressor 110 is shut down.
The ultra-low temperature high-efficiency refrigerating device and the refrigerating method provided by the invention firstly operate the cold carrying mode at the start-up, at the moment, the condensing evaporator/cold carrying device 300 executes the cold carrying function, the high-temperature stage compressor 110 directly acts on the evaporator 280, and after the temperature of the cooled medium outlet in the evaporator 280 is reduced to the condensing temperature of the low-temperature side refrigerant of the low-temperature refrigerating unit, the low-temperature stage compressor 210 reaches the operation interval and is switched to the overlapping refrigerating mode. In cascade refrigeration mode, the evaporator 280 is acted upon directly by the low-temperature stage compressor 210. By the means, the problems that the low-temperature stage compressor 210 cannot be normally started or the low-temperature stage compressor is damaged and the service life is shortened due to starting and the like when the low-temperature stage compressor 210 is directly started due to different temperature regions of the high-temperature compressor and the low-temperature stage compressor 210 are avoided.
In addition, the condensing evaporator/cold carrier 300 in the ultra-low temperature high-efficiency refrigerating device provided by the invention adopts a flooded condensing heat exchange and evaporation mode, so that the heat exchange efficiency is high, the stability and high efficiency of the refrigerating device can be ensured, and the limit operation capacity of the refrigerating device is greatly improved.
Specifically, the flooded condenser evaporator/chiller 300 employs a plate heat exchanger, and the flooded condenser evaporator/chiller structurally includes sequentially arranged plates, and heat exchange passages for cold and hot media are formed between adjacent plates.
Further, the high temperature refrigeration unit 100 further includes a high temperature stage oil separator 170 disposed between the high temperature stage compressor 110 and the condenser 120, and the low temperature refrigeration unit 200 further includes a low temperature stage oil separator 290 disposed between the low temperature stage compressor 210 and the precooler 220, so as to separate the lubricating oil mixed in the refrigerant vapor.
Furthermore, the high-temperature stage gas-liquid separator 160 and the evaporator gas-liquid separator 270 both adopt horizontal U-shaped tubular gas-liquid separators, and the size of the separators can be reduced while the separation length is increased. Specifically, as shown in fig. 4 and 5, the structure of the horizontal U-shaped tubular gas-liquid separator includes a U-shaped shell 400, and a shell working medium inlet 410 is disposed at a first end of the shell; a shell gas-phase working medium inlet 420 is close to the first end of the shell, a bent pipe is inserted into the shell gas-phase working medium inlet 420, and the upper port of the bent pipe extends into the shell; the shell gas-phase working medium outlet 430 is arranged at the top of the shell and is close to the second end of the shell; a shell liquid phase working fluid outlet 440 is provided at the bottom of the shell and near the second end of the shell.
For example, the first working medium inlet of the high-temperature stage gas-liquid separator 160 is disposed at the first end of the housing, the gas-phase working medium outlet is disposed at the top of the housing near the second end of the housing, the liquid-phase working medium outlet is disposed at the bottom of the housing near the second end of the housing, and the gas-phase working medium inlet is disposed near the first end of the housing.
Further, the cold carrying/cascade switching valve 321 adopts an electric three-way valve, and switching between the cold carrying mode and the cascade refrigeration mode is conveniently controlled.
Furthermore, a second low-temperature working medium outlet of the high-temperature flash barrel is connected with a working medium inlet of the high-temperature compressor, and a second working medium outlet of the low-temperature flash barrel is connected with a working medium inlet of the low-temperature compressor, so that gas phase enters a medium-pressure gas inlet of the compressor.
It should be noted that in the present application, the high temperature and the low temperature in the high temperature working medium and the low temperature working medium are relative temperatures of two mediums for heat exchange in the heat exchanger.
The above-described embodiments should not be construed as limiting the scope of the invention, and any alternative modifications or alterations to the embodiments of the present invention will be apparent to those skilled in the art.
The details of the present invention are not described in detail, but are known to those skilled in the art.
Claims (10)
1. An ultra-low temperature high-efficiency refrigerating device is characterized by comprising a high-temperature refrigerating unit and a low-temperature refrigerating unit which are coupled through a condensation evaporator/cold carrier and an evaporator gas-liquid separator, wherein the condensation evaporator/cold carrier is a flooded heat exchanger and is arranged above the evaporator gas-liquid separator;
the high-temperature refrigerating unit comprises a high-temperature stage compressor, a condenser, a high-temperature stage flash evaporation barrel throttling valve, a high-temperature stage flash evaporation barrel, a high-temperature stage gas-liquid separator throttling valve and a high-temperature stage gas-liquid separator, the high-temperature stage gas-liquid separator is arranged above the condensing evaporator/cold carrier, a working medium outlet of the high-temperature stage compressor is connected with a low-temperature working medium inlet of the high-temperature stage flash evaporation barrel through a condenser and a throttling valve of the high-temperature stage flash evaporation barrel, a first low-temperature working medium outlet of the high-temperature stage flash evaporation barrel is connected with a first working medium inlet of the high-temperature stage gas-liquid separator, a gas-phase working medium outlet of the high-temperature stage gas-liquid separator is connected with a working medium inlet of the high-temperature stage compressor, a liquid-phase working medium outlet of the high-temperature stage gas-liquid separator is connected with a liquid-phase working medium inlet of the condensing evaporator/cold carrier, and a gas-phase working medium outlet of the condensing evaporator/cold carrier is connected with the gas-phase working medium inlet of the high-temperature stage gas-liquid separator;
a gas-phase working medium inlet of the condensing evaporator/cold carrier is connected with a first gas-phase working medium outlet of a gas-liquid separator of the evaporator through a cold-carrying gas return pipeline, and a cold-carrying gas return electromagnetic valve is arranged on the cold-carrying gas return pipeline; a liquid phase working medium outlet of the condensation evaporator/cold carrier is connected with an inlet of the cold carrying/cascade switching valve, a first outlet of the cold carrying/cascade switching valve is connected with a first working medium inlet of the evaporator gas-liquid separator through a cold carrying liquid dropping pipeline, and the first working medium inlet and the first gas phase working medium outlet of the evaporator gas-liquid separator are both positioned at the upper part of the evaporator gas-liquid separator;
the low-temperature refrigerating unit comprises a low-temperature stage compressor, a precooler, a low-temperature stage flash evaporation barrel throttle valve, a low-temperature stage flash evaporation barrel, a heat regenerator, an evaporator throttle valve and an evaporator, wherein the evaporator is positioned below an evaporator gas-liquid separator, a working medium outlet of the low-temperature stage compressor is connected with a high-temperature working medium inlet of the high-temperature stage flash evaporation barrel through the precooler, a high-temperature working medium outlet of the high-temperature stage flash evaporation barrel is connected with a high-temperature working medium inlet of a condensing evaporator/cold carrier, a working medium inlet of the low-temperature stage flash evaporation barrel is connected with a second outlet of a cold carrier/cascade switching valve, a first working medium outlet of the low-temperature stage flash evaporation barrel is connected with a first working medium inlet of the heat regenerator, a first working medium outlet of the heat regenerator is connected with a second working medium inlet of the evaporator gas-liquid separator, a second gas-phase working medium outlet of the evaporator gas-liquid separator is connected with a second working medium inlet of the heat regenerator, a second working medium outlet of the heat regenerator is connected with a working medium inlet of the low-temperature stage compressor;
the liquid phase working medium outlet of the evaporator gas-liquid separator is connected with the liquid phase working medium inlet of the evaporator, and the gas phase working medium outlet of the evaporator is connected with the gas phase working medium inlet of the evaporator gas-liquid separator.
2. The ultra-low temperature high efficiency refrigeration apparatus according to claim 1, wherein the high temperature refrigeration unit further comprises a high temperature stage oil separator disposed between the high temperature stage compressor and the condenser.
3. The ultra-low temperature high efficiency refrigeration apparatus according to claim 1, wherein the cryogenic refrigeration unit further comprises a cryogenic stage oil separator disposed between the cryogenic stage compressor and the precooler.
4. An ultra-low temperature high-efficiency refrigerating device as claimed in claim 1, wherein the high temperature stage gas-liquid separator adopts a horizontal U-shaped tubular gas-liquid separator.
5. An ultra-low temperature high-efficiency refrigerating device as claimed in claim 1, characterized in that the evaporator gas-liquid separator adopts a horizontal U-shaped tubular gas-liquid separator.
6. The ultra-low temperature high-efficiency refrigerating device as claimed in claim 4 or 5, wherein the horizontal U-shaped tubular gas-liquid separator comprises a U-shaped shell, and a shell working medium inlet is arranged at the first end part of the shell; the shell gas phase working medium inlet is close to the first end of the shell, a bent pipe is inserted into the shell gas phase working medium inlet, and the upper port of the bent pipe extends into the shell; the shell gas-phase working medium outlet is arranged at the top of the shell and is close to the second end of the shell; the shell liquid phase working medium outlet is arranged at the bottom of the shell and close to the second end of the shell.
7. An ultra-low temperature high-efficiency refrigerating device as claimed in claim 1, wherein the second low temperature working medium outlet of the high temperature stage flash evaporation barrel is connected with the working medium inlet of the high temperature stage compressor, and the second working medium outlet of the low temperature stage flash evaporation barrel is connected with the working medium inlet of the low temperature stage compressor.
8. The ultra-low temperature high efficiency refrigerator according to claim 1, wherein the cold load/cascade switch valve is an electric three-way valve.
9. The refrigerating method of ultra-low temperature high efficiency refrigerating device as claimed in claim 1, which comprises a cold carrying mode and a cascade refrigerating mode which are sequentially operated, wherein the cold carrying mode comprises the following steps:
(1.1) opening a cold-carrying air return electromagnetic valve to conduct a cold-carrying liquid dropping pipeline, and adjusting a cold-carrying/overlapping switching valve to conduct the cold-carrying liquid dropping pipeline and close the connection between a condensation evaporator/cold carrier and a low-temperature flash evaporation barrel; meanwhile, a high-temperature-stage compressor is started, a high-temperature-side refrigerant is compressed by the high-temperature-stage compressor, condensed by a condenser, throttled and expanded by a throttle valve of the high-temperature-stage flash drum, enters the high-temperature-stage flash drum for supercooling, throttled and expanded by a throttle valve of a high-temperature-stage gas-liquid separator, enters the high-temperature-stage gas-liquid separator, a liquid-phase high-temperature-side refrigerant obtained by separation enters a condensation evaporator/cold carrier, absorbs heat in the liquid-phase high-temperature-side refrigerant in the condensation evaporator/cold carrier, evaporates into a gas phase, and then enters the high-temperature-stage gas-liquid separator again, and the gas-phase high-temperature-side refrigerant is sucked into the high-temperature-stage compressor for circulation;
gas-phase low-temperature side refrigerants in the evaporator gas-liquid separator enter the condensing evaporator/cold carrier through the cold carrier return pipeline to discharge heat and change into liquid phase, then enter the evaporator gas-liquid separator again through the cold carrier liquid falling pipeline, liquid-phase low-temperature side refrigerants in the evaporator gas-liquid separator enter the evaporator through gravity liquid supply, the liquid-phase low-temperature side refrigerants in the evaporator absorb the heat of a cooled medium to form a gas-liquid mixed phase, and the low-temperature side refrigerants of the gas-liquid mixed phase return to the evaporator gas-liquid separator through the evaporator;
(1.2) after the temperature of the cooled medium outlet in the evaporator is reduced to the condensation temperature of a low-temperature side refrigerant of the low-temperature refrigerating unit, starting the low-temperature stage compressor, closing the cold-carrying air return electromagnetic valve to stop the cold-carrying liquid falling pipeline, adjusting the cold-carrying/cascade switching valve to stop the cold-carrying liquid falling pipeline, and conducting the connection between the condensation evaporator/cold carrier and the low-temperature stage flash evaporation barrel, thus ending the cold-carrying mode, and starting to operate the cascade refrigerating mode.
10. The refrigerating method of an ultra-low temperature high efficiency refrigerating apparatus as claimed in claim 9, wherein the cascade refrigerating mode comprises the steps of:
the low-temperature side refrigerant is compressed by a low-temperature stage compressor, then is discharged partial sensible heat by a precooler, then enters a high-temperature stage flash barrel to exchange heat with the high-temperature side refrigerant and is cooled, then enters a condensation evaporator/cold carrier, the low-temperature side refrigerant in the condensation evaporator/cold carrier is changed into a liquid phase after being absorbed by the high-temperature side refrigerant, the low-temperature side refrigerant in the liquid phase is throttled and expanded by a low-temperature stage flash barrel throttle valve and then enters a low-temperature stage flash barrel to be subcooled again, then flows through a heat regenerator to exchange heat, and then is throttled and expanded by an evaporator throttle valve and then enters an evaporator gas-liquid separator, the low-temperature side refrigerant in the liquid phase in the evaporator gas-liquid separator is supplied to an evaporator by gravity, the low-temperature side refrigerant in the liquid phase in the evaporator absorbs the heat of a cooled medium to form a gas-liquid mixed phase, and the low-temperature side refrigerant in the gas-liquid mixed phase returns to the evaporator gas-liquid separator by the evaporator, and a gas-phase low-temperature side refrigerant in the evaporator gas-liquid separator is sucked into the low-temperature stage compressor through the heat regenerator for circulation.
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| CN114111232A (en) * | 2021-12-27 | 2022-03-01 | 山东新华医疗器械股份有限公司 | Temperature control system of freeze dryer |
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| CN101368775A (en) * | 2008-10-08 | 2009-02-18 | 天津商业大学 | Natural circulation gravity force liquid-supply evaporator |
| JP2014074507A (en) * | 2012-10-02 | 2014-04-24 | Samsung R&D Institute Japan Co Ltd | Cascade cycle system |
| CN210486159U (en) * | 2019-10-30 | 2020-05-08 | 儒竞艾默生环境优化技术（上海）有限公司 | Heat pump system |
| CN114111232A (en) * | 2021-12-27 | 2022-03-01 | 山东新华医疗器械股份有限公司 | Temperature control system of freeze dryer |
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Denomination of invention: A ultra-low temperature and high-efficiency refrigeration device and its refrigeration method Granted publication date: 20221122 Pledgee: Jinan Zhangqiu District Sub branch of Postal Savings Bank of China Co.,Ltd. Pledgor: SHANDONG SHENZHOU REFRIGERATION EQUIPMENT Co.,Ltd. Registration number: Y2024980010076 |
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