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CN-121993915-A - CO based on waste heat drive2Cascade refrigeration system

CN121993915ACN 121993915 ACN121993915 ACN 121993915ACN-121993915-A

Abstract

The invention relates to the technical field of refrigeration and discloses a CO 2 CO circulation module, a high-temperature end circulation module and an oil rectification module based on waste heat driving, wherein the oil rectification module receives oily liquid CO of a low-pressure circulation barrel through a buffer cavity, the waste heat of exhaust gas of a high Wen Duanya compressor recovered by a gas-liquid separation type gas-liquid heat exchanger is used as a heat source to realize separation of CO and lubricating oil, the separated pure lubricating oil is led into an oil storage tank and returned to a compressor together with oil return, and CO steam is returned to the low-temperature end for circulation. According to the invention, the gas-division type gas-liquid heat exchanger is arranged between the high-temperature-stage compressor and the high-temperature-stage condenser, so that heat in the exhaust gas of the high-temperature-stage compressor is transferred to the oil rectifying device through the gas-division type gas-liquid heat exchanger and is used as a heating source required by oil rectification, and therefore, the exhaust waste heat at the high temperature end is used for replacing an independent electric heating device, and the external energy consumption requirement in the oil rectification process is reduced.

Inventors

  • MIAO CHUNBO
  • CHANG SHAOLIN
  • HUANG MENGRU
  • Cui Yingguang
  • Zhai Saina
  • ZHANG JIAMENG
  • LI JIA
  • MA DAWEI
  • GUO MINGZHENG
  • CHENG QIANG
  • CHENG QINGFENG
  • CHEN TAO
  • ZHANG JUNYAN
  • ZHANG LINLIN

Assignees

  • 河南千年冷链设备有限公司

Dates

Publication Date
20260508
Application Date
20260228

Claims (10)

  1. 1. The CO 2 cascade refrigeration system based on waste heat driving is characterized by comprising a low-temperature end circulation module, a high-temperature end circulation module and an oil rectification module, wherein the low-temperature end circulation module comprises a CO 2 liquid storage tank (1), a low-pressure circulation barrel (2), a CO 2 pump (3), an evaporator body (4), a low-temperature-level compressor (5) and oil components (6), the high-temperature end circulation module comprises a condensation evaporator (7), a high-temperature-level compressor (8), a gas-separation type gas-liquid heat exchanger (9), a high-temperature-level condenser (10) and a liquid storage tank (11), the oil rectification module comprises a buffer cavity (12), an oil rectifying device (13), an oil storage tank (14), an ethylene glycol pump (15), a drying filter (16), an expansion tank (21), an oil return valve (19) and an air return valve (20), the low-temperature end circulation module and the high-temperature-end circulation module are in cascade heat exchange connection through the condensation evaporator (7), the high-temperature-level circulation module forms an ethylene glycol circulation loop through the gas-separation type gas-liquid heat exchanger (9) and the oil rectification module, and the oil rectification module is communicated with a low-level compressor (5) through a gas-phase compressor and an oil return pipeline (5).
  2. 2. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein a liquid phase outlet of the CO 2 liquid storage tank (1) is communicated with a liquid phase inlet of the low-pressure circulation tank (2) through a throttle valve (22), the liquid phase outlet of the low-pressure circulation tank (2) is divided into a first branch and a second branch, the first branch is communicated with the liquid phase inlet of the evaporator body (4) through a CO 2 pump (3), the second branch is communicated with a feed inlet of the oil finishing boiler (13) through a buffer cavity (12), a gas phase outlet of the evaporator body (4) is communicated with an air suction port of the low-temperature-stage compressor (5), an air exhaust port of the low-temperature-stage compressor (5) is communicated with an inlet of oil (6), the gas phase outlet of the oil (6) is communicated with a hot side inlet of the condensation evaporator (7), and the hot side outlet of the condensation evaporator (7) is communicated with a gas phase inlet of the CO 2 liquid storage tank (1).
  3. 3. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein a buffer cavity (12) is arranged between the low-pressure circulation barrel (2) and the oil finishing distiller (13), an inlet of the buffer cavity (12) is communicated with a liquid phase outlet of the low-pressure circulation barrel (2), an outlet of the buffer cavity (12) is communicated with a feed inlet of the oil finishing distiller (13), and the buffer cavity (12) is of a closed container structure.
  4. 4. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein a cold side outlet of the condensation evaporator (7) is communicated with an air suction port of the high-temperature stage compressor (8), an air exhaust port of the high-temperature stage compressor (8) is communicated with a hot side inlet of the gas-split type gas-liquid heat exchanger (9), a hot side outlet of the gas-split type gas-liquid heat exchanger (9) is communicated with an inlet of the high-temperature stage condenser (10), a liquid phase outlet of the high-temperature stage condenser (10) and a liquid phase outlet of the gas-split type gas-liquid heat exchanger (9) are converged and then enter the liquid reservoir (11), and an outlet of the liquid reservoir (11) is communicated with a cold side inlet of the condensation evaporator (7) through the throttle valve (22).
  5. 5. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein the gas-to-liquid heat exchanger (9) comprises a hot side loop and a cold side loop which are independent from each other, the hot side loop is connected in series between the high-temperature stage compressor (8) and the high-temperature stage condenser (10), the cold side loop is communicated with a heat exchange jacket inlet of the oil finishing distiller (13) through a glycol pump (15), and a heat exchange jacket outlet of the oil finishing distiller (13) is communicated with a cold side outlet of the gas-to-liquid heat exchanger (9).
  6. 6. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein the glycol circulation loop sequentially comprises a gas-liquid heat exchanger (9), a heat exchange jacket of an oil finishing distiller (13), an expansion tank (21), a drying filter (16) and a glycol pump (15), and is communicated end to form a closed loop.
  7. 7. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein the oil finishing device (13) is of a vertical container structure, a gas phase outlet is arranged at the top of the oil finishing device, a liquid phase outlet is arranged at the bottom of the oil finishing device, a feeding port is arranged in the middle of the oil finishing device, and a heat exchange jacket inlet and a heat exchange jacket outlet which are communicated with the ethylene glycol circulation loop are arranged on the side wall of the oil finishing device.
  8. 8. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein a gas phase outlet of the oil finishing device (13) is communicated with a gas return pipe of the low-temperature-stage compressor (5) through a gas return valve (20), and a liquid phase outlet of the oil finishing device (13) is communicated with an inlet of the oil storage tank (14).
  9. 9. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein the outlet of the oil storage tank (14) is connected in parallel with the oil return port of the oil (6) and then communicated with the oil return end of the low-temperature-stage compressor (5) through an oil return valve (19), and an oil sight glass (17) and an electromagnetic valve (23) are arranged on the oil return pipeline.
  10. 10. The CO 2 cascade refrigeration system based on waste heat driving according to claim 1, wherein temperature sensors (18) are arranged at the outlet of the evaporator body (4), the air suction port and the air discharge port of the low-temperature-stage compressor (5), the cold and hot side outlet of the condensing evaporator (7), the air suction port and the air discharge port of the high-temperature-stage compressor (8), the inlet and the outlet of the gas-separation type gas-liquid heat exchanger (9), the inlet and the outlet of the oil finishing distiller (13) and the inlet and the outlet of the heat exchange jacket of the oil finishing distiller (13).

Description

CO 2 cascade refrigeration system based on waste heat drive Technical Field The invention relates to the technical field of refrigeration, in particular to a CO 2 cascade refrigeration system based on waste heat driving. Background With the wide application of low-temperature refrigeration and ultralow-temperature process equipment in the fields of cold chain logistics, low-temperature chemical industry, new energy and the like, the adoption of a cascade refrigeration structure to obtain a larger temperature difference and higher system efficiency has become a common technical route. In the existing CO 2 cascade refrigeration system, in order to solve the problems of lubricating oil separation and recovery caused by mutual dissolution of the refrigerant and the lubricating oil, an oil rectifying device is often arranged to heat and separate the oil-containing refrigerant. In the prior art, an oil rectifying device mostly adopts an independent heating unit such as an electric heating pipe, an electric heating plate or a steam heater as a heat source, and lubricating oil dissolved in a refrigerant is separated from the refrigerant in a phase state by heating a rectifying tower body or a heat exchange jacket. At the same time, the refrigerant gas discharged from the high-temperature-stage compressor is cooled and condensed by a single cooling heat exchanger before entering the high-temperature-stage condenser, and a large amount of high-grade heat carried by the refrigerant gas is directly taken away by an environment cooling medium and is not utilized by the inside of the system. The inventor of the present application has found in the process of researching and implementing the coupling scheme of oil rectification and waste heat utilization of the cascade refrigeration system that the above-mentioned prior art has at least the following technical problems that under the condition that the exhaust side of the high-temperature-stage compressor already has stable and continuous high-temperature heat source conditions, the oil rectification device still needs to rely on an independent electric heating device to provide heating energy, so that the heating energy consumption in the oil rectification process is higher. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a CO 2 cascade refrigeration system based on waste heat drive, which solves the problem that the heating energy consumption in the oil rectification process is higher because an oil rectification device still needs to rely on an independent electric heating device to provide heating energy in the prior art. The CO 2 cascade refrigeration system based on waste heat driving comprises a low-temperature end circulation module, a high-temperature end circulation module and an oil rectification module, wherein the low-temperature end circulation module comprises a CO 2 liquid storage tank, a low-pressure circulation barrel, a CO 2 pump, an evaporator body, a low-temperature-level compressor and oil, the high-temperature end circulation module comprises a condensation evaporator, a high-temperature-level compressor, a gas-separation type gas-liquid heat exchanger, a high-temperature-level condenser and a liquid reservoir, the oil rectification module comprises a buffer cavity, an oil rectifying device, an oil storage tank, a glycol pump, a drying filter, an expansion tank, an oil return valve and an air return valve, the low-temperature end circulation module and the high-temperature end circulation module are in cascade heat exchange connection through the condensation evaporator, a glycol circulation loop is formed between the gas-separation type gas-liquid heat exchanger and the oil rectification module, a gas phase pipeline of the oil rectification module is communicated with an air return pipe of the low-temperature-level compressor, and a liquid phase pipeline is communicated with an oil return end of the low-temperature-level compressor. Preferably, the liquid phase outlet of the CO 2 liquid storage tank is communicated with the liquid phase inlet of the low-pressure circulation barrel through a throttle valve, the liquid phase outlet of the low-pressure circulation barrel is divided into a first branch and a second branch, the first branch is communicated with the liquid phase inlet of the evaporator body through a CO 2 pump, the second branch is communicated with the feed inlet of the oil finishing distillation device through a buffer cavity, the gas phase outlet of the evaporator body is communicated with the air suction port of the low-temperature-stage compressor, the air outlet of the low-temperature-stage compressor is communicated with the oil inlet, the gas phase outlet of the oil is communicated with the hot side inlet of the condensation evaporator, and the hot side outlet of the condensation evaporator is communicated with the gas phase inlet of the CO 2 liquid storage tank. Preferably, the buffer cavit