Heat sharing system of liquid-to-gasification system and direct-cooling refrigerating system

Abstract

The utility model belongs to the technical field of chemical equipment, and particularly relates to a heat sharing system of a liquid-to-gasification system and a direct-cooling refrigerating system. The direct-cooling refrigerating system and the liquid-to-gasification system are effectively combined, so that the refrigerating effect of the direct-cooling refrigerating system is improved, the refrigerating power consumption is reduced, the problems that a vaporizer in the liquid-to-gasification system is low in heat exchange efficiency and poor in safety are solved, and the maximum advantages of all the systems are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical equipment, and particularly relates to a heat sharing system of a liquid-vaporization system and a direct cooling refrigeration system. Background Technique

[0002] Inert gases such as nitrogen and argon generally participate in and protect chemical reactions as protective gases during the chemical production process. During use, liquid nitrogen, liquid argon, etc. need to be pressurized and enter an air-cooled cryogenic liquid vaporizer, then enter a storage tank, and be sent to each use unit.

[0003] However, during the use of liquefied gases (such as liquid nitrogen, liquid argon, etc.), the following problems exist: First, it is necessary to vaporize the liquefied gas, increasing the use cost; second, since the vaporization of liquefied gas in the vaporizer mainly absorbs the heat of the air outside the vaporizer, the water in the air will form white frost on the surface of the vaporizer under the action of the cold generated during the vaporization of the liquefied gas, which is extremely likely to cause incomplete vaporization of the liquefied gas in the vaporizer. When the incompletely vaporized liquefied gas flows into the conveying pipeline, it will continue to absorb heat and vaporize, so that the conveying pipeline operates at an extremely low temperature, not only greatly shortening the service life of the conveying pipeline and increasing the maintenance cost, but also posing a hidden danger to the safe and smooth progress of production; finally, liquefied gases have significant low-temperature cold energy characteristics and will absorb a large amount of heat from the air during the vaporization process, resulting in cold energy loss. Summary of the Utility Model

[0004] At present, the direct cooling refrigeration system and the liquid-vaporization system are independent of each other. During the vaporization process of the liquid-vaporization system, a large amount of cold energy is wasted. In order to improve the refrigeration effect of the direct cooling system, reduce the refrigeration power consumption, and avoid the problem that a large amount of ice blocks are formed in the vaporizer, which affects the heat exchange efficiency of the vaporizer, the utility model provides a heat sharing system of a liquid-vaporization system and a direct cooling refrigeration system, effectively combining the two systems to achieve the maximum advantages of each system.

[0005] The heat sharing system of the liquid-vaporization system and the direct cooling refrigeration system provided by the utility model includes a cold energy recovery system 9; the cold energy recovery system 9 includes a heat exchanger 12, a refrigerant inlet pipeline, a refrigerant outlet pipeline, a liquefied gas inlet pipeline, and a gas-phase gas outlet pipeline.

[0006] The refrigerant inlet pipeline is connected to the inlet of the tube side of the heat exchanger 12, and the refrigerant outlet pipeline is connected to the outlet of the tube side of the heat exchanger 12; the liquefied gas inlet pipeline is connected to the inlet of the shell side of the heat exchanger 12, and the gas-phase gas outlet pipeline is connected to the outlet of the shell side of the heat exchanger 12.

[0007] A three-way electric control valve 19 is provided on the liquid inlet pipeline of the liquefied gas, which is respectively connected to the liquefied gas storage tank 8, the heat exchanger 12, and the first vaporizer 11. When the supply amount of the liquefied gas exceeds the processing capacity of the heat exchanger 12, the excess liquefied gas enters the first vaporizer 11 for gasification.

[0008] A first thermometer 34 and a corresponding first temperature sensor 13 are provided on the refrigerant liquid outlet pipeline. The first temperature sensor 13 is connected to the three-way electric control valve 19 and controls the opening degree of the three-way electric control valve 19 through a PID algorithm. When the temperature collected by the first temperature sensor 13 is higher than the set temperature, the opening degree of the three-way electric control valve 19 is increased through an instruction to increase the flow rate of the liquefied gas, thereby reducing the outlet temperature of the refrigerant liquid outlet pipeline. When the temperature collected by the first temperature sensor 13 is lower than the set value, the opening degree of the three-way electric control valve is reduced through an instruction to reduce the flow rate of the liquefied gas, thereby increasing the outlet temperature of the refrigerant liquid outlet pipeline. Finally, the outlet temperature of the refrigerant liquid outlet pipeline is controlled at the set temperature value through the PID algorithm.

[0009] Preferably, the three-way electric control valve 19 is connected to the first vaporizer 11 through a valve V 18.

[0010] Preferably, a valve II 15, a three-way electric control valve 19, and a valve III 16 are sequentially provided on the liquefied gas inlet pipeline; a valve I 14 is provided in parallel on the liquefied gas inlet pipeline; the liquefied gas storage tank 8 can also be directly connected to the first vaporizer 11 through a valve IV 17.

[0011] When the three-way electric control valve 19 is under maintenance, the valve II 15, the valve III 16, and the valve V 18 are in the closed state, and the flow rates of the liquefied gas entering the heat exchanger 12 and the first vaporizer 11 are controlled through the valve I 14 and the valve IV 17 respectively.

[0012] Preferably, a valve VI 20 is provided on the refrigerant inlet pipeline, and a valve VII 21 is provided on the refrigerant outlet pipeline; the inlet end of the valve VI 20 is connected to the outlet end of the valve VII 21 through a heat exchange bypass pipeline; a valve VIII 22 is provided on the heat exchange bypass pipeline.

[0013] When the heat exchanger is under maintenance, the valve VI 20 and the valve VII 21 are in the closed state, and the valve VIII 22 is opened to ensure smooth refrigerant supply and does not affect the maintenance of the heat exchanger 12; the valve I 14, the valve III 16, the valve IV 17, and the valve X 25 are in the closed state, and the three-way electric control valve 19 is manually set to the minimum opening degree to ensure that all the liquefied gas enters the first vaporizer 11.

[0014] Preferably, a first pressure gauge 33 is further provided on the refrigerant liquid outlet pipeline.

[0015] Preferably, a second pressure gauge 26, a second thermometer 27, a flowmeter 28, a safety valve 32, valve XI 24, valve X 25, and a second vaporizer 35 are sequentially arranged on the gas-phase gas outlet pipeline. Correspondingly, pressure sensors 29, second temperature sensors 30, and flow sensors 31 are respectively configured for the second pressure gauge 26, the second thermometer 27, and the flowmeter 28. The valve X 25 is a check valve to prevent backflow; the valve XI 24 is provided to prevent the failure of the valve X 25, so as to manually prevent backflow.

[0016] Preferably, a maintenance pipeline is further connected to the shell side of the heat exchanger 12, and a valve IX 23 is provided on the maintenance pipeline. When the heat exchanger 12 is under maintenance, the valve IX 23 is opened to release the gas.

[0017] Furthermore, the heat sharing system of the liquid-vapor conversion system and the direct cooling refrigeration system further includes a refrigerant storage tank 4, a refrigeration unit economizer 5, and an evaporator 6.

[0018] The refrigerant storage tank 4 is connected to the cold energy recovery system 9 through a first pipeline and a second pipeline, and the first pipeline and the second pipeline are arranged in parallel. A first valve 1, a refrigeration unit economizer 5, and a second valve 2 are sequentially arranged on the first pipeline; a third valve 3 is arranged on the second pipeline.

[0019] Furthermore, the refrigerant inlet pipeline is respectively connected to the second valve 2 and the third valve 3; the liquefied gas inlet pipeline is connected to the liquefied gas storage tank 8; the outlets of the first vaporizer 11 and the second vaporizer 35 are connected to the gas usage unit 10; the refrigerant liquid outlet pipeline is connected to the refrigerant usage unit 7 through the evaporator 6.

[0020] The operation of the refrigeration unit economizer 5 and the cold energy recovery system 9 can be selected according to the actual situation. When the refrigeration unit economizer 5 can operate at high load and meets the operating requirements of the refrigeration unit economizer 5, the first valve 1 and the second valve 2 are opened, and the third valve 3 is closed. After passing through the refrigeration unit economizer 5, the refrigerant enters the evaporator 6 through the cold energy recovery system 9. When the refrigeration unit economizer 5 operates at low load, the first valve 1 and the second valve 2 are closed, and the third valve 3 is opened, and the refrigerant directly enters the evaporator 6 through the cold energy recovery system 9.

[0021] During normal operation, valve I 14, valve IV 17, and valve VIII 22 are in the normally closed state, and other valves are in the normally open state.

[0022] The liquefied gas includes liquid nitrogen, liquid argon, and liquid oxygen.

[0023] Beneficial effects:

[0024] The heat sharing system of the liquid-to-gasification system and the direct expansion refrigeration system provided by the present utility model improves the subcooling degree of the liquid supply of the economizer of the refrigeration unit, enhances the effect, reduces the refrigeration energy consumption, and improves the COP index of the refrigeration system. During the gasification process of the liquefied gas, through the recovery of cold energy, the problem of ice formation on the vaporizer is prevented, and the process of steam heating required for ice formation on the vaporizer is reduced, which also reduces the steam consumption, and further ensures the safety of the liquefied gas gasification process, preventing some potential safety hazards such as low temperature or gasification expansion caused by a large amount of liquefied gas usage and the introduction of cryogenic liquefied gas into the liquefied gas storage tank. Description of the drawings

[0025] Figure 1 It is a flow chart of the heat sharing system of the liquid-to-gasification system and the direct expansion refrigeration system;

[0026] Figure 2 It is a flow chart of the cold energy recovery system.

[0027] Among them, 1 is the first valve, 2 is the second valve, 3 is the third valve, 4 is the refrigerant storage tank, 5 is the economizer of the refrigeration unit, 6 is the evaporator, 7 is the refrigerant usage unit, 8 is the liquefied gas storage tank, 9 is the cold energy recovery system, 10 is the gas usage unit, 11 is the first vaporizer, 12 is the heat exchanger, 13 is the first temperature sensor, 14 is valve I, 15 is valve II, 16 is valve III, 17 is valve IV, 18 is valve V, 19 is the three-way electric control valve, 20 is valve VI, 21 is valve VII, 22 is valve VIII, 23 is valve IX, 24 is valve XI, 25 is valve X, 26 is the second pressure gauge, 27 is the second thermometer, 28 is the flow meter, 29 is the pressure sensor, 30 is the second temperature sensor, 31 is the flow sensor, 32 is the safety valve, 33 is the first pressure gauge, 34 is the first thermometer, and 35 is the second vaporizer. Detailed implementation manners

[0028] In the present utility model, the opening degree of the three-way electric control valve 19 is used to regulate the flow rate of the liquefied gas flowing to the heat exchanger 12. The larger the opening degree, the larger the flow rate of the liquefied gas flowing to the heat exchanger 12; when the opening degree is the smallest, the flow rate of the liquefied gas flowing to the heat exchanger 12 is 0.

[0029] Example 1

[0030] As Figure 1The figure shows a flowchart of the heat sharing system between the liquid-vapor conversion system and the direct cooling refrigeration system. The heat sharing system between the liquid-vapor conversion system and the direct cooling refrigeration system includes a refrigerant storage tank 4, an economizer 5 of the refrigeration unit, an evaporator 6, a refrigerant using unit 7, a liquefied gas storage tank 8, a cold energy recovery system 9, and a gas using unit 10. The refrigerant storage tank 4 is connected to the cold energy recovery system 9, the evaporator 6, and the refrigerant using unit 7 in sequence through a first pipeline and a second pipeline, wherein the first pipeline and the second pipeline are arranged in parallel.

[0031] A first valve 1, an economizer 5 of the refrigeration unit, and a second valve 2 are arranged in sequence on the first pipeline; a third valve 3 is arranged on the second pipeline.

[0032] The operation of the economizer 5 of the refrigeration unit and the cold energy recovery system 9 can be selected according to the actual situation. When the economizer 5 of the refrigeration unit can operate at a high load and meets the operation requirements of the economizer 5 of the refrigeration unit, the first valve 1 and the second valve 2 are opened, and the third valve 3 is closed. After passing through the economizer 5 of the refrigeration unit, the refrigerant enters the evaporator 6 through the cold energy recovery system 9. When the economizer 5 of the refrigeration unit operates at a low load, the first valve 1 and the second valve 2 are closed, and the third valve 3 is opened. The refrigerant directly enters the evaporator 6 through the cold energy recovery system 9.

[0033] The flowchart of the cold energy recovery system is as Figure 2 shown. The cold energy recovery system includes a heat exchanger 12, a refrigerant inlet pipeline, a refrigerant outlet pipeline, a liquefied gas inlet pipeline, and a gas-phase gas outlet pipeline.

[0034] The refrigerant inlet pipeline is connected to the inlet of the tube side of the heat exchanger 12, and the refrigerant outlet pipeline is connected to the outlet of the tube side of the heat exchanger 12; the liquefied gas inlet pipeline is connected to the inlet of the shell side of the heat exchanger 12, and the gas-phase gas outlet pipeline is connected to the outlet of the shell side of the heat exchanger 12.

[0035] A three-way electric control valve 19 is arranged on the liquefied gas inlet pipeline, which is respectively connected to the liquefied gas storage tank 8, the heat exchanger 12, and the first vaporizer 11; the three-way electric control valve 19 is connected to the first vaporizer 11 through a valve V18. When the supply amount of the liquefied gas exceeds the processing capacity of the heat exchanger 12, the excess liquefied gas enters the first vaporizer 11 for gasification.

[0036] A first thermometer 34 and a corresponding first temperature sensor 13 are provided on the refrigerant liquid outlet pipeline. The first temperature sensor 13 is connected to a three-way electric control valve 19, and the opening degree of the three-way electric control valve 19 is controlled by a PID algorithm. When the temperature collected by the first temperature sensor 13 is higher than the set temperature (-20 °C), the opening degree of the three-way electric control valve 19 is increased through an instruction to increase the flow rate of the liquefied gas, thereby reducing the outlet temperature of the refrigerant liquid outlet pipeline. When the temperature collected by the first temperature sensor 13 is lower than the set value, the opening degree of the three-way electric control valve is reduced through an instruction to reduce the flow rate of the liquefied gas, thereby increasing the outlet temperature of the refrigerant liquid outlet pipeline. Finally, the outlet temperature of the refrigerant liquid outlet pipeline is controlled at the set temperature value through the PID algorithm.

[0037] A valve II 15, a three-way electric control valve, and a valve III 16 are sequentially provided on the liquefied gas liquid inlet pipeline; a valve I 14 is provided in parallel on the liquefied gas liquid inlet pipeline; the liquefied gas storage tank 8 can also be directly connected to the first vaporizer 11 through a valve IV.

[0038] When the three-way electric control valve 19 is under maintenance, the valve II 15, the valve III 16, and the valve V 18 are in a closed state, and the flow rates of the liquefied gas entering the heat exchanger 12 and the first vaporizer 11 are controlled through the valve I 14 and the valve IV 17 respectively.

[0039] A valve VI 20 is provided on the refrigerant liquid inlet pipeline, and a valve VII 21 is provided on the refrigerant liquid outlet pipeline; the inlet end of the valve VI 20 is connected to the outlet end of the valve VII 21 through a heat exchange bypass pipeline; a valve VIII 22 is provided on the heat exchange bypass pipeline.

[0040] When the heat exchanger is under maintenance, the valve VI 20 and the valve VII 21 are in a closed state, and the valve VIII 22 is opened to ensure smooth refrigerant supply and not affect the maintenance of the heat exchanger 12; the valve I 14, the valve III 16, the valve IV 17, and the valve X 25 are in a closed state, and the three-way electric control valve 19 is manually set to the minimum opening degree to ensure that all the liquefied gas enters the first vaporizer 11.

[0041] A first pressure gauge 33 is also provided on the refrigerant liquid outlet pipeline.

[0042] A second pressure gauge 26, a second thermometer 27, a flow meter 28, a safety valve 32, a valve XI 24, a valve X 25, and a second vaporizer 35 are sequentially arranged on the gas-phase gas outlet pipeline. Correspondingly, the second pressure gauge 26, the second thermometer 27, and the flow meter 28 are respectively equipped with a pressure sensor 29, a second temperature sensor 30, and a flow sensor 31. The valve X 25 is a check valve to prevent backflow; the valve XI 24 is provided to prevent the valve X 25 from failing, so as to manually prevent backflow.

[0043] A maintenance pipeline is also connected to the shell side of the heat exchanger 12, and a valve IX 23 is arranged on the maintenance pipeline. When the heat exchanger 12 is under maintenance, the valve IX 23 is opened to release gas.

[0044] Furthermore, the refrigerant inlet pipeline is respectively connected to a second valve 2 and a third valve 3; the liquefied gas inlet pipeline is connected to a liquefied gas storage tank 8; the outlets of the first vaporizer 11 and the second vaporizer 35 are respectively connected to a gas usage unit 10; the refrigerant outlet pipeline is connected to an evaporator 6, and the evaporator 6 is connected to a refrigerant usage unit 7.

[0045] During normal operation, the valve I 14, the valve IV 17, and the valve VIII 22 are in a normally closed state, and other valves are in a normally open state.

Claims

1. A heat sharing system between a liquid-to-gasification system and a direct cooling refrigeration system, characterized in that: including a cold recovery system (9); The cold energy recovery system (9) comprises a heat exchanger (12), a refrigerant liquid inlet pipeline, a refrigerant liquid outlet pipeline, a liquefied gas liquid inlet pipeline, and a gas phase gas outlet pipeline; The refrigerant liquid inlet pipeline is connected to the tube side inlet of the heat exchanger (12), and the refrigerant liquid outlet pipeline is connected to the tube side outlet of the heat exchanger (12); the liquefied gas liquid inlet pipeline is connected to the shell side inlet of the heat exchanger (12), and the gas phase gas outlet pipeline is connected to the shell side outlet of the heat exchanger (12); A three-way electric regulating valve (19) is arranged on the liquefied gas inlet pipeline, and the three-way electric regulating valve (19) is respectively connected to the liquefied gas storage tank (8), the heat exchanger (12), and the first vaporizer (11).

2. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 1 is characterized in that: A first temperature meter (34) and a corresponding first temperature sensor (13) are arranged on the refrigerant liquid outlet pipeline; The first temperature sensor (13) is connected to the three-way electric regulating valve (19) and controls the opening degree of the three-way electric regulating valve (19).

3. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 2 is characterized in that: The liquefied gas inlet pipeline is provided with a valve II (15), a three-way electric regulating valve (19), and a valve III (16) in sequence; the liquefied gas inlet pipeline is provided with a valve I (14) in parallel; the liquefied gas storage tank (8) is also connected to the first vaporizer (11) via a valve IV (17); and a valve V (18) is provided between the three-way electric regulating valve (19) and the first vaporizer (11).

4. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 3 is characterized in that: A valve VI (20) is provided on the refrigerant inlet pipeline, and a valve VII (21) is provided on the refrigerant outlet pipeline; the inlet end of the valve VI (20) is connected to the outlet end of the valve VII (21) via a heat exchange bypass pipeline; a valve VIII (22) is provided on the heat exchange bypass pipeline; A second vaporizer (35) is provided on the gas phase gas outlet pipeline.

5. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 4 is characterized in that: The heat sharing system between the liquid-to-gasification system and the direct cooling refrigeration system further includes a refrigerant storage tank (4), a refrigeration unit economizer (5), and an evaporator (6); The refrigerant storage tank (4) is connected to a cold recovery system (9) via a first pipeline and a second pipeline, wherein the first pipeline and the second pipeline are arranged in parallel; a first valve (1), a refrigeration unit economizer (5), and a second valve (2) are arranged in sequence on the first pipeline; and a third valve (3) is arranged on the second pipeline.

6. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 5, characterized in that: The refrigerant liquid inlet pipeline is connected to the second valve (2) and the third valve (3) respectively; the liquefied gas liquid inlet pipeline is connected to the liquefied gas storage tank (8); the first vaporizer (11) outlet and the second vaporizer (35) outlet are connected to the gas use unit (10) respectively; and the refrigerant liquid outlet pipeline is connected to the refrigerant use unit (7) via the evaporator (6).

7. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 1, characterized in that: A first pressure gauge (33) is provided on the refrigerant liquid outlet pipeline.

8. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 1, characterized in that: A second pressure gauge (26), a second temperature gauge (27), a flow meter (28), a safety valve (32), a valve XI (24), and a valve X (25) are sequentially arranged between the heat exchanger (12) and the second vaporizer (35).

9. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 8, characterized in that: The second pressure gauge (26), the second temperature gauge (27), and the flow meter (28) are respectively equipped with a pressure sensor (29), a second temperature sensor (30), and a flow sensor (31).

10. The heat sharing system of the liquid-to-gasification system and the direct cooling refrigeration system according to claim 1, characterized in that: The shell side of the heat exchanger (12) is also connected to a maintenance pipeline, and a valve IX (23) is provided on the maintenance pipeline.

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