A cryogenic distillation apparatus for blast furnace oxygen

Abstract

This utility model relates to a low-temperature distillation device for blast furnace oxygen, comprising a distillation column, an upper column, a main condenser heat exchanger, and a lower column. The upper column is equipped with a main oxygen delivery pipe, which includes a first main heat exchanger, an oxygen delivery branch pipe, and a first regulating valve. A finished nitrogen delivery pipe is connected to the first main heat exchanger and the upper column. The finished nitrogen delivery pipe has a first nitrogen delivery branch pipe, which in turn has an expansion nitrogen delivery pipe. A nitrogen compressor unit is connected to the expansion nitrogen delivery pipe, the nitrogen circulation delivery pipe, and the oxygen delivery branch pipe, all equipped with a second main heat exchanger. A first post-machine heat exchanger and a first turbine expander are located on the nitrogen circulation delivery pipe, which is connected to the expansion nitrogen delivery pipe. This device can convert produced oxygen into liquid form when oxygen demand in steel production enterprises is at a low point. This utility model is easy to use and has broad market prospects.

Description

Technical Field

[0001] This utility model relates to the field of low-temperature distillation equipment for oxygen, and specifically to a low-temperature distillation device for oxygen from a blast furnace. Background Technology

[0002] Fuel combustion is a vigorous oxidation reaction involving fuel and an oxidizer under certain conditions, producing exothermic and luminescent emissions. Conventional fuel combustion uses air as an oxidizer, but air contains only 21% oxygen for combustion, while nitrogen accounts for a high 79% that does not. This nitrogen absorbs a large amount of heat from the combustion reaction and is ultimately released into the atmosphere with the flue gas, resulting in significant energy waste. Oxygen-enriched combustion refers to the combustion of fuels with an oxygen content greater than 21% in the oxidizer. This combustion method increases the useful oxygen content in the oxidizer and reduces the content of useless nitrogen, which is beneficial for stabilizing the combustion process, improving combustion efficiency, and enhancing heat transfer within the furnace.

[0003] Based on fundamental theories of fuel combustion, this paper elucidates the basic characteristics of combustion when using blast furnace gas as fuel and increasing the oxygen content in the combustion air, including combustion reaction rate, air consumption coefficient, amount of combustion products, and theoretical combustion temperature. Current processes achieve this by mixing high-concentration oxygen with air to form oxygen-enriched air, which is then supplied to the blast furnace for combustion. There are two sources of oxygen-enriched combustion air: compressed and filtered air, and oxygen sources. Existing processes primarily provide two sources of oxygen: oxygen produced using pressure swing adsorption (PSA) and oxygen produced using cryogenic distillation. PSA offers advantages such as convenient start-up and shutdown, simple process, and easy maintenance, but its energy consumption is relatively high, making it suitable for low-volume oxygen production. Cryogenic distillation offers the advantage of continuous oxygen production at a lower energy cost per unit volume compared to PSA, and it also produces nitrogen as a protective gas for steel mills. Therefore, steel mills generally use cryogenic distillation to produce oxygen as their oxygen-enriched source.

[0004] However, conventional cryogenic distillation processes produce a continuous supply of oxygen, while steelmaking furnaces operate on a cyclical basis. During off-peak hours, oxygen produced by the cryogenic distillation process is released to maintain its operation. This released oxygen incurs energy costs. Excessive release not only wastes energy but also materials, and can create oxygen-rich areas in nearby regions, potentially causing accidents. Therefore, existing technology has room for improvement. The aim is to convert gaseous oxygen into liquid for storage during off-peak oxygen supply periods, reducing material and energy losses, and enabling the use of liquid oxygen as a raw material for oxygen production during peak oxygen demand periods. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a low-temperature distillation device that can convert produced oxygen into liquid for storage when oxygen demand in steel production enterprises is at its lowest point, thereby overcoming the deficiencies in existing technologies.

[0006] The technical solution adopted by this utility model is as follows: a low-temperature distillation device for blast furnace oxygen, comprising a distillation column, wherein the distillation column comprises, from top to bottom, an upper column, a main condenser heat exchanger, and a lower column. An oxygen delivery main pipe is provided on the upper column. Along the direction from near to far from the upper column, a first main heat exchanger, an oxygen delivery branch pipe, and a first regulating valve are sequentially arranged on the oxygen delivery main pipe. A finished nitrogen delivery pipe is provided on the first main heat exchanger and the upper column. A second regulating valve is provided on the finished nitrogen delivery pipe on the side of the first main heat exchanger away from the upper column. The inlet end of a first nitrogen delivery branch pipe is provided on the finished nitrogen delivery pipe between the second regulating valve and the first main heat exchanger. An expansion nitrogen delivery pipe is installed at the outlet end. The inlet end of the nitrogen compressor unit is installed at the outlet end of the expansion nitrogen delivery pipe. The inlet end of the nitrogen circulation delivery pipe is installed at the outlet end of the nitrogen compressor unit. A second main heat exchanger is installed on the expansion nitrogen delivery pipe, nitrogen circulation delivery pipe, and oxygen delivery branch pipe on the side of the first nitrogen delivery branch pipe away from the nitrogen compressor unit. The pressure boosting end of the first turbine expander and the first post-machine heat exchanger are sequentially installed on the nitrogen circulation delivery pipe along the direction from the nitrogen compressor unit to the direction away from the nitrogen compressor unit. The expansion end inlet of the first turbine expander is connected to the outlet end of the nitrogen circulation delivery pipe, and the expansion end outlet of the first turbine expander is connected to the inlet end of the expansion nitrogen delivery pipe.

[0007] Preferably, the oxygen delivery branch pipe between the second main heat exchanger and the main oxygen delivery pipe is provided with a third regulating valve, an oxygen compressor unit, and a second post-compressor heat exchanger in sequence along the direction from the main oxygen delivery pipe to the second main heat exchanger. The inlet end of the oxygen delivery branch pipe is connected to the main oxygen delivery pipe, and a gas-liquid separator is provided on the outlet end of the oxygen delivery branch pipe. A low-temperature oxygen reflux pipe is provided on the top of the gas-liquid separator and on the second main heat exchanger. The outlet end of the oxygen delivery branch pipe between the third regulating valve and the oxygen compressor unit and the low-temperature oxygen reflux pipe are connected.

[0008] Preferably, a wire mesh coalescer is installed in the gas-liquid separation tank above the outlet end of the oxygen delivery branch pipe, a liquid level sensor is installed on the gas-liquid separation tank below the wire mesh coalescer, a first liquid oxygen delivery pipe is installed at the bottom of the gas-liquid separation tank, a fourth regulating valve, the outlet end of the second liquid oxygen delivery pipe and the heat source channel of the first subcooler are sequentially arranged along the direction from near the gas-liquid separation tank to far away from the gas-liquid separation tank on the first liquid oxygen delivery pipe, a fifth regulating valve is installed on the second liquid oxygen delivery pipe, and the finished nitrogen delivery pipe between the upper tower and the first main heat exchanger and the cold source channel of the first subcooler are connected.

[0009] Preferably, a gas flow sensor is installed on both the nitrogen circulation pipeline and the oxygen pipeline, and the inlet end of the second nitrogen pipeline is installed on the nitrogen circulation pipeline between the first heat exchanger and the first turbine expander. A sixth regulating valve is installed on both the second nitrogen pipeline and the first nitrogen pipeline.

[0010] Preferably, the inlet ends of the upper tower and the heat source channel of the main condenser heat exchanger are connected by a first pressure nitrogen delivery pipe. A second pressure nitrogen delivery pipe is installed on the first pressure nitrogen delivery pipe. A liquid nitrogen delivery main pipe is installed at the outlet end of the heat source channel of the main condenser heat exchanger. The liquid nitrogen delivery main pipe is sequentially provided with the inlet end of the first liquid nitrogen delivery branch pipe, the inlet end of the second liquid nitrogen delivery branch pipe, and a seventh regulating valve along the direction from near the main condenser heat exchanger to far away from the main condenser heat exchanger. The outlet end of the first liquid nitrogen delivery branch pipe is connected to the lower tower, and the outlet end of the second liquid nitrogen delivery branch pipe is connected to the upper tower. Oxygen-enriched liquid air delivery pipes are installed on the upper and lower towers. A second subcooler is installed on the liquid nitrogen delivery main pipe between the first and second liquid nitrogen delivery branch pipes, the finished product nitrogen delivery pipe between the upper tower and the first main heat exchanger, and the oxygen-enriched liquid air delivery pipe.

[0011] Preferably, a bubble pump is installed on the oxygen-enriched liquid air delivery pipe between the second subcooler and the lower tower. The bubble pump includes an inner pipe on the oxygen-enriched liquid air delivery pipe, a jacket on the outside of the inner pipe, a plurality of pressure equalizing rings arranged along the direction from the top to the bottom of the jacket on the outside of the jacket, a plurality of pressure equalizing pipes on two adjacent pressure equalizing rings, a plurality of delivery pipes respectively arranged on each pressure equalizing ring and the jacket, and a plurality of vent holes arranged on the inner pipe on the inside of the jacket; and the outlet end of the first compressed air delivery pipe located on the uppermost pressure equalizing ring.

[0012] Preferably, a second compressed air supply pipe is provided at the inlet end of the first compressed air supply pipe, on the lower tower, and on the first main heat exchanger. The outlet end of the second compressed air supply pipe is connected to the lower tower. A third compressed air supply pipe is provided at the inlet end of the second compressed air supply pipe and on the first main heat exchanger. A tenth regulating valve is provided on both the third compressed air supply pipe between the second compressed air supply pipe and the first main heat exchanger and the second compressed air supply pipe between the first compressed air supply pipe and the lower tower. The third compressed air supply pipe between the second compressed air supply pipe and the first main heat exchanger is provided with a third downstream heat exchanger and the pressurization end of the second turbine expander in sequence along the direction from near the first main heat exchanger to far away from the first main heat exchanger. The outlet end of the third compressed air supply pipe is connected to the expansion end inlet of the second turbine expander. The expansion end outlet of the second turbine expander is connected to the upper tower.

[0013] The beneficial effects of this utility model are as follows: First, this utility model enables timely adjustment of the oxygen supply according to the oxygen demand of steel production enterprises. Oxygen that is not supplied to steel production enterprises is supplied to the second main heat exchanger and liquefied using the cooling capacity provided by the refrigeration cycle. This reduces the waste of materials and energy caused by the large amount of oxygen produced and discharged when the steel production cycle is at its trough. The liquefied oxygen is then temporarily stored as liquid oxygen, realizing the adjustment of the supply of oxygen products in different states. The product form is more flexible and conducive to promotion.

[0014] Secondly, a liquid level sensor is installed on the gas-liquid separation tank below the wire mesh coalescer of this utility model, and the installation of the liquid level sensor facilitates the feedback of liquid level parameters.

[0015] Furthermore, both the nitrogen circulation conveying pipe and the oxygen conveying branch pipe described in this utility model are equipped with gas flow sensors, which facilitates the feedback of gas flow parameters.

[0016] This utility model has a simple structure, is easy to operate, and has a clever design, which greatly improves work efficiency and has good social and economic benefits. It is a product that is easy to promote and use. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the structure of this utility model.

[0018] Figure 2 for Figure 1 A magnified view of detail A.

[0019] Figure 3 for Figure 1 A magnified view of detail B.

[0020] Figure 4 for Figure 1 A magnified view of detail C. Detailed Implementation

[0021] like Figures 1 to 4 As shown, a low-temperature distillation device for blast furnace oxygen includes a distillation column. The distillation column, from top to bottom, comprises an upper column 1, a main condenser heat exchanger 2, and a lower column 3. The upper column 1 is equipped with a main oxygen delivery pipe 4. Along the direction from near to far from the upper column 1, the main oxygen delivery pipe 4 is sequentially equipped with a first main heat exchanger 5, an oxygen delivery branch pipe 6, and a first regulating valve 7. A finished nitrogen delivery pipe 8 is provided on the first main heat exchanger 5 and the upper column 1. A second regulating valve 9 is provided on the finished nitrogen delivery pipe 8 on the side of the first main heat exchanger 5 away from the upper column 1. The inlet end of a first nitrogen delivery branch pipe 10 is provided on the finished nitrogen delivery pipe 8 between the second regulating valve 9 and the first main heat exchanger 5. An expansion nitrogen delivery pipe is provided at the outlet end of the first nitrogen delivery branch pipe 10. The outlet end of the expansion nitrogen delivery pipe 11 is provided with the inlet end of the nitrogen compressor unit 12. The outlet end of the nitrogen compressor unit 12 is provided with the inlet end of the nitrogen circulation delivery pipe 13. The expansion nitrogen delivery pipe 11, the nitrogen circulation delivery pipe 13 and the oxygen delivery pipe 6 on the side of the first nitrogen delivery branch pipe 10 away from the nitrogen compressor unit 12 are provided with the second main heat exchanger 14. The nitrogen circulation delivery pipe 13 is provided with the pressurization end of the first turbine expander 16 and the first post-machine heat exchanger 15 in sequence along the direction from near the nitrogen compressor unit 12 to away from the nitrogen compressor unit 12. The expansion end inlet of the first turbine expander 16 is connected to the outlet end of the nitrogen circulation delivery pipe 13, and the expansion end outlet of the first turbine expander 16 is connected to the inlet end of the expansion nitrogen delivery pipe 11.

[0022] When the oxygen supply branch pipe 6 increases instantaneously, the supply rate of the nitrogen supply branch pipe 11, which provides cooling capacity, needs to be adjusted to match the oxygen supply rate of the oxygen supply branch pipe 6. This is because, after further increasing the load on the nitrogen compressor unit 12, the expanded nitrogen gas after expansion at the expansion end of the first turbine expander 16 will produce a gas-liquid mixture of expanded nitrogen gas and liquid nitrogen mist, thus increasing the nitrogen demand. The gas-liquid mixture of expanded nitrogen gas and liquid nitrogen mist is sent back to the second main heat exchanger 14 from the low-temperature end of the second main heat exchanger 14 and continuously supplied to the heat source of the second main heat exchanger 14 for heat exchange. During the adjustment of the supply rate of the nitrogen supply branch pipe 11, the oxygen supplied through the oxygen supply branch pipe 6 may not be completely liquid. In order to reduce the amount of unliquefied oxygen discharged and make full use of the cooling capacity carried by the undischarged liquefied oxygen, this product has a third regulating valve 17, an oxygen compressor unit 18, and a second downstream heat exchanger 19 arranged sequentially along the direction from the oxygen compressor unit 4 to the second main heat exchanger 14 via an oxygen delivery branch pipe 6 between the second main heat exchanger 14 and the oxygen delivery main pipe 4. The inlet end of the oxygen delivery branch pipe 6 is connected to the oxygen delivery main pipe 4, and a gas-liquid separator 20 is installed at the outlet end of the oxygen delivery branch pipe 6. A low-temperature oxygen return pipe 21 is installed on the top of the gas-liquid separator 20 and on the second main heat exchanger 14. The outlet end of the oxygen delivery branch pipe 6 between the third regulating valve 17 and the oxygen compressor unit 18 is connected to the low-temperature oxygen return pipe 21. When the oxygen delivery branch pipe 6 is instantaneously enlarged, the oxygen delivered to the second main heat exchanger 14 for heat exchange is discharged from the low-temperature end of the second main heat exchanger 14, forming a gas-liquid mixture. After the gas-liquid mixture is separated by the gas-liquid separator 20, the gas phase is the unliquefied oxygen. The gas phase is delivered to the low-temperature oxygen return pipe 21 as a cold source for the second main heat exchanger 14 and a heat source continuously delivered to the second main heat exchanger 14. After heat exchange, it is delivered to the oxygen delivery branch pipe 6 before the inlet end of the oxygen compressor unit 18 through the low-temperature oxygen return pipe 21 and then delivered to the oxygen compressor unit 18 for pressurization. While adjusting the power of the oxygen compressor unit 18, the flow rate of expanded nitrogen delivered through the expanded nitrogen delivery pipe 11 is increased, so that the oxygen delivered through the oxygen delivery branch pipe 6 can be completely liquefied.

[0023] Furthermore, to improve the gas-liquid separation effect of the gas-liquid separator 20, this product is equipped with a wire mesh coalescer 22 inside the gas-liquid separator 20 above the outlet end of the oxygen delivery branch pipe 6. The installation of the wire mesh coalescer 22 improves the gas-liquid separation effect. Liquid level sensors 23 are respectively installed on the gas-liquid separator 20 below the wire mesh coalescer 22 and at the bottom of the lower tower 3. The installation of liquid level sensors 23 facilitates the feedback of liquid level parameters. A first liquid oxygen delivery pipe 24 is installed at the bottom of the gas-liquid separator 20. The first liquid oxygen delivery pipe 24 is sequentially equipped with a fourth regulating valve 25, the outlet end of the second liquid oxygen delivery pipe 26, and the heat source channel of the first subcooler 27 along the direction from near the gas-liquid separator 20 to away from the gas-liquid separator 20. A fifth regulating valve 28 is installed on the second liquid oxygen delivery pipe 26. The finished nitrogen delivery pipe 8 between the upper tower 1 and the first main heat exchanger 5 and the cold source channel of the first subcooler 27 are connected.

[0024] Simultaneously, when the demand for oxygen from downstream steel production enterprises increases, and the amount of oxygen transported through the oxygen transport branch pipe 6 decreases, the transport volume through the expanded nitrogen transport pipe 11 and the load on the nitrogen compressor unit 12 must also be reduced accordingly, thereby reducing energy consumption. Therefore, gas flow sensors 29 are respectively installed on the nitrogen circulation transport pipe 13 and the oxygen transport branch pipe 6. The inlet end of the second nitrogen transport branch pipe 30 is installed on the nitrogen circulation transport pipe 13 between the first downstream heat exchanger 15 and the first turbine expander 16. A sixth regulating valve 31 is respectively installed on the second nitrogen transport branch pipe 30 and the first nitrogen transport branch pipe 10. This gradually reduces the load on the nitrogen compressor unit 12, and according to the feedback value of the gas flow sensor 29, a portion of the nitrogen transported by the nitrogen compressor unit 12 is gradually discharged through the second nitrogen transport branch pipe 30 into the finished nitrogen transport pipe 8.

[0025] To facilitate the supply of nitrogen at different pressures, this product connects the inlet ends of the heat source channels of the upper tower 1 and the main condenser heat exchanger 2 via a first-pressure nitrogen delivery pipe 32. A second-pressure nitrogen delivery pipe 33 is installed on the first-pressure nitrogen delivery pipe 32. A liquid nitrogen delivery main pipe 34 is installed at the outlet end of the heat source channel of the main condenser heat exchanger 2. Along the direction from near the main condenser heat exchanger 2 to away from the main condenser heat exchanger 2, the liquid nitrogen delivery main pipe 34 is sequentially provided with the inlet end of a first liquid nitrogen delivery branch pipe 35, a second liquid nitrogen delivery branch pipe 35, and a third liquid nitrogen delivery branch pipe 35. The inlet end of the second liquid nitrogen delivery branch pipe 36 is connected to the seventh regulating valve 37. The outlet end of the first liquid nitrogen delivery branch pipe 35 is connected to the lower tower 3. The outlet end of the second liquid nitrogen delivery branch pipe 36 is connected to the upper tower 1. An oxygen-enriched liquid air delivery pipe 38 is installed on the upper tower 1 and the lower tower 3. A second subcooler 39 is installed on the main liquid nitrogen delivery pipe 34 between the first liquid nitrogen delivery branch pipe 35 and the second liquid nitrogen delivery branch pipe 36, the finished nitrogen delivery pipe 8 between the upper tower 1 and the first main heat exchanger 5, and the oxygen-enriched liquid air delivery pipe 38. An eighth regulating valve 40 is installed on the first pressure nitrogen delivery pipe 32, the second pressure nitrogen delivery pipe 33, the first liquid nitrogen delivery branch pipe 35, and the second liquid nitrogen delivery branch pipe 36 between the second pressure nitrogen delivery pipe 33 and the main condensing heat exchanger 2. To reduce the energy consumption of oxygen-enriched liquid air transport, a bubble pump is installed on the oxygen-enriched liquid air transport pipe 38 between the second subcooler 39 and the lower tower 3. The bubble pump includes an inner pipe 41 on the oxygen-enriched liquid air transport pipe 38, a jacket 42 outside the inner pipe 41, several equalizing rings 43 arranged along the direction from the top to the bottom of the jacket 42, several equalizing pipes 44 on adjacent equalizing rings 43, several transport pipes 55 on each equalizing ring 43 and jacket 42, and several vent holes 45 on the inner pipe 41 inside the jacket 42; the outlet end of a first compressed air transport pipe 46 is located on the uppermost equalizing ring 43. A one-way valve 47, a pressure sensor 48, and a ninth regulating valve 49 are sequentially installed on the oxygen-enriched liquid air transport pipe 38 and the first compressed air transport pipe 46 between the bubble pump and the lower tower 3, along the direction from near to away from the bubble pump. The difference between this product and existing bubble pumps is that the compressed air received by this product is delivered to the jacket 42 through multiple points via several equalizing rings 43, several equalizing pipes 44 set on two adjacent equalizing rings 43, and several delivery pipes 55 set on each equalizing ring 43 and jacket 42. This allows the jacket 42 to receive compressed air more evenly. The compressed air received by the jacket 42 is then delivered through several vent holes 45 to the oxygen-rich liquid air delivered through the inner pipe 41 to form an oxygen-rich liquid air gas-liquid mixture jet.

[0026] Meanwhile, a second compressed air supply pipe 50 is provided at the inlet end of the first compressed air supply pipe 46, the lower tower 3, and the first main heat exchanger 5. The outlet end of the second compressed air supply pipe 50 is connected to the lower tower 3. A third compressed air supply pipe 51 is provided at the inlet end of the second compressed air supply pipe 50 and the first main heat exchanger 5. A tenth regulating valve 52 is provided on the third compressed air supply pipe 51 between the second compressed air supply pipe 50 and the first main heat exchanger 5, and on the second compressed air supply pipe 50 between the first compressed air supply pipe 46 and the lower tower 3. The third compressed air supply pipe 51 between the second compressed air supply pipe 50 and the first main heat exchanger 5 is provided with a third downstream heat exchanger 53 and a pressurization end of the second turbine expander 54 in sequence along the direction from near the first main heat exchanger 5 to away from the first main heat exchanger 5. The outlet end of the third compressed air supply pipe 51 is connected to the expansion end inlet of the second turbine expander 54. The expansion end outlet of the second turbine expander 54 is connected to the upper tower 1.

[0027] The instructions for using this product are as follows: Figures 1 to 4 As shown, it includes the following steps: S1. The compressed air purified by the upstream purification system is continuously supplied to the third compressed air supply pipe 51 and divided into two parts, namely the first part of compressed air and the second part of compressed air. The first part of compressed air continues to be pressurized along the third compressed air supply pipe 51 through the pressurization end of the second turbine expander 54 and supplied to the heat source channel of the third turbine heat exchanger 53 and the circulating water continuously supplied to the cold source channel of the third turbine heat exchanger 53 for countercurrent heat exchange. After heat exchange, it is supplied to the first heat source channel of the first main heat exchanger 5 and the cold source continuously supplied to the first main heat exchanger 5 for heat exchange. After heat exchange, it is supplied to the expansion end of the second turbine expander 54 for expansion and cooling and then supplied to the upper column 1 as one of the distillation raw materials of the upper column 1. The second portion of compressed air, supplied to the second compressed air delivery pipe 50, exchanges heat with the second heat source channel of the first main heat exchanger 5 and the continuously supplied cold source to the first main heat exchanger 5, and is then divided into two parts again: a third portion of compressed air and a fourth portion of compressed air. The third portion of compressed air continues along the second compressed air delivery pipe 50 and is supplied to the lower column 3 as the distillation feedstock for the lower column 3. The fourth portion of compressed air is supplied to the bubble pump via the first compressed air delivery pipe 46 as the air source for the bubble pump.

[0028] S2. After the third part of compressed air enters the lower tower 3, it forms a first upward airflow. The first upward airflow goes up along the inner cavity of the lower tower 3 and exchanges heat with the first reflux condensate continuously received at the top of the lower tower 3 in a countercurrent manner. Finally, a pressure nitrogen enrichment zone is formed at the top of the lower tower 3, and an oxygen-rich liquid air enrichment zone is formed at the bottom of the lower tower 3.

[0029] The pressure nitrogen enrichment zone continuously supplies pressure nitrogen outward. This pressure nitrogen is divided into two parts: a first part and a second part. The first part is sequentially supplied to the first cold source channel of the first main heat exchanger 5 via the first pressure nitrogen supply pipe 32 and the second pressure nitrogen supply pipe 33. After heat exchange with the heat source of the first main heat exchanger 5, it is supplied to the user of the pressure nitrogen via the outlet end of the second pressure nitrogen supply pipe 33. The second part is supplied to the heat source channel of the main condensing heat exchanger 2 via the first pressure nitrogen supply pipe 32. During heat exchange with the medium in the cold source channel of the main condensing heat exchanger 2, it is liquefied to form liquid nitrogen. This liquid nitrogen is continuously supplied to the liquid nitrogen supply main pipe 34 via the outlet end of the cold source channel of the main condensing heat exchanger 2 and is divided into two parts: a first part and a second part. The first part is supplied to the top of the lower tower 3 via the first liquid nitrogen supply branch pipe 35 for use as the first reflux condenser. The second portion of liquid nitrogen is supplied to the first heat source channel of the second subcooler 39 and the cold source continuously supplied to the second subcooler 39 for heat exchange to form subcooled liquid nitrogen. The subcooled liquid nitrogen is divided into two parts, namely the first part of subcooled liquid nitrogen and the second part of subcooled liquid nitrogen. The first part of subcooled liquid nitrogen is transported to the top of the upper tower 1 through the second liquid nitrogen transport branch pipe 36 as the second reflux condensate. The second part of subcooled liquid nitrogen is transported to the liquid nitrogen storage device through the outlet end of the liquid nitrogen transport main pipe 34 as one of the liquid products of this product.

[0030] The oxygen-enriched liquid air enrichment zone continuously supplies oxygen-enriched liquid air to the oxygen-enriched liquid air delivery pipe 38. During this process, the oxygen-enriched liquid air passes through the inner pipe 41 of the bubble pump and mixes with the fourth part of compressed air that is sequentially delivered to the inner pipe 41 via the first compressed air delivery pipe 46, the equalizing ring 43, the delivery pipe 55, the jacket 42, and the vent 45 to form an oxygen-enriched liquid air jet. The oxygen-enriched liquid air jet is then delivered to the upper column 1 via the oxygen-enriched liquid air delivery pipe 38 as one of the distillation feedstocks for the upper column 1.

[0031] S3. After the first part of compressed air enters the upper tower 1, it forms a second rising airflow and continues to rise along the upper tower 1. The second rising airflow first exchanges heat with the liquid phase of the oxygen-enriched liquid air jet that enters the upper tower 1 in a countercurrent manner. Then, during the continued rise of the second rising airflow, the gas phase of the oxygen-enriched liquid air jet merges into the second rising airflow to form a third rising airflow. The third rising airflow exchanges heat with the second reflux condensate transported at the top of the upper tower 1 in a countercurrent manner, and finally forms a low-pressure nitrogen enrichment zone at the top of the upper tower 1.

[0032] After the second reflux condensate enters the upper column 1, it first exchanges heat with the third rising gas flow in a countercurrent manner. Then, the liquid phase of the second reflux condensate and the liquid phase of the oxygen-enriched liquid air jet merge to form a descending liquid flow. The descending liquid flow continues to flow down the upper column 1 and is eventually delivered to the cold source channel of the main condenser heat exchanger 2 for heat exchange with the medium continuously delivered to the heat source channel of the main condenser heat exchanger 2. The cold source channel of the main condenser heat exchanger 2 continuously delivers a fourth rising gas flow into the upper column 1. The fourth rising gas flow first exchanges heat with the descending liquid flow in a countercurrent manner and then merges with the second rising gas flow. Finally, a liquid oxygen enrichment zone is formed in the cold source channel of the main condenser heat exchanger 2, and an oxygen enrichment zone is formed at the bottom of the upper column 1.

[0033] S4. The low-pressure nitrogen enrichment zone continuously supplies low-pressure nitrogen to the finished nitrogen delivery pipe 8. The low-pressure nitrogen is first delivered to the cold source channel of the second subcooler 39 and continuously supplied to the heat source for heat exchange, then delivered to the cold source channel of the first subcooler 27 and continuously supplied to the heat source for heat exchange, and then delivered to the second cold source channel of the first main heat exchanger 5 and continuously supplied to the heat source for heat exchange, and then discharged from the high-temperature end of the first main heat exchanger 5 and divided into two parts, namely the first part of low-pressure nitrogen and the second part of low-pressure nitrogen. The first part of low-pressure nitrogen is delivered to the low-pressure nitrogen pipeline network through the outlet end of the finished nitrogen delivery pipe 8. The second portion of low-pressure nitrogen is supplied to the expansion nitrogen supply pipe 11. The second portion of low-pressure nitrogen is supplied to the inlet end of the nitrogen compressor unit 12 via the expansion nitrogen supply pipe 11. After the first compression, it is supplied to the pressurization end of the first turbine expander 16 for a second compression. Then, it is supplied to the heat source channel of the first heat exchanger 15 and the circulating water continuously supplied to the cold source channel of the first heat exchanger 15 for counter-current heat exchange. After the heat exchange, it is supplied to the first heat source channel of the second main heat exchanger 14 and the cold source channel of the second main heat exchanger 14 for counter-current heat exchange. Then, it is supplied to the expansion end of the first turbine expander 16 for expansion and cooling. The second portion of low-pressure nitrogen after expansion and cooling is converted into expanded nitrogen and supplied to the first cold source channel of the second main heat exchanger 14 and the heat source continuously supplied to the second main heat exchanger 14 for counter-current heat exchange. Then, it is supplied to the nitrogen compressor unit 12 again to form a refrigeration cycle. When the feedback parameter from the gas flow sensor 29 installed on the expanding nitrogen delivery pipe 11 reaches the first preset range, the supply of the second portion of low-pressure nitrogen to the expanding nitrogen delivery pipe 11 should be stopped. The first preset range of the gas flow sensor 29 installed on the expanding nitrogen delivery pipe 11 is the minimum nitrogen flow rate required to maintain the expansion cycle. The oxygen enrichment zone continuously supplies finished oxygen to the oxygen delivery main pipe 4. After exchanging heat with the third cold source channel of the first main heat exchanger 5 and the heat source continuously supplied to the first main heat exchanger 5, the finished oxygen is discharged from the high-temperature end of the first main heat exchanger 5 and then supplied to the low-pressure oxygen pipeline network through the oxygen delivery main pipe 4 as the oxygen enrichment source for the blast furnace.

[0034] When downstream customers do not require oxygen enrichment, the first regulating valve 7 should be closed and the third regulating valve 17 opened promptly. At this time, the finished oxygen discharged from the high-temperature end of the first main heat exchanger 5 is transported to the oxygen transmission branch pipe 6 via the oxygen transmission main pipe 4. The finished oxygen entering the oxygen transmission branch pipe 6 is first transported to the oxygen compressor unit 18 for pressurization, and then transported to the heat source channel of the second heat exchanger 19 and the circulating water continuously transported to the cold source channel of the second heat exchanger 19 for heat exchange. After that, it is transported to the second heat source channel of the second main heat exchanger 14 and the circulating water continuously transported to the second main heat exchanger 14. After heat exchange with the cold source, an oxygen gas-liquid mixture is formed. This oxygen gas-liquid mixture is then transported to a gas-liquid separator 20 for gas-liquid separation. The liquid phase of the oxygen gas-liquid mixture is temporarily stored in the gas-liquid separator 20, forming a liquid oxygen storage area. The gas phase of the oxygen gas-liquid mixture is the unliquefied oxygen. This unliquefied oxygen is continuously transported to the low-temperature oxygen return pipe 21, where it undergoes countercurrent heat exchange with the heat source continuously supplied to the second main heat exchanger 14. After this exchange, it is returned to the oxygen compressor unit 18 and combined with the oxygen transported via the oxygen transport main pipe 4. Simultaneously, the finished nitrogen transport pipe 8 should promptly supply the second portion of low-pressure nitrogen to the expansion nitrogen transport pipe 11 until the gas flow sensor 29 installed on the expansion nitrogen transport pipe 11 receives feedback parameters indicating that the parameters have reached a second preset range. The second preset range of the gas flow sensor 29 installed on the expansion nitrogen transport pipe 11 is the maximum nitrogen flow rate required for the refrigeration cycle.

[0035] When downstream customers require oxygen again, the opening of the first regulating valve 7 and the third regulating valve 17 should be adjusted in a timely manner according to the customer's needs, so as to ensure that the oxygen flow rate delivered through the outlet of the oxygen delivery main pipe 4 meets the needs of the downstream customers. The excess oxygen is delivered to the second main heat exchanger 14 through the oxygen delivery branch pipe 6 for liquefaction. During this period, the sixth regulating valve 31 on the second nitrogen delivery branch pipe 30 should also be opened, so that part of the nitrogen compressed by the nitrogen compressor unit 12 is discharged into the finished nitrogen delivery pipe 8 and then delivered to the low-pressure nitrogen pipeline network.

[0036] The liquid oxygen temporary storage area of ​​the gas-liquid separator 20 continuously supplies first liquid oxygen to the first liquid oxygen delivery pipe 24. During this period, the liquid oxygen enrichment area in the cold source channel of the main condenser heat exchanger 2 continuously supplies second liquid oxygen to the first liquid oxygen delivery pipe 24 via the second liquid oxygen delivery pipe 26. The second liquid oxygen merges with the first liquid oxygen to form a liquid oxygen product. The liquid oxygen product continues to exchange heat along the first liquid oxygen delivery pipe 24 through the heat source channel of the first subcooler 27 and the medium continuously supplied to the cold source channel of the first subcooler 27 to form a subcooled liquid oxygen product. Finally, it is transported to the liquid oxygen storage device for temporary storage through the outlet end of the first liquid oxygen delivery pipe 24 as one of the liquid products of this product.

[0037] This embodiment enables timely adjustment of oxygen supply based on the oxygen demand of steel production enterprises. Oxygen not supplied to steel production enterprises is liquefied by the cooling capacity provided by the second main heat exchanger 14, thereby reducing the waste of materials and energy caused by the large amount of oxygen produced and discharged during the off-peak of the steel production cycle. The liquefied oxygen is then temporarily stored as liquid oxygen, realizing the adjustment of oxygen supply in different states, making the product form more flexible and conducive to promotion.

[0038] The embodiments described above are merely preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the patent claims of this utility model should be included within the scope of the patent application of this utility model.

Claims

1. A low-temperature distillation apparatus for blast furnace oxygen, comprising a distillation column, wherein the distillation column comprises, from top to bottom, an upper column (1), a main condenser heat exchanger (2), and a lower column (3), characterized in that: The upper tower (1) and the first main heat exchanger (5) are provided with an oxygen delivery main pipe (4). The oxygen delivery main pipe (4) is provided with the first main heat exchanger (5), an oxygen delivery branch pipe (6) and a first regulating valve (7) in sequence along the direction from near the upper tower (1) to away from the upper tower (1). The first main heat exchanger (5) and the upper tower (1) are provided with a finished nitrogen delivery pipe (8). The finished nitrogen delivery pipe (8) on the side of the first main heat exchanger (5) away from the upper tower (1) is provided with a second regulating valve (9). The finished nitrogen delivery pipe (8) between the second regulating valve (9) and the first main heat exchanger (5) is provided with the inlet end of the first nitrogen delivery branch pipe (10). The outlet end of the first nitrogen delivery branch pipe (10) is provided with an expansion nitrogen delivery pipe (11). The outlet end of the expansion nitrogen delivery pipe (11) is provided with the... The inlet end of the nitrogen compressor unit (12) is provided on the upper part, and the inlet end of the nitrogen circulation conveying pipe (13) is provided on the outlet end of the nitrogen compressor unit (12). The first nitrogen conveying branch pipe (10) away from the nitrogen compressor unit (12) is provided with the second main heat exchanger (14) on the expansion nitrogen conveying pipe (11), the nitrogen circulation conveying pipe (13) and the oxygen conveying branch pipe (6). The nitrogen circulation conveying pipe (13) is provided with the pressure boosting end of the first turbine expander (16) and the first machine post heat exchanger (15) in sequence along the direction from close to the nitrogen compressor unit (12) to away from the nitrogen compressor unit (12). The expansion end inlet of the first turbine expander (16) is connected to the outlet end of the nitrogen circulation conveying pipe (13), and the expansion end outlet of the first turbine expander (16) is connected to the inlet end of the expansion nitrogen conveying pipe (11).

2. The cryogenic distillation apparatus for blast furnace oxygen according to claim 1, characterized in that: The oxygen delivery branch pipe (6) between the second main heat exchanger (14) and the oxygen delivery main pipe (4) is provided with a third regulating valve (17), an oxygen compressor unit (18) and a second post-heat exchanger (19) in sequence along the direction from the oxygen delivery main pipe (4) to the second main heat exchanger (14). The inlet end of the oxygen delivery branch pipe (6) is connected to the oxygen delivery main pipe (4). A gas-liquid separator (20) is provided on the outlet end of the oxygen delivery branch pipe (6). A low-temperature oxygen return pipe (21) is provided on the top of the gas-liquid separator (20) and the second main heat exchanger (14). The outlet end of the oxygen delivery branch pipe (6) between the third regulating valve (17) and the oxygen compressor unit (18) and the low-temperature oxygen return pipe (21) is connected.

3. The low-temperature distillation apparatus for blast furnace oxygen according to claim 2, characterized in that: A wire mesh coalescer (22) is installed in the gas-liquid separator (20) above the outlet end of the oxygen delivery branch pipe (6). A liquid level sensor (23) is installed on the gas-liquid separator (20) below the wire mesh coalescer (22). A first liquid oxygen delivery pipe (24) is installed at the bottom of the gas-liquid separator (20). A fourth regulating valve (25), the outlet end of the second liquid oxygen delivery pipe (26), and the heat source channel of the first subcooler (27) are sequentially installed along the direction from near the gas-liquid separator (20) to away from the gas-liquid separator (20). A fifth regulating valve (28) is installed on the second liquid oxygen delivery pipe (26). The finished nitrogen delivery pipe (8) between the upper tower (1) and the first main heat exchanger (5) and the cold source channel of the first subcooler (27) are connected.

4. The cryogenic distillation apparatus for blast furnace oxygen according to claim 1, characterized in that: Gas flow sensors (29) are respectively installed on the nitrogen circulation conveying pipe (13) and the oxygen conveying branch pipe (6). The inlet end of the second nitrogen conveying branch pipe (30) is installed on the nitrogen circulation conveying pipe (13) between the first machine heat exchanger (15) and the first turbine expander (16). The second nitrogen conveying branch pipe (30) and the first nitrogen conveying branch pipe (10) are respectively equipped with a sixth regulating valve (31).

5. The cryogenic distillation apparatus for blast furnace oxygen according to claim 1, characterized in that: The inlet ends of the heat source channels of the upper tower (1) and the main condenser heat exchanger (2) are connected by a first pressure nitrogen delivery pipe (32). A second pressure nitrogen delivery pipe (33) is provided on the first pressure nitrogen delivery pipe (32). A liquid nitrogen delivery main pipe (34) is provided on the outlet end of the heat source channel of the main condenser heat exchanger (2). The liquid nitrogen delivery main pipe (34) is provided with the inlet end of the first liquid nitrogen delivery branch pipe (35) and the inlet end of the second liquid nitrogen delivery branch pipe (36) in sequence along the direction from near the main condenser heat exchanger (2) to away from the main condenser heat exchanger (2). The outlet end of the first liquid nitrogen delivery branch pipe (35) is connected to the lower tower (3), and the outlet end of the second liquid nitrogen delivery branch pipe (36) is connected to the upper tower (1). The upper tower (1) and the lower tower (3) are equipped with oxygen-enriched liquid air delivery pipes (38). The liquid nitrogen delivery main pipe (34) between the first liquid nitrogen delivery branch pipe (35) and the second liquid nitrogen delivery branch pipe (36), the finished nitrogen delivery pipe (8) between the upper tower (1) and the first main heat exchanger (5), and the oxygen-enriched liquid air delivery pipe (38) are equipped with a second subcooler (39).

6. The cryogenic distillation apparatus for blast furnace oxygen according to claim 5, characterized in that: A bubble pump is installed on the oxygen-enriched liquid air delivery pipe (38) between the second subcooler (39) and the lower tower (3). The bubble pump includes an inner pipe (41) installed on the oxygen-enriched liquid air delivery pipe (38), a jacket (42) installed outside the inner pipe (41), a number of equalizing rings (43) installed outside the jacket (42) along the direction from the top of the jacket (42) to the bottom of the jacket (42), a number of equalizing pipes (44) installed on two adjacent equalizing rings (43), a number of delivery pipes (55) installed on each equalizing ring (43) and the jacket (42), and a number of vent holes (45) installed on the inner pipe (41) inside the jacket (42); and the outlet end of the first compressed air delivery pipe (46) installed on the uppermost equalizing ring (43).

7. The cryogenic distillation apparatus for blast furnace oxygen according to claim 6, characterized in that: A second compressed air supply pipe (50) is provided at the inlet end of the first compressed air supply pipe (46), on the lower tower (3), and on the first main heat exchanger (5). The outlet end of the second compressed air supply pipe (50) is connected to the lower tower (3). A third compressed air supply pipe (51) is provided at the inlet end of the second compressed air supply pipe (50) and on the first main heat exchanger (5). The third compressed air supply pipe (51) between the second compressed air supply pipe (50) and the first main heat exchanger (5) and the second compressed air supply pipe (46) between the first compressed air supply pipe (46) and the lower tower (3) are connected. Each compressed air delivery pipe (50) is equipped with a tenth regulating valve (52). The third compressed air delivery pipe (51) between the second compressed air delivery pipe (50) and the first main heat exchanger (5) is arranged in sequence along the direction from near the first main heat exchanger (5) to far away from the first main heat exchanger (5) with the third downstream heat exchanger (53) and the pressurization end of the second turbine expander (54). The outlet end of the third compressed air delivery pipe (51) is connected to the expansion end inlet of the second turbine expander (54). The expansion end outlet of the second turbine expander (54) is connected to the upper tower (1).

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