Cooling capacity migration device

Abstract

The invention discloses a cooling capacity migration device which is mounted on deep cooling air separation equipment and comprises a cold box, a main heat exchanger arranged in the cold box, a liquid oxygen evaporator, a liquid nitrogen subcooler, a liquid oxygen condenser and a gas-liquid separation tank. According to the invention, redundant liquid oxygen produced by the original cryogenic air separation equipment can be used for liquefying nitrogen purified by the cryogenic equipment, so that the output efficiency of a liquid nitrogen product is improved, or redundant liquid nitrogen generated by the cryogenic air separation equipment can be used for liquefying oxygen purified by the cryogenic equipment, so that the output efficiency of a liquid oxygen product is improved; therefore, waste of liquid nitrogen or liquid oxygen resources is avoided, the production cost is reduced, and the environment is protected.

Description

Technical Field

[0001] The present invention relates to the technical field of air separation equipment, and particularly to a cold quantity transfer device. Background Art

[0002] In the process of modern chemical production, as a key gas supply source, the continuous and stable operation of air separation equipment is crucial. Air separation equipment is mainly used to separate the main components in air, such as oxygen and nitrogen, and through processes such as cryogenic rectification, the air is separated into gas products with different purities to meet the requirements of various processes in chemical production for specific gases.

[0003] However, due to the continuous operation characteristics of air separation equipment, its product output is also continuous and stable. This leads to a problem: when the storage tank for liquid products is full, the excess liquid products have to be discharged. Such discharge not only directly causes waste of resources, increases production costs, but also may have a certain impact on the environment.

[0004] In addition, the demand in the chemical market and product prices are volatile. Under different market conditions, the demand and prices of liquid oxygen and liquid nitrogen may vary greatly. For example, in certain specific industrial applications, the demand for liquid oxygen may suddenly increase, resulting in an increase in its price; while in other cases, the market demand for liquid nitrogen may decrease and the price may fall. Facing such market changes, chemical enterprises need to flexibly adjust their production strategies to maximize profits.

[0005] Therefore, how to effectively manage and utilize the products produced by air separation equipment, avoid waste, and at the same time flexibly adjust the product variety and output according to the market conditions is a technical problem that urgently needs to be solved now.

[0006] This has become an important issue faced by chemical production enterprises. This prompts enterprises to seek more advanced technologies and management methods to optimize the operation of air separation equipment and product management, and improve production efficiency and market competitiveness. Summary of the Invention

[0007] The purpose of the present invention is to provide a cold quantity transfer device to solve the problem in the background art that the existing air separation equipment cannot adjust the output according to demand, resulting in waste of resources.

[0008] To achieve the above purpose, the present invention provides a cold quantity transfer device, which is installed on a cryogenic air separation equipment and includes a cold box, a main heat exchanger, a liquid oxygen evaporator, a liquid nitrogen subcooler, a liquid oxygen condenser and a gas-liquid separation tank arranged in the cold box.

[0009] Optionally, the main heat exchanger is used to exchange heat between nitrogen and oxygen, and a nitrogen-oxygen inlet and outlet pipe group connected to the cryogenic air separation equipment is connected to the main heat exchanger.

[0010] Optionally, a liquid oxygen inlet pipe, an evaporator nitrogen inlet pipe, and an evaporator oxygen outlet pipe are provided on the liquid oxygen evaporator. Both the evaporator oxygen outlet pipe and the evaporator nitrogen inlet pipe are connected to the main heat exchanger, and the liquid oxygen inlet pipe is connected to the liquid oxygen storage tank in the cryogenic air separation plant.

[0011] Optionally, a liquid nitrogen connection pipe, a liquid nitrogen product pipe, and a first nitrogen discharge pipe are provided on the liquid nitrogen subcooler. The liquid nitrogen connection pipe is connected to the liquid oxygen evaporator, and the liquid nitrogen product pipe is connected to the liquid nitrogen storage tank; the first nitrogen discharge pipe is connected to the main heat exchanger to transport the nitrogen after heat exchange into the main heat exchanger for further heat exchange.

[0012] Optionally, a cold source pipe, an oxygen inlet connection pipe, and a liquid oxygen connection pipe are provided on the liquid oxygen condenser. The oxygen inlet connection pipe is connected to the evaporator oxygen outlet pipe, the cold source pipe is connected to the liquid nitrogen product pipe, and the liquid oxygen connection pipe is connected to the inlet end of the gas-liquid separation tank.

[0013] Optionally, the gas-liquid separation tank is used to separate liquid oxygen and oxygen. A liquid oxygen product pipe and an oxygen vent pipe are provided at the outlet end of the gas-liquid separation tank, and the liquid oxygen product pipe is connected to the liquid oxygen storage tank in the cryogenic air separation plant.

[0014] Optionally, there are two cold quantity transfer methods in the main heat exchanger, namely nitrogen cold quantity transfer and oxygen cold quantity transfer. When the main heat exchanger performs nitrogen cold quantity transfer, the pressurized nitrogen in the cryogenic air separation plant is transported into the main heat exchanger through the nitrogen-oxygen inlet and outlet pipe group to exchange heat with the oxygen transported from the liquid oxygen evaporator. Finally, the liquid nitrogen generated by the liquid nitrogen subcooler is transported into the liquid nitrogen storage tank through the liquid nitrogen product pipe; when the main heat exchanger performs oxygen cold quantity transfer, the oxygen in the cryogenic air separation plant is transported into the main heat exchanger through the nitrogen-oxygen inlet and outlet pipe to exchange heat with the nitrogen transported from the liquid oxygen condenser. Finally, the liquid oxygen is transported into the liquid oxygen storage tank through the liquid oxygen product pipe by the gas-liquid separation tank.

[0015] Optionally, the nitrogen-oxygen inlet and outlet pipe group includes a second nitrogen discharge pipe connected to the cryogenic air separation plant, a pressurized nitrogen inlet pipe, and an oxygen inlet and outlet pipe; the second nitrogen discharge pipe is used to transport the nitrogen in the main heat exchanger to the cryogenic air separation plant; the pressurized nitrogen inlet pipe is used to transport the pressurized nitrogen in the cryogenic air separation plant into the main heat exchanger; the flow direction of the oxygen in the oxygen inlet and outlet pipe is adjusted and changed according to the cold quantity transfer method; when the main heat exchanger performs nitrogen cold quantity transfer, the flow direction of the oxygen in the oxygen inlet and outlet pipe is from the main heat exchanger to the cryogenic air separation plant; when the main heat exchanger performs oxygen cold quantity transfer, the flow direction of the oxygen in the oxygen inlet and outlet pipe is from the cryogenic air separation plant to the main heat exchanger.

[0016] Optionally, drain pipes are provided on both the second nitrogen discharge pipe and the oxygen inlet and outlet pipe, and drain control valves are installed on the drain pipes.

[0017] Optionally, automatic control valves are provided on both the pressure nitrogen inlet pipe and the oxygen inlet and outlet pipe, and the second nitrogen discharge pipe is connected to the first nitrogen discharge pipe through the main heat exchanger.

[0018] Optionally, the oxygen inlet and outlet pipe is connected to the oxygen outlet pipe of the evaporator through the main heat exchanger.

[0019] Optionally, an oxygen liquefaction inlet pipe is further provided on the oxygen inlet and outlet pipe. For the oxygen entering through the oxygen liquefaction inlet pipe, an oxygen control valve is installed on the oxygen liquefaction inlet pipe.

[0020] Optionally, an evaporator control valve is installed on the oxygen outlet pipe of the evaporator; the oxygen inlet connecting pipe is connected to the oxygen outlet pipe of the evaporator, and the connection position is between the evaporator control valve and the main heat exchanger.

[0021] Optionally, a liquid nitrogen return pipe is provided on the liquid nitrogen product pipe. The other end of the liquid nitrogen return pipe is connected to the first nitrogen discharge pipe through a liquid nitrogen subcooler, and a temperature control valve is installed on the liquid nitrogen return pipe.

[0022] Optionally, a liquid nitrogen shut-off valve is further installed on the liquid nitrogen product pipe. The connection position of the liquid nitrogen return pipe and the liquid nitrogen product pipe is between the liquid nitrogen shut-off valve and the liquid nitrogen subcooler.

[0023] Optionally, a liquid nitrogen inlet pipe is further connected to the liquid nitrogen product pipe. A second liquid nitrogen control valve is installed on the liquid nitrogen inlet pipe, and the connection point of the liquid nitrogen inlet pipe and the liquid nitrogen product pipe is at the outlet end of the liquid nitrogen shut-off valve.

[0024] Optionally, a first liquid nitrogen control valve is further installed on the liquid nitrogen product pipe. The connection position of the cold source pipe and the liquid nitrogen product pipe is between the installation position of the first liquid nitrogen control valve and the liquid nitrogen shut-off valve.

[0025] Optionally, a flow control valve is installed on the cold source pipe; a liquid oxygen connection control valve is installed on the liquid oxygen connection pipe.

[0026] Optionally, an oxygen vent control valve is installed on the oxygen vent pipe; a liquid oxygen control valve is installed on the liquid oxygen product pipe.

[0027] Compared with the prior art, the present invention provides a cold quantity transfer device, which has the following beneficial effects: Through the cooperation of the main heat exchanger, the liquid oxygen evaporator, the liquid nitrogen subcooler and the liquid oxygen condenser, the cold quantity transfer device uses the surplus liquid oxygen produced by the original cryogenic air separation equipment to liquefy the nitrogen purified by the cryogenic equipment, improving the output efficiency of the liquid nitrogen product. Or, it uses the surplus liquid nitrogen already produced by the cryogenic air separation equipment to liquefy the oxygen purified by the cryogenic equipment, improving the output efficiency of the liquid oxygen product. Thus, it avoids the waste of liquid nitrogen or liquid oxygen resources, reduces the production cost, and protects the environment. In addition, this application does not require any changes to the operation of the original cryogenic air separation equipment. Therefore, it can be added according to user needs without replacing the existing cryogenic air separation equipment, reducing production costs. Moreover, only the transfer of cold energy occurs in the entire equipment, and high-power equipment such as conventional air compressors and refrigerators are not required, thereby reducing the operating costs of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0029] Reference numerals in the figure: 1, cold box; 2, main heat exchanger; 21, nitrogen-oxygen inlet and outlet pipe group; 211, second nitrogen discharge pipe; 212, pressure nitrogen inlet pipe; 213, oxygen inlet and outlet pipe; 214, evacuation pipe; 215, evacuation regulating valve; 216, oxygen liquefaction inlet pipe; 217, automatic control valve; 218, oxygen control valve; 3, liquid oxygen evaporator; 31, liquid oxygen inlet pipe; 311, liquid oxygen control valve; 32, evaporator nitrogen inlet pipe; 33, evaporator oxygen outlet pipe; 331, evaporator control valve; 4, liquid nitrogen subcooler; 41, liquid nitrogen connection pipe; 42, liquid nitrogen product pipe; 421, liquid nitrogen return pipe; 422, temperature control valve; 423, liquid nitrogen on-off valve; 424, liquid nitrogen inlet pipe; 425, second liquid nitrogen control valve; 426, first liquid nitrogen control valve; 43, first nitrogen discharge pipe; 5, liquid oxygen condenser; 51, cold source pipe; 511, flow control valve; 52, oxygen inlet connection pipe; 53, liquid oxygen connection pipe; 531, liquid oxygen connection control valve; 6, gas-liquid separation tank; 61, liquid oxygen product pipe; 611, liquid oxygen control valve; 62, oxygen vent pipe; 621, oxygen vent control valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will be described in detail in conjunction with the drawings and specific embodiments. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0031] A cold energy transfer device of the present application can be applicable to occasions such as when the liquid nitrogen storage tank or liquid oxygen storage tank is full, and the excess liquid product is used as a cold source to liquefy another liquid product that needs to be liquefied. Of course, it can also be used in other similar application scenarios. A cold energy transfer device will be described in detail below.

[0032] Refer to the attached Figure 1As shown in the figure, a schematic structural diagram of a preferred embodiment of a cold quantity transfer device of the present application is shown. The cold quantity transfer device is installed on a cryogenic air separation device. Among them, it includes a cold box 1, a main heat exchanger 2, a liquid oxygen evaporator 3, a liquid nitrogen subcooler 4, a liquid oxygen condenser 5, and a gas-liquid separation tank 6 arranged in the cold box 1. The main heat exchanger 2 is used for the first heat exchange between nitrogen and oxygen. That is, when nitrogen needs to be cooled and liquefied, oxygen with a temperature lower than that of nitrogen is used to conduct the first heat exchange with nitrogen to lower the temperature of nitrogen. If oxygen needs to be cooled and liquefied, nitrogen with a temperature lower than that of oxygen is used to conduct the first heat exchange with oxygen to provide conditions for subsequent cooling and liquefaction. Through the setting of the liquid oxygen evaporator 3, it is used for the second heat exchange between liquid oxygen and nitrogen passing through the main heat exchanger 2, so that the temperature of nitrogen is further reduced and liquefied to form liquid nitrogen. Through the setting of the liquid nitrogen subcooler 4, it is used to further reduce the temperature of liquid nitrogen and reduce the flashing loss of liquid nitrogen in the pipeline after leaving the cold box 1. Through the setting of the liquid oxygen condenser 5, it is used for the heat exchange between oxygen and liquid nitrogen to liquefy oxygen to form liquid oxygen. Through the setting of the gas-liquid separation tank 6, it is used to separate liquid oxygen and gaseous oxygen.

[0033] Refer to the appendix Figure 1 In the present invention, a nitrogen-oxygen inlet and outlet pipe group 21 connected to the cryogenic air separation device is connected to the main heat exchanger 2, and the nitrogen-oxygen inlet and outlet pipe group 21 includes a second nitrogen discharge pipe 211, a pressurized nitrogen inlet pipe 212, and an oxygen inlet and outlet pipe 213 connected to the cryogenic air separation device.

[0034] In the present invention, by connecting the second nitrogen discharge pipe 211, the pressurized nitrogen inlet pipe 212, and the oxygen inlet and outlet pipe 213 to the cryogenic air separation device, the purified nitrogen and oxygen in the cryogenic air separation device can be directly heat-exchanged and liquefied, and there is no need to purify oxygen or nitrogen again. Moreover, the nitrogen or oxygen that changes from liquid to gas after heat exchange can return to the cryogenic air separation device for liquefaction or be directly discharged. It should be particularly noted that in the present application, the second nitrogen discharge pipe 211 is used to convey the nitrogen generated during the process of transferring the cold quantity of liquid nitrogen to oxygen to convert oxygen into liquid oxygen in the direction of the cryogenic air separation device. The pressurized nitrogen inlet pipe 212 is used to convey the required purified nitrogen from the cryogenic air separation device to the main heat exchanger 2 for heat exchange and liquefaction when transferring the cold quantity of liquid oxygen to nitrogen to form liquid nitrogen. The oxygen inlet and outlet pipe 213 is used for the mutual flow of oxygen between the cryogenic air separation device and the main heat exchanger 2. Specifically, when the cold quantity of liquid nitrogen needs to be transferred to oxygen to form liquid oxygen, the oxygen in the cryogenic air separation device is conveyed to the main heat exchanger 2. And when the cold quantity of liquid oxygen needs to be transferred to nitrogen to form liquid nitrogen, the oxygen generated by vaporizing liquid oxygen is conveyed to the cryogenic air separation device. That is, the flow direction of oxygen in the oxygen inlet and outlet pipe 213 is related to the cold quantity transfer object. Different objects result in different oxygen flow directions.

[0035] Refer to the attached Figure 1 In the present invention, drain pipes 214 are provided on both the second nitrogen discharge pipe 211 and the oxygen inlet / outlet pipe 213, and a drain regulating valve 215 is installed on the drain pipe 214; automatic control valves 217 are provided on both the pressurized nitrogen inlet pipe 212 and the oxygen inlet / outlet pipe 213, and the second nitrogen discharge pipe 211 is connected to the first nitrogen discharge pipe 43 through the main heat exchanger 2.

[0036] Through the arrangement of the drain pipe 214 in the present invention, the nitrogen generated by the heat exchange of liquid nitrogen and oxygen, or the oxygen generated by the heat exchange of liquid oxygen and nitrogen is directly discharged into the air, thereby preventing the heat-exchanged oxygen or nitrogen from re-entering the cryogenic equipment, accelerating the efficiency of the cryogenic equipment to generate liquid nitrogen and liquid oxygen, and avoiding the situation that the corresponding liquid storage tank of the cryogenic equipment is full and cannot store the newly generated liquid gas; through the arrangement of the drain regulating valve 215, it can be used to control the on / off of the drain pipe 214, so as to control the flow direction of the gas, that is, to control whether the gas is discharged or returned to the cryogenic air separation equipment. It should be particularly noted that the installation positions of the two drain pipes 214 are both between the automatic control valve 217 and the main heat exchanger 2 on the corresponding pipe body.

[0037] Refer to the attached Figure 1 As shown, in the present invention, the oxygen inlet / outlet pipe 213 is connected to the evaporator oxygen outlet pipe 33 through the main heat exchanger 2; an oxygen liquefaction inlet pipe 216 is further provided on the oxygen inlet / outlet pipe 213, and an oxygen control valve 218 is installed on the oxygen liquefaction inlet pipe 216. By connecting the oxygen inlet / outlet pipe 213 to the evaporator oxygen outlet pipe 33 in the present invention, the oxygen formed by the evaporation of liquid oxygen in the liquid oxygen evaporator 3 can be transported or discharged to the cryogenic air separation equipment; through the arrangement of the oxygen liquefaction inlet pipe 216, the oxygen liquefaction inlet pipe 216 is used to transport the purified oxygen in the cryogenic air separation equipment into the main heat exchanger 2; through the arrangement of the oxygen control valve 218, it is ensured that the oxygen in the oxygen liquefaction inlet pipe 216 flows in one direction; it should be particularly noted that the connection position of the oxygen liquefaction inlet pipe 216 and the oxygen inlet / outlet pipe 213 is between the automatic control valve 217 and the main heat exchanger 2.

[0038] Refer to the attached Figure 1 As shown, in the present invention, a liquid oxygen inlet pipe 31 communicating with the liquid oxygen storage tank in the cryogenic air separation equipment, an evaporator nitrogen inlet pipe 32 and an evaporator oxygen outlet pipe 33 connected to the main heat exchanger 2 are provided on the liquid oxygen evaporator 3, and an evaporator control valve 331 is installed on the evaporator oxygen outlet pipe 33; the evaporator oxygen outlet pipe 33 is connected to the oxygen inlet connection pipe 52, and the connection position is between the evaporator control valve 331 and the main heat exchanger 2, and a liquid oxygen control valve 311 is provided on the liquid oxygen inlet pipe 31.

[0039] Through the setting of the evaporator control valve 331, the present invention is used to control the connection between the liquid oxygen evaporator 3 and the main heat exchanger 2, and can control the oxygen to be liquefied entering through the oxygen inlet and outlet pipe 213.

[0040] Refer to the appendix Figure 1 As shown in the figure, in the present invention, the liquid nitrogen subcooler 4 is provided with a liquid nitrogen connection pipe 41 communicating with the liquid oxygen evaporator 3, a liquid nitrogen product pipe 42 communicating with the liquid nitrogen storage tank of the cryogenic air separation plant, and a first nitrogen discharge pipe 43 communicating with the main heat exchanger 2; wherein, a liquid nitrogen return pipe 421 is provided on the liquid nitrogen product pipe 42, and the other end of the liquid nitrogen return pipe 421 is connected to the first nitrogen discharge pipe 43 through the liquid nitrogen subcooler 4, and a temperature control valve 422 is installed on the liquid nitrogen return pipe 421.

[0041] Through the setting of the liquid nitrogen connection pipe 41, the present invention is used to transport the liquid nitrogen after heat exchange with liquid oxygen in the liquid oxygen evaporator 3 to the liquid nitrogen subcooler 4; through the setting of the liquid nitrogen product pipe 42, it is used to transport the liquid nitrogen product to the liquid nitrogen storage tank; through the setting of the liquid nitrogen return pipe 421, it is used to extract part of the liquid nitrogen and return it to the liquid nitrogen subcooler 4 as a cold source; through the setting of the first nitrogen discharge pipe 43, it is used to transport the nitrogen gas generated after gasification as a cold source in the liquid nitrogen subcooler 4 to the main heat exchanger 2; through the setting of the temperature control valve 422, it is used to control the temperature and flow rate of the returned liquid nitrogen.

[0042] Refer to the appendix Figure 1 As shown in the figure, in the present invention, a liquid nitrogen switch valve 423 is further installed on the liquid nitrogen product pipe 42, and the connection position of the liquid nitrogen return pipe 421 and the liquid nitrogen product pipe 42 is located between the liquid nitrogen switch valve 423 and the liquid nitrogen subcooler 4; wherein, a liquid nitrogen inlet pipe 424 is further connected to the liquid nitrogen product pipe 42, a second liquid nitrogen control valve 425 is installed on the liquid nitrogen inlet pipe 424, and the connection point of the liquid nitrogen inlet pipe 424 and the liquid nitrogen product pipe 42 is located at the outlet end of the liquid nitrogen switch valve 423; a first liquid nitrogen control valve 426 is further installed on the liquid nitrogen product pipe 42, the connection position of the cold source pipe 51 and the liquid nitrogen product pipe 42 is located between the installation position of the first liquid nitrogen control valve 426 and the installation position of the liquid nitrogen switch valve 423, and the outlet end of the liquid nitrogen switch valve 423 is connected to the inlet end of the first liquid nitrogen control valve 426.

[0043] In the present invention, through the setting of the liquid nitrogen switching valve 423, it is used to control the on-off of the liquid nitrogen product pipe 42; by defining the connection position between the liquid nitrogen return pipe 421 and the liquid nitrogen product pipe 42, the opening and closing of the liquid nitrogen switching valve 423 will not affect the return of the liquid nitrogen return pipe 421; through the setting of the liquid nitrogen inlet pipe 424, it is used for the entry of liquid nitrogen. In this application, the discharge and entry of liquid nitrogen are divided into two pipes, making the operation of the equipment more stable; through the setting of the second liquid nitrogen control valve 425, it prevents the liquid nitrogen product generated by liquefaction from being discharged from the liquid nitrogen inlet pipe 424; through the setting of the first liquid nitrogen control valve 426, it is used to control the liquid nitrogen flow rate of the liquid nitrogen product pipe 42.

[0044] Refer to the appendix Figure 1 As shown in the figure, in the present invention, on the liquid oxygen condenser 5, there is a cold source pipe 51 connected to the liquid nitrogen product pipe 42, an oxygen inlet connection pipe 52 connected to the oxygen outlet pipe 33 of the evaporator, and a liquid oxygen connection pipe 53 connected to the inlet end of the gas-liquid separation tank 6; a flow control valve 511 is installed on the cold source pipe 51; a liquid oxygen connection control valve 531 is installed on the liquid oxygen connection pipe 53.

[0045] In the present invention, through the setting of the cold source pipe 51, it is used to direct the liquid nitrogen, so that the liquid nitrogen is transported to the liquid oxygen condenser 5 as a cold source; through the setting of the oxygen inlet connection pipe 52, it is used to transport the oxygen that has passed through the main heat exchanger 2 to the liquid oxygen condenser 5 for re-heat exchange and liquefaction; through the setting of the flow control valve 511, it is used to control the flow rate of the liquid nitrogen; through the setting of the liquid oxygen connection control valve 531, it is used to control the on-off of the liquid oxygen connection pipe 53.

[0046] Refer to the appendix Figure 1 As shown in the figure, in the present invention, the gas-liquid separation tank 6 is used to separate liquid oxygen and oxygen. The outlet end of the gas-liquid separation tank 6 is provided with a liquid oxygen product pipe 61 and an oxygen vent pipe 62. The liquid oxygen product pipe 61 is connected to the liquid oxygen storage tank in the cryogenic air separation equipment; among them, an oxygen vent control valve 621 is installed on the oxygen vent pipe 62, and a liquid oxygen control valve 611 is installed on the liquid oxygen product pipe 61.

[0047] In the present invention, through the setting of the gas-liquid separation tank 6, it is used to separate gaseous oxygen and liquid oxygen, ensuring that the liquid oxygen enters the liquid oxygen storage tank and preventing gaseous oxygen from entering.

[0048] Refer to the appendix Figure 1 As shown in the figure, the working principle of the present invention is described as follows: When it is necessary to transfer the cold energy of liquid oxygen to nitrogen to form liquid nitrogen, the specific operation is as follows: The liquid oxygen with a temperature lower than 93.03 enters the liquid oxygen inlet pipe 31 at 2950 , and through the adjustment of the liquid oxygen control valve 311, the pressure parameter of the liquid oxygen entering the liquid oxygen evaporator 3 reaches 1.38 , since the liquid oxygen connection control valve 531 is closed, the oxygen formed by the evaporation of liquid oxygen in the liquid oxygen evaporator 3 enters the main heat exchanger 2 through the evaporator oxygen outlet pipe 33; at the same time, the purified pressurized nitrogen in the cryogenic air separation equipment enters through the pressurized nitrogen inlet pipe 212, and through the automatic control valve 217 on the pressurized nitrogen inlet pipe 212, the nitrogen enters the main heat exchanger 2 at 4000 and the pressure of this nitrogen is 6 . After passing through the main heat exchanger 2, the nitrogen is cooled to the saturated gas state, that is, the pressure of the nitrogen is 5.8 and the temperature is 96.04 , thus ensuring that there is a sufficient heat exchange temperature difference between nitrogen and liquid oxygen to ensure the normal operation of the liquid oxygen evaporator 3. In the liquid oxygen evaporator 3, the liquid oxygen evaporates to form saturated oxygen, and the pressurized and saturated nitrogen is heat-exchanged and cooled again, so that part of the nitrogen is liquefied to form liquid nitrogen. In order to reduce the pipeline flashing loss after the liquid nitrogen exits the cold box 1, the liquefied liquid nitrogen enters the liquid nitrogen subcooler 4 through the liquid nitrogen connection pipe 41. The valve of the flow control valve 511 is closed, and then part of the liquid nitrogen is drawn from the liquid nitrogen in the liquid nitrogen product pipe 42 into the liquid nitrogen return pipe 421. Through the temperature control valve 422 on the liquid nitrogen return pipe 421, the returned liquid nitrogen enters the liquid nitrogen subcooler 4 at a volume flow rate of 850 , a temperature of 80.7 and a pressure of 1.45 to subcool the liquid nitrogen; at the same time, the liquid nitrogen returning through the liquid nitrogen return pipe 421 passes through the liquid nitrogen subcooler 4 and then enters the main heat exchanger 2 through the first nitrogen discharge pipe 43 to adjust the heat exchange efficiency of the main heat exchanger 2. After passing through the main heat exchanger 2, this part of nitrogen enters the second nitrogen discharge pipe 211, and the staff can choose to transport the nitrogen into the cryogenic air separation equipment or evacuate it through the evacuation pipe 214 according to the demand. The subcooled liquid nitrogen flows into the liquid nitrogen storage tank through the liquid nitrogen product pipe 42; When it is necessary to transfer the cold energy of liquid nitrogen to oxygen to form liquid oxygen, the specific operation is as follows: The liquid nitrogen with a temperature lower than 89.5 in the storage tank enters the liquid nitrogen inlet pipe 424 at a volume flow rate of 2960 to bypass the closed first liquid nitrogen control valve 426, and the pressure of the liquid nitrogen reaches 3.4 through the second liquid nitrogen control valve 425 Enter the liquid nitrogen product pipe 42. Due to the closing of the liquid nitrogen switch valve 423, this part of the liquid nitrogen enters the liquid oxygen condenser 5 from the cold source pipe 51, and after passing through the liquid oxygen condenser 5, it enters the first nitrogen discharge pipe 43 through the opened flow control valve 511, and enters the main heat exchanger 2 through the first nitrogen discharge pipe 43; at the same time, the oxygen purified by the cryogenic equipment bypasses the automatic control valve 217 on the closed oxygen inlet and outlet pipe 213 through the oxygen liquefaction inlet pipe 216, and through the adjustment of the oxygen control valve 218, the oxygen enters the oxygen inlet and outlet pipe 213 with a pressure of 1.23 , a volume flow rate of 2950 under the parameter conditions, and then enters the main heat exchanger 2 for heat exchange, and is cooled to a saturated gas state with a pressure of 1.14 and a temperature of 91.1 K. The heat-exchanged oxygen enters the evaporator oxygen outlet pipe 33, and the evaporator control valve 331 is closed. This part of the oxygen can only enter the liquid oxygen condenser 5 through the oxygen inlet connection pipe 52 for liquefaction. The heat-exchanged gaseous oxygen and liquid oxygen enter the gas-liquid separation tank 6 through the liquid oxygen connection pipe 53. The liquid oxygen is transported into the liquid oxygen storage tank through the liquid oxygen product pipe 61, and the oxygen can be transported into the cryogenic air separation equipment or directly discharged.

[0049] The above embodiments are illustrative of the present application and not restrictive thereof. Any solution obtained by simply transforming the present application falls within the protection scope of the present application.

Claims

1. A cold mass migration device installed on a cryogenic air separation device, characterized in that: It comprises a cold box (1), a main heat exchanger (2), a liquid oxygen evaporator (3), a liquid nitrogen subcooler (4), a liquid oxygen condenser (5) and a gas-liquid separation tank (6) arranged in the cold box (1); The main heat exchanger (2) is used to perform heat exchange between nitrogen and oxygen, and the main heat exchanger (2) is connected to a nitrogen and oxygen inlet and outlet pipe group (21) connected to a cryogenic air separation device; The liquid oxygen evaporator (3) is provided with a liquid oxygen inlet pipe (31), an evaporator nitrogen inlet pipe (32) and an evaporator oxygen outlet pipe (33); the evaporator oxygen outlet pipe (33) and the evaporator nitrogen inlet pipe (32) are both connected to the main heat exchanger (2); and the liquid oxygen inlet pipe (31) is connected to a liquid oxygen storage tank in the cryogenic air separation device; The liquid nitrogen subcooler (4) is provided with a liquid nitrogen connecting pipe (41), a liquid nitrogen product pipe (42) and a first nitrogen gas discharge pipe (43); the liquid nitrogen connecting pipe (41) is connected to the liquid oxygen evaporator (3), and the liquid nitrogen product pipe (42) is connected to the liquid nitrogen storage tank; the first nitrogen gas discharge pipe (43) is connected to the main heat exchanger (2) to transport the heat-exchanged nitrogen to the main heat exchanger (2) for further heat exchange; The liquid oxygen condenser (5) is provided with a cold source pipe (51), an oxygen inlet connecting pipe (52) and a liquid oxygen connecting pipe (53); the oxygen inlet connecting pipe (52) is connected to the oxygen outlet pipe (33) of the evaporator; the cold source pipe (51) is connected to the liquid nitrogen product pipe (42); and the liquid oxygen connecting pipe (53) is connected to the inlet end of the gas-liquid separation tank (6); The gas-liquid separation tank (6) is used to separate liquid oxygen and oxygen. A liquid oxygen product pipe (61) and an oxygen vent pipe (62) are provided at the outlet end of the gas-liquid separation tank (6). The liquid oxygen product pipe (61) is connected to a liquid oxygen storage tank in a cryogenic air separation device. The main heat exchanger (2) has two cooling energy transfer modes, namely nitrogen cooling energy transfer and oxygen cooling energy transfer; When the main heat exchanger (2) is transferring the cold capacity of nitrogen, the pressurized nitrogen in the cryogenic air separation equipment is transported into the main heat exchanger (2) through the nitrogen oxygen inlet and outlet pipe group (21) to exchange heat with the oxygen transported from the liquid oxygen evaporator (3), and finally the liquid nitrogen generated by the liquid nitrogen subcooler (4) is transported into the liquid nitrogen storage tank through the liquid nitrogen product pipe (42); When the main heat exchanger (2) is performing oxygen cold capacity migration, the oxygen in the cryogenic air separation equipment is transported into the main heat exchanger (2) through the nitrogen oxygen inlet and outlet pipes (21) to exchange heat with the nitrogen transported from the liquid oxygen condenser (5), and finally the liquid oxygen is transported into the liquid oxygen storage tank through the liquid oxygen product pipe (61) through the gas-liquid separation tank (6).

2. The cold energy migration device according to claim 1, characterized in that: The nitrogen oxygen inlet and outlet pipe group (21) comprises a second nitrogen outlet pipe (211) connected to the cryogenic air separation equipment, a pressure nitrogen inlet pipe (212) and an oxygen inlet and outlet pipe (213); The second nitrogen discharge pipe (211) is used to transport the nitrogen in the main heat exchanger (2) to the cryogenic air separation equipment; The pressure nitrogen inlet pipe (212) is used to transport the pressure nitrogen in the cryogenic air separation equipment into the main heat exchanger (2); The flow direction of oxygen in the oxygen inlet and outlet pipe (213) is adjusted and changed according to the cold energy migration mode; When the main heat exchanger (2) performs nitrogen cooling capacity migration, the flow direction of oxygen in the oxygen inlet and outlet pipe (213) moves from the main heat exchanger (2) to the cryogenic air separation equipment; When the main heat exchanger (2) performs oxygen cold capacity migration, the flow direction of the oxygen in the oxygen inlet and outlet pipe (213) is from the cryogenic air separation equipment to the main heat exchanger (2).

3. The cold mass migration device according to claim 2, characterized in that: The second nitrogen discharge pipe (211) and the oxygen inlet and outlet pipe (213) are both provided with an exhaust pipe (214), and an exhaust regulating valve (215) is installed on the exhaust pipe (214); The pressure nitrogen inlet pipe (212) and the oxygen inlet and outlet pipe (213) are both provided with automatic control valves (217), and the second nitrogen outlet pipe (211) is connected to the first nitrogen outlet pipe (43) through the main heat exchanger (2).

4. The cold mass migration device according to claim 2, characterized in that: The oxygen inlet and outlet pipe (213) is connected to the evaporator oxygen outlet pipe (33) through the main heat exchanger (2).

5. The cold mass migration device according to claim 2, characterized in that: The oxygen inlet and outlet pipe (213) is also provided with an oxygen liquefaction inlet pipe (216), and oxygen entering through the oxygen liquefaction inlet pipe (216) is provided with an oxygen control valve (218).

6. The cold energy migration device according to claim 1, characterized in that: An evaporator control valve (331) is installed on the evaporator oxygen outlet pipe (33); The oxygen inlet connecting pipe (52) is connected to the evaporator oxygen outlet pipe (33), and the connection position is located between the evaporator control valve (331) and the main heat exchanger (2).

7. The cold energy migration device according to claim 1, characterized in that: A liquid nitrogen reflux pipe (421) is provided on the liquid nitrogen product pipe (42); the other end of the liquid nitrogen reflux pipe (421) is connected to the first nitrogen gas discharge pipe (43) via a liquid nitrogen subcooler (4); and a temperature control valve (422) is installed on the liquid nitrogen reflux pipe (421).

8. The cold energy migration device according to claim 6, characterized in that: A liquid nitrogen switch valve (423) is also installed on the liquid nitrogen product pipe (42), and the connection position between the liquid nitrogen reflux pipe (421) and the liquid nitrogen product pipe (42) is located between the liquid nitrogen switch valve (423) and the liquid nitrogen supercooler (4); The liquid nitrogen product pipe (42) is also connected to a liquid nitrogen inlet pipe (424), a second liquid nitrogen control valve (425) is installed on the liquid nitrogen inlet pipe (424), and the connection point between the liquid nitrogen inlet pipe (424) and the liquid nitrogen product pipe (42) is located at the outlet end of the liquid nitrogen switch valve (423); A first liquid nitrogen control valve (426) is also installed on the liquid nitrogen product pipe (42), and the connection position between the cold source pipe (51) and the liquid nitrogen product pipe (42) is located between the installation position of the first liquid nitrogen control valve (426) and the liquid nitrogen switch valve (423).

9. The cold energy migration device according to claim 1, characterized in that: A flow control valve (511) is installed on the cold source pipe (51); The liquid oxygen connecting pipe (53) is provided with a liquid oxygen connecting control valve (531).

10. The cold energy migration device according to claim 1, characterized in that: An oxygen venting control valve (621) is installed on the oxygen venting pipe (62); A liquid oxygen control valve (611) is installed on the liquid oxygen product pipe (61).

Images