Zero-carbon flash reduction ironmaking device and use method

Abstract

A zero-carbon flash reduction ironmaking device comprises a reaction tower, the reaction tower is arranged upside down, a flash reduction area, an iron powder waste heat boiler and a green oxygen preheater are sequentially arranged in an inner cavity of the tower from top to bottom, oxyhydrogen powder entering the tower is subjected to oxyhydrogen combustion, mineral powder green hydrogen absorbs heat and is heated to the high temperature, and all hydrogen reduction reaction is completed before the mineral powder flows out of the flash reduction area. Iron powder is cooled through an iron powder waste heat boiler and a green oxygen preheater, hydrogen steam is cooled through a hydrogen steam waste heat boiler and a mineral powder preheater, and hydrogen water is separated through a cyclone dehydrator and a drying filter. The iron ore concentrate powder with the particle size smaller than 200 meshes falls into a powder bin, the reduction temperature ranges from 1100 DEG C to 1200 DEG C, the time for the ore powder to flow through a flash reduction area ranges from 2 s to 3 s, and the temperature for the ore powder to leave an iron powder waste heat boiler and the temperature for hydrogen steam to leave a hydrogen steam waste heat boiler range from 125 DEG C to 175 DEG C. The invention can be used for flash smelting of iron ore concentrate powder. The invention has the advantages of high waste heat recovery rate, long service life of the furnace lining, low energy consumption and zero carbon emission, and can avoid using the key management object coke ironmaking blast furnace device of the national two-high project.

Description

TECHNICAL FIELD

[0001] The application relates to a zero-carbon flash reduction ironmaking device and a use method thereof, which is used for green hydrogen flash reduction of iron concentrate powder at a temperature of 1100 DEG C to 1200 DEG C, preparation of sponge iron powder, power generation by recycling high-temperature waste heat of iron powder, recycling of hydrogen vapor latent heat and water resources to replace waste gas denitrification and denitration purification, and is suitable for the fields of iron concentrate powder flash smelting in green power-rich areas, iron ore green hydrogen reduction smelting, iron oxide slag powder resource disposal, sponge iron manufacturing and the like. BACKGROUND

[0002] The blast furnace coke ironmaking is still the main way of global pig iron production due to its high efficiency, low energy consumption, strong adaptability of raw materials and the like. Although the technology is mature, there are still the following main defects: the device system is complex, including a sintering-blast furnace system and a large supporting flue gas denitration and desulfurization system, and the one-time investment is large. The traditional blast furnace ironmaking needs to consume a large amount of coke (about 600 kg of coke / t of pig iron), and the coke production itself has high energy consumption and serious pollution. The blast furnace fuel ratio (coke + pulverized coal) in China is 50-100 kg / t of molten iron higher than the international advanced level, but about 1.8 tons of CO2 are generated per ton of pig iron, accounting for more than 70% of the total emissions of the steel industry, the carbon capture cost is high and is not popularized. High-grade iron ore is needed, and the adaptability to poor ore is poor, and sintering pretreatment is needed, increasing the cost. The smelting temperature is as high as 1400 DEG C to 1450 DEG C, the high-temperature corrosion of the melt to the furnace lining is large, the average service life of the domestic blast furnace is only 5 to 10 years, the furnace hearth erosion and cooling wall damage occur frequently, and the maintenance cost is high. The prices of coke and ore fluctuate greatly, and enterprises may sacrifice environmental protection investment to reduce costs, forming a vicious cycle. For the above reasons, the blast furnace and non-blast furnace ironmaking devices (except hydrogen reduction) in the ironmaking (3110) industry have been included in the key management range of the national “two high” project (2025 version), that is, the government will strictly approve the investment construction of the blast furnace and non-blast furnace ironmaking devices (except hydrogen reduction) for new and expanded ironmaking projects, and requires that the new and expanded ironmaking devices are hydrogen reduction ironmaking devices with high efficiency, energy saving, low carbon and environmental protection advantages. The traditional blast furnace and non-blast furnace ironmaking devices (except hydrogen reduction) even face the risk of elimination.

[0003] The fine iron ore powder with particle size less than 200 mesh replaces the traditional pellet / sinter, and the green hydrogen flash reduction smelting iron ore powder and the generation of sponge iron powder are carried out without CO2 emission and waste gas purification treatment involving denitrification and desulfurization treatment. Sponge iron is a porous iron product produced by direct reduction method, with its pure chemical composition, unique physical structure and diverse forms, it has become an indispensable functional material in modern metallurgical industry and water treatment field, and the industrial demand is large. In electric furnace steelmaking, it is an ideal substitute for high-quality scrap steel; in the field of powder metallurgy, it is a high-quality raw material for high-purity iron powder; in the water treatment system, it is an efficient and economical oxygen removal filter material. The development and promotion of zero-carbon flash reduction iron smelting device and its use method can avoid the selection of traditional coke reduction iron smelting furnace (blast furnace, non-blast furnace device), which is helpful to promote the "30.60" target process of iron smelting industry. SUMMARY

[0004] In view of the problems of traditional coke ironmaking temperature up to 1400℃-1450℃, obvious corrosion of smelting slag melting on the lining of the furnace, large investment and operation and maintenance cost of the device (including blast furnace, non-blast furnace device, etc.) and supporting equipment, emission of large amount of greenhouse gases and the need for waste gas denitrification and desulfurization purification treatment, etc., a zero-carbon flash reduction iron smelting device and its use method are invented, which is designed under the temperature condition of 1100℃-1200℃, green hydrogen is prepared by green electricity electrolysis, green hydrogen flash reduction smelting iron ore powder, manufacturing sponge iron powder, and recycling hydrogen gas iron powder high-temperature waste heat.

[0005] The zero-carbon flash reduction iron smelting device mainly comprises a water pump, a steam turbine generator set, a drying filter, a cyclone water separator, a hydrogen steam waste heat boiler, a green hydrogen flash reduction furnace, a ventilator, a water electrolysis tank, a mineral powder preheater and a belt feeder. The green hydrogen flash reduction furnace mainly comprises a powder bin, a green hydrogen inlet pipe and a reaction tower. The green hydrogen inlet pipe penetrates the inner cavity of the powder bin. A seal is arranged at the mineral powder falling inlet of the powder bin. The powder bin is vertically arranged above the top wall of the reaction tower. The central axes of the reaction tower, the powder bin and the green hydrogen inlet pipe are collinear. The outlet of the powder bin is connected to the top inlet of the reaction tower. The outlet of the powder bin, the outlet of the green hydrogen inlet pipe and the top surface of the inner cavity of the reaction tower are coplanar. The reaction tower is vertically inverted and in the shape of an elongated barrel. The inner cavity of the reaction tower comprises a flash reduction zone, an iron powder primary cooling zone, an iron powder secondary cooling zone and an iron powder stacking zone from top to bottom. A spiral discharging machine is arranged in the iron powder stacking zone. A green oxygen preheater with a plurality of oxygen cooling pipes arranged in a horizontal staggered manner is arranged on the wall of the iron powder secondary cooling zone. An iron powder waste heat boiler with a plurality of water cooling pipes arranged in a horizontal staggered manner is arranged in the iron powder primary cooling zone. Iron concentrate is transported to the mineral powder preheater by the belt feeder, preheated by low-temperature hydrogen steam flow and then falls into the powder bin through the seal. Green hydrogen and green oxygen are generated by electrolysis of the water electrolysis tank. Part of the green oxygen is sold. Part of the green oxygen is introduced into the powder bin after absorbing the low-temperature sensible heat of the iron powder by the green oxygen preheater. The mineral powder and green oxygen are mixed in the powder bin. The green hydrogen introduced by the ventilator and through the green hydrogen inlet pipe is further mixed at the outlet of the powder bin. The mineral powder hydrogen-oxygen gas flow is sprayed into the reaction tower at a certain speed. The mineral powder hydrogen-oxygen gas flow is ignited as soon as it is sprayed into the inner cavity of the tower to cause hydrogen-oxygen combustion. The remaining green hydrogen of the mineral powder rapidly absorbs part of the combustion heat to be heated to a high temperature in the flash reduction zone. The fine mineral powder particles and the high temperature condition in the flash reduction zone strengthen the green hydrogen permeation reduction process, so that the green hydrogen permeation and reduction reaction is completed before the mineral powder flows out of the flash reduction zone, generating high-temperature sponge iron powder and high-temperature hydrogen steam flow. The high-temperature iron powder falls into the iron powder primary cooling zone and falls under the action of gravity, collides with the water cooling pipe, changes the stroke and transmits the sensible heat to the water, and then falls into the iron powder secondary cooling zone after being cooled to a low temperature. The low-temperature iron powder falls under the action of gravity, collides with the oxygen cooling pipe, changes the stroke and transmits the sensible heat to the green oxygen, and then falls into the iron powder stacking zone after being cooled to a lower temperature. The iron powder is discharged from the iron powder stacking zone by the spiral discharging machine and sold in bags. The hydrogen steam flow flows into the hydrogen steam waste heat boiler after leaving the flash reduction zone and is cooled by water. The hydrogen steam flow is cooled to a low temperature and then flows into the mineral powder preheater and is further cooled by the mineral powder to a lower temperature, becoming a hydrogen mist flow. The hydrogen water separation is performed by the cyclone water separator and the drying filter. The hydrogen is supplemented to the green hydrogen. The water flow returns to the water electrolysis tank to maintain the water level in the tank. The high-temperature and high-pressure steam of the hydrogen steam waste heat boiler and the iron powder waste heat boiler is mixed and enters the steam turbine generator set to generate electricity and mix green electricity. The condensed water is pressurized by the water pump, divided and returned to the iron powder waste heat boiler and the hydrogen steam waste heat boiler.

[0006] When the zero-carbon flash reduction ironmaking device is used, the iron concentrate powder with a particle size of less than 200 mesh is sealed into the powder bin, the temperature of the flash reduction zone is 1100-1200 DEG C, the time of the mineral powder flowing through the flash reduction zone is 2-3 seconds, the temperature of the mineral powder leaving the iron powder waste heat boiler and the hydrogen gas stream leaving the hydrogen gas waste heat boiler is 125-175 DEG C, and the temperature of the iron powder stacking zone is not more than 80-90 DEG C.

[0007] The iron concentrate powder flash smelting, the iron ore green hydrogen reduction smelting, the oxidized iron slag powder resource disposal, and the sponge iron manufacturing can all use the present application.

[0008] The present application is suitable for high-strength reduction ironmaking in green electricity resource-rich areas, has small unit investment, low smelting reaction temperature of 1100-1200 DEG C, high high-temperature waste heat recovery rate, long service life of the furnace lining, low energy consumption, zero carbon emission, and does not involve denitriding and denitrating purification treatment, and the device product energy efficiency and carbon efficiency are advanced, the sponge iron powder has large specific surface area and uniform quality, the use of the national “two high” project key management object ironmaking (3110) industry steelmaking pig iron, smelting reduction iron or cast pig iron product is avoided, and the coke ironmaking blast furnace and the non-blast furnace ironmaking device (except hydrogen reduction) are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 It is a zero-carbon flash reduction ironmaking device principle diagram.

[0010] Figure 1 In the figure, 1 is a water pump, 2 is a steam turbine generator unit, 3 is a drying filter, 4 is a cyclone water separator, 5 is a hydrogen gas waste heat boiler, 6 is a green hydrogen flash reduction furnace, 7 is a ventilator, 8 is a water electrolysis tank, 9 is a mineral powder preheater, and 10 is a belt feeder. In the green hydrogen flash reduction furnace 6, 61 is a powder bin, 62 is a green hydrogen introduction pipe, and 63 is a reaction tower. In the powder 61, 611 is a material seal. In the reaction tower 63, 631 is a spiral discharger, 632 is a green oxygen preheater, and 633 is an iron powder waste heat boiler.

[0011] Figure 1 In the figure, F is iron concentrate powder, P is sponge iron powder, E is green electricity, e is waste heat power generation, and O is green oxygen. DETAILED DESCRIPTION

[0012] The present application will be further described below in combination with the drawings.

[0013] As Figure 1The zero-carbon flash reduction ironmaking device mainly comprises a water pump 1, a steam turbine generator set 2, a drying filter 3, a cyclone water separator 4, a hydrogen steam waste heat boiler 5, a green hydrogen flash reduction furnace 6, a ventilator 7, a water electrolysis tank 8, a mineral powder preheater 9 and a belt feeder 10. The green hydrogen flash reduction furnace 6 mainly comprises a powder bin 61, a green hydrogen inlet pipe 62 and a reaction tower 63. The green hydrogen inlet pipe 62 penetrates through the inner cavity of the powder bin 61, the powder bin 61 is vertically arranged above the top wall of the reaction tower 63, the central axes of the reaction tower 63, the powder bin 61 and the green hydrogen inlet pipe 62 are collinear, the outlet of the powder bin 61 is connected to the top inlet of the reaction tower 63, and the outlet face of the powder bin 61, the outlet face of the green hydrogen inlet pipe 62 and the top face of the inner cavity of the reaction tower 63 are coplanar. The reaction tower 63 mainly comprises a spiral discharger 631, a green oxygen preheater 632 and an iron powder waste heat boiler 633. The reaction tower 63 is vertically arranged in an inverted and elongated barrel shape, and the inner cavity of the tower comprises a flash reduction zone, an iron powder primary cooling zone, an iron powder secondary cooling zone and an iron powder stacking zone from top to bottom. The iron powder stacking zone is arranged with the spiral discharger 631. The iron powder secondary cooling zone is arranged with the green oxygen preheater 632, and the green oxygen preheater 632 comprises a plurality of oxygen cooling pipes arranged horizontally and staggered. The iron powder primary cooling zone is arranged with the iron powder waste heat boiler 633, and the iron powder waste heat boiler 633 comprises a plurality of water cooling pipes arranged horizontally and staggered.

[0014] The iron ore concentrate powder is delivered to the ore powder preheater 9 by the belt feeder 10, preheated by low-temperature hydrogen vapor flow, and then falls into the powder bin 61 through the material seal 611. The water electrolysis tank 8 generates green hydrogen and green oxygen by electrolysis, part of the green oxygen is sold, and part of the green oxygen is introduced into the powder bin 61 after absorbing the low-temperature sensible heat of the iron powder in the green oxygen preheater 632. The ore powder and green oxygen are uniformly mixed in the powder bin 61, and then further mixed with green hydrogen introduced by the blower 7 and through the green hydrogen introduction pipe 62 at the outlet of the powder bin 61, forming an ore powder hydrogen-oxygen gas flow which is sprayed into the reaction tower 63 at a certain speed. The ore powder hydrogen-oxygen gas flow is ignited as soon as it enters the tower cavity, and hydrogen-oxygen combustion occurs, the ore powder and the remaining green hydrogen rapidly absorb part of the combustion heat and are heated to the high temperature of the flash reduction zone, the fine ore powder and the high temperature of the flash reduction zone speed up the green hydrogen permeation reduction reaction, so that the complete green hydrogen reduction reaction is completed before the ore powder flows out of the flash reduction zone, that is, the flash hydrogen reduction reaction, generating high-temperature iron powder and high-temperature hydrogen vapor flow. The high-temperature iron powder falls into the iron powder primary cooling zone, under the action of gravity, collides with the water cooling pipe wall, changes the travel, and conducts sensible heat to the water, and then falls into the iron powder secondary cooling zone after being reduced to low temperature. The low-temperature iron powder in the iron powder secondary cooling zone falls under the action of gravity, collides with the oxygen cooling pipe wall, changes the travel, and conducts sensible heat to the green oxygen, and then falls into the iron powder storage area after being reduced to a lower temperature. The spiral feeder 631 of the iron powder storage area discharges the iron powder from the iron powder storage area and packs it for sale. The hydrogen vapor flow flows into the hydrogen vapor waste heat boiler 5 after leaving the flash reduction zone and is cooled by water, and then flows into the ore powder preheater 9 after being reduced to low temperature. The hydrogen vapor flow in the ore powder preheater 9 is further cooled by the ore powder and is reduced to a lower temperature to become a hydrogen mist flow, and then the hydrogen water separation is carried out through the cyclone water remover 4 and the drying filter 3, the hydrogen is supplemented into the green hydrogen, and the water flows back to the water electrolysis tank 8 to maintain the water level of the water electrolysis tank 8 unchanged. The high-temperature and high-pressure steam of the hydrogen vapor waste heat boiler 5 and the iron powder waste heat boiler 633 is combined and enters the steam turbine generator set 2 to expand and generate electricity, and the condensed water is pressurized by the water pump 1 and then flows back to the iron powder waste heat boiler 633 and the hydrogen vapor waste heat boiler 5, and the green electricity is mixed into the steam turbine generator set 2 to generate electricity.

[0015] The raw material iron ore concentrate powder at point F falls into the belt feeder 10, which delivers it to the ore powder preheater 9. The ore powder in the ore powder preheater 9 is preheated by hydrogen vapor flow, and then falls into the powder bin 61 through the material seal 611. The water electrolysis tank 8 consumes green electricity supplied at point E to electrolyze water into green hydrogen and green oxygen 2H2O = 2H2 + O2 + e, part of the green oxygen is sold at point O, and part of the green oxygen flows into the green oxygen preheater 632 to absorb the low-temperature waste heat of the iron powder, and then enters the powder bin 61. The ore powder and green oxygen in the powder bin 61 are uniformly mixed and leave the outlet of the powder bin 61, and further mix with green hydrogen introduced by the blower 7 and through the green hydrogen introduction pipe 62 at the outlet of the powder bin 61, forming an ore powder hydrogen-oxygen (ore powder + green oxygen + green hydrogen) gas flow which is sprayed into the reaction tower 63.

[0016] The green hydrogen flash reduction furnace 6 mainly comprises a powder bin 61, a green hydrogen introduction pipe 62 and a reaction tower 63. The green hydrogen introduction pipe 62 penetrates through the inner cavity of the powder bin 61. The top wall of the powder bin 61 is provided with a mineral powder falling inlet and a green oxygen inlet. The mineral powder falling inlet is provided with a material seal 611. The powder bin 61 is vertically arranged above the top wall of the reaction tower 63. The central axes of the reaction tower 63, the powder bin 61 and the green hydrogen introduction pipe 62 are collinear. The outlet of the powder bin 61 is connected to the top inlet of the reaction tower 63. The top surface of the inner cavity of the reaction tower 63, the outlet surface of the powder bin 61 and the outlet surface of the green hydrogen introduction pipe 62 are coplanar. The reaction tower 63 is vertically arranged in an inverted elongated barrel shape. The inner cavity of the reaction tower 63 comprises, from top to bottom, a flash reduction zone, a primary iron powder cooling zone, a secondary iron powder cooling zone and an iron powder stacking zone. The iron powder stacking zone is horizontally arranged with a spiral discharging machine 631. The secondary iron powder cooling zone is arranged with a green oxygen preheater 632. The green oxygen preheater 632 comprises a plurality of oxygen cooling pipes arranged horizontally and staggered. The primary iron powder cooling zone is arranged with an iron powder waste heat boiler 633. The iron powder waste heat boiler 633 comprises a plurality of water cooling pipes arranged horizontally and staggered.

[0017] The mineral powder hydrogen-oxygen gas flow leaving the outlet of the powder bin 61 is ignited by an igniter to start the green hydrogen and green oxygen combustion 2H2+O2=2H2O-ΔQ. The mineral powder and the remaining green hydrogen rapidly absorb part of the combustion heat ΔQ1 to be heated to a high temperature of 1100-1200℃ in the flash reduction zone. The fine particle size of the mineral powder up to 200 mesh and the high temperature of 1100-1200℃ in the flash reduction zone increase the hydrogen reduction smelting speed. Therefore, when the mineral powder leaves the flash reduction zone, the complete green hydrogen reduction smelting of the iron concentrate powder reaction Fe x O y +yH2=xFe+yH2O(g)-ΔQ2 is completed, i.e. the flash reduction smelting is realized to generate 1100-1200℃ sponge iron powder and 1100-1200℃ hydrogen vapor flow. The height of the flash reduction zone is optimized so that the mineral powder flow through the flash reduction zone takes no more than 2-3s, and the green hydrogen reduction reaction is fast enough to complete the complete green hydrogen reduction reaction within 2-3s of the mineral powder staying in the flash reduction zone. The mineral powder reaction is complete and does not contain Fe x O y component, but only contains elemental Fe. The product is a uniform Fe content sponge iron product. The hydrogen-oxygen combustion heat release ΔQ=the heating endothermic ΔQ1 of the mineral powder and the remaining green hydrogen+the hydrogen reduction endothermic ΔQ2.

[0018] 1100℃~1200℃ sponge iron powder flows into the first iron powder cooling area, and falls under the action of its own gravity, constantly touches the water-cooled tube wall of the iron powder waste heat boiler 633, constantly changes the flow trajectory and travel, and constantly conducts its own sensible heat to the cooling medium water in the tube, and leaves the first iron powder cooling area at a low temperature of 125℃~175℃ and flows into the second iron powder cooling area. 125℃~175℃ sponge iron powder flows into the second iron powder cooling area, and falls under the action of its own gravity, constantly touches the oxygen-cooled tube wall of the green oxygen preheater 632, constantly changes the flow trajectory and travel, and constantly conducts its own sensible heat to the cooling medium green oxygen in the tube, and leaves the second iron powder cooling area at a lower temperature of 80℃~90℃ and flows into the sponge iron powder stacking area. 80℃~90℃ sponge iron powder flows into the sponge iron powder stacking area, and is discharged from the sponge iron powder stacking area by the spiral discharge machine 631 to point P for safe bagging and sale.

[0019] 1100℃~1200℃ high-temperature hydrogen vapor flow leaves the flash reduction area and enters the hydrogen vapor waste heat boiler 5. The hydrogen vapor flow in the hydrogen vapor waste heat boiler 5 transfers heat to the cooling medium water through the partition wall. The hydrogen vapor flow is cooled from 1100℃~1200℃ high temperature to 125℃~175℃ low temperature, and the cooling medium water is changed from low-temperature and low-pressure condensed water to high-temperature and high-pressure water vapor. 125℃~175℃ low-temperature hydrogen vapor flow leaves the hydrogen vapor waste heat boiler 5 and enters the ore powder preheater 9. The hydrogen vapor flow in the ore powder preheater 9 transfers heat to the ore powder through the metal partition wall. The hydrogen vapor flow is cooled from 125℃~175℃ low temperature to 80℃~90℃ lower temperature, and the hydrogen vapor flow (hydrogen gas + water vapor) becomes hydrogen mist flow (hydrogen gas + water mist beads). The hydrogen mist flow leaves the ore powder preheater 9 and flows into the cyclone water separator 4. Under the action of centrifugal force, the hydrogen mist flow becomes hydrogen gas flow + water beads. The hydrogen gas flow leaves the cyclone water separator 4 and flows into the dry filter 3. The fine water mist in the hydrogen gas flow is further removed, the hydrogen gas purity is further improved, and finally the hydrogen gas is combined with the green hydrogen extracted from the water electrolysis tank 8 and sent into the green hydrogen guide pipe 62 driven by the blower 7. The accumulated water in the cyclone water separator 4 and the dry filter 3 is combined and flows back to the water electrolysis tank 8 as water supplement for the water electrolysis tank 8, maintaining the water level in the water electrolysis tank 8 constant.

[0020] The high-temperature and high-pressure water vapor flowing out of the hydrogen vapor waste heat boiler 5 and the high-temperature and high-pressure water vapor flowing out of the iron powder waste heat boiler 633 are combined and enter the steam turbine generator set 2 to expand and generate electricity. The water vapor is converted into low-temperature and low-pressure condensed water due to the conversion of internal energy into shaft work. The condensed water is pumped by the water pump 1 to increase the pressure and is divided into two streams to flow back to the iron powder waste heat boiler 633 and the hydrogen vapor waste heat boiler 5. The condensed water absorbs the high-temperature sensible heat of hydrogen vapor and iron powder in the hydrogen vapor waste heat boiler 5 and the iron powder waste heat boiler 633, and the hydrogen vapor and iron powder are cooled from 1100℃~1200℃ high temperature to 125℃~175℃ low temperature. The low-temperature and low-pressure condensed water becomes high-temperature and high-pressure water vapor, completing the high-temperature sensible heat recovery and power generation process of the hydrogen vapor and iron powder flowing out of the flash reduction area. The power generated by the steam turbine generator set 2 is supplemented into the green electricity of the water electrolysis tank 8 to reduce the consumption of external green electricity.

[0021] Zero-carbon flash reduction ironmaking device, with green hydrogen flash reduction furnace 6 as the core device, matched with iron concentrate powder supply system, water electrolysis green hydrogen and oxygen system, hydrogen gas waste water waste heat recovery system, iron powder waste heat recovery system and high temperature waste heat recovery power generation system. Green hydrogen flash reduction furnace 6 includes powder bin 61, green hydrogen introduction pipe 62 and reaction tower 63, and the inner cavity of reaction tower 63 is sequentially arranged from top to bottom iron powder waste heat boiler 633, green oxygen preheater 632 and spiral discharger 631. The iron concentrate powder supply system includes belt feeder 10, ore powder preheater 9, powder bin 61 and reaction tower 63, and the flow direction of iron concentrate powder is: belt feeder 10→ore powder preheater 9→powder bin 61→reaction tower 63. The water electrolysis green hydrogen and oxygen system includes water electrolysis tank 8, ventilator 7, green hydrogen introduction pipe 62, green oxygen preheater 632 and reaction tower 63, and the flow direction of green hydrogen is: water electrolysis tank 8→ventilator 7→green hydrogen introduction pipe 62→reaction tower 63, and the flow direction of green oxygen is: water electrolysis tank 8→green oxygen preheater 632→powder bin 61→reaction tower 63. The hydrogen gas waste water waste heat recovery system includes hydrogen gas waste heat boiler 5, ore powder preheater 9, cyclone water remover 4, drying filter 3 and water electrolysis tank 8, and the flow direction of hydrogen gas is: hydrogen gas waste heat boiler 5→ore powder preheater 9→cyclone water remover 4→drying filter 3→ventilator 7→green hydrogen introduction pipe 62→reaction tower 63, and the flow direction of water is: hydrogen gas waste heat boiler 5→ore powder preheater 9→cyclone water remover 4→drying filter 3→water electrolysis tank 8. The iron powder waste heat recovery system includes iron powder waste heat boiler 633 and green oxygen preheater 632, and the flow direction of iron powder is: iron powder waste heat boiler 633→green oxygen preheater 632→spiral discharger 631. The high temperature waste heat recovery power generation system includes hydrogen gas waste heat boiler 5, iron powder waste heat boiler 633, steam turbine generator set 2 and water pump 1, and the flow direction of water is: hydrogen gas waste heat boiler 5→steam turbine generator set 2→water pump 1→hydrogen gas waste heat boiler 5, and the flow direction of iron powder waste heat boiler 633 is: iron powder waste heat boiler 633→steam turbine generator set 2→water pump 1→iron powder waste heat boiler 633. Reaction tower 63 is the common starting device or converging device of each system, and hydrogen gas waste heat boiler 5, ore powder preheater 9, iron powder waste heat boiler 633 and green oxygen preheater 632 are the common devices of two systems.

[0022] Zero-carbon flash reduction ironmaking device, which meets the material balance and energy balance. The device consumes raw materials of iron concentrate powder Fe x O y, the product is sponge iron powder Fe and green oxygen O2, and the consumption of energy-consuming working medium water is eliminated, and the consumption of raw materials and the yield of products meet the law of conservation of mass. The energy consumption of the device is green electricity, and the generated electricity is not exported. When the remaining green hydrogen in the flash reduction zone is heated to 1100°C-1200°C to increase the heat absorption of the reduction smelting reaction, the amount of water electrolysis in the water electrolysis tank 8 increases, and the electrolysis of water generates H2 and O2, H2 and O2 are regenerated by combustion to form H2O, H2O exists in the hydrogen gas stream, and after the hydrogen gas stream passes through the hydrogen gas waste heat boiler 5 and the ore powder preheater 9 to release heat and cool down, the cyclone water collector 4 and the drying filter 3 can collect an equal amount of H2O and return it to the water electrolysis tank 8, forming an internal circulating water flow in the water electrolysis tank 8, increasing the amount of water storage, and not needing to supplement water to the water electrolysis tank 8. At this time, the water electrolysis consumes more green electricity, which is equivalent to consuming more green electricity to maintain the increased heat absorption of the flash reduction zone.

[0023] When using the zero-carbon flash reduction ironmaking device, the particle size of the iron concentrate powder is less than 200 mesh, and the ore powder falls into the powder bin 61 before passing through the material seal 611 to prevent the inclusion of ambient air in the flash reduction zone. The temperature in the flash reduction zone is controlled in the range of 1100°C-1200°C, the time for the ore powder to flow through the flash reduction zone is controlled in the range of 2s-3s, and the temperature of the iron powder leaving the iron powder waste heat boiler 633 and the hydrogen gas stream leaving the hydrogen gas waste heat boiler 5 is controlled in the range of 125°C-175°C. The temperature of the iron powder storage area does not exceed 80°C-90°C to meet the safety packaging requirements.

[0024] The beneficial effects of using the zero-carbon flash reduction ironmaking device include at least:

[0025] (1) Direct production of solid powder sponge iron products, no smelting and slagging, reduced requirements for high-temperature and corrosion-resistant devices, extended service life, and reduced investment.

[0026] (2) Flash reduction short process ironmaking process, replacing the sintering- blast furnace smelting and slagging long process steelmaking process, changing the raw material from pellet / sinter to iron concentrate powder with a particle size of less than 200 mesh, avoiding the sintering device, and simplifying the traditional ironmaking process. The iron concentrate powder is fine, the hydrogen gas and ore particle contact area is expanded, the reduction speed is increased (flash reduction), the reaction tower 63 is compact, the green hydrogen dynamically reduces the ore powder instead of CO statically reducing the pellet / sinter, the reduction time is shortened, the unit volume smelting intensity and the utilization rate of the cavity space in the tower are increased, the smelting reaction is complete, the smelting production efficiency is improved, and the utilization rate of green hydrogen is more than 90%.

[0027] (3) Sponge iron replaces the national "two high" project key management object pig iron for steelmaking, smelted reduced iron or cast pig iron, and the new zero-carbon emission flash reduction ironmaking device replaces the traditional high-carbon emission sintering-blast furnace system, which meets the requirements of national industrial target policy.

[0028] (4) The smelting temperature of the flash reduction zone is reduced from 1400-1450℃ to 1100-1200℃, reducing the requirements for high-temperature resistance and molten corrosion resistance of the wall of the reaction tower 63, and reducing the investment of the green hydrogen flash reduction furnace 6. The mineral powder particles remain in a non-molten solid particle state, the powder particle micro capillary pores are not blocked, and the sponge iron powder maintains good porous performance.

[0029] (5) The only energy consumption is green electricity, without consuming carbon fuels such as coal or coke, and without greenhouse gas emissions, achieving truly "zero" carbon smelting, and the carbon efficiency index of the device products is advanced.

[0030] (6) The flash reduction zone does not involve coal or coke, and the exhaust gas does not contain SO2 components. It does not involve N elements, and the exhaust gas does not contain NO x components. The reduction of flue gas purification is replaced by water purification instead of traditional desulfurization and denitrification purification, and the environmental protection investment of the device is greatly reduced.

[0031] (7) The hydrogen gas waste heat boiler 5, the iron powder waste heat boiler 633, the steam turbine generator set 2, and the water pump 1 are matched to recover the high-temperature waste heat of the iron powder, plus the hydrogen gas waste heat recovery to recover the steam condensation latent heat, which significantly improves the energy utilization rate of the device, and the energy efficiency index of the device products is advanced.

[0032] (8) The zero-carbon emission flash reduction ironmaking device is suitable for iron ore concentrate powder flash smelting in areas rich in green electricity resources and precious water resources, green hydrogen reduction smelting of iron ore, resource disposal of iron oxide slag powder, and use of sponge iron manufacturing sites.

Claims

1. A zero-carbon flash reduction ironmaking unit, mainly comprising a water pump, a steam turbine generator set, a dryer filter, a cyclone separator, a hydrogen waste heat boiler, a green hydrogen flash reduction furnace, a ventilator, a water electrolysis cell, a mineral powder preheater, and a belt conveyor, characterized in that: The green hydrogen flash reduction furnace mainly consists of a powder silo, a green hydrogen inlet pipe, and a reaction tower. The green hydrogen inlet pipe passes through the inner cavity of the powder silo, and the powder powder inlet of the silo is equipped with a material seal. The powder silo is vertically arranged on the top wall of the reaction tower. The central axes of the reaction tower, the powder silo, and the green hydrogen inlet pipe are collinear. The outlet of the powder silo is connected to the top inlet of the reaction tower. The outlet of the powder silo, the outlet of the green hydrogen inlet pipe, and the top surface of the inner cavity of the reaction tower are coplanar. The reaction tower is vertically inverted and shaped like a long, thin cylinder. From top to bottom, the inner cavity of the tower includes a flash reduction zone, a primary iron powder cooling zone, a secondary iron powder cooling zone, and an iron powder stacking zone. A spiral feeder is installed in the iron powder stacking zone, and the walls of the secondary iron powder cooling zone are covered with... A green oxygen preheater with numerous horizontally staggered oxygen-cooled pipes is installed. An iron powder waste heat boiler with numerous horizontally staggered water-cooled pipes is installed in the primary iron powder cooling zone. Iron concentrate powder is conveyed to the powder preheater by a belt conveyor, preheated by low-temperature hydrogen vapor, and then falls into the powder silo through a material seal. A water electrolysis cell generates green hydrogen and green oxygen. Part of the green oxygen is sold externally, and the rest is fed into the powder silo after absorbing the low-temperature sensible heat of the iron powder in the green oxygen preheater. The powder and green oxygen mix in the silo, and are further mixed at the silo outlet with green hydrogen driven by a fan and introduced through a green hydrogen inlet pipe, forming a powder-hydrogen-oxygen flow that is injected into the reaction tower at a certain speed. The powder-hydrogen-oxygen flow is injected into the tower immediately upon entering. The cavity is ignited, resulting in hydrogen-oxygen combustion. The remaining green hydrogen in the mineral powder rapidly absorbs some of the combustion, releasing heat and raising the temperature to the high temperature of the flash reduction zone. The fine mineral powder particles, combined with the high temperature conditions of the flash reduction zone, enhance the green hydrogen permeation and reduction process, so that the green hydrogen permeation and reduction reaction is completed before the mineral powder flows out of the flash reduction zone, generating high-temperature sponge iron powder and high-temperature hydrogen vapor. The high-temperature iron powder falls into the primary cooling zone of the iron powder, simultaneously falling under gravity, touching the water-cooling pipe, changing its path, and conducting sensible heat to supply water. After cooling down to a low temperature, it falls into the secondary cooling zone of the iron powder. Under gravity, the low-temperature iron powder simultaneously falls, touching the oxygen-cooling pipe, changing its path, and conducting sensible heat to supply green oxygen, cooling down to a lower temperature. After being cooled to a low temperature, the iron powder falls into the iron powder storage area, where it is then discharged by a screw conveyor and bagged for sale. The hydrogen vapor flows out of the flash reduction zone and into the hydrogen waste heat boiler, where it is cooled by water and then flows into the mineral powder preheater. It is further cooled by the mineral powder to an even lower temperature and becomes a hydrogen mist. The mist then passes through a cyclone dewatering device and a dryer filter for hydrogen-water separation. The hydrogen is added to the green hydrogen, and the water flows back to the water electrolysis cell to maintain a constant water level. The high-temperature and high-pressure steam from the hydrogen waste heat boiler and the iron powder waste heat boiler merges and enters the steam turbine generator set to expand and generate electricity, mixing with the green electricity. The condensate is pressurized by a water pump and diverted back to the iron powder waste heat boiler and the hydrogen waste heat boiler.

2. When using the zero-carbon flash reduction ironmaking device as described in claim 1, the iron concentrate powder has a particle size finer than 200 mesh and falls into the powder silo through the material seal. The temperature of the flash reduction zone is 1100℃~1200℃, the time for the ore powder to flow through the flash reduction zone is 2s~3s, the temperature of the ore powder leaving the iron powder waste heat boiler and the temperature of the hydrogen vapor leaving the hydrogen vapor waste heat boiler are both 125℃~175℃, and the temperature of the iron powder stacking zone does not exceed 80℃~90℃.

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