Normal-pressure liquid oxygen vaporization recovery system and recovery process

By designing a normal pressure liquid oxygen vaporization recovery system, reheating and compressing the non-condensed gas in the liquid oxygen storage tank, the oxygen enrichment and energy waste caused by the emission of non-condensed gas in the liquid oxygen storage tank is solved, and the effective utilization of resources and the reduction of production costs are achieved.

CN119508735APending Publication Date: 2025-02-25SICHUAN FANGDA VANADIUM & TITANIUM GROUP CO LTD
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Patent Information

Application Number
CN202411683657.2
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-11-22
Publication Date
2025-02-25

AI Technical Summary

Technical Problem

In the existing blast furnace smelting, the non-condensed gas from the liquid oxygen storage tank must be discharged, causing oxygen enrichment to cause safety hazards and energy waste, increasing the production costs of enterprises.

Method used

A normal pressure liquid oxygen vaporization recovery system is designed, including a first liquid oxygen storage tank, a second liquid oxygen storage tank, a heat exchanger, an oxygen compressor and an oxygen pipeline network. Reheating, compressing non-condensed gas and recycling it into the oxygen pipeline network to realize the utilization of resources.

Benefits of technology

The recycling and utilization of non-condensed gas is achieved, oxygen enrichment and energy waste are avoided, enterprise production costs are reduced, and system stability and safety are improved.

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Abstract

The invention discloses a normal-pressure liquid oxygen vaporization recovery system and a recovery process, relates to the field of steel smelting air separation backup systems, and solves the problems that non-condensable gas in a liquid oxygen storage tank must be discharged, oxygen enrichment has potential safety hazards, energy is wasted, and enterprise cost is high. The recovery system comprises a first liquid oxygen storage tank, a second liquid oxygen storage tank, a heat exchanger communicated with the first liquid oxygen storage tank and the second liquid oxygen storage tank, an oxygen compressor connected with an outlet of the heat exchanger, and an oxygen pipe network communicated with the oxygen compressor. The invention further provides a non-condensable gas recovery process, the product liquid oxygen of the air separation device is placed in the first liquid oxygen storage tank, and the purchased standby liquid oxygen is placed in the second liquid oxygen storage tank; oxygen in the first liquid oxygen storage tank and the second liquid oxygen storage tank is discharged into a heat exchanger to be reheated, the oxygen is introduced into an oxygen compressor to be compressed, and then the oxygen is introduced into an oxygen pipe network; and controlling the oxygen pipe network to use oxygen in the subsequent process.
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Description

Technical Field

[0001] The invention relates to the technical field of steel smelting air separation backup system, and in particular to a normal pressure liquid oxygen vaporization recovery system and a recovery process. Background Art

[0002] In blast furnace smelting, liquid oxygen storage tank is a relatively important equipment in the manufacturing process. Liquid oxygen storage tank is used to store liquid oxygen, and the stored liquid oxygen mainly comes from the safe discharge of the main condenser evaporator of the air separation unit. In addition, the liquid oxygen storage tank is also used as a backup oxygen supply after the air separation unit fails and stops, and is an important part of the air separation backup system. Therefore, the liquid oxygen storage tank is an extremely important part of the production process.

[0003] The liquid oxygen storage tank consists of an inner tank and an outer tank, and the inner and outer tanks are filled with insulation materials to reduce the loss of cold. The boiling point of liquid oxygen in the storage tank is -183℃. With the loss of cold, the supercooling of liquid oxygen gradually decreases, producing some non-condensable gas. The design pressure of the storage tank is 25KPa, and the normal working pressure is 20KPa. Therefore, in order to ensure the safe and stable operation of the storage tank, the non-condensable gas produced by the decrease in supercooling must be directly discharged through the top pressure relief regulating valve. The normal storage tank is designed to have a gasification volume of 0.5%.

[0004] Since the non-condensable gas is directly discharged through the pressure relief regulating valve, the density of oxygen is greater than that of air, so the discharged oxygen will sink, resulting in regional oxygen enrichment, which poses certain safety hazards. The direct discharge of oxygen that consumes energy to purify also causes certain energy waste.

[0005] Therefore, the existing liquid oxygen storage tank has the defect that non-condensable gas must be discharged, resulting in oxygen enrichment, potential safety hazards, energy waste, and increased production costs for enterprises. Summary of the invention

[0006] The purpose of the present invention is to solve the problem that in the existing blast furnace smelting, the non-condensable gas in the liquid oxygen storage tank must be discharged, resulting in oxygen enrichment, potential safety hazards, energy waste, and increased production costs of the enterprise. The present invention provides a normal pressure liquid oxygen vaporization recovery system and a recovery process.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0008] A normal pressure liquid oxygen vaporization recovery system, the recovery system comprising: a first liquid oxygen storage tank, a second liquid oxygen storage tank, a heat exchanger connected to both the first liquid oxygen storage tank and the second liquid oxygen storage tank, an oxygen compressor connected to an outlet of the heat exchanger, and an oxygen pipeline network connected to the oxygen compressor.

[0009] Furthermore, a first storage tank pressure regulating valve is provided at the gas outlet end of the first liquid oxygen storage tank.

[0010] Furthermore, a second storage tank pressure regulating valve is provided at the gas outlet end of the second liquid oxygen storage tank.

[0011] Furthermore, the outlet end of the heat exchanger is communicated with the inlet end of the oxygen compressor.

[0012] Furthermore, a control regulating valve is provided on the pipeline connecting the heat exchanger and the oxygen compressor.

[0013] Furthermore, the outlet end of the oxygen compressor is connected to the inlet end of the oxygen pipeline network.

[0014] Furthermore, a stop valve and a check valve are provided in sequence on the pipeline connecting the oxygen compressor and the oxygen pipeline network.

[0015] A recovery process based on the above-mentioned atmospheric pressure liquid oxygen vaporization recovery system is also provided, comprising the following steps:

[0016] S1, placing the product liquid oxygen of the air separation unit in the first liquid oxygen storage tank, and placing the purchased backup liquid oxygen in the second liquid oxygen storage tank;

[0017] S2, discharging oxygen from the first liquid oxygen storage tank and the second liquid oxygen storage tank into a heat exchanger;

[0018] S3, controlling the heat exchanger to reheat the oxygen, turning on the oxygen compressor, and passing the oxygen into the oxygen compressor;

[0019] S4, controlling the oxygen compressor to compress the oxygen, and after the compression is completed, passing the oxygen into the oxygen pipe network;

[0020] S5. Control the oxygen pipeline network to use oxygen in subsequent processes, thereby completing gas recycling.

[0021] Furthermore, S2 specifically includes opening the first storage tank pressure regulating valve, the second storage tank pressure regulating valve, and the heat exchanger to discharge the oxygen in the first liquid oxygen storage tank and the second liquid oxygen storage tank into the heat exchanger.

[0022] Furthermore, S4 specifically includes controlling the oxygen compressor to compress the oxygen, and after the compression is completed, opening the stop valve and the check valve to pass the oxygen into the oxygen pipeline network.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] 1. The atmospheric pressure liquid oxygen vaporization recovery system involved in the present invention can reheat and compress the non-condensable gas and recover it and pass it into the subsequent pipeline network for utilization by setting up a recovery system, thereby achieving no waste of resources. Moreover, in the event of an accident or failure, the system can reduce human operation and intervention, and the system has high stability. It can control the pressure in the storage tank to avoid too low pressure in the storage tank and maintain stable working conditions.

[0025] The cold loss of the storage tank is recovered and turned into treasure, achieving the effect of energy recycling, contributing to energy saving and consumption reduction, and reducing the production cost of the enterprise. It solves the problem that the non-condensable gas in the liquid oxygen storage tank must be discharged in the existing blast furnace smelting, causing oxygen enrichment, safety hazards, energy waste, and increased production costs of the enterprise.

[0026] 2. The recycling process involved in the present invention is simple, easy to promote and has great advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a structural diagram of a normal pressure liquid oxygen vaporization recovery system.

[0028] Figure markings: 1-first liquid oxygen storage tank, 2-second liquid oxygen storage tank, 3-heat exchanger, 4-oxygen compressor, 5-first storage tank pressure regulating valve, 6-second storage tank pressure regulating valve, 7-control regulating valve, 8-stop valve, 9-check valve, 10-oxygen pipeline network.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0031] All other obtained embodiments belong to the protection scope of the present invention. DETAILED DESCRIPTION

[0032] First, the present invention provides a normal pressure liquid oxygen vaporization recovery system, please refer to Figure 1 The recovery system includes: a first liquid oxygen storage tank 1, a second liquid oxygen storage tank 2, a heat exchanger 3 connected to the first liquid oxygen storage tank 1 and the second liquid oxygen storage tank 2, an oxygen compressor 4 connected to the outlet of the heat exchanger 3, and an oxygen pipeline 10 connected to the oxygen compressor 4.

[0033] It can be understood that when using the present recovery system, the product liquid oxygen of the air separation unit is placed in the first liquid oxygen storage tank 1, and the purchased spare liquid oxygen is placed in the second liquid oxygen storage tank 2; the oxygen in the first liquid oxygen storage tank 1 and the second liquid oxygen storage tank 2 is discharged into the heat exchanger 3, the heat exchanger 3 is controlled to reheat the oxygen, the oxygen compressor 4 is turned on, and the oxygen is passed into the oxygen compressor 4; the oxygen compressor 4 is controlled to compress the oxygen, and after the compression is completed, the oxygen is passed into the oxygen pipeline 10; the oxygen pipeline 10 is controlled to use the oxygen in subsequent processes, thereby completing the recovery and utilization of the gas.

[0034] This recovery system realizes the reheating and compression of non-condensable gas for use by setting up multiple liquid oxygen storage tanks in combination with heat exchangers 3, oxygen compressors 4, and oxygen pipelines 10, thereby achieving no waste of resources. In the event of an accident or failure, human operation and intervention are reduced, providing system stability. The pressure in the storage tank can be automatically and timely controlled to avoid excessively low pressure in the storage tank and maintain stable working conditions. The loss of cold energy in the storage tank is recovered and turned into treasure, achieving the effect of energy recycling, contributing to energy conservation and consumption reduction, and reducing the production costs of the enterprise. It solves the problem that in the existing blast furnace smelting, the non-condensable gas in the liquid oxygen storage tank must be discharged, resulting in oxygen enrichment, potential safety hazards, energy waste, and increased production costs for the enterprise.

[0035] In addition, two liquid oxygen storage tanks are provided, namely, a first liquid oxygen storage tank 1 and a second liquid oxygen storage tank 2. Since the temperature of the non-condensable gas is relatively low, the second liquid oxygen storage tank 2 can be used as a gas buffer and also as a cold exchange.

[0036] In certain embodiments of the present invention, a first storage tank pressure regulating valve 5 is provided at the gas outlet end of the first liquid oxygen storage tank 1 .

[0037] In some embodiments of the present invention, the gas outlet of the second liquid oxygen storage tank 2 is provided with a second storage tank pressure regulating valve 6. By providing the first storage tank pressure regulating valve 5 and the second storage tank pressure regulating valve 6, the system is more controllable and safer.

[0038] In some embodiments of the present invention, the outlet end of the heat exchanger 3 is communicated with the inlet end of the oxygen compressor 4 .

[0039] In certain embodiments of the present invention, a control regulating valve 7 is provided on the pipeline connecting the heat exchanger 3 and the oxygen compressor 4. The setting of the control regulating valve 7 can control the speed and flow of the gas entering the oxygen compressor 4, making the system safer.

[0040] In certain embodiments of the present invention, the outlet end of the oxygen compressor 4 is connected to the inlet end of the oxygen pipeline network 10 .

[0041] In certain embodiments of the present invention, a stop valve 8 and a check valve 9 are sequentially provided on the pipeline connecting the oxygen compressor 4 and the oxygen network 10. A stop valve 8 and a check valve 9 are sequentially provided on the pipeline connecting the oxygen compressor 4 and the oxygen network 10 to prevent the original oxygen on the oxygen network 10 from flowing back into the oxygen compressor 4, so that the system operates normally.

[0042] A recovery process based on the above-mentioned atmospheric pressure liquid oxygen vaporization recovery system is also provided, comprising the following steps:

[0043] S1, placing the product liquid oxygen of the air separation unit in the first liquid oxygen storage tank 1, and placing the purchased spare liquid oxygen in the second liquid oxygen storage tank 2;

[0044] S2, discharging oxygen from the first liquid oxygen storage tank 1 and the second liquid oxygen storage tank 2 into the heat exchanger 3;

[0045] S3, controlling the heat exchanger 3 to reheat the oxygen, turning on the oxygen compressor 4, and passing the oxygen into the oxygen compressor 4;

[0046] S4, controlling the oxygen compressor 4 to compress the oxygen, and after the compression is completed, passing the oxygen into the oxygen pipeline network 10; S5, controlling the oxygen pipeline network 10 to use the oxygen in subsequent processes, thereby completing the recycling of the gas.

[0047] It can be understood that the non-condensable gas recovery process of the present invention is simple, easy to promote, highly universal, and has strong advantages.

[0048] In certain embodiments of the present invention, S2 specifically includes opening the first storage tank pressure regulating valve 5, the second storage tank pressure regulating valve 6, and the heat exchanger 3 to discharge the oxygen in the first liquid oxygen storage tank 1 and the second liquid oxygen storage tank 2 into the heat exchanger 3.

[0049] In certain embodiments of the present invention, S4 specifically includes controlling the oxygen compressor 4 to compress the oxygen, and after the compression is completed, opening the stop valve 8 and the check valve 9 to pass the oxygen into the oxygen pipeline network 10.

[0050] Example 1

[0051] In this example, see Figure 1 , provides a normal pressure liquid oxygen vaporization recovery system, please refer to Figure 1The recovery system includes: a first liquid oxygen storage tank 1, a second liquid oxygen storage tank 2, a heat exchanger 3 connected to the first liquid oxygen storage tank 1 and the second liquid oxygen storage tank 2, an oxygen compressor 4 connected to the outlet of the heat exchanger 3, and an oxygen pipeline 10 connected to the oxygen compressor 4. A first storage tank pressure regulating valve 5 is provided at the gas outlet end of the first liquid oxygen storage tank 1. A second storage tank pressure regulating valve 6 is provided at the gas outlet end of the second liquid oxygen storage tank 2. The outlet end of the heat exchanger 3 is connected to the inlet end of the oxygen compressor 4. A control regulating valve 7 is provided on the pipeline connecting the heat exchanger 3 and the oxygen compressor 4. The outlet end of the oxygen compressor 4 is connected to the inlet end of the oxygen pipeline 10. A stop valve 8 and a check valve 9 are provided in sequence on the pipeline connecting the oxygen compressor 4 and the oxygen pipeline 10.

[0052] Example 2

[0053] On the basis of Example 1, a certain enterprise used the following recovery process in production and preparation, including the following steps:

[0054] S1. Place the product liquid oxygen of the air separation unit in the first liquid oxygen storage tank 1, and place the purchased spare liquid oxygen in the second liquid oxygen storage tank 2.

[0055] S2. Open the first storage tank pressure regulating valve 5, the second storage tank pressure regulating valve 6, and the heat exchanger 3, and discharge the oxygen in the first liquid oxygen storage tank 1 and the second liquid oxygen storage tank 2 into the heat exchanger 3.

[0056] S3, controlling the heat exchanger 3 to reheat the oxygen, turning on the oxygen compressor 4, and passing the oxygen into the oxygen compressor 4.

[0057] S4, controlling the oxygen compressor 4 to compress the oxygen, and after the compression is completed, opening the stop valve 8 and the check valve 9 to pass the oxygen into the oxygen pipe network 10.

[0058] S5. Control the oxygen pipe network 10 to use the oxygen in subsequent processes, thereby completing gas recycling.

[0059] Among them, the specification of the first liquid oxygen storage tank 1 is 1500m 3 The specification of the second liquid oxygen storage tank 2 is 150m 3 , oxygen compressor 4 is 300m 3 Model of compressor.

[0060] The product liquid oxygen of the air separation unit and the purchased liquid oxygen are stored in the first liquid oxygen storage tank 1 and the second liquid oxygen storage tank 2. During the production process, a large amount of cold capacity loss of liquid oxygen in the storage tank will be caused, so it is recovered and reheated through the system, compressed and used, and the pressure relief pipe interface of the liquid oxygen storage tank is connected to the pipe, and a heat exchanger is added to the pipeline to reheat part of the oxygen lost in the storage tank, and compressed through the oxygen compressor. Check valves and stop valves are added to the compressor outlet pipeline to prevent the original pipeline oxygen from flowing back to the compressor. Edit the start / release button at the cold loss gas discharge valve of the storage tank on the DCS screen. After the equipment is running normally, click the start button to interlock and start normally.

[0061] When the inlet pressure of the product gas compressor reaches the set stop value, an exhaust valve control opening instruction is issued.

[0062] By using this process, the company can recycle a portion of the oxygen vaporized from the pressure relief valve on the top of the liquid oxygen storage tank into the oxygen compressor for compression to increase the oxygen compression volume, supplement the oxygen used in steelmaking, achieve the effect of energy recycling, realize effective energy conservation and consumption reduction, and reduce production costs.

[0063] The above embodiment is only one implementation of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A normal pressure liquid oxygen vaporization recovery system, characterized in that: The recovery system includes: a first liquid oxygen storage tank, a second liquid oxygen storage tank, a heat exchanger connected to the first liquid oxygen storage tank and the second liquid oxygen storage tank, an oxygen compressor connected to the outlet of the heat exchanger, and an oxygen pipeline network connected to the oxygen compressor.

2. The atmospheric pressure liquid oxygen vaporization recovery system according to claim 1, characterized in that: A first storage tank pressure regulating valve is provided at the gas outlet end of the first liquid oxygen storage tank.

3. The atmospheric pressure liquid oxygen vaporization recovery system according to claim 1, characterized in that: A second storage tank pressure regulating valve is provided at the gas outlet end of the second liquid oxygen storage tank.

4. The atmospheric pressure liquid oxygen vaporization recovery system according to claim 1, characterized in that: The outlet end of the heat exchanger is communicated with the inlet end of the oxygen compressor.

5. A normal pressure liquid oxygen vaporization recovery system according to claim 4, characterized in that: A control regulating valve is provided on the pipeline connecting the heat exchanger and the oxygen compressor.

6. The atmospheric pressure liquid oxygen vaporization recovery system according to claim 1, characterized in that: The outlet end of the oxygen compressor is connected to the inlet end of the oxygen pipeline network.

7. The atmospheric pressure liquid oxygen vaporization recovery system according to claim 6, characterized in that: A stop valve and a check valve are arranged in sequence on the pipeline connecting the oxygen compressor and the oxygen pipeline network.

8. A recovery process of a normal pressure liquid oxygen vaporization recovery system according to any one of claims 1 to 7, characterized in that: The following steps are included: S1, placing the product liquid oxygen of the air separation unit in the first liquid oxygen storage tank, and placing the purchased backup liquid oxygen in the second liquid oxygen storage tank; S2, discharging oxygen from the first liquid oxygen storage tank and the second liquid oxygen storage tank into a heat exchanger; S3, controlling the heat exchanger to reheat the oxygen, turning on the oxygen compressor, and passing the oxygen into the oxygen compressor; S4, controlling the oxygen compressor to compress the oxygen, and after the compression is completed, passing the oxygen into the oxygen pipe network; S5. Control the oxygen pipeline network to use oxygen in subsequent processes, thereby completing gas recycling.

9. A recycling process according to claim 8, characterized in that: Specifically, S2 is to open the first storage tank pressure regulating valve, the second storage tank pressure regulating valve, and the heat exchanger to discharge the oxygen in the first liquid oxygen storage tank and the second liquid oxygen storage tank into the heat exchanger.

10. A recycling process according to claim 8, characterized in that: Specifically, S4 is to control the oxygen compressor to compress the oxygen, and after the compression is completed, open the stop valve and the check valve to pass the oxygen into the oxygen pipeline network.