CN115468327B - Self-cascade refrigeration system with grading and dephlegmator - Google Patents
Self-cascade refrigeration system with grading and dephlegmator Download PDFInfo
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- CN115468327B CN115468327B CN202211145868.1A CN202211145868A CN115468327B CN 115468327 B CN115468327 B CN 115468327B CN 202211145868 A CN202211145868 A CN 202211145868A CN 115468327 B CN115468327 B CN 115468327B
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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
- F25B39/04—Condensers
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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
- F25B40/00—Subcoolers, desuperheaters or superheaters
- F25B40/06—Superheaters
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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
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
- F25B9/006—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant containing more than one component
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- General Engineering & Computer Science (AREA)
- Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
Abstract
The invention provides a self-cascade refrigeration system with a grading condenser, which comprises a compressor, wherein the grading compressor is adopted and is provided with a first-stage air suction port a, a second-stage air suction port b and an air discharge port c; the condenser is used for condensing the high-temperature high-pressure gaseous mixed refrigerant discharged by the compressor into a gas-liquid two-phase mixed refrigerant; the inlet of the gas-liquid separator is connected with the outlet of the refrigerant working medium channel of the condenser and is used for carrying out flash evaporation separation on the gas-liquid two-phase mixed refrigerant working medium discharged by the condenser; the upper part of the inside of the gas-liquid separator is provided with a grading dephlegmator component which is used for rectifying and purifying the gaseous mixed refrigerant working medium which is subjected to flash evaporation in the gas-liquid separator, so that the pressure ratio of the mixed refrigerant which is rich in high-component branches in the compression process can be effectively reduced, the gradient utilization of low-temperature cold quantity is realized, and the lower refrigeration temperature is obtained; the scheme has the advantages of simple structure, obvious energy-saving effect and reliable and stable operation.
Description
Technical Field
The invention belongs to a mixed working medium low-temperature throttling refrigeration technology, and particularly relates to a self-cascade refrigeration system with a grading and condensing device.
Background
The self-cascade refrigerating system is a refrigerating system which uses non-azeotropic mixed working medium and realizes multistage cascade through a single compressor to obtain low temperature below-60 ℃, has the advantages of simple structure, reliable operation, low cost and the like, and is widely applied to the fields of low-temperature refrigeration and the like. Therefore, the self-cascade refrigeration system has important significance for saving energy and protecting environment. The traditional single-stage self-cascade refrigeration cycle adopts single-stage compression and has low-temperature performance requirements, so that the compression ratio of working media which flows out from the bottom of the gas-liquid separator and is rich in branches with high boiling point components is higher, the total energy consumption of the compressor is high, and the refrigeration efficiency obtained by the traditional single-stage compression cycle is lower and the refrigeration temperature is limited. The traditional self-cascade technology also has the problems of adoption of a phase separator to separate mixed refrigerant, low separation efficiency and the like, and in order to solve the problems, on one hand, the two-stage or multi-stage separation is adopted to separate the binary non-azeotropic mixed refrigerant effectively from the cascade refrigeration cycle, the purity of low-boiling components is improved, the lower evaporation temperature can be realized, but the pressure ratio is larger, so that the energy consumption of the system is higher, and on the other hand, the rectification device is adopted to improve the self-cascade refrigeration cycle to realize the efficient separation of the mixed refrigerant, but the problems of poor rectification effect and the like exist when the ambient temperature is increased.
In the prior art, a refrigeration system with two compressors connected in series is taken as an example, so that a high-boiling point working medium is directly mixed with a working medium at the outlet of a first-stage compressor after absorbing heat in a low-temperature-stage condenser and then enters a second-stage compressor, and the air suction temperature of the second-stage compressor can be reduced, thereby reducing the exhaust temperature of the second-stage compressor. However, the system has the problems that the complexity and the cost of the system are increased due to the fact that two compressors connected in series are required to be arranged, and the gas-liquid separator in the system has low separation efficiency for separating high and low boiling point components due to the fact that an effective component separation device is not arranged, so that the purity of the low boiling point components cannot be effectively improved, and the refrigeration temperature which can be prepared by the system is limited. In particular, the refrigeration system adopting the serial connection mode of two compressors in series has the defects that lubricating oil carried by working media rich in high-boiling components only enters the secondary compressor, and working media with low-boiling components entering the primary compressor do not carry lubricating oil through gas-liquid separation, so that internal moving parts of the primary compressor cannot be lubricated, faults such as dry combustion of the compressors, insufficient oil seal and the like occur, and the damage of the primary compressor is aggravated.
Disclosure of Invention
The invention aims to solve the problems in the prior art, and provides a self-cascade refrigeration system with a grading dephlegmator, which is applied to low-temperature throttling refrigeration in specific places and can realize high-low boiling point high-efficiency separation and low-temperature refrigeration.
In order to achieve the above purpose, the invention adopts the following technical scheme: a self-cascade refrigeration system with a grading dephlegmator comprises a compressor, wherein the compressor is provided with a first-stage air suction port a, a second-stage air suction port b and an air discharge port c, and a grading compressor is adopted; the condenser is used for condensing the high-temperature high-pressure gaseous mixed refrigerant discharged by the compressor into a gas-liquid two-phase mixed refrigerant; the inlet of the gas-liquid separator is connected with the outlet of the refrigerant working medium channel of the condenser and is used for carrying out flash evaporation separation on the gas-liquid two-phase mixed refrigerant working medium discharged by the condenser; the gas-phase refrigerant working medium after rectification and purification flowing out of the top of the gas-liquid separator is mixed with a part of liquid-phase refrigerant working medium discharged from an outlet at the bottom of the gas-liquid separator, and finally enters a first-stage air suction port a of the compressor through a first refrigerant working medium pipeline of the grading and condensing device assembly; and the other part of liquid-phase refrigerant working medium discharged from the outlet at the bottom of the gas-liquid separator finally enters the secondary air suction port b of the compressor through the second refrigerant working medium pipeline of the grading segregation component, thereby realizing grading compression.
Preferably, the fractional condenser assembly comprises a first sub-condenser and a second sub-condenser, and the first sub-condenser is positioned below the second sub-condenser; the gas-phase refrigerant working medium flowing out of the top of the gas-liquid separator is mixed with a part of liquid-phase refrigerant working medium discharged from the outlet at the bottom of the gas-liquid separator; the refrigerant passes through a refrigerant working medium pipeline of the second sub condenser and then enters a first-stage air suction port a of the compressor; and the other part of liquid-phase refrigerant working medium discharged from the bottom of the gas-liquid separator enters the secondary air suction port b of the compressor through a refrigerant working medium pipeline of the first sub-condenser.
The first regenerator is used for superheating the refrigerant passing through the refrigerant passage of the second sub-condenser and finally entering the first-stage air suction port a of the compressor.
As a preferred scheme, the first heat regenerator comprises a low-temperature side channel and a high-temperature side channel, a refrigerant working medium channel outlet of the second sub-condenser is connected with a low-temperature side channel inlet of the first heat regenerator, and an outlet of the low-temperature side channel of the first heat regenerator is connected with a first-stage air suction port a of the compressor, so that the refrigerant working medium discharged by the second sub-condenser enters the first-stage air suction port a of the compressor after being overheated by the first heat regenerator; and the inlet of the high-temperature side channel of the first heat regenerator is connected with the bottom outlet of the gas-liquid separator.
As a preferable scheme, the outlet of the high-temperature side channel of the first heat regenerator is divided into two branches, wherein the refrigerant working medium flowing out of the first branch enters the refrigerant working medium channel of the first sub-condenser, and the refrigerant working medium flowing out of the second branch is mixed with the refrigerant working medium flowing out of the outlet at the top of the gas-liquid separator and then enters the refrigerant working medium channel of the second sub-condenser.
As a preferable scheme, a first throttling component and an evaporation condenser are sequentially arranged on the first branch, an inlet of the first throttling component is connected with a high-temperature side channel outlet of the first heat regenerator, an outlet of the first throttling component is connected with a low-temperature side channel inlet of the evaporation condenser, and a low-temperature side channel outlet of the evaporation condenser is connected with a refrigerant working medium channel inlet of the first sub-condenser.
As a preferred scheme, a high-temperature side channel inlet of the evaporation condenser is connected with a top outlet of the gas-liquid separator, a high-temperature side channel outlet of the evaporation condenser is connected with a high-temperature side channel inlet of the second heat regenerator, a high-temperature side channel outlet of the second heat regenerator is connected with a refrigerant working medium channel inlet of the evaporator through a third throttling component, a refrigerant working medium channel outlet of the evaporator is connected with a low-temperature side channel inlet of the second heat regenerator, and the refrigerant working medium at the low-temperature side channel outlet of the second heat regenerator and part of liquid-phase refrigerant working medium discharged from a bottom outlet of the gas-liquid separator are throttled and then mixed into a refrigerant working medium channel of the second sub-condenser.
As a preferable scheme, the refrigerant working medium is a binary or more than binary non-azeotropic mixed refrigerant working medium formed by mixing a high-boiling-point refrigerant working medium and a low-boiling-point refrigerant working medium, the low-boiling-point refrigerant working medium adopts HC or HFC refrigerant working medium, and the low-boiling-point refrigerant working medium is one or more of R1150, R50 or R23; the high-boiling-point refrigerant working medium adopts HC or HFC refrigerant working medium, and the high-boiling-point refrigerant working medium is one or more of R134a, R152a, R600 and R600 a.
Advantageous effects
The invention can realize high-low boiling point high-efficiency separation and low-temperature refrigeration, and is different from the common technical route in the prior art, the scheme adopts a specific technical route, and utilizes a stage compressor with two stages of air inlets, so that most of mixed working media rich in high boiling point components from the bottom of the gas-liquid separator only flow into the stage compressor through a medium-pressure air inlet of the compressor to realize the compression process with low compression ratio, and all mixed working media rich in low boiling point components from the top of the gas-liquid separator and a part of mixed working media rich in high boiling point components from the bottom of the gas-liquid separator only flow into the stage compressor through the low-pressure air inlet of the compressor to realize the compression process with high compression ratio, thereby realizing the stage compression process of the mixed working media, reducing the compression ratio of the compressor, and obviously reducing the total energy consumption of the compressor.
Secondly, the scheme adopts the structural design ideas of the first sub condenser and the second sub condenser which are stacked up and down, realizes the step rectification purification process of the low boiling point components of the gaseous mixed working medium in the gas-liquid separator and the step utilization of the low temperature cold energy of different temperature positions, thereby obtaining lower refrigeration temperature and improving refrigeration efficiency.
Third, this scheme still increases the supercooling degree of the liquid mixed working medium of gas-liquid separator bottom export through setting up first regenerator in gas-liquid separator bottom export to ensure that the mixed working medium of the first induction port that gets into the stage compressor is in overheated or saturated steam state, plays the effect that improves refrigeration efficiency and ensure the dry compression process of compressor.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a self-cascade refrigeration system with a staged dephlegmator of the present invention;
the marks in the figure: 1. the device comprises a compressor, 2, a condenser, 3, a gas-liquid separator, 4, a first throttling component, 5, an evaporation condenser, 6, a second heat regenerator, 7, a third throttling component, 8, an evaporator, 9, a second sub-condenser, 10, a first sub-condenser, 11, a first heat regenerator, 12 and a second throttling component; a. a first-stage air suction port, a second-stage air suction port, and c, an exhaust port.
Detailed Description
The invention is described in detail below by way of exemplary embodiments. It is to be understood that elements, structures and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
It should be noted that: unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. As used in the specification and claims of this application, the terms "a," "an," and "the" and similar referents are not to be construed to limit the scope of at least one. The word "comprising" or "comprises", and the like, indicates that elements or items listed thereafter or equivalents thereof may be substituted for elements or items thereof in addition to those listed thereafter or equivalents thereof without departing from the scope of the word "comprising" or "comprising".
The embodiment provides a self-cascade refrigeration system with a fractional condenser, which comprises a compressor 1, a condenser 2, a gas-liquid separator 3, a first throttling component 4, an evaporation condenser 5, a second heat regenerator 6, a third throttling component 7, an evaporator 8, a second fractional condenser 9, a first fractional condenser 10, a first heat regenerator 11 and a second throttling component 12.
In the embodiment, the compressor 1 adopts a stage compressor and is provided with a first-stage air suction port a, a second-stage air suction port b and a high-pressure air discharge port c; the first-stage air suction port a is a low-pressure air suction port, the second-stage air suction port b is a medium-pressure air suction port, the first-stage air suction port a and the second-stage air suction port b which are arranged in the compressor 1 can realize the step compression process that working media flowing out from the bottom and the top of the gas-liquid separator 3 enter the compressor 1 respectively, the air outlet c of the compressor 1 is connected with the inlet of the gas-liquid separator 3 through the condenser 2, the gas-liquid separator 3 is also provided with a top outlet and a bottom outlet, the top outlet of the gas-liquid separator 3, the high-temperature side channel of the evaporation condenser 5, the high-temperature side channel of the second heat regenerator 6, the third throttling part 7 and the inlet of the evaporator 8 are sequentially connected in series, and the outlet of the evaporator 8 is connected with the outlet pipeline of the second throttling part 12 through the low-temperature side channel of the second heat regenerator 6; the bottom outlet of the gas-liquid separator 3 is connected with the high-temperature side channel inlet of the first heat regenerator 11, and the high-temperature side channel outlet of the first heat regenerator 11 is divided into two branches; a branch is connected with the inlet of the first throttling part 4, the outlet of the first throttling part 4 is connected with the inlet of the low-temperature side channel of the evaporative condenser 5, the outlet of the low-temperature side channel of the evaporative condenser 5 is connected with the inlet of the first sub-condenser 10, and the outlet of the first sub-condenser 10 is connected with the secondary air suction port b of the compressor 1; the other branch of the high temperature side passage outlet of the first regenerator 11 is connected to the inlet of the second throttling part 12, the outlet of the second throttling part 12 is connected to the inlet of the second partial condenser 9, the outlet of the second partial condenser 9 is connected to the low temperature side passage inlet of the first regenerator 11, and the low temperature side passage outlet of the first regenerator 11 is connected to the first stage suction port a of the compressor 1. Wherein the low temperature channel outlet of the second regenerator 6 is connected to a conduit between the outlet of the second restriction 12 and the inlet of the second sub-condenser 9. The first throttling part 4 is arranged on a pipeline between the gas-liquid separator 3 and the evaporation condenser 5, the second throttling part 12 is arranged on a pipeline between the gas-liquid separator 3 and the second sub-condenser 9, and the third throttling part 7 is arranged on a connecting pipeline between the evaporator 8 and a high Wen Ceguan pipeline of the second regenerator 6.
In this scheme, the exhaust port c of the compressor 1 is connected with the inlet of the gas-liquid separator 3 through the condenser 2, so that the high-temperature and high-pressure gaseous mixed refrigerant working medium from the exhaust port c of the compressor 1 is condensed and released into a high-temperature and high-pressure gas-liquid two-phase mixed refrigerant working medium through the condenser 2, and then enters the gas-liquid separator 3 to perform flash evaporation separation, the second-stage air suction port b of the compressor 1 is connected with the low-temperature side channel of the evaporation condenser 5 through the first sub-condenser 10, so that part of liquid mixed refrigerant working medium from the bottom of the gas-liquid separator 3 and gaseous mixed refrigerant working medium from the top of the gas-liquid separator 3 exchange heat through the evaporation condenser 5, and finally flows into the compressor 1 through the second-stage air suction port b of the compressor 1 to complete the compression process with low compression ratio, and the first-stage air suction port a of the compressor 1 is connected with the second sub-condenser 9 through the first regenerator 11, so that the gaseous refrigerant working medium from the second regenerator 6 and the liquid refrigerant working medium from the second throttle component 12 are mixed, and finally enter the first-stage air suction port a of the compressor 1 to complete the compression process with high compression ratio after the second sub-stage condenser 9, and finally the compression process is completed in the compressor 1. And the condenser 2 is used for condensing the high-temperature high-pressure gaseous mixed refrigerant discharged by the compressor 1 into a gas-liquid two-phase mixed refrigerant, and the inlet of the refrigerant passage of the condenser is connected with the exhaust port c of the compressor 1.
According to the scheme, the characteristics that the zeotropic mixed working medium is subjected to flash evaporation separation into the gas-phase mixed working medium and the liquid-phase mixed working medium in the gas-liquid separator 3 are utilized by the compressor 1, the working medium rich in the high-boiling-point component branch is high in evaporation temperature after throttling, the evaporation pressure of the working medium is also high, the gas-phase mixed working medium entering the secondary air suction port b of the compressor 1 is higher in purity, the working medium rich in the low-boiling-point component branch is low in evaporation temperature after throttling, the evaporation pressure of the working medium is also low, and only flows into the primary air suction port a of the compressor 1, so that the working medium of the two branches is subjected to graded compression in the compressor 1, the energy consumption is reduced, and the lower refrigeration temperature is prepared.
The gas-liquid separator 3 has the functions of: the high-temperature high-pressure gas-liquid two-phase mixed working medium from the condenser 2 is separated into a gas-phase mixed working medium rich in low boiling point components, the gas-phase mixed working medium flows out from a working medium outlet at the top of the gas-phase mixed working medium, the liquid-phase mixed working medium rich in high boiling point components flows out from a working medium outlet at the bottom of the gas-liquid mixed working medium, and meanwhile, the gas-liquid separator 3 is provided with a segregation structure, and the segregation structure is a classification segregation component, so that the gas-phase working medium rich in low boiling point components, separated by the gas-liquid separator 3, is partially condensed, thereby obtaining a saturated gas-phase refrigerant working medium rich in high-purity low boiling point components, flows out from the top of the gas-liquid separator 3, wherein the condensed liquid-phase refrigerant working medium flows back to the bottom of the gas-liquid separator 3, and the liquid-phase refrigerant working medium rich in high boiling point components, separated by flash evaporation, flows out from the bottom of the gas-liquid separator 3.
In this embodiment, the refrigerant inlet of the gas-liquid separator 3 is connected to the exhaust port c of the compressor 1 through the condenser 2, so that the high-temperature high-pressure gas-liquid two-phase mixed refrigerant from the condenser 2 is flash-separated into a liquid-phase mixed refrigerant rich in high boiling point components and a gas-phase mixed refrigerant rich in low boiling point components in the gas-liquid separator 3, and a fractional condenser assembly is disposed above the inside of the gas-liquid separator 3, and is used for rectifying and purifying the gas-phase mixed refrigerant flash-evaporated in the gas-liquid separator 3. The vapor-phase refrigerant working medium which is rich in low boiling point components and separated by flash evaporation of the vapor-liquid separator 3 is partially condensed under the action of the classifying and separating condenser component, and the obtained vapor-phase refrigerant working medium with higher purity and low boiling point components flows out from the top outlet of the vapor-liquid separator 3; the liquid refrigerant condensed by the classifying and dephlegmator component flows back to the bottom of the gas-liquid separator 3, is mixed with the liquid refrigerant rich in high boiling point components separated by flash evaporation of the gas-liquid separator 3, and is discharged through the bottom outlet of the gas-liquid separator 3.
In this solution, the fractional condenser assembly comprises a first partial condenser 10 and a second partial condenser 9, the first partial condenser 10 being located below the second partial condenser 9. The function of the second partial condenser 9 is: the gas phase mixed working medium which flows out from the working medium outlet at the top of the gas-liquid separator 3 and is rich in low boiling point components flows through the second heat regenerator 6 to be overheated and then continuously passes through the second sub condenser 9 to be overheated, so that low-pressure overheated steam enters the first-stage air suction port a of the compressor 1, and the first sub condenser 10 has the functions that: the liquid mixed working medium rich in high boiling point components flowing out from the working medium outlet at the bottom of the gas-liquid separator 3 is evaporated and absorbed by the evaporation side of the evaporation condenser 5 and then continuously superheated, and then the obtained medium-pressure superheated steam enters the secondary air suction port b of the compressor 1, so that the fractional compression process of the working medium of the two branches is realized, and the energy consumption of the compressor 1 is further reduced.
In one particular embodiment: the first sub-condenser 10 and the second sub-condenser 9 are both arranged in the upper space in the gas-liquid separator 3, and working medium steam of the gas-liquid separator 3 flows through the outside of the first sub-condenser 10 from bottom to top to undergo a first-stage rectification purification process, and then flows through the outside of the second sub-condenser 9 to undergo a second-stage rectification purification process; the first sub condenser 10 and the second sub condenser 9 arranged in the gas-liquid separator 3 realize the step rectification purification effect on the low boiling point components of the gaseous mixed working medium in the gas-liquid separator 3 and realize the step utilization of the low temperature cold energy of different temperature positions.
In this embodiment, the first regenerator 11 is disposed between the gas-liquid separator 3 and the second throttling member 12, so that after the liquid mixed refrigerant working medium rich in high boiling components from the bottom of the gas-liquid separator 3 is supercooled at the high temperature side of the first regenerator 11, a part of the liquid mixed refrigerant working medium flows into the second throttling member 12 to be mixed with the refrigerant working medium rich in low boiling components from the second regenerator 6, and flows into the second sub condenser 9, thereby realizing the rectification requirement of the second sub condenser 9, and the first regenerator 11 is disposed between the second sub condenser 9 and the compressor 1, and the purpose of the first regenerator 11 is that: the device is used for recovering low-temperature cold energy of the mixed refrigerant working medium at the outlet of the second sub condenser 9, and simultaneously ensuring that the mixed refrigerant working medium before entering the air suction port a of the compressor 1 is in a saturated steam state or an overheated state, so that a wet compression process is avoided in the compression process in the compressor 1. The gaseous refrigerant working medium which is rich in low boiling point components and comes from the top outlet of the gas-liquid separator 3 is subjected to heat absorption and temperature reduction through the second sub condenser 9, and meanwhile, the overheat of the refrigerant working medium in the second sub condenser 9 is ensured, so that the dryness requirement of the compression process of the compressor 1 is ensured.
In this solution, in a specific embodiment, the liquid working medium rich in high boiling components flowing out of the first regenerator 11 is divided into two branches: the liquid working medium of the first branch is throttled and cooled by the first throttling part 4 and then enters the evaporation condenser 5 to absorb the condensation heat of the gaseous refrigerant working medium rich in low boiling point components from the gas-liquid separator 3, and then enters the first sub-condenser 10 to realize the first-stage rectification and purification of the gaseous mixed refrigerant working medium in the gas-liquid separator 3, and then enters the second-stage air suction port b of the compressor 1 to complete the compression process with low compression ratio; the liquid refrigerant working medium of the second branch is throttled, cooled and depressurized by the second throttling component 12, then mixed with the refrigerant working medium from the second heat regenerator 6 and enters the second sub condenser 9 to realize the second-stage rectification purification of the gaseous mixed working medium in the gas-liquid separator 3, and after absorbing heat by the first heat regenerator 11, the liquid refrigerant working medium finally flows into the compressor 1 through the first-stage air suction port a of the compressor 1 to finish the compression process with high compression ratio.
In this embodiment, a gas-phase mixed refrigerant rich in low boiling point components flowing out from a working medium outlet at the top of the gas-liquid separator 3 is condensed by the evaporation condenser 5 and then enters the high temperature side supercooling of the second regenerator 6 and the third throttling component 7, so as to obtain a low-pressure two-phase refrigerant working medium, the low-temperature side of the second regenerator 6 is overheated and then mixed with a working medium throttled and depressurized by the second throttling component 12, the mixed gas-liquid two-phase refrigerant working medium enters the first air suction port a of the compressor 1 after being overheated by the second partial condenser 9 and the low temperature side of the first regenerator 11, the liquid-phase mixed refrigerant working medium rich in high boiling point components flowing out from a refrigerant working medium outlet at the bottom of the gas-liquid separator 3 is separated into two branches after being supercooled by the high temperature side of the first regenerator 11, one branch flows into the first throttling component 4 to obtain a medium-pressure two-phase refrigerant working medium, then enters the evaporation condenser 5 to evaporate and absorb heat, the first partial condenser 10 is overheated, the obtained medium-pressure overheated steam enters the second stage b of the compressor 1, and is depressurized by the second air suction port b of the compressor 1 after entering the second partial condenser 11, and then flows out from the second air suction port 1 after being overheated by the second partial condenser 11, and finally flows out from the second partial condenser 11 after being throttled by the second partial condenser 1, and flows into the second air suction port after flowing into the second part, and is mixed refrigerant. Compared with the prior art, the compressor lubrication is ensured to be sufficient by adopting the classification compressor and adopting the refrigerant working medium flowing direction. (in the prior art, in the refrigerating system with two compressors connected in series, during the running process of the system, lubricating oil of the system is often wrapped by refrigerants and is discharged out of the compressors, and is brought back to the compressors by refrigerants after circulation, two phases of liquid refrigerants and vapor refrigerants exist in the circulating process of the system, and the lubricating oil is basically in a liquid state, when the refrigerants are converted from the liquid state to the vapor state in a gas-liquid separator, the lubricating oil can be separated from the vapor refrigerants and does not flow along with the vapor refrigerants any more, if the lubricating oil carried by the separated liquid refrigerant working medium only enters the two-stage compressors and does not enter the one-stage compressors, the internal moving parts of the one-stage compressors are not sufficiently lubricated, the dry burning of the compressors, the insufficient oil sealing and other faults occur, and the like are aggravated in the using process of the one-stage compressors.)
The working principle of the scheme is as follows: the superheated steam flowing out from the exhaust port c of the compressor 1 is partially condensed by the condenser 2, enters the gas-liquid separator 3 with a two-stage segregator structure for flash separation and purification, the refrigerant working medium steam entering the gas-liquid separator 3 flows through the outside of the first segregator 10 from bottom to top to undergo a first-stage rectification purification process, flows through the outside of the second segregator 9 to undergo a second-stage rectification purification process, so that a saturated gas-phase refrigerant working medium rich in low-boiling-point components with higher purity flows out from the top of the gas-liquid separator 3, the condensed liquid refrigerant working medium flows back to the bottom of the gas-liquid separator 3, and flows out from the bottom of the gas-liquid separator 3 together with the liquid working medium rich in high-boiling-point components separated by flash evaporation. The mixed refrigerant working medium is divided into two branches, and the flow direction of one branch of the working medium is as follows: the saturated gaseous refrigerant which flows out from the top of the gas-liquid separator 3 and is rich in low boiling point components with higher purity firstly enters a high-temperature side channel of the condensing evaporator 5 to be partially condensed into gas-liquid two-phase refrigerant, then enters a high-temperature side channel of the second heat regenerator 6 to be supercooled, enters a third throttling part 7 to throttle and decompress to obtain low-pressure two-phase refrigerant, then enters the evaporator 8 to evaporate and absorb heat to realize low-temperature refrigeration, and the saturated gaseous refrigerant which flows out from the evaporator 8 is overheated by the low-temperature side channel of the second heat regenerator 6 and then is mixed with the liquid refrigerant which flows out from the second throttling part 12 to be throttled, then enters the second heat-separating condenser 9 to be overheated and the low-temperature side channel of the first heat regenerator 11 to be overheated, and the low-pressure gaseous refrigerant which flows out from the first heat regenerator 11 is inhaled by the first air suction port a of the compressor 1 to complete the compression process of high compression ratio.
Meanwhile, after the saturated liquid working medium rich in high boiling point components flows out of the other branch from the bottom of the gas-liquid separator 3 and flows into the high-temperature side channel of the first heat regenerator 11 to be supercooled, the obtained liquid working medium rich in high boiling point components is divided into two branches, one branch flows to the first throttling part 4 to be throttled and decompressed, the flowing medium-pressure two-phase state refrigerant working medium flows into the second air suction port b of the compressor 1 after passing through the low-temperature side channel of the evaporative condenser 5 to exchange heat, the medium-pressure superheated steam obtained after entering the first sub-condenser 10 to exchange heat enters the second air suction port b of the compressor 1, meanwhile, the liquid working medium of the other branch flows into the second throttling part 12 to be throttled, cooled and decompressed, then is mixed with the gaseous refrigerant from the second heat regenerator 6 and enters the second sub-condenser 9, so that the second-stage rectification purification of the gaseous mixed working medium in the gas-liquid separator 3 is realized, and then the heat absorption process of the medium flows into the first stage air suction port a of the compressor 1 after passing through the low-temperature side channel of the first heat regenerator 11 is finished, so that the compression process of the high compression ratio is finished, and a cycle is completed. The refrigerating cycle system can effectively reduce the compressor pressure ratio of the mixed working medium rich in the high-component branch circuit in the compression process.
According to the scheme, the cascade compression effect of working media is realized through one grading compressor, so that the compression ratio of the compressor is reduced, and the energy consumption and the exhaust temperature of the compressor are reduced; the stepped rectification and purification of the gaseous mixed working medium are realized by arranging the double-stage condenser, the stepped utilization of low-temperature cold quantity is realized, the purity of low-boiling-point components is improved, and the lower refrigeration temperature is obtained; the supercooling degree of the mixed working medium is increased and the wet compression process of the mixed working medium is avoided by arranging the first heat regenerator 11. The system has the advantages of simple structure, obvious energy-saving effect, reliable and stable operation and wide application prospect.
In the scheme, the adopted working medium is binary or non-azeotropic mixed working medium with more than binary formed by mixing high-boiling point working medium and low-boiling point working medium, the low-boiling point working medium is HC or HFC working medium such as R1150, R50, R23 and the like, and the high-boiling point working medium is HC or HFC working medium such as R134a, R152a, R600a and the like.
The present invention is not limited to the above-mentioned embodiments, but is intended to be limited to the following embodiments, and any modifications, equivalent changes and variations in the above-mentioned embodiments can be made by those skilled in the art without departing from the scope of the present invention.
Claims (4)
1. A take hierarchical dephlegmator's self-cascade refrigerating system, its characterized in that: the device comprises a compressor, a condenser and a gas-liquid separator, wherein the compressor adopts a grading compressor and is provided with a first-stage air suction port a, a second-stage air suction port b and an air discharge port c; the exhaust port c of the compressor is connected with the inlet of the gas-liquid separator through the condenser; the first sub-condenser and the second sub-condenser are both arranged in an upper space in the gas-liquid separator, the first sub-condenser is positioned below the second sub-condenser, and an inlet of the gas-liquid separator is positioned below the first sub-condenser;
the gas-liquid separator is also provided with a top outlet and a bottom outlet;
the top outlet of the gas-liquid separator, the high-temperature side channel of the evaporative condenser, the high-temperature side channel of the second heat regenerator, the third throttling component and the inlet of the evaporator are sequentially connected in series; the outlet of the evaporator is connected with an outlet pipeline of the second throttling component through a low-temperature side channel of the second heat regenerator;
the bottom outlet of the gas-liquid separator is connected with the high-temperature side channel inlet of the first heat regenerator, and the high-temperature side channel outlet of the first heat regenerator is divided into two branches; a branch is connected with an inlet of a first throttling component, an outlet of the first throttling component is connected with an inlet of a low-temperature side channel of the evaporative condenser, an outlet of the low-temperature side channel of the evaporative condenser is connected with an inlet of a first sub-condenser, and an outlet of the first sub-condenser is connected to a secondary air suction port b of the compressor; the other branch is connected with an inlet of a second throttling component, an outlet of the second throttling component is connected with an inlet of a second sub condenser, an outlet of the second sub condenser is connected with an inlet of a low-temperature side channel of the first heat regenerator, and an outlet of the low-temperature side channel of the first heat regenerator is connected to a first-stage air suction port a of the compressor.
2. A self-cascade refrigeration system with a staged dephlegmator as defined in claim 1, wherein: working medium steam of the gas-liquid separator flows through the outside of the first sub-condenser from bottom to top to undergo a first-stage rectification purification process, and then flows through the outside of the second sub-condenser to undergo a second-stage rectification purification process.
3. A self-cascade refrigeration system with a staged dephlegmator as defined in claim 1, wherein: the first heat regenerator is used for superheating the refrigerant working medium passing through the refrigerant working medium channel of the second sub condenser.
4. A self-cascade refrigeration system with a staged dephlegmator as defined in any one of claims 1-3, wherein: the refrigerant working medium is binary or more than binary non-azeotropic mixed refrigerant working medium formed by mixing high-boiling-point refrigerant working medium and low-boiling-point refrigerant working medium, and the low-boiling-point refrigerant working medium is one or more of R1150, R50 or R23; the high-boiling-point refrigerant working medium is one or more of R134a, R152a, R600 and R600 a.
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