A process for recovering and utilizing waste heat from an air separation unit

Abstract

The application discloses a waste heat recycling process of an air separation device, comprising two technical solutions: one is that in the heating regeneration stage of a molecular sieve adsorber, high-temperature condensed water discharged from a steam heater is directly introduced into a water-side cavity of a liquid argon water bath type gasifier, and the sensible heat of the high-temperature condensed water is used to heat liquid argon, thereby replacing the consumption of part of steam and normal-temperature water; the other is that when the steam heat exchange pipe of the liquid argon water bath type gasifier is continuously put into operation, the high-temperature condensed water discharged from the outlet of the steam heat exchange pipe is recycled and input into the water-side cavity of the liquid argon water bath type gasifier, so that the high-temperature condensed water and waste heat are recycled, and the consumption of part of steam and normal-temperature water is replaced; the two technical solutions can be implemented independently or simultaneously; the technical solution of the application has remarkable energy-saving effect on the waste heat recycling of a large-sized air separation device.

Description

Technical Field

[0001] This invention belongs to the field of deep refrigeration air separation, specifically relating to a waste heat recovery and utilization process and device for deep refrigeration air separation equipment. Background Technology

[0002] The deep-cooled air separation system (abbreviated as: air separation unit) utilizes the principle of low-temperature refrigeration distillation to compress the raw material air through an air compressor, cool and purify it through an air precooling system, adsorb it through a molecular sieve adsorber, refrigerate it through an expander, transfer heat through a heat exchanger, and separate it through a distillation column. Liquid nitrogen and nitrogen gas are produced in the lower column and the top of the upper column, oxygen and liquid oxygen are produced in the lower part of the upper column and the main refrigeration unit, and liquid argon is produced in the bottom of the argon refining column.

[0003] Molecular sieve adsorbers in air separation units remove impurities such as moisture, carbon dioxide, and hydrocarbons from the raw air, ensuring the safe operation of the air separation unit. The air separation unit is designed with two molecular sieve adsorbers: one for adsorption and one for regeneration. When the designed adsorption time has been reached in one of the molecular sieve adsorbers, a valve is opened to switch the adsorbers, alternating between adsorption and regeneration. If the adsorption capacity of a molecular sieve adsorber is low after reaching the designed adsorption time, a variable-temperature regeneration method is used to remove the adsorbed moisture, carbon dioxide, and hydrocarbons, restoring the adsorption capacity to the designed value.

[0004] The temperature-controlled regeneration process of the molecular sieve adsorber in an air separation unit includes four stages: depressurization, heating, cooling, and pressurization. The heating stage involves heating the ambient temperature regeneration waste nitrogen gas to high temperature regeneration waste nitrogen gas, which then desorbs the moisture, carbon dioxide, and hydrocarbons already adsorbed within the molecular sieve adsorber. Many molecular sieve adsorber regeneration systems incorporate steam heaters to heat the regeneration waste nitrogen gas. During the heating stage, the ambient temperature waste nitrogen gas is heated to high temperature by exchanging heat with high-temperature steam in the steam heater before entering the molecular sieve adsorber to desorb moisture, carbon dioxide, and hydrocarbons.

[0005] In molecular sieve adsorber regeneration systems, the steam heaters are often designed as shell-and-tube heat exchangers. During the heating stage of molecular sieve adsorber regeneration, ambient temperature regenerated nitrogen gas is input into the shell side of the steam heater, while high-temperature steam is input into the tube side. Heat exchange occurs through latent and sensible heat, causing the high-temperature steam to undergo a phase change and cool down to become high-temperature saturated condensate. The temperature of the regenerated nitrogen gas rises to the set value of 140–170°C. During the heating stage of molecular sieve adsorber regeneration, the inlet of the steam heater typically uses high-temperature steam at 0.4–1.0 MPa and 150–200°C. At the outlet of the steam heater, the high-temperature steam undergoes a phase change to become high-temperature saturated condensate with a temperature 5–15°C lower than the steam temperature.

[0006] Metallurgical production lines require continuous, long-cycle argon supply. Air separation units produce -186℃ liquid argon, which is compressed by a liquid argon pump, vaporized and reheated in a vaporizer to become room-temperature gaseous argon, and then supplied to the argon pipeline network for production line use. The vaporization and heating process of liquid argon consumes a significant amount of heat energy. Water bath vaporizers are commonly used for liquid argon vaporization. A water bath liquid argon vaporizer consists of a water-side chamber and two sets of heat exchange tubes installed within the water-side chamber. Room-temperature water is injected into the water-side chamber and between the heat exchange tubes as an intermediate heat transfer medium. One set of heat exchange tubes receives -186℃ liquid argon, while the other set receives high-temperature steam. In the water bath liquid argon vaporizer of the air separation unit, the high-temperature steam in one set of heat exchange tubes heats the room-temperature water, raising its temperature to 85-95℃ (hot water). Simultaneously, the high-temperature steam exchanges heat through latent and sensible heat, transforming into condensate, which is then released into the atmosphere. In another set of heat exchange tubes, cryogenic liquid argon exchanges heat with hot water through the tube wall, absorbs heat, vaporizes, reheats to room temperature, and is then transported to the argon gas pipeline network.

[0007] In existing technologies, the regeneration steam heater of the molecular sieve adsorber and the water bath liquid argon vaporizer of the liquid argon vaporization device are designed to operate in isolation, which presents the following problems:

[0008] Firstly, during the heating stage of molecular sieve adsorber regeneration, the regeneration steam heater operates. After the high-temperature steam heats the waste nitrogen, the resulting high-temperature condensate is directly discharged into the atmosphere, and the waste heat is not effectively recovered and utilized.

[0009] Secondly, with the liquid argon vaporization system in operation and the water bath liquid argon vaporizer running, the liquid argon vaporization process requires long-term continuous consumption of high-temperature steam. This high-temperature steam releases latent heat, and after sensible heat exchange, the resulting high-temperature condensate is directly discharged into the atmosphere. The waste heat from this high-temperature condensate is not effectively recovered and utilized. For example:

[0010] I. Maanshan Iron & Steel 35000m 3 The / h air separation unit is equipped with one steam heater for regenerating waste nitrogen. The design values ​​for the mass flow rate, pressure, and temperature of the high-temperature steam at the inlet of the steam heater are 4T / h, 0.65MPa, and 160℃, respectively. The design values ​​for the mass flow rate, pressure, and temperature of the high-temperature condensate discharged from the outlet of the steam heater are 4T / h, 0.6MPa, and 150℃, respectively.

[0011] 35000m 3 The design regeneration heating time for the molecular sieve adsorber in the air separation unit is 1 hour, with 8 heating cycles per day and a total regeneration heating time of 8 hours per day. Based on an annual calculation of 35,000 m³ / h... 3 The atmospheric discharge of high-temperature condensate at 4T / h, 0.6MPa, and 150℃ from the regenerated steam heater of the air separation unit is 4×8×30×12=11520 tons.

[0012] The heat wasted annually by high-temperature condensate discharge is equivalent to the following amount of standard coal:

[0013] 1 ton of saturated condensate at 0.6 MPa and 150℃ is approximately equivalent to 18.57 kgce (kilograms of standard coal).

[0014] If converted to tons of standard coal: 0.01857 tce / ton of water

[0015] 11520 × 0.01857 tce / ton of water = 213.93 tons of standard coal.

[0016] II. Maanshan Iron & Steel 35000m 3 The / h air separation unit is equipped with one liquid argon water bath vaporizer. The design values ​​for the mass flow rate, pressure, and temperature of the high-temperature steam at its inlet are 6T / h, 0.65MPa, and 160℃, respectively. The design values ​​for the mass flow rate, pressure, and temperature of the high-temperature condensate discharged from the outlet of the liquid argon water bath vaporizer are 6T / h, 0.6MPa, and 150℃, respectively.

[0017] Based on an annual calculation, the consumption of high-temperature condensate at 6T / h, 0.6MPa, and 150℃ for a liquid argon water bath vaporizer is 6×24×30×12=51840 tons.

[0018] The heat wasted annually by high-temperature condensate discharge is equivalent to the following amount of standard coal:

[0019] 51840 × 0.01857 tce / ton of water = 962.67 tons of standard coal. Summary of the Invention

[0020] (a) Technical problems to be solved

[0021] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a technical solution for the waste heat recovery and utilization process of air separation unit, so as to solve the problem that the waste heat of high-temperature condensate emitted by molecular sieve regeneration steam heater and liquid argon water bath vaporizer during their independent operation is not effectively recovered, resulting in energy waste.

[0022] (II) Technical Solution

[0023] To achieve the above objectives, the waste heat recovery and utilization process of the air separation unit of the present invention is implemented through the following two technical solutions:

[0024] Technical Solution 1: Waste heat recovery and utilization process of molecular sieve adsorber regeneration steam heater.

[0025] The process includes: a molecular sieve adsorber regeneration steam heater and a liquid argon water bath vaporizer; high-temperature steam from the steam pipeline enters the steam heater through a high-temperature steam inlet valve at the high-temperature steam inlet end, heating the ambient temperature regenerated waste nitrogen gas; the high-temperature condensate generated after the high-temperature steam heat exchange is discharged into the atmosphere through a high-temperature condensate discharge pipe at the outlet end via a manual discharge valve; the liquid argon water bath vaporizer is a rectangular open container, including a water-side cavity, an ambient temperature water inlet pipe and a manual inlet valve and a check valve installed on it; ambient temperature water enters the water-side cavity through the manual inlet valve and the check valve; the water-side cavity is equipped with a level gauge and also includes a manual drain valve for ambient temperature water in the water-side cavity. A steam heat exchanger tube and a liquid argon heat exchanger tube are connected in parallel in the water-side cavity. High-temperature steam from the steam network enters the steam heat exchanger tube through the steam inlet valve, heating the room-temperature water in the water-side cavity to a high-temperature water setpoint. The high-temperature condensate produced after steam heat exchange is discharged to the atmosphere through the high-temperature condensate discharge pipe and the manual discharge valve. Liquid argon output from the liquid argon pump enters the liquid argon heat exchanger tube through the liquid argon inlet valve. After heat exchange with the high-temperature water in the water-side cavity, the liquid argon is reheated into room-temperature argon gas and output into the argon network through the room-temperature argon gas delivery valve on the argon gas outlet side of the liquid argon heat exchanger tube. A room-temperature argon gas thermometer is installed on the argon gas outlet side of the liquid argon heat exchanger tube of the liquid argon water bath vaporizer to control the outlet argon gas temperature within the set value range.

[0026] Within the water-side cavity of the liquid argon water bath vaporizer, the high-temperature steam in the steam heat exchange tube transfers heat to the room-temperature water in the water-side cavity of the vaporizer through heat exchange, raising its temperature to and maintaining it within the temperature range of 85–95°C suitable for liquid argon vaporization. Simultaneously, the high-temperature water, heated to 85–95°C, serves as a heat source, exchanging heat with the -186°C cryogenic liquid argon in the liquid argon heat exchange tube through the tube wall. The cryogenic liquid argon absorbs the heat from the high-temperature water, causing the -186°C cryogenic liquid argon to vaporize, reheat to room temperature, and be input into the room-temperature argon gas pipeline.

[0027] Technical Solution 1 of the present invention: In the regeneration heating stage of the molecular sieve adsorber, the high-temperature condensate discharged from the steam heater is directly introduced into the water-side cavity of the liquid argon water bath vaporizer. In the water-side cavity of the liquid argon water bath vaporizer, the high-temperature condensate transfers heat to the room-temperature water in the water-side cavity of the vaporizer, and the room-temperature water is heated by the sensible heat of the high-temperature condensate, which replaces part of the consumption of high-temperature steam and room-temperature water.

[0028] A further technical solution of the present invention: A steam heater high-temperature condensate recovery pipeline is led out from the inlet end of the manual discharge valve on the high-temperature condensate discharge pipeline at the outlet end of the steam heater, and connected to the pipeline on the outlet side of the normal temperature water check valve on the water side inlet pipeline of the liquid argon water bath vaporizer. The high-temperature condensate is merged with the normal temperature water and enters the water side cavity of the liquid argon water bath vaporizer. A pressure transmitter, a steam heater high-temperature condensate pneumatic conveying valve, and a check valve are sequentially arranged on the high-temperature condensate recovery pipeline from the direction of high-temperature condensate input.

[0029] The diameter and pressure rating of the high-temperature condensate recovery pipeline are the same as those of the high-temperature condensate discharge pipeline. The high-temperature condensate recovery pipeline is designed to be made of stainless steel and is suitable for conveying high-temperature condensate at 0.4–1.0 MPa and 80–200°C.

[0030] A further technical solution of the present invention: the pneumatic conveying valve on the high-temperature condensate recovery pipeline is an air-opening diaphragm ball valve and is electrically connected to the operating station of the air separation unit's DCS control system; the one-way valve on the high-temperature condensate recovery pipeline is a lift-type check valve; the manual discharge valve for high-temperature condensate is replaced with a pneumatic discharge valve, which is an air-closed diaphragm Y-type shut-off valve; the manual water inlet valve for the water-side cavity is replaced with a pneumatic water inlet valve, and the manual drain valve for the ambient temperature water in the water-side cavity is replaced with a pneumatic drain valve; both the pneumatic water inlet valve and the pneumatic drain valve are pneumatic sleeve single-seat regulating valves; the pneumatic water inlet valve and pneumatic drain valve of the liquid argon water bath vaporizer and the high-temperature condensate discharge valve of the steam heater are all electrically connected to the operating station of the air separation unit's DCS control system; in the air separation unit's DCS control system, an automatic control logic for the waste heat recovery and utilization process of the molecular sieve adsorber regeneration steam heater is added.

[0031] The original design of the water-side chamber level gauge, argon-side outlet thermometer, and pneumatic steam inlet valve of the liquid argon water bath vaporizer remains unchanged, and they are still electrically connected to the DCS control system operating station of the air separation unit.

[0032] In the DCS control system of the air separation unit, a three-way control logic is designed for the automatic feeding, regulation, and shutdown of the waste heat recovery and utilization process of the molecular sieve adsorber regeneration steam heater.

[0033] First, the automatic delivery control logic.

[0034] During the heating stage of the molecular sieve adsorber, the steam heater is automatically put into operation, the high-temperature condensate pneumatic conveying valve on the high-temperature condensate recovery pipeline is automatically opened, and the high-temperature condensate pneumatic discharge valve is automatically closed, so that the high-temperature condensate is input into the water side cavity of the liquid argon water bath vaporizer.

[0035] Secondly, automatic adjustment control logic.

[0036] The liquid argon water bath vaporizer is designed to automatically adjust the ambient temperature water inlet valve and drain valve according to the liquid level gauge reading in the water-side cavity, thereby controlling the water level in the water-side cavity within the set range.

[0037] The temperature of the argon gas at the outlet of the liquid argon heat exchange tube in the liquid argon water bath vaporizer is automatically adjusted according to the displayed value of the ambient temperature argon gas. The opening of the pneumatic steam inlet valve is adjusted according to the set value of the ambient temperature argon gas at the outlet of the liquid argon heat exchange tube in the liquid argon water bath vaporizer, so as to control the ambient temperature argon gas at the outlet of the liquid argon heat exchange tube in the liquid argon water bath vaporizer within the set value range.

[0038] Finally, the automatic shutdown control logic.

[0039] When the steam heater automatically shuts down, the high-temperature condensate pneumatic delivery valve and the high-temperature condensate pneumatic discharge valve on the high-temperature condensate recovery pipeline are automatically closed, disconnecting the high-temperature condensate input to the liquid argon water bath vaporizer. At this time, the ambient temperature water inlet valve and the steam inlet valve of the water side cavity of the liquid argon water bath vaporizer are automatically adjusted to increase their opening degree, maintaining the liquid level in the water side cavity of the liquid argon water bath vaporizer and the ambient temperature of the argon gas at the argon outlet side within the design value range.

[0040] Technical Solution 2: Waste heat recovery and utilization process for liquid argon water bath vaporizer.

[0041] The second technical solution of this invention includes: a liquid argon water bath vaporizer, comprising a water-side cavity, wherein a steam heat exchange tube and a liquid argon heat exchange tube are connected in parallel within the water-side cavity, the water-side cavity is filled with room temperature water, which is introduced into the water-side cavity through a water inlet pipe via a manual room temperature water inlet valve and a room temperature water check valve; the water-side cavity is equipped with a level gauge, and water exceeding the maximum alarm level is discharged through a manual water drain valve; the high-temperature steam at the inlet end of the steam heat exchange tube comes from the steam network and passes through the steam inlet valve of the liquid argon water bath vaporizer. The steam heat exchanger tube exchanges heat with room temperature water in the water-side cavity. The resulting high-temperature condensate is discharged into the atmosphere through a high-temperature condensate discharge pipe and a manual high-temperature condensate discharge valve at the outlet end of the steam heat exchanger tube. The inlet end of the liquid argon heat exchanger tube is connected to a liquid argon pump through a liquid argon inlet valve. Liquid argon from the liquid argon pump enters the liquid argon heat exchanger tube for reheating and vaporization into argon gas at a set room temperature. This argon gas is then transported to the argon gas pipeline network through a room temperature argon gas delivery valve. A room temperature argon gas thermometer is installed on the argon gas outlet side of the liquid argon heat exchanger tube of the liquid argon water bath vaporizer to control the outlet argon gas temperature within the set range.

[0042] Technical Solution 2 of the present invention: When the steam heat exchange tube of the liquid argon water bath vaporizer is continuously in operation, the high-temperature condensate at the outlet of the steam heat exchange tube is recovered and input into the water-side cavity of the liquid argon water bath vaporizer. The sensible heat of the high-temperature condensate is used to heat the room-temperature water in the water-side cavity, replacing part of the consumption of steam and room-temperature water, realizing the recycling and utilization of waste heat inside the equipment, and further improving the waste heat utilization efficiency of the air separation unit.

[0043] A further technical solution of the second technical solution of the present invention: A high-temperature condensate recovery pipeline for the liquid argon water bath vaporizer is led out from the inlet end of the high-temperature condensate discharge valve on the high-temperature condensate discharge pipeline at the outlet end of the steam heat exchanger tube of the liquid argon water bath vaporizer, and connected to the outlet end of the normal temperature water inlet pipeline. The high-temperature condensate is then incorporated into the normal temperature water input into the water-side cavity of the liquid argon water bath vaporizer. The high-temperature condensate recovery pipeline for the liquid argon water bath vaporizer is sequentially equipped with a high-temperature condensate pneumatic conveying valve and a one-way valve at the outlet end of the steam heat exchanger tube from the direction of high-temperature condensate input.

[0044] The diameter and pressure rating of the high-temperature condensate recovery pipeline of the liquid argon water bath vaporizer are the same as those of the high-temperature condensate discharge pipeline of the liquid argon water bath vaporizer. The high-temperature condensate recovery pipeline is made of stainless steel and is suitable for conveying high-temperature condensate at 0.4-1.0 MPa and 80-200℃.

[0045] A further technical solution of the second technical solution of the present invention: the pneumatic conveying valve for high-temperature condensate at the outlet end of the steam heat exchanger of the liquid argon water bath vaporizer is an air-opening diaphragm ball valve, electrically connected to the operating station of the DCS control system of the air separation unit; the one-way valve for high-temperature condensate at the outlet end of the steam heat exchanger is a lift-type check valve; the manual water inlet valve of the water-side cavity is replaced with a pneumatic water inlet valve, and the ambient temperature water drain valve of the water-side cavity is replaced with a pneumatic drain valve; both the pneumatic water inlet valve and the pneumatic drain valve are pneumatic sleeve single-seat regulating valves. Both the water valve and the pneumatic drain valve are electrically connected to the operating station of the air separation unit's DCS control system. Simultaneously, the manual drain valve for high-temperature condensate at the outlet of the steam heat exchanger tube is replaced with a pneumatic drain valve, which is an airtight diaphragm ball valve, electrically connected to the operating station of the air separation unit's DCS control system. The valve diameter and flow rate of the pneumatic conveying valve and check valve for high-temperature condensate at the outlet of the steam heat exchanger tube are the same as those of the original manual drain valve for high-temperature condensate. All valves are made of stainless steel and are suitable for high-temperature condensate operation.

[0046] In the DCS control system of the air separation unit, an automatic control logic for the waste heat recovery and utilization process of the liquid argon water bath vaporizer is added; the original design of the water-side cavity level gauge, argon-side outlet thermometer, and pneumatic steam inlet valve of the liquid argon water bath vaporizer remains unchanged, and they are still electrically connected to the operating station of the DCS control system of the air separation unit.

[0047] In the DCS control system of the air separation unit, a three-way control logic is designed for the automatic feeding, adjustment, and shutdown of the waste heat recovery and utilization process of the liquid argon water bath vaporizer.

[0048] First, the automatic delivery control logic.

[0049] When the liquid argon water bath vaporizer is running, and the high-temperature steam inlet valve is opened, the pneumatic conveying valve on the high-temperature condensate recovery pipeline automatically opens, and the high-temperature condensate pneumatic discharge valve automatically closes.

[0050] Secondly, automatic adjustment control logic.

[0051] The liquid argon water bath vaporizer features automatic water level regulation. The pneumatic inlet valve and pneumatic drain valve automatically adjust based on the water level displayed by the level gauge in the water-side cavity, maintaining the water level within the designed range. When the water level in the water-side cavity rises to a high alarm value, the pneumatic inlet valve automatically closes fully and the pneumatic drain valve automatically opens, keeping the water level below the high alarm value. Conversely, when the water level drops to a low alarm value, the pneumatic inlet valve automatically opens and the pneumatic drain valve automatically closes fully, keeping the water level above the low alarm value.

[0052] Automatic temperature regulation of ambient argon gas at the outlet of the liquid argon heat exchange tube in the liquid argon water bath vaporizer: The opening of the steam inlet valve of the liquid argon water bath vaporizer is automatically adjusted according to the display value of the ambient argon gas thermometer at the outlet of the liquid argon heat exchange tube in the liquid argon water bath vaporizer, so as to keep the ambient argon gas temperature at the outlet of the liquid argon heat exchange tube in the liquid argon water bath vaporizer within the design value range.

[0053] Finally, the automatic shutdown control logic.

[0054] When the high-temperature steam inlet valve of the steam side of the steam heat exchanger tube of the liquid argon water bath vaporizer is closed, the pneumatic conveying valve on the high-temperature condensate recovery pipeline is automatically fully closed, and the pneumatic discharge valve of the high-temperature condensate of the steam heat exchanger tube is automatically opened.

[0055] Implementation results:

[0056] This invention recovers, either separately or simultaneously, the high-temperature condensate discharged from the regeneration steam heater of the molecular sieve adsorber and the high-temperature condensate discharged from the steam heat exchange tube of the liquid argon water bath vaporizer, and uses them to heat the room-temperature water in the water-side chamber of the liquid argon water bath vaporizer. It directly utilizes a large amount of high-temperature condensate that would otherwise be wasted and recovers its residual heat, replacing part of the high-temperature steam and room-temperature water. This reduces the amount of high-temperature steam and room-temperature water used, lowers the operating cost of the air separation unit, and has a particularly significant energy-saving effect on large-scale air separation units.

[0057] This invention features an adaptive operating mode, ensuring safety and reliability. The solution incorporates operating logic tailored to the process, automatically adapting to changes in operating conditions, guaranteeing a continuous and stable heat supply to the liquid argon water bath vaporizer, and without affecting the independent and safe operation of existing systems.

[0058] This invention requires minimal structural modifications and is easy to implement. It primarily connects existing equipment via pipelines and valves, eliminating the need for major alterations to core components. This simplifies implementation, reduces modification costs, and facilitates widespread application in existing systems.

[0059] In summary, this invention effectively solves the common industry problem of waste heat from high-temperature condensate in air separation units, achieving the green operation goals of energy saving, consumption reduction, and efficiency improvement.

[0060] The technical solution of this invention is not only applicable to liquid argon vaporization, but also to the recovery and utilization of waste heat in the water bath vaporization process of other cryogenic liquid products such as liquid nitrogen and liquid oxygen. Attached Figure Description

[0061] Figure 1 A schematic diagram of the regeneration steam heater process for a molecular sieve adsorber in an existing air separation unit.

[0062] Figure 2 A schematic diagram of the liquid argon water bath vaporizer process in an existing air separation unit.

[0063] Figure 3 A schematic diagram of the steam waste heat recovery and utilization process of the regeneration steam heater of the molecular sieve adsorber in the air separation unit of this invention.

[0064] Figure 4 A schematic diagram of the steam waste heat recovery and utilization process of the liquid argon water bath vaporizer in the air separation unit of this invention.

[0065] Figure 5 A schematic diagram of the steam waste heat recovery and utilization process of the molecular sieve adsorber regeneration steam heater and liquid argon water bath gasifier in the air separation unit of this invention.

[0066] Explanation of symbols in the attached diagram: 1. Molecular sieve adsorber regeneration steam heater (abbreviated as: steam heater); 10. High-temperature condensate discharge pipe of steam heater 1; 11a. Manual discharge valve for high-temperature condensate of steam heater 1; 12. High-temperature steam inlet valve of steam heater 1; 2. High-temperature condensate recovery pipe of steam heater 1; 23. High-temperature condensate pressure transmitter of steam heater 1; 21. High-temperature condensate delivery valve of steam heater 1; 22. One-way valve for high-temperature condensate of steam heater 1; 11b. Pneumatic discharge valve for high-temperature condensate of steam heater 1; 3. Liquid argon water bath vaporizer; 31. Liquid argon Heat exchange tube; 36, liquid argon heat exchange tube 31, liquid argon inlet valve; 38, liquid argon water bath vaporizer 3, ambient temperature argon delivery valve; 37, ambient temperature argon thermometer; 32, steam heat exchange tube; 50, steam heat exchange tube 32, steam inlet valve; 5, steam heat exchange tube 32, high temperature condensate discharge pipe at outlet end; 51a, steam heat exchange tube 32, high temperature condensate manual discharge valve at outlet end; 33, liquid argon water bath vaporizer 3, water side chamber; 34, water side chamber 33, high temperature water level gauge; 4, water side chamber 33, water inlet pipe; 41a. Manual inlet valve for ambient temperature water; 42. One-way valve for ambient temperature water; 43a. Manual drain valve for water-side cavity 33; 6. High-temperature condensate recovery pipeline for liquid argon water bath vaporizer 3; 62. One-way valve for high-temperature condensate at the outlet end of steam heat exchanger tube 32; 61. High-temperature condensate delivery valve at the outlet end of steam heat exchanger tube 32; 41b. Pneumatic inlet valve for ambient temperature water; 51b. Pneumatic discharge valve for high-temperature condensate at the outlet end of steam heat exchanger tube 32; 43b. Pneumatic drain valve for water-side cavity 33. Detailed Implementation

[0067] The following is in conjunction with the appendix of this invention. Figures 1-5 The technical solutions of the embodiments of the present invention will be clearly and completely described herein. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0068] Example 1, see Figure 1 , 3 35000m 3 The process of recovering and utilizing the waste heat of steam from the regenerated steam heater 1 of the molecular sieve adsorber in the / h air separation unit.

[0069] The existing equipment and process of Embodiment 1 of the present invention are as follows:

[0070] The high-temperature steam originates from the steam pipeline network of Maanshan Iron and Steel Group. A high-temperature steam inlet valve 12 is installed at the high-temperature steam inlet of steam heater 1. High-temperature condensate at the outlet is discharged to the atmosphere via a high-temperature condensate discharge pipe 10 and a manual discharge valve 11a. The manual discharge valve 11a is made of stainless steel and has a diameter of 40 mm. The design values ​​for the high-temperature steam mass flow rate, pressure, temperature, and pipe diameter at the inlet of steam heater 1 are 4 T / h, 0.65 MPa, 160℃, and 150 mm, respectively. The design values ​​for the high-temperature condensate mass flow rate, pressure, temperature, and pipe diameter at the outlet are 4 T / h, 0.6 MPa, 150℃, and 40 mm, respectively.

[0071] The liquid argon water bath vaporizer 3 is a rectangular open container, including a water-side cavity 33 and a room temperature water inlet pipe 4. Room temperature water enters the water-side cavity 33 through a room temperature water manual inlet valve 41a and a room temperature water one-way valve 42. A steam heat exchange pipe 32 and a liquid argon heat exchange pipe 31 are installed inside the water-side cavity 33. High-temperature steam from the Maanshan Iron and Steel steam network enters the steam heat exchange pipe 32 through a steam inlet valve 50. After heat exchange, the steam is discharged into the atmosphere through a high-temperature condensate discharge pipe 5 at the outlet of the steam heat exchange pipe 32 and a manual discharge valve 51a. Liquid argon output from the liquid argon pump enters the liquid argon heat exchange pipe 31 through a liquid argon inlet valve 36. After heat exchange, the liquid argon is reheated into room temperature argon gas and output through a room temperature argon gas delivery valve 38 into the Maanshan Iron and Steel argon gas network.

[0072] The design values ​​for the high-temperature steam mass flow rate, pressure, and temperature at the inlet end of the steam heat exchanger tube 32 of the liquid argon water bath vaporizer 3 are 6T / h, 0.65MPa, and 160℃, respectively. The design values ​​for the high-temperature condensate mass flow rate, pressure, and temperature at the outlet end of the steam heat exchanger tube 32 are 6T / h, 0.6MPa, and 150℃, respectively. The design value for the ambient temperature water mass flow rate of the water-side cavity 33 of the liquid argon water bath vaporizer 3 is 8T / h. The diameters of the ambient temperature water inlet pipe 4 and the ambient temperature water manual inlet valve 41a are both 80mm. The diameters of the original drainage pipe and the manual drainage valve 43a on the water-side cavity 33 are both 100mm. The diameters and materials of the original high-temperature condensate discharge pipe 5 and the manual discharge valve 51a at the outlet end of the steam heat exchanger tube 32 are 40mm and stainless steel, respectively. The original liquid level gauge 34 and the original ambient temperature argon thermometer 37 at the outlet end of the liquid argon heat exchange tube 31 of the liquid argon water bath vaporizer 3 are both at 35000m 3 Electrical connection of the DCS control system operator station for the / h air separation unit.

[0073] The technical solution of Embodiment 1 of the present invention is as follows:

[0074] In this embodiment of the invention, a high-temperature condensate recovery pipeline 2 is led out from the inlet end of the original manual discharge valve 11a on the high-temperature condensate discharge pipeline 10 at the outlet end of the steam heater 1, and connected to the pipeline on the outlet side of the normal temperature water check valve 42 on the water inlet pipeline 4 of the water side cavity 33 of the liquid argon water bath vaporizer 3. The high-temperature condensate is combined with the normal temperature water and enters the water side cavity 33 of the liquid argon water bath vaporizer 3. A pressure transmitter 23, a pneumatic delivery valve 21 and a check valve 22 are sequentially installed on the high-temperature condensate recovery pipeline 2 from the direction of high-temperature condensate input. At the same time, the manual discharge valve 11a at the steam outlet end of the high-temperature condensate is replaced with a pneumatic discharge valve 11b.

[0075] During the regeneration and heating stage of the molecular sieve adsorber, steam heater 1 is put into operation. The high-temperature condensate discharged from steam heater 1 is fed into the water-side cavity 33 of liquid argon water bath vaporizer 3 through high-temperature condensate recovery pipe 2. In the water-side cavity 33 of liquid argon water bath vaporizer 3, the high-temperature condensate heats up the room temperature water in the water-side cavity 33 through heat exchange. The insufficient heat is supplemented by steam in the steam heat exchange tube 32 of liquid argon water bath vaporizer, so that the room temperature water in the water-side cavity 33 is heated up and maintained at the design value of 90℃. The 90℃ high-temperature water heats the -186℃ low-temperature liquid argon in the liquid argon heat exchange tube 31, so that the -186℃ liquid argon is vaporized and reheated to the room temperature design value of 20℃, and then fed into the Maanshan Iron and Steel argon pipeline network. Since the design diameter of the high-temperature condensate discharge pipe 10 at the outlet of the steam heater 1 is 40mm, and the design diameter of the inlet pipe 4 of the water side cavity 33 of the liquid argon water bath vaporizer 3 is 80mm, the high-temperature condensate with a design capacity of 4T / h at the outlet of the steam heater 1 can be completely incorporated into the ambient temperature water inlet pipe 4. Therefore, the high-temperature condensate discharged from the steam heater 1 can be fully recycled and participate in the ambient temperature water heat exchange.

[0076] Since the residual heat from the high-temperature condensate recovered from steam heater 1 is insufficient to cover all the heat energy required to reheat liquid argon to room temperature, the amount of steam to be supplemented is estimated through the following calculations:

[0077] Steam releases latent heat upon condensation at 0.65 MPa and 160 °C, with a latent heat value of 2075 kJ / kg. When condensate is cooled from 150 °C to 20 °C (ambient temperature), the specific heat capacity of the condensate is cp = 4.2 kJ / (kg·°C).

[0078] The heat generated by 6T / h, 0.65MPa, 160℃ high-temperature steam is the total heat required to heat liquid argon.

[0079] Calculate the heat release per unit mass of steam: q1 = 2075 kJ / kg.

[0080] Calculate the heat released per unit mass of condensate: q2 = 4.2 × ΔT = 4.2 × (150 - 20) = 546 kJ / kg.

[0081] Calculate the total heat required to completely heat liquid argon:

[0082] Q1=6T / h×2075kJ / kg=6000kg / h×2075kJ / kg=12,450,000kJ / h.

[0083] Calculate the heat provided by 4 T / h of condensate:

[0084] Q2=4T / h×546kJ / kg=4000kg / h×546kJ / kg=2,184,000kJ / h.

[0085] Calculate the insufficient heat: ΔQ = Q1 - Q2 = 12,450,000 - 2,184,000 kJ / h = 10,266,000 kJ / h.

[0086] Calculate the required steam mass flow rate: m = ΔQ / q1 = 10,266,000 / 2075 kg / h ≈ 4947 kg / h = 4.95 T / h.

[0087] Therefore, in the liquid argon water bath vaporizer 3, while recovering and utilizing all the waste heat of the high-temperature condensate at 4T / h, 0.6MPa, and 150℃ at the outlet of the steam heater 1, the mass flow rate of the supplemented high-temperature steam at 0.65MPa and 160℃ is 4.95T / h, which is less than the 6T / h steam consumption of the prior art, thus significantly reducing the steam consumption.

[0088] In the above embodiment, the diameter, pressure rating, and material of the high-temperature condensate recovery pipeline 2 are 40mm, 2.5MPa, and 304 stainless steel, respectively; the pressure transmitter 23, pneumatic delivery valve 21, and check valve 22 sequentially installed on the high-temperature condensate recovery pipeline 2 are all connected to the 35000m... 3 The DCS control system operator station of the / h air separation unit is electrically connected; the pressure transmitter 23 is a diaphragm-sealed pressure transmitter with a pressure setpoint of 0.8MPa; the pneumatic delivery valve 21 is a 40mm diameter, 316 stainless steel air-opening diaphragm pneumatic ball valve; the one-way valve 22 is a 40mm diameter, 316 stainless steel lift check valve.

[0089] The original manual high-temperature condensate drain valve 11a on the steam heater 1 is replaced with a pneumatic drain valve 11b. The pneumatic drain valve 11b is a pneumatically closed diaphragm Y-type shut-off valve with a valve diameter of 40mm and made of 316 stainless steel. The original manual inlet valve 41a of the water-side cavity 33 of the liquid argon water bath vaporizer 3 is replaced with a pneumatic inlet valve 41b, and the original manual drain valve 43a is replaced with a pneumatic drain valve 43b. Both the pneumatic inlet valve 41b and the pneumatic drain valve 43b are pneumatic single-seat regulating valves with valve diameters of 80mm and 100mm respectively, made of 304 stainless steel. The inlet valve 41b and drain valve 43b of the liquid argon water bath vaporizer 3, and the high-temperature condensate drain valve 11b of the steam heater 1 are all compatible with 35000m. 3 Electrical connection of the DCS control system operator station for the / h air separation unit.

[0090] The liquid argon water bath vaporizer 3 retains its original configuration, including the level gauge 34, thermometer 37, and high-temperature steam inlet valve 50, all of which are consistent with the 35000m... 3 / h air separation unit DCS control system operator station electrical connection; set the low alarm value, set value, and high alarm value of the liquid level gauge 34 to 1500mm, 2500mm, and 3000mm respectively, and set the low alarm value, set value, and high alarm value of the temperature gauge 37 to 10℃, 20℃, and 30℃ respectively.

[0091] Example 35000m of the present invention 3 The automatic operation steps of the steam recovery and utilization unit of the / h air separation unit regenerated steam heater 1 are as follows:

[0092] 1. First, automatic operation is initiated. When the steam heater 1 is put into operation, the pneumatic conveying valve 21 on the high-temperature condensate recovery pipeline automatically opens, and the pneumatic discharge valve 11b of the high-temperature condensate at the steam outlet automatically closes. The high-temperature condensate is then incorporated into the ambient temperature water in the inlet pipeline 4 of the liquid argon water bath vaporizer 3 and injected into the water-side cavity 33 of the liquid argon water bath vaporizer 3.

[0093] 2. Secondly, automatic adjustment. The ambient temperature water pneumatic inlet valve 41b of the liquid argon water bath vaporizer 3 automatically adjusts the valve opening to control the water level displayed by the level gauge 34 in the water side cavity 33 of the liquid argon water bath vaporizer 3 to be within the set value range of 2500mm; when the liquid level value of the level gauge 34 drops to the low alarm value of 1500mm, the pneumatic drain valve 43b automatically closes to maintain the water level in the water side cavity 33; when the liquid level value of the level gauge 34 rises to the high alarm value of 3000mm, the ambient temperature water pneumatic inlet valve 41b automatically closes completely and the pneumatic drain valve 43b automatically opens to maintain the water level in the water side cavity 33 below the low alarm value of 3000mm. The steam inlet valve 50 automatically adjusts the valve opening to control the argon outlet side ambient temperature argon thermometer 37 of the liquid argon water bath vaporizer 3 to be within the 20℃ set value range. When the temperature displayed by the ambient temperature argon thermometer 37 on the argon outlet side is higher than 30℃, the opening of the steam inlet valve 50 decreases. When the displayed temperature is lower than 10℃, the opening of the steam inlet valve 50 increases.

[0094] 3. Finally, stop operation. When steam heater 1 stops operating, the pneumatic delivery valve 21 on the high-temperature condensate recovery pipeline 2 automatically closes, and the high-temperature condensate pneumatic discharge valve 11b automatically opens. Simultaneously, the ambient temperature water pneumatic inlet valve 41b and steam inlet valve 50 automatically adjust their openings to maintain the water level in the water-side chamber 33 of the liquid argon water bath vaporizer 3 within the design range of 2500 mm, and the ambient temperature argon at the argon outlet side within the design range of 20℃.

[0095] Example 2, see Figure 2 , 4 35000m 3 Waste heat recovery and utilization process of steam from liquid argon water bath vaporizer 3 in / h air separation unit.

[0096] The existing equipment and process for Embodiment 2 of the present invention are as follows:

[0097] The liquid argon water bath vaporizer 3 includes a water-side cavity 33, which contains a parallel steam heat exchange tube 32 and a liquid argon heat exchange tube 31. The water-side cavity 33 is filled with room temperature water, which is introduced into the water-side cavity 33 through the water inlet pipe 4 via the room temperature water manual inlet valve 41a and the room temperature water one-way valve 42. Water exceeding the maximum water level alarm value is discharged through the water-side cavity 33 manual drain valve 43a. The high-temperature steam at the inlet end of the steam heat exchange tube 32 comes from the steam network of Maanshan Iron and Steel Group and is introduced into the steam heat exchange tube 32 through the steam inlet valve 50 of the liquid argon water bath vaporizer 3. The high-temperature saturated cold water generated after heat exchange with the room temperature water in the water-side cavity 33 is cooled. Condensate is discharged into the atmosphere at the outlet of steam heat exchanger tube 32 via high-temperature condensate discharge pipe 5 and high-temperature condensate manual discharge valve 51a. The inlet of liquid argon heat exchanger tube 31 is connected to a liquid argon pump via liquid argon inlet valve 36. Liquid argon from the pump enters the liquid argon heat exchanger tube 31 for reheating and vaporization. High-temperature steam in steam heat exchanger tube 32 exchanges heat with room-temperature water in water-side chamber 33, maintaining the water temperature at the design value of 90℃. The -186℃ low-temperature liquid argon in liquid argon heat exchanger tube 31 is heated by the 90℃ high-temperature water, causing the liquid argon to vaporize and reheat to the room-temperature set value. This vaporized liquid argon is then transported to the Maanshan Iron & Steel argon pipeline network via room-temperature argon delivery valve 38. The design value for the room-temperature water mass flow rate of the liquid argon water bath vaporizer 3 is 8T / h, and the diameter of the delivery pipe 4 is 80mm.

[0098] The technical solution of Embodiment 2 of the present invention is as follows:

[0099] A high-temperature condensate recovery pipeline 6, connected to the inlet of the manual discharge valve 51a on the high-temperature condensate discharge pipeline 5 at the outlet of the steam heat exchanger tube 32, leads to the outlet of the ambient temperature water inlet pipeline 4. The high-temperature condensate is then incorporated into the ambient temperature water input into the water-side cavity 33 of the liquid argon water bath vaporizer 3. A high-temperature condensate pneumatic delivery valve 61 and a one-way valve 62 are sequentially installed on the high-temperature condensate recovery pipeline 6 from the direction of high-temperature condensate input. The high-temperature condensate pneumatic delivery valve 61 is a 40mm diameter, air-operated diaphragm ball valve made of 316 stainless steel, and is compatible with 35000m... 3 The air separation unit's DCS control system operator station is electrically connected; the one-way valve 62 is a 40mm diameter, lift-type check valve made of 316 stainless steel; the original high-temperature condensate manual drain valve 51a is replaced with a pneumatic drain valve 51b, which is a 40mm diameter, airtight diaphragm ball valve, and is connected to the 35000m... 3 / h air separation unit DCS control system operator station electrical connection; replace the original manual water inlet valve 41a of the water side cavity 33 of the liquid argon water bath vaporizer 3 with a pneumatic water inlet valve 41b, and replace the original manual drain valve 43a with a pneumatic drain valve 43b. Both the pneumatic water inlet valve 41b and the pneumatic drain valve 43b are pneumatic sleeve single-seat regulating valves with valve diameters of 80mm and 100mm respectively, made of 304 stainless steel; the liquid argon water bath vaporizer 3 water inlet valve 41b and drain valve 43b are both connected to the 35000m 3 Electrical connection of the DCS control system operator station for the / h air separation unit.

[0100] The original settings of the liquid argon water bath vaporizer 3 (water side chamber 33), liquid level gauge 34, liquid argon heat exchange tube 31 (outlet argon thermometer 37), and pneumatic steam inlet valve 50 remain unchanged, and are still consistent with the 35000m 3 Electrical connection of the DCS control system operator station for the / h air separation unit.

[0101] When the liquid argon water bath vaporizer 3 is running, the high-temperature condensate from the outlet of the steam heat exchange tube 32 is fed into the water-side cavity 33 of the liquid argon water bath vaporizer 3 through the high-temperature condensate recovery pipe 6. The high-temperature condensate exchanges heat with the room-temperature water in the water-side cavity 33 of the liquid argon water bath vaporizer 3, and the temperature of the room-temperature water in the water-side cavity 33 increases, reducing the amount of steam required for heating and recovering all the high-temperature condensate and waste heat discharged by itself.

[0102] When the steam heat exchange tube 32 of the liquid argon water bath vaporizer 3 is running alone, since the design value of the mass flow rate of the liquid argon water bath vaporizer 3 is 6T / h and the design value of the diameter of the condensate recovery pipe 6 is 40mm, the 6T / h high-temperature condensate of the liquid argon water bath vaporizer 3 can be fully input into the 80mm diameter room temperature water inlet pipe 4 of the water side cavity 33 of the liquid argon water bath vaporizer 3 and injected into the water side cavity 33.

[0103] The embodiments of the present invention are at 35000m 3 In the DCS control system of the / h air separation unit, a three-way control logic is designed to automatically supply, regulate, and shut down the high-temperature condensate recovery device emitted by the liquid argon water bath vaporizer 3.

[0104] The design specifies that the low alarm value, set value, and high alarm value of the liquid level in the water-side cavity 33 and the liquid level gauge 34 are 1500mm, 2500mm, and 3000mm, respectively. The design specifies that the low alarm value, set value, and high alarm value of the argon gas temperature at the outlet end of the liquid argon heat exchange tube 37 are 10℃, 20℃, and 30℃, respectively.

[0105] (1) Design the high temperature steam inlet valve 50 of the liquid argon water bath vaporizer 3 as the condition for opening the high temperature condensate delivery valve 61 and closing the high temperature condensate discharge valve 51b.

[0106] When the steam heat exchange tube 32 of the liquid argon water bath vaporizer 3 is put into operation, the high-temperature steam inlet valve 50 and the high-temperature condensate delivery valve 61 open automatically in sequence, and the high-temperature condensate discharge valve 51b closes automatically, and the high-temperature condensate enters the water side cavity 33 of the liquid argon water bath vaporizer 3.

[0107] (2) Automatic water level adjustment of the water side chamber 33 of the liquid argon water bath vaporizer 3: The water inlet valve 41b of the liquid argon water bath vaporizer 3 is designed to automatically adjust the valve opening according to the liquid level setting value of 2500mm on the liquid level gauge 34, so as to keep the water level of the water side chamber 33 within the 2500mm setting value range. When the liquid level value of the liquid level gauge 34 drops to the low alarm value of 1500mm, the drain valve 43b is designed to automatically close, so as to keep the water level of the water side chamber 33 above the low alarm value of 1500mm; when the liquid level value of the liquid level gauge 34 rises to the high alarm value of 3000mm, the water inlet valve 41b is designed to automatically close completely and the drain valve 43b is designed to automatically open, so as to keep the water level of the water side chamber 33 below the low alarm value of 3000mm.

[0108] Automatic temperature regulation of ambient argon gas at the argon outlet side of the liquid argon water bath vaporizer 3: The steam inlet valve 50 is designed to automatically adjust the valve opening according to the argon thermometer 37 setting value of 20℃, so as to keep the ambient argon gas temperature at the argon outlet side of the liquid argon water bath vaporizer 3 within the set value range of 20℃.

[0109] (3) Design the high temperature steam inlet valve 50 of the liquid argon water bath vaporizer 3 as the closing condition of the high temperature condensate delivery valve 61.

[0110] 35000m 3 The automatic operation method of the steam recovery and utilization device of the liquid argon water bath vaporizer 3 in the / h air separation unit is as follows:

[0111] 1. First, it is automatically put into operation. When the steam heat exchange tube 32 of the liquid argon water bath vaporizer 3 is put into operation, the high temperature steam inlet valve 50 and the high temperature condensate delivery valve 61 are automatically opened in sequence, and the high temperature condensate discharge valve 51b is automatically closed. The high temperature condensate is input into the water side cavity 33 of the liquid argon water bath vaporizer 3.

[0112] 2. Secondly, automatic adjustment: the water inlet valve 41b automatically adjusts the valve opening to keep the water level in the water side chamber 33 of the liquid argon water bath vaporizer 3 within the set value range of 2500MM; the steam inlet valve 50 automatically adjusts the valve opening to control the ambient temperature argon gas temperature on the argon outlet side of the liquid argon water bath vaporizer 3 within the set value range of 20℃.

[0113] 3. Finally, the system will automatically shut down. When the liquid argon water bath vaporizer 3 steam heat exchange tube 32 stops operating, the high-temperature steam inlet valve 50 and the high-temperature condensate delivery valve 61 will automatically close, and the high-temperature condensate pneumatic discharge valve 51b will automatically open.

[0114] Embodiments one and two of the present invention can be implemented separately, such as... Figure 3 , Figure 4 As shown; it can also be implemented jointly as follows: Figure 5 As shown, when both the steam heater 1 and the liquid argon water bath vaporizer 3 are in operation, since the diameters of the high-temperature condensate recovery pipe 2 of the steam heater 1 and the high-temperature condensate recovery pipe 6 of the liquid argon water bath vaporizer 3 are both 40mm, the 4T / h high-temperature condensate discharged from the steam heater 1 and the 6T / h high-temperature condensate discharged from the liquid argon water bath vaporizer 3 can be simultaneously injected into the water-side cavity 33 of the liquid argon water bath vaporizer 3 through the 80mm diameter room temperature water inlet pipe 4, thus recovering the high-temperature condensate and residual heat discharged from the steam heater 1 and the liquid argon water bath vaporizer 3. This embodiment of the invention is also applicable to the waste heat recovery of liquid oxygen and liquid nitrogen vaporization devices, especially suitable for large air distribution units, with a larger waste heat recovery capacity and more significant energy-saving effect.

Claims

1. A waste heat recovery and utilization process for an air separation unit, the process comprising: Steam heater (1) and liquid argon water bath vaporizer (3); high-temperature steam from the steam network enters the steam heater (1) through the high-temperature steam inlet valve (12) set at the high-temperature steam inlet end of the steam heater (1), heating the ambient temperature regenerated waste nitrogen gas, and the high-temperature condensate generated after the high-temperature steam heat exchange is discharged to the atmosphere through the high-temperature condensate discharge pipe (10) at the outlet end and the manual discharge valve (11a); the liquid argon water bath vaporizer (3) is a rectangular open container, including a water-side cavity (33), an ambient temperature water inlet pipe (4) and The manual water inlet valve (41a) and check valve (42) are installed on it. Room temperature water enters the water-side cavity (33) through the manual water inlet valve (41a) and check valve (42). The water-side cavity (33) is equipped with a level gauge (34) and also includes a manual drain valve (43a) for room temperature water in the water-side cavity (33). A steam heat exchange tube (32) and a liquid argon heat exchange tube (31) are connected in parallel in the water-side cavity (33). High temperature steam from the steam pipeline enters the steam heat exchange tube (31) through the steam inlet valve (50). 2) The room temperature water in the water-side cavity (33) is heated to the high temperature water set value. The high temperature condensate generated after steam heat exchange is discharged to the atmosphere through the high temperature condensate discharge pipe (5) at the outlet end of the steam heat exchange pipe (32) via the manual discharge valve (51a). The liquid argon output by the liquid argon pump is input into the liquid argon heat exchange pipe (31) through the liquid argon inlet valve (36). After heat exchange with the high temperature water in the water-side cavity (33), the liquid argon is reheated into room temperature argon gas and then passes through the room temperature argon gas delivery valve (38) at the outlet side of the liquid argon heat exchange pipe (31). The output enters the argon gas pipeline network. A room temperature argon gas thermometer (37) is installed in front of the room temperature argon gas delivery valve (38) at the outlet end of the liquid argon heat exchange tube (31) to control the outlet argon gas temperature within the set value range. Its feature is that: during the regeneration heating stage of the molecular sieve adsorber, the high temperature condensate discharged by the steam heater (1) is directly introduced into the water side cavity (33) of the liquid argon water bath vaporizer (3), and the residual heat of the high temperature condensate is used to heat the room temperature water in the water side cavity (33), replacing part of the consumption of high temperature steam and room temperature water.

2. The waste heat recovery and utilization process of an air separation unit according to claim 1, characterized in that: A high-temperature condensate recovery pipeline (2) is led out from the inlet end of the manual discharge valve (11a) on the high-temperature condensate discharge pipeline (10) at the outlet end of the steam heater (1), and connected to the pipeline on the outlet side of the normal temperature water check valve (42) on the water inlet pipeline (4) of the liquid argon water bath vaporizer (3). The high-temperature condensate is merged with the normal temperature water and enters the water side cavity (33) of the liquid argon water bath vaporizer (3). A pressure transmitter (23), a pneumatic delivery valve (21) and a check valve (22) are sequentially installed on the high-temperature condensate recovery pipeline (2) from the direction of high-temperature condensate input.

3. The waste heat recovery and utilization process of an air separation unit according to claim 2, characterized in that: The pneumatic delivery valve (21) is an air-opening diaphragm ball valve, and the one-way valve (22) is a lift-type check valve; the pneumatic delivery valve (21) is electrically connected to the operating station of the air separation unit DCS control system; the high-temperature condensate manual drain valve (11a) is replaced with a pneumatic drain valve (11b), and the pneumatic drain valve (11b) is an air-closed diaphragm Y-type shut-off valve; the manual water inlet valve (41a) of the water-side cavity (33) is replaced with a pneumatic water inlet valve (41b), and the normal temperature water inlet valve of the water-side cavity (33) is replaced. The pneumatic drain valve (43a) is a pneumatic drain valve (43b). The pneumatic water inlet valve (41b) and the pneumatic drain valve (43b) are both pneumatic sleeve single-seat regulating valves. The pneumatic water inlet valve (41b), the pneumatic drain valve (43b) of the liquid argon water bath vaporizer (3) and the high temperature condensate discharge valve (11b) of the steam heater (1) are all electrically connected to the operating station of the DCS control system of the air separation unit. In the DCS control system of the air separation unit, an automatic control logic for the waste heat recovery and utilization process of the steam heater (1) is added.

4. A waste heat recovery and utilization process for an air separation unit, the process comprising: The liquid argon water bath vaporizer (3) includes a water-side cavity (33), which has a built-in steam heat exchange tube (32) and a liquid argon heat exchange tube (31) connected in parallel. The water-side cavity (33) is filled with room temperature water, which is introduced into the water-side cavity (33) through the water inlet pipe (4) via the room temperature water manual inlet valve (41a) and the room temperature water one-way valve (42). The water-side cavity (33) is equipped with a level gauge. 34), water exceeding the highest alarm level is discharged through the manual drain valve (43a) of the water-side cavity (33); the high-temperature steam at the inlet end of the steam heat exchanger (32) comes from the steam network, enters the steam heat exchanger (32) through the steam inlet valve (50) of the liquid argon water bath vaporizer (3), and after exchanging heat with the room temperature water in the water-side cavity (33), the generated high-temperature condensate flows through the high-temperature condensate discharge pipe (5) at the outlet end of the steam heat exchanger (32). The liquid argon heat exchanger tube (31) is connected to the liquid argon pump through the liquid argon inlet valve (36). The liquid argon from the liquid argon pump enters the liquid argon heat exchanger tube (31) for reheating and vaporization into argon gas at the set room temperature. The argon gas is then transported to the argon gas pipeline through the room temperature argon gas delivery valve (38) on the outlet side of the liquid argon heat exchanger tube (31). A room temperature argon gas thermometer (37) is installed in front of the room temperature argon gas delivery valve (38) to control the outlet argon gas temperature within the set range. The feature is that when the steam heat exchanger tube (32) of the liquid argon water bath vaporizer (3) is continuously in operation, the high temperature condensate at the outlet of the steam heat exchanger tube (32) is recovered and input into the water side cavity (33) of the liquid argon water bath vaporizer. The waste heat of the high temperature condensate is used to heat the room temperature water in the water side cavity (33), thereby realizing the recovery of its own high temperature condensate and waste heat, and replacing part of the consumption of steam and room temperature water.

5. The waste heat recovery and utilization process of an air separation unit according to claim 4, characterized in that: A liquid argon water bath vaporizer (3) high-temperature condensate recovery pipeline (6) is led out from the inlet end of the manual discharge valve (51a) on the high-temperature condensate discharge pipeline (5) at the outlet end of the steam heat exchanger (32) and connected to the outlet end of the normal temperature water inlet pipeline (4). The high-temperature condensate is then incorporated into the water side cavity (33) of the normal temperature water inlet liquid argon water bath vaporizer (3). A high-temperature condensate pneumatic delivery valve (61) and a one-way valve (62) are installed sequentially on the high-temperature condensate recovery pipeline (6) from the direction of high-temperature condensate input.

6. The waste heat recovery and utilization process of an air separation unit according to claim 5, characterized in that: The high-temperature condensate recovery pipeline (6) has a pneumatic conveying valve (61) that is an air-opening diaphragm ball valve, which is electrically connected to the DCS control system operating station of the air separation unit; the high-temperature condensate recovery pipeline (6) has a lift-type check valve (62); the manual inlet valve (41a) of the water-side cavity (33) is replaced with a pneumatic inlet valve (41b), and the manual drain valve (43a) of the room temperature water in the water-side cavity (33) is replaced with a pneumatic drain valve (43b). The pneumatic inlet valve (41b) and the pneumatic... All drain valves (43b) are pneumatic sleeve single-seat regulating valves. The pneumatic water inlet valve (41b) and pneumatic drain valve (43b) are electrically connected to the operating station of the air separation unit DCS control system. At the same time, the manual discharge valve (51a) of high-temperature condensate is replaced with a pneumatic discharge valve (51b). The pneumatic discharge valve (51b) is a gas-closed diaphragm ball valve and is electrically connected to the operating station of the air separation unit DCS control system. In the air separation unit DCS control system, an automatic control logic for the waste heat recovery and utilization process of the liquid argon water bath vaporizer (3) is added.

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