CO2 cascade refrigeration device arranged in tunnel and capable of shortening construction period

Abstract

The utility model relates to a CO2 cascade refrigeration device which is arranged in a tunnel and can shorten the construction period. The problems that in the background technology, in the stratum freezing process of a tunnel, when a CO2 refrigerating unit is used, energy is not saved, an equipment structure is arranged too wide and too high, when the CO2 refrigerating unit is placed in the tunnel, a very wide passing channel is occupied, construction of other working procedures is affected, construction cannot be conducted synchronously with other working procedures, and the construction cost is low are solved. And the construction period of the whole project is prolonged, and the construction cost is increased. According to the technical scheme for solving the technical problem, the device is divided into two or more than two modules, and the modules are connected through a plurality of pipelines; the multiple modules comprise a compressor, an oil separator, a condenser, an economizer, a first throttling valve, a condensation evaporator, a second throttling valve, a CO2 liquid reservoir, a CO2 compressor, a CO2 oil separator, a CO2 low-pressure circulation barrel, a third throttling valve and a refrigeration pump. The method is suitable for stratum freezing construction in the tunnel.

Description

Technical Field

[0001] The utility model belongs to refrigeration technology, specifically a CO2 condenser placed in a tunnel to shorten the construction period. 2 Cascade refrigeration unit. Background Art

[0002] At present, the existing ground freezing technologies in the industry are divided into three types: brine freezing, liquid nitrogen freezing and low-temperature carbon dioxide freezing. Under similar costs, low-temperature carbon dioxide has the highest freezing efficiency. 2 Subcritical refrigeration system according to CO 2 The presence or absence of a compressor is divided into CO 2 Cascade Refrigeration System and CO 2 There are two refrigeration cycles in the cold refrigeration system. The applicable evaporation temperature ranges of the two are different. At higher evaporation temperatures, CO 2 The COP of the cold refrigeration system is high; at a lower evaporation temperature, CO 2 The cascade refrigeration system has a high COP. In the frozen ground of the tunnel, CO 2 Most of them work below -40℃, and CO 2 The invention patent with application number 202210450347.0 discloses a carbon dioxide cooling unit for artificial ground freezing system. The problems of this cooling unit are: 1. This device is CO 2 The COP of the refrigeration unit is low when working below -40℃; second, this equipment is an integrated equipment, and the compressor, water-cooled condenser and carbon dioxide storage tank are placed side by side in the width direction of the equipment, and the equipment as a whole is too wide; third, the condenser evaporator and carbon dioxide storage tank used are two separate devices. Due to the need for gravity drop, the condenser evaporator must be placed above the carbon dioxide storage tank, so the equipment will be very high. If the height is lowered, only the height between the refrigeration pump and the CO2 storage tank can be lowered, which will greatly reduce the safety cavitation margin of the pump. The pump is prone to cavitation, which poses a great safety hazard to the refrigeration pump; the equipment in the patent will occupy a very wide passage if placed in the tunnel as a whole, which will affect the construction of other processes and cannot be constructed synchronously with other processes. It can only wait until other processes in the tunnel are completed before the ground is frozen. The ground freezing time is generally very long, which will result in problems such as extended construction period of the entire project and increased construction costs. Utility Model Content

[0003] The purpose of the utility model is to propose a CO2 cascade refrigeration device placed in a tunnel to shorten the construction period, so as to solve the problem of the background technology: when the ground in the tunnel is frozen, the use of CO 2The cooling unit is not energy-efficient, and the equipment structure is too wide and too high. When placed in the tunnel, it will occupy a wide passage, affecting the construction of other processes and making it impossible to synchronize the construction with other processes, resulting in problems such as the entire project construction period being extended and the construction cost being increased. The technical solution adopted to solve this technical problem is: a CO2-free cooling unit placed in the tunnel can shorten the construction period. 2 Cascade refrigeration device, in which the refrigeration system is: the high-temperature stage cycle is: the compressor exhaust port is connected to the oil separator, condenser, economizer B port and C port, throttle valve 2 and condenser evaporator F port and L port through a pipeline in sequence to return to the compressor suction port, and the A port in the pipeline is connected to the throttle valve 1, economizer D port and E port through a pipeline in sequence to return to the compressor air supply port; the low-temperature stage cycle is: CO 2 The compressor exhaust port is connected to the CO 2 Oil separator, condenser evaporator N and M ports, CO 2 Liquid receiver, throttle valve 3, CO 2 Low-pressure circulation barrel G and I ports, refrigeration pump, terminal evaporator outside this device, CO 2 The low-pressure circulation barrel J and H ports return CO 2 The compressor suction port; the high temperature oil cycle is: the oil separator outlet is connected to the compressor oil inlet through a pipeline; the low temperature oil cycle is: CO 2 The oil separator outlet is connected to the CO 2 The oil inlet of the compressor is characterized in that the device is divided into two or more modules, which are connected by several pipelines. The modules include: the compressor, oil separator, condenser, economizer, and throttle valve 1 in the high-temperature compression condensing unit and its ancillary equipment; the modules also include: the condensing evaporator, throttle valve 2, CO 2 Liquid receiver; some modules also include: CO in low temperature compressor unit and its auxiliary equipment 2 Compressor, CO 2 Oil separator; some modules also include: CO in low temperature barrel pump unit and its ancillary equipment 2 Low-pressure circulation barrel, throttle valve 3. Refrigeration pump. Each module is 1 to 2 meters wide and 2 to 3 meters high. The condenser evaporator and CO2 liquid storage tank are either combined into one device: condenser evaporator liquid storage tank, or two devices: condenser evaporator with gas separation and CO2 liquid storage tank, or three devices: gas-liquid separator, condenser evaporator and CO2 liquid storage tank. Compressor, CO 2 The number of compressors is single or multiple. The economizer is either dry type, full liquid type, or flash tank type. The number of refrigeration pumps is single or multiple. Each module in this refrigeration device is either arranged left and right in a horizontal shaft, or arranged up and down in a vertical shaft. The high temperature side refrigerant is either Freon or ammonia.

[0004] The B port of the economizer is the liquid inlet, the C port of the economizer is the liquid outlet, the D port of the economizer is the liquid inlet on the evaporation side, and the E port of the economizer is the gas outlet on the evaporation side. The F port of the condenser evaporator is the inlet of the refrigerant on the high temperature side, the L port of the condenser evaporator is the outlet of the refrigerant on the high temperature side, the M port of the condenser evaporator is located at the liquid outlet end of the low temperature CO2 side, and the N port of the condenser evaporator is located at the gas inlet end of the low temperature CO2 side. The G port of the CO2 low pressure circulation barrel is the low temperature CO2 liquid inlet, the H port of the CO2 low pressure circulation barrel is located in the gas phase area at the gas outlet end, the I port of the CO2 low pressure circulation barrel is located in the liquid phase area, and the J port of the CO2 low pressure circulation barrel is located in the gas phase area at the gas inlet end.

[0005] Compared with the prior art, the utility model has the following beneficial effects: the above technical solution is used for the freezing construction of the ground in the tunnel. On the one hand, due to the freezing of the ground, CO 2 Most of them work below -40℃. It is calculated that when the terminal CO 2 When the evaporation temperature is -45℃, CO 2 The COP of the cooling system is 0.8, CO 2 The COP of the cascade refrigeration system is 1.46. Obviously, the use of CO 2 The cascade refrigeration system is more energy-efficient; on the other hand: the device is divided into two or more modules, and the modules include: the compressor, oil separator, condenser, economizer, and throttle valve 1 in the high-temperature compression condensing unit and its ancillary equipment; the modules also include: the condensing evaporator, throttle valve 2, CO 2 Liquid receiver; some modules also include: CO in low temperature compressor unit and its auxiliary equipment 2 Compressor, CO 2 Oil separator; some modules also include: CO in low temperature barrel pump unit and its ancillary equipment 2 Low-pressure circulation barrel, throttle valve, refrigeration pump. Several modules are connected by several pipelines, so that the device can be modularized under the premise of complete equipment. The width of each module is no more than 2 meters. Because the tunnel cross-section is circular, the height of the equipment is also limited when it is placed on one side. The overall height of each module is no more than 3 meters. When it is placed on one side of the tunnel, the remaining channel width can reach 3.5 meters, which greatly reduces the size of the equipment on one side of the tunnel. The freezing of the stratum can be carried out simultaneously with other processes in the tunnel without affecting each other, and finally shorten the construction period of the entire project and reduce the construction cost. On the other hand: the condenser evaporator adopts a plate and shell heat exchanger with gas separation, which can reduce the overall height of the equipment, making it easier to put it into the tunnel on one side and reduce the equipment footprint; on the other hand: the compressor, CO 2When there are two compressors, when one fails, one can still continue to work, and the on-site freezing equipment does not need to be shut down to continue the ground freezing work; on the other hand, when the economizer adopts the flash tank form, the temperature of the refrigerant liquid is lower and the economy of the system is better; on the other hand: when there are two refrigeration pumps, when one fails, one can still continue to work, and the on-site freezing equipment does not need to be shut down to continue the ground freezing work; on the other hand, this refrigeration device can be used in different fields, according to the actual application occasions and the on-site location size, it can be arranged either left and right in the horizontal shaft, or arranged up and down in the vertical shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a structural schematic diagram of four modules of the utility model. Figure 2 yes Figure 1 Left view of . Figure 3 It is a schematic diagram of the pipelines of four modules of the utility model. Figure 4 This is a diagram showing the equipment of the utility model in position in a tunnel. DETAILED DESCRIPTION

[0007] Example 1: Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 , a CO placed in the tunnel to shorten the construction period 2 Cascade refrigeration device, wherein the refrigeration system is: the high temperature stage cycle is: the exhaust port of compressor 3 is connected to oil separator 2, condenser 1, economizer 8B port and C port, throttle valve 2 9 and condenser evaporator 4F port and L port in sequence through pipelines to return to the compressor 3 suction port, and the A port in the pipeline is connected to throttle valve 1 7, economizer 8D port and E port in sequence through pipelines to return to the compressor 3 air supply port; the low temperature stage cycle is: the exhaust port of CO2 compressor 6 is connected to CO2 compressor 6 through pipelines in sequence 2 The oil separator 5, the N and M ports of the condenser evaporator 4, the CO2 liquid storage tank 10, the throttle valve 3 11, the G and I ports of the CO2 low-pressure circulation barrel 12, the refrigeration pump 13, the terminal evaporator 14 outside the device, the J and H ports of the CO2 low-pressure circulation barrel 12 return to the CO2 compressor 6 suction port; the high-temperature oil circulation is: the oil separator 2 oil outlet is connected to the compressor 3 oil inlet through a pipeline; the low-temperature oil circulation is: CO 2 The oil outlet of the oil separator 5 is connected to the oil inlet of the CO2 compressor 6 through a pipeline; the characteristic is that the device is divided into four modules: A, B, C, and D. Module A includes: a compressor 3, an oil separator 2, a condenser 1, an economizer 8, and a throttle valve 7 in a high-temperature compression condensing unit and its ancillary equipment; Module B includes: a condensing evaporator 4, a throttle valve 2 9, and a CO2 liquid storage tank 10 in a condensing skid-mounted unit and its ancillary equipment; Module C includes: a CO2 compressor 6, a CO2 liquid storage tank 10 in a low-temperature compressor unit and its ancillary equipment;2 Oil separator 5; module D includes: CO2 low-pressure circulation barrel 12, throttle valve 3 11, refrigeration pump 13 in the low-temperature barrel pump unit and its auxiliary equipment. Modules A, B, C, and D are arranged on the left and right in the horizontal shaft and connected by several pipelines, so that the device realizes modularization under the premise of complete equipment; each module is 1.2 meters wide and 2.5 meters high. When it is placed on one side of the tunnel, the remaining channel width can reach 3.5 meters, and the freezing of the stratum can be carried out simultaneously with other processes in the tunnel without affecting each other; the condenser evaporator 4 and the CO2 liquid storage tank 10 are two devices: the condenser evaporator with gas separation and the CO 2 Liquid receiver; compressor, CO 2 The number of compressors is one; the economizer 8 is a dry type; the number of refrigeration pumps 13 is two; and the high temperature side refrigerant is Freon.

Claims

1. A CO2 cascade refrigeration device placed in a tunnel to shorten the construction period, wherein the refrigeration system is: the high-temperature cycle is: the exhaust port of the compressor (3) is connected to the oil separator (2), condenser (1), economizer (8) B port and C port, throttle valve 2 (9) and condenser evaporator (4) F port and L port in sequence through a pipeline to return to the compressor (3) suction port, and the A port in the pipeline is connected to the throttle valve 1 (7), economizer (8) D port and E port in sequence through a pipeline to return to the compressor (3) air supply port; the low-temperature cycle is: the exhaust port of the CO2 compressor (6) is connected to the CO2 oil separator (2), condenser (1), economizer (8) B port and C port, throttle valve 2 (9) and condenser evaporator (4) F port and L port in sequence through a pipeline to return to the compressor (3) suction port The separator (5), the N port and the M port of the condenser evaporator (4), the CO2 liquid storage tank (10), the throttle valve three (11), the G port and the I port of the CO2 low-pressure circulation barrel (12), the refrigeration pump (13), the terminal evaporator (14) outside the device, the J port and the H port of the CO2 low-pressure circulation barrel (12) return to the CO2 compressor (6) suction port; the high-temperature oil circulation is: the oil outlet of the oil separator (2) is connected to the oil inlet of the compressor (3) through a pipeline; the low-temperature oil circulation is: the oil outlet of the CO2 oil separator (5) is connected to the oil inlet of the CO2 compressor (6) through a pipeline; the characteristics are: The device is divided into two or more modules, which are connected by a number of pipelines. The modules include: a compressor (3), an oil separator (2), a condenser (1), an economizer (8), and a throttle valve 1 (7) in a high-temperature compression condensing unit and its ancillary equipment; the modules also include: a condensing evaporator (4), a throttle valve 2 (9), and a CO2 liquid storage tank (10) in a condensing skid-mounted unit and its ancillary equipment; the modules also include: a CO2 compressor (6) and a CO2 oil separator (5) in a low-temperature compressor unit and its ancillary equipment; the modules also include: a CO2 low-pressure circulation barrel (12), a throttle valve 3 (11), and a refrigeration pump (13) in a low-temperature barrel pump unit and its ancillary equipment.

2. According to claim 1, a CO2 cascade refrigeration device placed in a tunnel to shorten the construction period is characterized in that: Each module is 1 to 2 meters wide and 2 to 3 meters high.

3. A CO2 cascade refrigeration device placed in a tunnel to shorten the construction period according to claim 1 or 2, characterized in that: The condenser evaporator (4) and the CO2 liquid storage device (10) are either combined into one device: a condenser evaporator liquid storage device; or two devices: a condenser evaporator with gas separation and a CO2 liquid storage device; or three devices: a gas-liquid separator, a condenser evaporator and a CO2 liquid storage device.

4. A CO2 cascade refrigeration device placed in a tunnel to shorten the construction period according to claim 1 or 2, characterized in that: The number of compressors (3) and CO2 compressors (6) may be a single unit or a plurality of units.

5. The CO2 cascade refrigeration device placed in a tunnel to shorten the construction period according to claim 3 is characterized in that: The number of compressors (3) and CO2 compressors (6) may be a single unit or a plurality of units.

6. A CO2 cascade refrigeration device placed in a tunnel to shorten the construction period according to claim 1 or 2, characterized in that: The economizer (8) is either of the dry type, the flooded type, or the flash tank type.

7. A CO2 cascade refrigeration device placed in a tunnel to shorten the construction period according to claim 1 or 2, characterized in that: The number of refrigeration pumps (13) is one or more.

8. A CO2 cascade refrigeration device placed in a tunnel to shorten the construction period according to claim 1 or 2, characterized in that: Each module in this refrigeration device is either arranged left and right in a horizontal shaft, or arranged up and down in a vertical shaft.

9. A CO2 cascade refrigeration device placed in a tunnel to shorten the construction period according to claim 1 or 2, characterized in that: The high temperature side refrigerant is either Freon or ammonia.

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