Pure hydrogen shaft furnace and hydrogen circulation system and production method thereof

Abstract

The invention relates to a hydrogen circulation system which comprises a heating furnace, a thermochemical hydrogen production mechanism, a gas outlet pipeline connected with a top gas outlet of a shaft furnace, and a gas return pipeline connected with a reaction gas inlet of the shaft furnace, the gas outlet pipeline is connected with a heat source channel of an H2SO4 decomposer and a heat source channel of an HI decomposer of the thermochemical hydrogen production mechanism in series and then is connected with a heat exchange gas inlet of the heating furnace, and the gas return pipeline is connected with a heat exchange gas outlet of the heating furnace; and hydrogen produced by the thermochemical hydrogen production mechanism is supplied to the shaft furnace as reaction gas. Correspondingly, the invention further provides a pure hydrogen shaft furnace provided with the hydrogen circulation system and a production method of the pure hydrogen shaft furnace. According to the system, the gas outlet pipeline is connected with the heat source channel of the H2SO4 decomposer and the heat source channel of the HI decomposer in series, part of heat energy of the furnace top gas is recycled for sulfur-iodine thermochemical hydrogen production, the high-temperature requirement of sulfur-iodine thermochemical hydrogen production is met, and hydrogen circulation of the pure hydrogen shaft furnace can be achieved; the production cost of the pure hydrogen shaft furnace can be obviously reduced, and the production reliability of the pure hydrogen shaft furnace is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of shaft furnace production, and specifically relates to a hydrogen circulation system for a pure hydrogen shaft furnace, a pure hydrogen shaft furnace equipped with the hydrogen circulation system, and a production method for the pure hydrogen shaft furnace. Background Art

[0002] The iron and steel industry has long been a major emitter of carbon emissions, and has a heavy task of carbon emission reduction. At present, the technologies of blast furnace hydrogen-rich and low-carbon smelting and gas-based shaft furnace low-carbon smelting have been successfully applied in actual production, proving the effectiveness of these technologies in reducing carbon emissions in the iron and steel industry. The pure hydrogen shaft furnace direct reduction technology is a low-carbon smelting technology with even lower carbon emissions. However, the pure hydrogen shaft furnace direct reduction technology requires a large amount of hydrogen as a reaction gas, with high energy consumption and high production costs, thus restricting the popularization and application of this technology. Summary of the Invention

[0003] The present invention relates to a hydrogen circulation system for a pure hydrogen shaft furnace, a pure hydrogen shaft furnace equipped with the hydrogen circulation system, and a production method for the pure hydrogen shaft furnace, which can at least solve some defects of the prior art.

[0004] The present invention relates to a hydrogen circulation system for a pure hydrogen shaft furnace, including a heating furnace, a thermochemical hydrogen production mechanism, an outlet pipeline connected to the top gas outlet of the shaft furnace, and a return pipeline connected to the reaction gas inlet of the shaft furnace;

[0005] The thermochemical hydrogen production mechanism includes a reaction kettle, an H2SO4 decomposer, and an HI decomposer. The H2SO4 decomposer is connected to the H2SO4 phase outlet of the reaction kettle through an H2SO4 medium pipe, and the HI decomposer is connected to the HI phase outlet of the reaction kettle through an HI medium pipe;

[0006] The outlet pipeline is connected to the heat exchange gas inlet of the heating furnace after connecting in series the heat source channels of the H2SO4 decomposer and the HI decomposer, and the return pipeline is connected to the heat exchange gas outlet of the heating furnace;

[0007] The HI decomposer is connected to a hydrogen gas storage tank, and the hydrogen gas storage tank is communicated with the reaction gas inlet of the shaft furnace through a green hydrogen supply pipe.

[0008] As one of the implementation manners, the outlet end of the green hydrogen supply pipe is connected in parallel to the outlet pipeline.

[0009] As one of the implementation manners, a first bypass pipe is also connected in parallel to the green hydrogen supply pipe. The first bypass pipe is directly connected to the shaft furnace, and control valves are respectively provided on the green hydrogen supply pipe and the first bypass pipe. The control valve on the green hydrogen supply pipe is located downstream of the parallel connection point of the first bypass pipe.

[0010] As one of the implementation manners, a dehydrator is provided on the air outlet pipeline, and the dehydrator is located upstream of the heat source channel series connection area.

[0011] As one of the implementation manners, the thermochemical hydrogen production mechanism further includes a premixing tank. The mixed medium outlet of the premixing tank is communicated with the reaction medium inlet of the reaction kettle, and the water outlet of the dehydrator is communicated with the water replenishing port of the premixing tank.

[0012] As one of the implementation manners, the thermochemical hydrogen production mechanism further includes a premixing tank. The mixed medium outlet of the premixing tank is communicated with the reaction medium inlet of the reaction kettle, and the heating furnace is configured with a water collecting pipe, and the water collecting pipe is connected to the water replenishing port of the premixing tank.

[0013] As one of the implementation manners, a recuperator is further arranged on the air outlet pipeline, and the recuperator is located downstream of the heat source channel series connection area.

[0014] As one of the implementation manners, a second bypass pipe is also connected in parallel to the air outlet pipeline, and the outlet end of the second bypass pipe is connected to the fuel gas inlet of the heating furnace.

[0015] The present invention also relates to a pure hydrogen shaft furnace configured with a hydrogen circulation system of the pure hydrogen shaft furnace as described above.

[0016] The present invention also relates to a production method of a pure hydrogen shaft furnace, which is implemented based on the above pure hydrogen shaft furnace. The production method includes:

[0017] Leading out the top gas of the shaft furnace,

[0018] Introducing at least part of the top gas into the thermochemical hydrogen production mechanism as the heat source for H2SO4 decomposition and HI decomposition, and then sending the top gas led out from the thermochemical hydrogen production mechanism into the shaft furnace as reaction gas and / or into the heating furnace as fuel gas;

[0019] Sending the hydrogen produced by the thermochemical hydrogen production mechanism into the shaft furnace as reaction gas.

[0020] The present invention has at least the following beneficial effects:

[0021] In the present invention, a thermochemical hydrogen production mechanism is configured, and the air outlet pipeline is connected in series with the heat source channels of the H2SO4 decomposer and the HI decomposer, and part of the heat energy of the top gas is recovered for sulfur-iodine thermochemical hydrogen production, meeting the high-temperature requirements of sulfur-iodine thermochemical hydrogen production, enabling the hydrogen circulation of the pure hydrogen shaft furnace, and significantly reducing the production cost of the pure hydrogen shaft furnace and improving the production reliability of the pure hydrogen shaft furnace. Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a schematic structural diagram of the hydrogen circulation system provided by the embodiment of the present invention;

[0024] Figure 2 It is a schematic structural diagram of the thermochemical hydrogen production mechanism provided by the embodiment of the present invention. Detailed implementation manners

[0025] The following clearly and completely describes the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] Embodiment 1

[0027] As shown in Figure 1 and Figure 2 , the embodiment of the present invention provides a hydrogen circulation system for a pure hydrogen shaft furnace, including a heating furnace 5, a thermochemical hydrogen production mechanism 3, an outlet pipeline 2 connected to the top gas outlet of the shaft furnace 1, and a return gas pipeline 4 connected to the reaction gas inlet of the shaft furnace 1.

[0028] In one embodiment, as shown in Figure 1 , a dust collector 21 is provided on the outlet pipeline 2 for dust removal of the top gas. The dust collector 21 includes, but is not limited to, dust removal equipment such as a cyclone dust collector 21.

[0029] In one embodiment, as shown in Figure 1 , a dehydrator 22 is arranged on the outlet pipeline 2 for dehydration of the top gas. When the dust collector 21 is provided, preferably, the dehydrator 22 is arranged downstream of the dust collector 21, that is, the dust collector 21 and the dehydrator 22 are arranged in sequence along the flow direction of the top gas.

[0030] In one embodiment, as shown in Figure 1 , a top gas compressor 23 is also arranged on the outlet pipeline 2, which can pressurize the gas in the pipeline for subsequent treatment. When the dehydrator 22 is provided, preferably, the top gas compressor 23 is arranged downstream of the dehydrator 22.

[0031] In one embodiment, as shown in Figure 2, the thermochemical hydrogen production mechanism 3 includes a reaction kettle 31, an H2SO4 decomposer 331, and an HI decomposer 341. The H2SO4 decomposer 331 is connected to the H2SO4 phase outlet of the reaction kettle 31 through an H2SO4 medium pipe, and the HI decomposer 341 is connected to the HI phase outlet of the reaction kettle 31 through an HI medium pipe.

[0032] Among them, the above-mentioned reaction kettle 31 is used to carry out the Bunsen reaction, and the reaction raw materials include SO2, H2O, and I2; optionally, as Figure 2 , the thermochemical hydrogen production mechanism 3 further includes a premixing tank 32. The mixed medium outlet of the premixing tank 32 is communicated with the reaction medium inlet of the reaction kettle 31. SO2, H2O, and I2 are pre-mixed in proportion in the premixing tank 32, which can improve the Bunsen reaction effect.

[0033] In the reaction kettle 31, H2SO4 phase and HI phase solutions will be generated. The H2SO4 phase solution has a lower density and mostly accumulates in the upper part of the reaction kettle 31 and can be led out through the H2SO4 medium pipe; the HI phase solution has a higher density and mostly accumulates in the lower part of the reaction kettle 31 and can be led out through the HI medium pipe.

[0034] Furthermore, as Figure 2 , an H2SO4 purification tower 332 and an H2SO4 concentration tower 333 are successively arranged on the H2SO4 medium pipe. The H2SO4 phase solution purified by the H2SO4 purification tower 332 enters the H2SO4 decomposer 331 after being concentrated by the H2SO4 concentration tower 333.

[0035] H2SO4 absorbs heat and decomposes into O2, SO2, and H2O in the H2SO4 decomposer 331. Optionally, the H2SO4 decomposer 331 is configured with an oxygen storage tank 334, and the decomposed O2 is led to the oxygen storage tank 334 for storage. SO2 and H2O are preferably returned to the premixing tank 32 as reaction raw materials.

[0036] Furthermore, as Figure 2 , an HI purification tower 342 and an HI concentration device are successively arranged on the HI medium pipe. The HI phase solution purified by the HI purification tower 342 enters the HI decomposer 341 after being concentrated by the HI concentration device. Preferably, the HI concentration device adopts an electrodialysis concentration device 343 and an HI rectification tower 344. In the electrodialysis concentration device 343, the I2 concentrated solution at the anode can be returned to the premixing tank 32 as a reaction raw material, and the HI phase concentrated solution at the cathode enters the HI rectification tower 344 for further rectification.

[0037] HI undergoes endothermic decomposition into H2 and I2 in the HI decomposer 341. Optionally, the HI decomposer 341 is connected to a hydrogen gas storage tank 345, and the decomposed H2 is led into this hydrogen gas storage tank 345. The I2 is preferably returned to the premixing tank 32 as a reaction raw material.

[0038] The hydrogen gas decomposed in the HI decomposer 341 can be supplied as reaction gas to the shaft furnace 1, that is: the hydrogen gas storage tank 345 is communicated with the reaction gas inlet of the shaft furnace 1 through the green hydrogen supply pipe 30.

[0039] In one embodiment, as Figure 2 , the outlet pipeline 2 is connected to the heat source channel of the H2SO4 decomposer 331 and the heat source channel of the HI decomposer 341 in series and then connected to the heat exchange gas inlet of the heating furnace 5, and the return gas pipeline 4 is connected to the heat exchange gas outlet of the heating furnace 5.

[0040] Among them, the heating furnace 5 is used to heat the hydrogen gas, thereby improving the reaction efficiency and effect in the pure hydrogen shaft furnace 1.

[0041] Preferably, the indirect heat exchange method is adopted in the H2SO4 decomposer 331 and the HI decomposer 341, including but not limited to respectively arranging heat exchange tubes in the H2SO4 decomposer 331 and the HI decomposer 341 as heat source channels, and these heat exchange tubes are connected in series to the outlet pipeline 2. Or rather, the outlet pipeline 2 includes two heat exchange tube sections extending into the H2SO4 decomposer 331 and the HI decomposer 341. Specifically, the outlet pipeline 2 includes a first pipe section, a second pipe section and a third pipe section. The inlet end of the first pipe section is connected to the top gas outlet of the shaft furnace 1, the outlet end of the first pipe section is connected to the heat exchange tube inlet end of the H2SO4 decomposer 331, the inlet end of the second pipe section is connected to the heat exchange tube outlet end of the H2SO4 decomposer 331, the outlet end of the second pipe section is connected to the heat exchange tube inlet end of the HI decomposer 341, the inlet end of the third pipe section is connected to the heat exchange tube outlet end of the HI decomposer 341, and the outlet end of the third pipe section is connected to the heat exchange gas inlet of the heating furnace 5.

[0042] In this embodiment, the thermochemical hydrogen production mechanism 3 is configured, and the outlet pipeline 2 is connected to the heat source channels of the H2SO4 decomposer 331 and the HI decomposer 341 in series, recovering part of the heat energy of the top gas for sulfur-iodine thermochemical hydrogen production, meeting the high-temperature requirements of sulfur-iodine thermochemical hydrogen production, realizing the hydrogen cycle of the pure hydrogen shaft furnace 1, and being able to significantly reduce the production cost of the pure hydrogen shaft furnace 1 and improve the production reliability of the pure hydrogen shaft furnace 1.

[0043] In one embodiment, when the dehydrator 22 is provided, the water outlet of the dehydrator 22 is communicated with the water replenishing port of the premixing tank 32, and the water vapor removed from the top gas of the recovery furnace is recycled as a raw material for hydrogen production, reducing the water resources required for thermochemical hydrogen production and further improving the self-sufficiency of the hydrogen cycle.

[0044] Among them, when the dehydrator 22 is provided, the dehydrator 22 is located upstream of the heat source channel series connection area, which includes the heat exchange tubes of the H2SO4 decomposer 331, the second pipe section, and the heat exchange tubes of the HI decomposer 341.

[0045] In one embodiment, the oxygen decomposed in the H2SO4 decomposer 331 can be supplied to the heating furnace 5 as fuel, further improving the self-sufficiency of the hydrogen cycle. Alternatively, the obtained oxygen can also be supplied to other oxygen-consuming units such as an oxygen-enriched blast furnace.

[0046] In one embodiment, the water generated by combustion in the heating furnace 5 can also be collected and fed into the thermochemical hydrogen production mechanism 3 as a raw material. Specifically, the heating furnace 5 is equipped with a water collecting pipe, and the water collecting pipe is connected to the water replenishing port of the premixing tank 32, reducing the water resources required for thermochemical hydrogen production and further improving the self-sufficiency of the hydrogen cycle.

[0047] For the hydrogen supply in the hydrogen storage tank 345, it can be directly supplied to the shaft furnace 1, or share the hydrogen channel with the top gas. Optionally, as Figure 1 , the outlet end of the green hydrogen supply pipe 30 is connected in parallel to the outlet pipe 2, so that the green hydrogen can be heated by the heating furnace 5 to ensure the smelting effect of the pure hydrogen shaft furnace 1. Further, as Figure 1 , a first bypass pipe 302 is also connected in parallel to the green hydrogen supply pipe 30, and the first bypass pipe 302 is directly connected to the shaft furnace 1. Control valves are respectively provided on the green hydrogen supply pipe 30 and the first bypass pipe 302, and the control valve on the green hydrogen supply pipe 30 is located downstream of the connection point of the first bypass pipe 302; based on this design, the green hydrogen can be sent into the shaft furnace 1 after being heated by the heating furnace 5, or directly supplied to the shaft furnace 1, or the two methods are coupled for supply, so the flexibility is relatively high. Especially, when two sets of reaction gas inlets are adopted on the shaft furnace 1, the effect of secondary reduction can be achieved, and accordingly, the smelting effect of the shaft furnace 1 is improved. When the return gas pipe 4 is connected to the upper reaction gas inlet and the first bypass pipe 302 is connected to the lower reaction gas inlet, the directly supplied green hydrogen exchanges heat with the furnace charge, pre-cooling the furnace charge while fully utilizing the heat of the furnace charge to heat this part of the directly supplied green hydrogen, ensuring the effect and efficiency of its upward reaction.

[0048] Optionally, a green hydrogen compressor 301 is provided on the green hydrogen supply pipe 30.

[0049] In one embodiment, as Figure 1, a recuperator 24 is further arranged on the gas outlet pipe 2. The recuperator 24 is located downstream of the heat source channel series connection area, and the recuperator 24 can recover the heat of the top gas of the furnace, further improving the energy efficiency of the hydrogen circulation system.

[0050] In one embodiment, as Figure 1 , a second bypass pipe 25 is also connected in parallel to the gas outlet pipe 2. The outlet end of the second bypass pipe 25 is connected to the fuel gas inlet of the heating furnace 5, that is, a part of the top gas of the furnace is used as the fuel gas of the heating furnace 5, which can further reduce the energy consumption of the hydrogen circulation system, and further reduce the production cost of the pure hydrogen shaft furnace 1. Among them, the inlet end of the second bypass pipe 25 is preferably located upstream of the heat source channel series connection area; when there is a recuperator 24, the second bypass pipe 25 is preferably connected in series with the recuperator 24 and the heating furnace 5 in sequence.

[0051] In an alternative embodiment, the top gas after heat exchange in the H2SO4 decomposer 331 and the HI decomposer 341 can also be used as the fuel gas of the heating furnace 5, and the heat of these top gases can be further utilized. Correspondingly, a third bypass pipe is also connected in parallel to the gas outlet pipe 2. The inlet end of the third bypass pipe is located downstream of the heat source channel series connection area, and the outlet end of the third bypass pipe is connected to the fuel gas inlet of the heating furnace 5.

[0052] In one embodiment, as Figure 2 , a fourth bypass pipe 26 is also connected in parallel to the gas outlet pipe 2. Both ends of the fourth bypass pipe 26 are respectively located upstream and downstream of the heat source channel series connection area, and a bypass valve is provided on the fourth bypass pipe 26. Based on this design, it is possible to control whether the top gas passes through the H2SO4 decomposer 331 and the HI decomposer 341, or control the flow rate of the top gas passing through the H2SO4 decomposer 331 and the HI decomposer 341, further improving the production flexibility and reliability of the hydrogen circulation system.

[0053] By distributing the flow rate of the top gas as the reaction gas and the fuel gas, and distributing the flow rate of the top gas passing through the H2SO4 decomposer 331 and the HI decomposer 341, and distributing the flow rate of the hydrogen passing through the heating furnace 5 and the direct supply shaft furnace 1, the production flexibility and reliability of the hydrogen circulation system and the pure hydrogen shaft furnace 1 can be greatly improved, and the energy efficiency control accuracy of the hydrogen circulation system can be greatly improved.

[0054] Embodiment 2

[0055] This embodiment provides a pure hydrogen shaft furnace configured with the hydrogen circulation system of the pure hydrogen shaft furnace provided in the above Embodiment 1. The connection relationship between the gas outlet pipe 2, the gas return pipe 4 and the shaft furnace 1 has been described in the above Embodiment 1 and will not be elaborated here.

[0056] Embodiment 3

[0057] The present embodiment provides a production method for a pure hydrogen shaft furnace, which can be implemented based on the pure hydrogen shaft furnace provided in the above-mentioned Embodiment 2; the production method includes:

[0058] Leading out the top gas of the shaft furnace 1,

[0059] Introducing at least part of the top gas into the thermochemical hydrogen production mechanism 3 as the heat source for the decomposition of H2SO4 and HI, and then sending the top gas led out from the thermochemical hydrogen production mechanism 3 into the shaft furnace 1 as the reaction gas and / or into the heating furnace 5 as the fuel gas;

[0060] Sending the hydrogen produced by the thermochemical hydrogen production mechanism 3 into the shaft furnace 1 as the reaction gas.

[0061] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hydrogen circulation system for a pure hydrogen shaft furnace, characterized in that, It includes a heating furnace, a thermochemical hydrogen production mechanism, an outlet pipeline connected to the top gas outlet of the shaft furnace, and a return gas pipeline connected to the reaction gas inlet of the shaft furnace; The thermochemical hydrogen production mechanism includes a reaction kettle, an H2SO4 decomposer, and an HI decomposer. The H2SO4 decomposer is connected to the H2SO4 phase outlet of the reaction kettle through an H2SO4 medium pipe, and the HI decomposer is connected to the HI phase outlet of the reaction kettle through an HI medium pipe; The outlet pipeline is connected to the heat exchange gas inlet of the heating furnace after connecting in series the heat source channels of the H2SO4 decomposer and the HI decomposer, and the return gas pipeline is connected to the heat exchange gas outlet of the heating furnace; The HI decomposer is connected to a hydrogen gas storage tank, and the hydrogen gas storage tank is communicated with the reaction gas inlet of the shaft furnace through a green hydrogen supply pipe.

2. The hydrogen circulation system of the pure hydrogen shaft furnace according to claim 1, characterized in that: The outlet end of the green hydrogen supply pipe is branched and connected to the outlet pipeline.

3. The hydrogen circulation system of the pure hydrogen shaft furnace according to claim 2, characterized in that: A first bypass pipe is also branched on the green hydrogen supply pipe. The first bypass pipe is directly connected to the shaft furnace. Control valves are respectively arranged on the green hydrogen supply pipe and the first bypass pipe. The control valve on the green hydrogen supply pipe is located downstream of the branch point of the first bypass pipe.

4. The hydrogen circulation system of the pure hydrogen shaft furnace according to claim 1, characterized in that: A dehydrator is arranged on the outlet pipeline, and the dehydrator is located upstream of the series connection area of the heat source channels.

5. The hydrogen circulation system of the pure hydrogen shaft furnace according to claim 4, characterized in that: The thermochemical hydrogen production mechanism further includes a premixing tank. The mixed medium outlet of the premixing tank is communicated with the reaction medium inlet of the reaction kettle, and the water outlet of the dehydrator is communicated with the water replenishing port of the premixing tank.

6. The hydrogen circulation system of the pure hydrogen shaft furnace according to claim 1 or 5, characterized in that: The thermochemical hydrogen production mechanism further includes a premixing tank. The mixed medium outlet of the premixing tank is communicated with the reaction medium inlet of the reaction kettle. The heating furnace is equipped with a water collecting pipe, and the water collecting pipe is connected to the water replenishing port of the premixing tank.

7. The hydrogen circulation system of the pure hydrogen shaft furnace according to claim 1, characterized in that: A recuperator is also arranged on the outlet pipeline, and the recuperator is located downstream of the series connection area of the heat source channels.

8. The hydrogen circulation system of the pure hydrogen shaft furnace according to claim 7, characterized in that: A second bypass pipe is also branched on the outlet pipeline. The outlet end of the second bypass pipe is connected to the fuel gas inlet of the heating furnace.

9. A pure hydrogen shaft furnace, characterized in that, A hydrogen circulation system of a pure hydrogen shaft furnace configured as described in any one of claims 1 to 8.

10. A production method of a pure hydrogen shaft furnace, characterized in that, Implemented based on the pure hydrogen shaft furnace described in claim 9, the production method includes: Leading out the top gas of the shaft furnace, Introducing at least part of the top gas into the thermochemical hydrogen production mechanism as the heat source for H2SO4 decomposition and HI decomposition, and then sending the top gas led out from the thermochemical hydrogen production mechanism into the shaft furnace as reaction gas and / or into the heating furnace as fuel gas; Sending the hydrogen gas produced by the thermochemical hydrogen production mechanism into the shaft furnace as reaction gas.

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