Low-cost air separation device with power generation function

Abstract

The invention provides a low-cost air separation device with a power generation function, and particularly relates to the technical field of air separation.The low-cost air separation device with the power generation function comprises a storage unit, an air separation unit and a recovery unit, and the recovery unit comprises a first-stage intercooler and a second-stage intercooler; the air separation unit comprises a first regenerator and a second regenerator, compression heat, air and cold energy in the regenerator are recycled through the regenerator set and the interstage cooler set, energy in the device can be fully utilized, and energy loss is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of air separation, and particularly to a low-cost air separation device with power generation function. Background Art

[0002] The air separation industry is the basis of industries such as metallurgy and chemical industry. During the steel smelting process, a large supply of pure oxygen can significantly reduce the smelting energy consumption and increase the steel output.

[0003] Traditional air separation devices usually liquefy air by cooling it into air liquid, and then separate different air liquids through a distillation column. Due to the high power consumption of the current large-scale industrial air separation devices, and it is easy to generate cold energy or heat energy in the air separation device, with large energy losses, and most of the current air separation devices cannot make good use of the generated heat energy or cold energy, especially the compression heat generated during the compression process.

[0004] In view of this, the present invention provides a low-cost air separation device with power generation function. Summary of the Invention

[0005] In order to solve the problem that the cold energy or heat energy of the air separation device cannot be fully utilized, the present invention proposes a low-cost air separation device with power generation function.

[0006] The present invention is realized through the following technical solutions:

[0007] The present invention proposes that the low-cost air separation device with power generation function includes a recovery unit, a storage unit and an air separation unit, wherein:

[0008] The storage unit includes a first storage tank, a second storage tank, a third storage tank and a fourth storage tank;

[0009] The recovery unit includes a low-temperature storage tank, an inter-stage cooler group, a high-temperature storage tank and a generator. The inter-stage cooler group includes a first inter-stage cooler and a second inter-stage cooler. One outlet of the low-temperature storage tank is sequentially connected to the first inter-stage cooler and the inlet end of the high-temperature storage tank, and the other inlet of the low-temperature storage tank is sequentially connected to the second inter-stage cooler and the inlet end of the high-temperature storage tank. A power generation unit or a power generation cycle unit is connected between the outlet end of the high-temperature storage tank and the inlet end of the low-temperature storage tank;

[0010] The air separation unit includes a rectification column, a compressor unit, a regenerator unit, and an expansion unit. The compressor unit includes a first compressor and a second compressor. The regenerator unit includes a first regenerator and a second regenerator. The expansion unit includes a first expander, a second expander, and a third expander. One end of the first compressor is sequentially connected to the first intercooler, the second compressor, the second intercooler, and the first regenerator. One outlet end of the first regenerator is sequentially connected to the third expander and the rectification column. The other outlet end of the first regenerator is connected to the second regenerator. The outlet ends of the second regenerator are respectively connected to the first expander and the second expander. The outlet end of the first expander is sequentially connected to the first storage tank, the second regenerator, and the first regenerator. The outlet end of the second expander is sequentially connected to the rectification column and the first storage tank. The first storage tank, the second storage tank, the third storage tank, and the fourth storage tank are connected to the rectification column. The outlet ends of the rectification column, the second storage tank, the third storage tank, and the fourth storage tank are respectively sequentially connected to the second regenerator and the first regenerator.

[0011] Further, the power generation cycle unit includes a fourth expander, a heat exchanger, a working fluid pump, and a condenser. The outlet end of the fourth expander is sequentially connected to the heat exchanger, the working fluid pump, the condenser, and then back to the inlet end of the fourth expander.

[0012] Further, when the heat exchanger is connected to the high-temperature storage tank and the low-temperature storage tank, the sections between the first storage tank and the second regenerator, on both sides of the first expander, and on both sides of the third expander are in a disconnected state.

[0013] Further, the power generation unit includes a generator set. Both ends of the generator set are respectively connected to the high-temperature storage tank and the low-temperature storage tank.

[0014] Further, when the generator set is connected to the high-temperature storage tank and the low-temperature storage tank, the sections between the first storage tank and the second regenerator, on both sides of the first expander, and on both sides of the third expander are in a disconnected state.

[0015] Further, a throttle valve is provided between the first expander and the first storage tank.

[0016] Further, when there is no power generation unit or power generation cycle unit connected between the high-temperature storage tank and the low-temperature storage tank, both sides of the second expander are in a disconnected state.

[0017] Advantages of the present invention:

[0018] (1) The low-cost air separation device with power generation function proposed by the present invention recovers the cold energy of the unliquefied air and the cold energy inside the regenerator and the compression heat generated by the compressor unit through the regenerator group and the inter-stage cooler group, and can make full use of the heat energy and cold energy generated in the system to avoid a large amount of energy waste.

[0019] (2) The low-cost air separation device with power generation function proposed by the present invention has multiple working modes. In the low valley working mode, the compression heat can be stored in the first storage tank. In the non-low valley working mode, the compression heat can be used for power generation or the heat can be recovered by using the power generation cycle unit. Through multiple working modes, it can be well adapted to different environments and requirements.

[0020] (3) The low-cost air separation device with power generation function provided by the present invention can store cold energy by storing liquid air in the first storage tank during the low valley period. When the rectification column operates, the first storage tank can supply cold energy to the rectification column and supply it for the rectification column to use throughout the day, concentrating the energy consumption of the rectification column in the low valley period of electricity and reducing the cost of the entire device. Description of the Drawings

[0021] Figure 1 is the overall structure diagram of the low-cost air separation device with power generation function of the present invention;

[0022] Figure 2 is another overall structure diagram of the low-cost air separation device with power generation function of the present invention;

[0023] Figure 3 is the connection structure diagram of the low-cost air separation device with power generation function of the present invention during the low valley period;

[0024] Figure 4 is a connection structure diagram of the low-cost air separation device with power generation function of the present invention during the non-low valley period;

[0025] Figure 5 is another connection structure diagram of the low-cost air separation device with power generation function of the present invention during the non-low valley period;

[0026] In the figure: air separation unit 1, first compressor 11, second compressor 12, first regenerator 13, second regenerator 14, first expander 15, second expander 16, third expander 17, rectification column 18, recovery unit 2, first inter-stage cooler 21, second inter-stage cooler 22, high-temperature storage tank 23, low-temperature storage tank 24, storage unit 3, first storage tank 31, second storage tank 32, third storage tank 33, fourth storage tank 34, throttle valve 4, power generation unit 5, power generation cycle unit 6, fourth expander 61, heat exchanger 62, condenser 63, working fluid pump 64

[0027] For the realization of the object, functional features and advantages of the present invention, further explanations will be made with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0028] In order to more clearly and completely illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0029] Please refer to Figures 1 - 5 , the present invention provides a low-cost air separation device with a power generation function, which includes a recovery unit 2, a storage unit 3 and an air separation unit 1, wherein:

[0030] The storage unit 3 includes a first storage tank 31, a second storage tank 32, a third storage tank 33 and a fourth storage tank 34;

[0031] The recovery unit 2 includes a cryogenic storage tank 24, an inter-stage cooler group, a high-temperature storage tank 23 and a generator. The inter-stage cooler group includes a first inter-stage cooler 21 and a second inter-stage cooler 22. An outlet of the cryogenic storage tank 24 is sequentially connected to the first inter-stage cooler 21 and the inlet end of the high-temperature storage tank 23, and another inlet of the cryogenic storage tank 24 is sequentially connected to the second inter-stage cooler 22 and the inlet end of the high-temperature storage tank 23. A power generation unit 5 or a power generation cycle unit 6 is connected between the outlet end of the high-temperature storage tank 23 and the inlet end of the cryogenic storage tank 24;

[0032] The air separation unit 1 includes a rectification column 18, a compressor set, a regenerator group and an expansion unit. The compressor set includes a first compressor 11 and a second compressor 12. The regenerator group includes a first regenerator 13 and a second regenerator 14. The expansion unit includes a first expander 15, a second expander 16 and a third expander 17. One end of the first compressor 11 is sequentially connected to the first inter-stage cooler 21, the second compressor 12, the second inter-stage cooler 22 and the first regenerator 13. An outlet end of the first regenerator 13 is sequentially connected to the third expander 17 and the rectification column 18. Another outlet end of the first regenerator 13 is connected to the second regenerator 14. The outlet end of the second regenerator 14 is respectively connected to the first expander 15 and the second expander 16. The outlet end of the first expander 15 is sequentially connected to the first storage tank 31, the second regenerator 14 and the first regenerator 13. The outlet end of the second expander 16 is sequentially connected to the rectification column 18 and the first storage tank 31. The first storage tank 31, the second storage tank 32, the third storage tank 33, the fourth storage tank 34 are connected to the rectification column 18, and the outlet ends of the rectification column 18, the second storage tank 32, the third storage tank 33 and the fourth storage tank 34 are sequentially connected to the second regenerator 14 and the first regenerator 13.

[0033] In this embodiment:

[0034] The first compressor 11 and the second compressor 12 are used to compress air;

[0035] The first inter-stage cooler 21 and the second inter-stage cooler 22 are used to recover the compression heat;

[0036] The first cold accumulator 13 and the second cold accumulator 14 are used to recover the released cold;

[0037] The first expander 15 is a liquid expander;

[0038] The second expander 16 and the third expander 17 are cryogenic gas expanders;

[0039] The rectifying column 18 is used to separate air;

[0040] The first storage tank 31 is used to store liquid air;

[0041] The second storage tank 32, the third storage tank 33 and the fourth storage tank 34 are respectively used to store liquid oxygen, liquid argon and liquid nitrogen;

[0042] Specifically, after the air passes through the compressor unit for heat exchange, the compression heat is recovered through the inter-stage cooler group at the same time, and finally enters the cold accumulator group for cooling. After passing through the expander and expanding to the pressure required by the rectifying column 18, it enters the rectifying column 18 for rectification to separate out various liquid gases, including liquid air, liquid oxygen, liquid argon, liquid nitrogen, etc., which are respectively stored in the storage unit 3. After the gas is released from the storage unit 3, the cold energy can be recovered through the cold accumulator group; the medium in the intermediate low-temperature storage tank 24 stores the heat recovered by the cooler group in the high-temperature storage tank 23, and the heat energy flowing out of the high-temperature storage tank 23 re-uses the heat energy through the power generation unit 5 or the power generation cycle unit 6 and stores it in the low-temperature storage tank 24. The first cold accumulator 13 and the second cold accumulator 14 can recover the cold energy to achieve the energy balance in each period.

[0043] In one embodiment, the number of compressors, inter-stage coolers, cold accumulators and expanders in the compressor unit, inter-stage cooler group, cold accumulator group and expander group can be selected according to actual needs, and can be three or four. At the same time, the number of storage tanks in the storage unit 3 can also be selected according to the actual situation. The media in the low-temperature storage tank 24 and the high-temperature storage tank 23 can be selected according to the actual situation, and can be gas or liquid, and can be solid-phase heat storage or phase-change heat storage.

[0044] In one embodiment, it is possible to connect pipelines at the outlets of the second storage tank 32, the third storage tank 33, and the fourth storage tank 34 and sequentially connect the second cold accumulator 14 and the first cold accumulator 13. When transporting the liquid gas to the outside, the cold energy can be recovered through the second cold accumulator 14 and the first cold accumulator 13. When it is necessary to store the liquid gas, the pipelines at the outlets of the second storage tank 32, the third storage tank 33, and the fourth storage tank 34 can be closed.

[0045] Furthermore, the power generation cycle unit 6 includes a fourth expander 61, a heat exchanger 62, a working fluid pump 64, and a condenser 63. The outlet end of the fourth expander 61 is sequentially connected to the heat exchanger 62, the working fluid pump 64, the condenser 63, and then connected back to the inlet end of the fourth expander 61.

[0046] In this embodiment:

[0047] The power generation cycle unit 6 is used to form a cycle loop to provide a cold source;

[0048] Specifically, the fourth expander 61 expands the gas and sequentially exchanges heat through the heat exchanger 62. After heat exchange, it is condensed through the condenser 63 and then enters the fourth expander 61 again for expansion to provide cold energy for the heat exchanger 62. The high-temperature medium in the high-temperature storage tank 23 enters the low-temperature storage tank 24 for storage again after heat exchange through the heat exchanger 62.

[0049] Furthermore, when the heat exchanger 62 is connected to the high-temperature storage tank 23 and the low-temperature storage tank 24, the sections between the first storage tank 31 and the second cold accumulator 14, both sides of the first expander 15, and both sides of the third expander 17 are in a disconnected state.

[0050] Specifically, refer to Figure 5, during non-low valley periods, the heat exchanger 62 is connected to the outlet of the high-temperature storage tank 23 and the inlet of the low-temperature storage tank 24. Both sides of the first expander 15 and the third expander 17 are in a disconnected state. At this time, the first compressor 11 and the second compressor 12 compress a small amount of air to the medium pressure state, and are cooled to room temperature at the first intercooler 21 and the second intercooler 22 respectively. The medium-pressure air enters the first regenerator 13 and the second regenerator 14 for cooling. The cooled medium-pressure air is in a gaseous state and then enters the second expander 16 to expand to the corresponding pressure of the rectification column 18, and is sent to the rectification column 18 for residual air separation. At the same time, a part of the liquid air is drawn from the first storage tank 31 and sent to the rectification equipment for residual air separation. After separation, the produced gaseous product enters the first regenerator 13 and the second regenerator 14 to provide cold for the compressed air. The liquid products enter the second storage tank 32, the third storage tank 33 and the fourth storage tank 34 for storage respectively; at the same time, during the operation of the entire device, the low-temperature medium in the low-temperature storage tank 24 provides cold for the first intercooler 21 and the second intercooler 22 and becomes a high-temperature medium and enters the high-temperature storage tank 23. Subsequently, the heat of the high-temperature medium at the outlet of the high-temperature storage tank 23 is absorbed by the heat exchanger 62 and becomes a low-temperature medium and is stored in the low-temperature storage tank 24 again. At the same time, the medium in the heat exchanger 62 is always in a low-temperature state through the cycle of the working fluid pump 64, the condenser 63 and the fourth expander 61.

[0051] Further, the power generation unit 5 includes a generator set, and both ends of the generator set are respectively connected to the high-temperature storage tank 23 and the low-temperature storage tank 24.

[0052] In this embodiment:

[0053] The generator set is a Stirling generator;

[0054] Specifically, the generator set can be one generator or multiple generators, and the actual type of the generator can also be selected as other generators using temperature difference to generate heat according to the actual situation, such as the Kenlon cycle and other power generation cycles.

[0055] Further, when the generator set is connected to the high-temperature storage tank 23 and the low-temperature storage tank 24, the connection between the first storage tank 31 and the second regenerator 14, both sides of the first expander 15, and both sides of the third expander 17 are in a disconnected state.

[0056] Specifically, refer to Figure 4, during non-low valley periods, when the generator set is connected to the high-temperature storage tank 23 and the low-temperature storage tank 24, the sections between the first storage tank 31 and the second regenerator 14, on both sides of the first expander 15, and on both sides of the third expander 17 are in a disconnected state. At this time, the first compressor 11 and the second compressor 12 compress a small amount of air to a medium pressure state, and at the same time are cooled to room temperature in the first intercooler 21 and the second intercooler 22 respectively. The medium-pressure air enters the first regenerator 13 and the second regenerator 14 for cooling. The cooled medium-pressure air is in a gaseous phase and then enters the second expander 16 to expand to the corresponding pressure of the distillation column 18 and is sent into the distillation column 18 for the separation of residual air. At the same time, a part of the liquid air is drawn from the first storage tank 31 and sent into the distillation equipment for the separation of residual air. After separation, the produced gaseous product enters the first regenerator 13 and the second regenerator 14 to provide cold energy for the compressed air, and the liquid product enters the second storage tank 32, the third storage tank 33 and the fourth storage tank 34 for storage respectively; at the same time, during the operation of the entire device, the low-temperature medium in the low-temperature storage tank 24 provides cold energy for the first intercooler 21 and the second intercooler 22 and becomes a high-temperature medium and enters the high-temperature storage tank 23. Subsequently, the heat of the high-temperature medium at the outlet of the high-temperature storage tank 23 forms a temperature difference with the cold end of the generator set to generate electricity for the generator set, which can improve the utilization of energy.

[0057] Further, a throttle valve 4 is provided between the first expander 15 and the first storage tank 31;

[0058] When there is no power generation unit 5 or power generation cycle unit 6 connected between the high-temperature storage tank 23 and the low-temperature storage tank 24, both sides of the second expander 16 are in a disconnected state.

[0059] Specifically, refer to Figure 3When the system operates during the low-demand period, there is no power generation unit 5 or power generation cycle unit 6 connected between the high-temperature storage tank 23 and the low-temperature storage tank 24, and when both sides of the second expander 16 are disconnected, after the compressed air is compressed in the first compressor 11 and the second compressor 12, it is cooled to normal temperature through the cooling capacity provided by the low-temperature storage tank 24 in the first inter-stage cooler 21 and the second inter-stage cooler respectively, and the medium that absorbs the temperature is stored in the high-temperature storage tank 23. The compressed air cooled to normal temperature enters the first cold storage device 13 and the second cold storage device 14 and is cooled again by the cold storage medium in the first cold storage device 13 and the second cold storage device 14. A part of the air in the middle of the first cold storage device 13 enters the third expander 17 and expands to the pressure required in the rectification column 18, and then participates in air separation in the rectification column 18. The remaining compressed air enters the second cold storage device 14 and is cooled to liquefaction, then expands to a low pressure through the first expander 15, and then enters the throttle valve 4 and is throttled to normal pressure. It includes a gas-liquid two-phase, where the liquid is stored in the first storage tank 31, and the gas returns to the first cold storage device 13 and the second cold storage device 14 to recover the cold quantity. A part of the liquid air in the first storage tank 31 is pumped out and sent into the rectification column 18 to provide raw materials for the liquid phase. The products produced by the rectification column 18 are nitrogen, liquid nitrogen, liquid oxygen, liquid argon, and waste nitrogen. The gas enters the first cold storage device 13 and the second cold storage device 14 to recover the cold quantity, and the liquid enters the second storage tank 32, the third storage tank 33, and the fourth storage tank 34 for storage respectively. A large amount of compression heat during the low-demand period can be stored in the high-temperature storage tank 23.

[0060] In one embodiment, the throttle valve 4 can also be used to achieve the effect of reducing pressure and temperature, thus playing the same role as the expander.

[0061] In summary, through various operating modes such as non-low-demand and low-demand periods, the energy consumption can be fully utilized, and the situation of energy waste can be avoided.

[0062] Of course, the present invention can also have many other embodiments. Based on this embodiment, other embodiments obtained by those of ordinary skill in the art without any creative work belong to the scope protected by the present invention.

Claims

1. A low-cost air separation device with power generation function, characterized in that, It includes a recovery unit, a storage unit, and an air separation unit, where: The storage unit includes a first storage tank, a second storage tank, a third storage tank, and a fourth storage tank; The recovery unit includes a low-temperature storage tank, an inter-stage cooler group, a high-temperature storage tank, and a generator. The inter-stage cooler group includes a first inter-stage cooler and a second inter-stage cooler. One outlet of the low-temperature storage tank is sequentially connected to the first inter-stage cooler and the inlet end of the high-temperature storage tank. The other inlet of the low-temperature storage tank is sequentially connected to the second inter-stage cooler and the inlet end of the high-temperature storage tank. A power generation unit or a power generation cycle unit is connected between the outlet end of the high-temperature storage tank and the inlet end of the low-temperature storage tank; The air separation unit includes a rectifying column, a compressor unit, a regenerator group, and an expansion unit. The compressor unit includes a first compressor and a second compressor. The regenerator group includes a first regenerator and a second regenerator. The expansion unit includes a first expander, a second expander, and a third expander. One end of the first compressor is sequentially connected to the first inter-stage cooler, the second compressor, the second inter-stage cooler, and the first regenerator. One outlet end of the first regenerator is sequentially connected to the third expander and the rectifying column. The other outlet end of the first regenerator is connected to the second regenerator. The outlet end of the second regenerator is respectively connected to the first expander and the second expander. The outlet end of the first expander is sequentially connected to the first storage tank, the second regenerator, and the first regenerator. The outlet end of the second expander is sequentially connected to the rectifying column and the first storage tank. The first storage tank, the second storage tank, the third storage tank, and the fourth storage tank are connected to the rectifying column. The outlet ends of the rectifying column, the second storage tank, the third storage tank, and the fourth storage tank are respectively sequentially connected to the second regenerator and the first regenerator.

2. The low-cost air separation device with power generation function according to claim 1, wherein The power generation cycle unit includes a fourth expander, a heat exchanger, a working fluid pump, and a condenser. The outlet end of the fourth expander is sequentially connected to the heat exchanger, the working fluid pump, the condenser, and then connected back to the inlet end of the fourth expander.

3. The low-cost air separation device with power generation function according to claim 5, characterized in that When the heat exchanger is connected to the high-temperature storage tank and the low-temperature storage tank, the sections between the first storage tank and the second regenerator, both sides of the first expander, and both sides of the third expander are in a disconnected state.

4. The low-cost air separation device with power generation function according to claim 1, characterized in that, The power generation unit includes a generator set, and both ends of the generator set are respectively connected to the high-temperature storage tank and the low-temperature storage tank.

5. The low-cost air separation device with power generation function according to claim 4, characterized in that, When the generator set is connected to the high-temperature storage tank and the low-temperature storage tank, the sections between the first storage tank and the second regenerator, both sides of the first expander, and both sides of the third expander are in a disconnected state.

6. The low-cost air separation device with power generation function according to claim 1, characterized in that, A throttle valve is provided between the first expander and the first storage tank.

7. The low-cost air separation device with power generation function according to claim 6, characterized in that, When there is no power generation unit or power generation cycle unit connected between the high-temperature storage tank and the low-temperature storage tank, both sides of the second expander are in a disconnected state.

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