CN115491454B - Iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method - Google Patents
Iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method Download PDFInfo
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 276
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 133
- 230000009467 reduction Effects 0.000 title claims abstract description 115
- 238000000034 method Methods 0.000 title claims abstract description 103
- 238000005245 sintering Methods 0.000 title claims abstract description 58
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 155
- 239000001257 hydrogen Substances 0.000 claims abstract description 154
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 148
- 239000002994 raw material Substances 0.000 claims abstract description 60
- 230000008569 process Effects 0.000 claims abstract description 56
- 238000002485 combustion reaction Methods 0.000 claims abstract description 24
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 claims abstract description 17
- 238000006722 reduction reaction Methods 0.000 claims description 148
- 239000007789 gas Substances 0.000 claims description 96
- 238000001816 cooling Methods 0.000 claims description 68
- 239000002918 waste heat Substances 0.000 claims description 28
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 21
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 21
- 239000001301 oxygen Substances 0.000 claims description 21
- 229910052760 oxygen Inorganic materials 0.000 claims description 21
- 239000000463 material Substances 0.000 claims description 19
- 238000005485 electric heating Methods 0.000 claims description 18
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 17
- 239000003546 flue gas Substances 0.000 claims description 17
- 238000001465 metallisation Methods 0.000 claims description 17
- 238000011084 recovery Methods 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 15
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 14
- 239000000112 cooling gas Substances 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 12
- 230000001502 supplementing effect Effects 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims description 11
- 238000007599 discharging Methods 0.000 claims description 9
- 239000003345 natural gas Substances 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 238000005406 washing Methods 0.000 claims description 8
- 235000019738 Limestone Nutrition 0.000 claims description 7
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 7
- 239000000920 calcium hydroxide Substances 0.000 claims description 7
- 235000011116 calcium hydroxide Nutrition 0.000 claims description 7
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 7
- 239000000292 calcium oxide Substances 0.000 claims description 7
- 235000012255 calcium oxide Nutrition 0.000 claims description 7
- 239000010459 dolomite Substances 0.000 claims description 7
- 229910000514 dolomite Inorganic materials 0.000 claims description 7
- 239000006028 limestone Substances 0.000 claims description 7
- 229910052595 hematite Inorganic materials 0.000 claims description 6
- 239000011019 hematite Substances 0.000 claims description 6
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims description 6
- 239000000843 powder Substances 0.000 claims description 6
- 239000000428 dust Substances 0.000 claims description 5
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 4
- 230000035484 reaction time Effects 0.000 claims description 4
- 238000009826 distribution Methods 0.000 claims description 3
- 238000002844 melting Methods 0.000 claims description 3
- 230000008018 melting Effects 0.000 claims description 3
- 238000009423 ventilation Methods 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 abstract description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 19
- 238000011946 reduction process Methods 0.000 abstract description 16
- 229910000831 Steel Inorganic materials 0.000 abstract description 12
- 239000010959 steel Substances 0.000 abstract description 12
- 238000005265 energy consumption Methods 0.000 abstract description 9
- 239000003344 environmental pollutant Substances 0.000 abstract description 8
- 231100000719 pollutant Toxicity 0.000 abstract description 8
- 238000005054 agglomeration Methods 0.000 abstract description 7
- 230000002776 aggregation Effects 0.000 abstract description 7
- 238000011161 development Methods 0.000 abstract description 7
- 239000002803 fossil fuel Substances 0.000 abstract description 6
- 230000002349 favourable effect Effects 0.000 abstract description 5
- 238000010438 heat treatment Methods 0.000 description 15
- 239000000571 coke Substances 0.000 description 11
- 238000005516 engineering process Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 8
- 150000002431 hydrogen Chemical class 0.000 description 6
- 239000008188 pellet Substances 0.000 description 6
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 5
- 239000003638 chemical reducing agent Substances 0.000 description 5
- 239000000446 fuel Substances 0.000 description 5
- 238000011068 loading method Methods 0.000 description 5
- 230000001590 oxidative effect Effects 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000005431 greenhouse gas Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 238000003723 Smelting Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000005255 carburizing Methods 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 239000004484 Briquette Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 238000009924 canning Methods 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011335 coal coke Substances 0.000 description 1
- 239000003034 coal gas Substances 0.000 description 1
- 238000004939 coking Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 235000003642 hunger Nutrition 0.000 description 1
- 238000007885 magnetic separation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000009768 microwave sintering Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 230000037351 starvation Effects 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/14—Multi-stage processes processes carried out in different vessels or furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0046—Making spongy iron or liquid steel, by direct processes making metallised agglomerates or iron oxide
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0073—Selection or treatment of the reducing gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
- C21B13/029—Introducing coolant gas in the shaft furnaces
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/16—Sintering; Agglomerating
- C22B1/22—Sintering; Agglomerating in other sintering apparatus
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/24—Binding; Briquetting ; Granulating
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Mechanical Engineering (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention discloses an iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method, wherein the iron ore microwave high-temperature sintering hydrogen-cooled reduction device comprises a continuous belt roasting system and a hydrogen-based shaft furnace reduction system; the roasting process and the reduction process of the iron-ore-containing raw materials are carried out separately, so that three technical problems of large pollutant discharge, low utilization rate of direct reduction hydrogen reduction and high energy consumption in the sintering reduction caused by fossil fuel combustion in the traditional iron-ore agglomeration process are solved, carbon discharge of the traditional steel process is reduced, and favorable conditions are created for green development of the traditional process.
Description
Technical Field
The invention belongs to a ferrous metal metallurgical raw material pretreatment technology in the field of steel smelting, and particularly relates to an iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method.
Background
As an important process of the whole process, the energy consumption and carbon emission of iron making account for 70-80% of the whole process, and carbon is mainly used as a heat source and a reducing agent in the iron making process. Therefore, how to find alternative energy sources and reducing agents is a key to reduce carbon emissions of ironmaking processes; it is widely considered in the industry that with the gradual turning of the electric power industry to generate electricity by new energy, the energy utilization mode of China actively advances towards the direction of carbon neutralization, so that the adoption of electric heating to replace the combustion of fossil fuel is one of the technical directions of realizing low-carbon development in the steel industry; in addition, the use of hydrogen reduction instead of carbon reduction is an important technical direction for reducing carbon emissions.
In the field of steelmaking, related researchers have conducted a great deal of research, such as techniques of replacing coke oven gas or carbon heating with microwave heating: chinese patent CN100547091C discloses a method for sintering ignition of iron ore, which uses microwave high-temperature hot air to replace coke oven gas for sintering ignition, so that sintering energy consumption can be greatly reduced, and sintering ore strength and yield can be improved.
Chinese patent CN 110273065B discloses a microwave sintering method of iron ore, which adopts microwave electric heating to replace coke powder combustion, completes iron ore sintering agglomeration, can thoroughly solve pollutant emission and reduce energy consumption in the iron ore sintering process, and realizes green and environment-friendly production.
Chinese patent CN 103290159B discloses a method for producing direct reduced iron powder by microwave heating, which comprises 60-73% of iron raw material, 22-30% of coal coke reducer, 3-7% of desulfurizing agent and 2-3% of bentonite; adding water, mixing, pelletizing and screening to obtain green pellets with the spherical diameter of 10-15 mm; after drying, sending the mixture into a microwave heating furnace, heating the mixture to 1050-1150 ℃, and reducing the mixture for 160-180 min to obtain metallized pellets; crushing and grinding into fine powder with granularity smaller than 0.2 mm; magnetic separation to obtain direct reduced iron powder; the technology overcomes the defects of long reduction time, difficult control of product quality, large investment, large occupied area and the like in the process of producing the direct reduced iron by a coal-based tunnel kiln canning external carbon method; however, the industrial microwave oven introduced by the technology is used for charging the material tray, and the intermittent production is not introduced in the aspect of production efficiency.
Publication No. CN 112410546A discloses a method for sintering hydrogen energy medium by combining microwave and a sintering heating system, wherein iron ore, coal and flux are mixed, fuel in the mixture is ignited by microwave, and generated carbon dioxide and water vapor enter a gasification furnace and are converted into CO and H 2 Then the mixture is led into a sintering cover for burning, thus improving the sintering effect and saving the energy consumption. The product is conventional sinter, and the waste gas discharge capacity is greatly reduced. The technology adopts microwave electric heating technology to replace coke oven gas or carbon heating, has the function of reducing greenhouse gas emission in the agglomeration process, and is beneficial to environmental protection.
Still others use shaft furnaces as reduction devices: publication number CN 112159880a discloses a method and apparatus for hydrogen ironmaking, wherein iron-ore-containing raw materials are adopted to realize hydrogen-rich or pure hydrogen smelting of iron ore by microwave irradiation in hydrogen or hydrogen-rich gas atmosphere, so as to obtain direct reduced iron; the technology uses microwaves to provide a heat source, uses pure hydrogen or hydrogen-rich gas as a reducing agent, places a sample in a crucible, adopts a kg-scale microwave oven as core equipment, and has limited treatment scale.
Chinese patent CN103261446B discloses a method and apparatus for producing directly reduced iron from a source of reducing gas containing hydrogen and CO, and high oxidation (CO) containing CO and hydrogen prepared using coal gas 2 And H 2 The DRI (direct reduced iron) is produced by the reducing gas of O), which breaks through the limit of natural gas used in the prior gas-based direct reduction shaft furnace.
Chinese patent CN 103608468B discloses a system and method for reducing iron oxide to metallic iron using coke oven gas and oxygen steelmaking furnace gas, so that gas inside long-process steel enterprises can be used to produce direct reduced iron, solving the bottleneck of developing direct reduced iron in the natural gas starvation area. Chinese patent CN103898265B discloses a system device and method for directly reducing iron ore by coke oven gas modification, which uses coke oven gas generated in coking process to modify and convert it into hydrogen-rich reducing gas (H) 2 And CO) and then introduced into the shaft furnace to directly reduce the iron ore; the technology can reduce carbon dioxide emission in the iron ore reduction process, is different from a direct reduction iron route of natural gas, and can be better suitable for the characteristics of Chinese energy resources.
Publication No. CN110484672A discloses a method for producing direct reduced iron by using a gas-based shaft furnace, which adopts the method for producing direct reduced iron by using crushed coke and CO under the screen of the blast furnace 2 The Boolean reaction of the furnace can effectively reduce the temperature in the shaft furnace, reduce the generation of furnace burden hotknot, effectively utilize the reduction heat-release energy, improve the overall energy utilization rate, generate CO to improve the reduction potential in the furnace, promote the reduction of iron ore, and facilitate the application of the technology for directly reducing iron ore by the air-based shaft furnace; the iron ore is pellet or lump ore and the mixture of the pellet and lump ore. The technology uses the shaft furnace as the reduction device, has the advantages of large treatment capacity, high efficiency and the like, and heats the iron ore with high-temperature reducing gas after adding the iron ore into the furnace for filtration at normal temperatureExchanging, heating and reaching the temperature required by reduction, gradually reducing to a higher metallization rate, and then using the metallization rate as the raw material of an electric furnace to match with scrap steel to obtain steel; the inherent thermodynamic limiting link exists in the treatment method, mainly in that after the specific heat capacity of ferric oxide is large and natural gas or coke oven gas is reformed, hydrogen is mainly used as a reducing agent, a great amount of heat is absorbed in the reduction process, and the reduction temperature is difficult to maintain, so that the gas needs to be heated and circulated for a plurality of times, the utilization rate of the hydrogen is relatively low in the whole process, and is usually about 30%, so that the gas-based direct reduction process is difficult to popularize in the world, and only has certain development in China such as middle east and south america where the price of the natural gas is low;
in view of the above, the industry is urgent to study a new iron ore sintering reduction technology, which can solve three technical problems of large pollutant discharge, low utilization rate of direct reduction hydrogen reduction and high energy consumption in sintering reduction caused by fossil fuel combustion in the traditional iron ore agglomeration process, thereby reducing carbon discharge of the traditional steel process and creating favorable conditions for green development of the traditional process.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the microwave high-temperature sintering hydrogen-cooled reduction device and method for iron ores, which organically combine the oxidizing roasting process of the iron ores with the reduction process of furnace charges, sinter the iron ores by utilizing microwave heating, then provide heat required by the reduction process by utilizing the high temperature of the iron ores to obtain the prereduced furnace charges with a certain metallization rate, solve three technical problems of high pollutant discharge, low utilization rate of direct reduction hydrogen reduction and high energy consumption in the sintering reduction process caused by the combustion of fossil fuels in the traditional iron ore agglomeration process, reduce the carbon discharge of the traditional steel process, and create favorable conditions for the green development of the traditional process.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the first aspect of the invention provides an iron ore microwave high-temperature sintering hydrogen-cooled reduction device, which comprises a continuous belt roasting system and a hydrogen-based shaft furnace reduction system;
the continuous belt roasting system is used for drying, preheating and roasting the iron ore-containing raw materials; the continuous belt type roasting system is electrically heated by microwaves and is provided with a drying section, a preheating section and a high-temperature roasting section along the moving direction of the iron-ore-containing raw materials;
the hydrogen-based shaft furnace reduction system is used for reducing high-temperature furnace burden obtained by roasting by the continuous belt roasting system; the hydrogen-based shaft furnace reduction system comprises a hydrogen-based shaft furnace, a feeding system, a reducing gas system, a cooling system and a discharging system; the feeding system is arranged at the upper part of the hydrogen-based shaft furnace; the reducing gas system is used for providing reducing gas required by reduction treatment; the cooling system is used for cooling the reduced pre-reduced furnace burden; the blanking system is arranged at the bottom of the hydrogen-based shaft furnace.
Preferably, an air inlet is arranged above a high-temperature roasting section of the continuous belt roasting system, and an air outlet is arranged above the drying section; the exhaust port is connected with the bag-type dust collector through a fan; and/or
The feeding system comprises an upper hopper, a middle hopper and a lower hopper; valves are arranged among the upper hopper, the middle hopper and the lower hopper; and/or
The reducing gas system comprises a waste heat boiler/tubular heat exchanger, a first scrubber, a circulating fan and a pressurizing fan; one end of the waste heat boiler/tubular heat exchanger is connected with a flue gas outlet at the top of the hydrogen-based shaft furnace, and the other end of the waste heat boiler/tubular heat exchanger is connected with an air inlet of the first scrubber; one end of the circulating fan is connected with the air outlet of the first scrubber, and the other end of the circulating fan is communicated with the annular air port in the middle of the hydrogen-based shaft furnace; the pressurizing fan pressurizes the reducing gas from the circulating fan; and/or
The cooling system comprises an oxygen supplementing combustion unit, a waste heat recovery unit, a second scrubber and a cooling fan; the oxygen supplementing combustion unit is connected with an air outlet at the lower part of the hydrogen-based shaft furnace; one end of the waste heat recovery unit is connected with the oxygen supplementing combustion unit, and the other end of the waste heat recovery unit is connected with the air inlet of the second scrubber; one end of the cooling fan is connected with the air outlet of the second scrubber, and the other end of the cooling fan is communicated with the air inlet at the lower part of the hydrogen-based shaft furnace; the air outlet is arranged at the upper part of the air inlet.
Preferably, a vent pipe is arranged on the upper hopper; the middle hopper is provided with a pressure equalizing device; the lower hopper is provided with a universal distributing device.
According to a second aspect of the invention, a microwave high-temperature sintering hydrogen-cooled reduction method for iron ores is provided, wherein the microwave high-temperature sintering hydrogen-cooled reduction device for iron ores is used, the microwave high-temperature sintering hydrogen-cooled reduction method for iron ores is used for loading iron-ore-containing raw materials into a continuous belt type roasting system, and after high-temperature roasting is carried out through microwave electric heating, the raw materials are directly fed into a hydrogen-based shaft furnace reduction system for reduction.
Preferably, the iron ore microwave high-temperature sintering hydrogen-cooled reduction method comprises the following steps:
(1) Adding dolomite, limestone and quicklime/slaked lime into the iron ore raw materials, adding water, and mixing, granulating or mixing and briquetting to obtain the iron ore-containing raw materials;
(2) Loading the iron ore-containing raw materials into a continuous belt roasting system with a bed charge, and drying, preheating and high-temperature roasting by utilizing microwave electric heating to obtain a high-temperature furnace charge;
(3) The high-temperature furnace burden enters a hydrogen-based shaft furnace reduction system to undergo a reduction reaction with reducing gas, and then is subjected to cooling treatment by cooling gas to obtain pre-reduced furnace burden or hot-pressed iron.
Preferably, in the step (1), the iron ore raw material is selected from one or more of magnetite, hematite and limonite; and/or
In the step (2), the thickness of the bottom material is 20-50mm, and the total height of the material layer is 200-300mm after the iron ore-containing raw materials are filled in the bottom material; and/or
The bed charge adopts hematite powder with granularity smaller than 5mm and melting point larger than 1300 ℃; and/or
When magnetite is contained in the iron-ore-containing raw material, air is supplemented above the iron-ore-containing raw material, and the oxygen content is controlled to be more than 14%; and/or
In the high-temperature roasting process, the high-temperature roasting temperature is controlled to be 1250-1350 ℃, and the high-temperature roasting time is controlled to be 5-10min.
Preferably, in the step (3), the pressure of the hydrogen-based shaft furnace reduction system is 200-250kPa; and/or
The reducing gas adopts pure hydrogen or coke oven gas; and/or
In the course of said reduction reaction, the consumption of said reducing gas is 800-1200m 3 T, the reduction reaction time is 40-100min; and/or
The cooling gas adopts nitrogen and a small amount of natural gas; and/or
In the cooling treatment process, the cooling air flow is 1200-1800m 3 T; and/or
The discharging temperature of the pre-reduced furnace burden or the hot-pressed block iron is lower than 150 ℃;
the metallization rate of the pre-reduced furnace burden or hot-pressed block iron is more than or equal to 40 percent.
Preferably, in the step (3), the reducing gas is pure hydrogen, and in the reducing reaction process, the hydrogen utilization rate reaches more than 55%;
the metallization rate of the pre-reduced furnace burden or hot-pressed block iron is 40-66%.
Preferably, in the step (3), the hydrogen utilization rate reaches more than 60% in the reduction reaction process; and/or
The high-temperature furnace burden enters a feeding system of the hydrogen-based shaft furnace reduction system through a high-temperature resistant charging bucket, is distributed by the feeding system and enters a hydrogen-based shaft furnace of the hydrogen-based shaft furnace reduction system, and participates in reduction reaction in the middle of the hydrogen-based shaft furnace;
the reducing gas participates in the reduction reaction through a reducing gas system, and flue gas after the reduction reaction enters the reducing gas system from a flue gas outlet at the top of the hydrogen-based shaft furnace, and enters the middle part of the hydrogen-based shaft furnace to participate in the reduction reaction after waste heat recovery and washing;
the cooling gas participates in cooling treatment through a cooling system, and the mixed gas after cooling treatment enters the cooling system from a gas outlet at the lower part of the hydrogen-based shaft furnace, and enters the lower part of the hydrogen-based shaft furnace to participate in cooling treatment after oxygen supplementing combustion, waste heat recovery and washing.
Preferably, in the step (3), the material distribution mode of the material loading system is as follows:
after entering the feeding system, the high-temperature furnace burden sequentially passes through an upper hopper, a middle hopper and a lower hopper of the feeding system and then is distributed into the hydrogen-based shaft furnace;
after the high-temperature furnace burden is filled into the upper hopper, high-temperature high-pressure steam or high-temperature high-pressure nitrogen is introduced to replace the high-temperature high-pressure steam or high-temperature high-pressure nitrogen, after the oxygen content in the upper hopper is less than or equal to 1%, the valve below the upper hopper is opened, after the high-temperature furnace burden completely enters the middle hopper, the valve below the upper hopper is closed, the pressure equalizing process is completed by adopting gas with the same composition as the gas on the inner top of the hydrogen-based shaft furnace, after the pressure equalizing is completed, the valve below the middle hopper is opened, after the high-temperature furnace burden completely enters the lower hopper, the valve below the middle hopper is closed, the valve below the lower hopper is opened, and the high-temperature furnace burden is distributed into the hydrogen-based shaft furnace.
The beneficial effects of the invention are as follows:
1. according to the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method provided by the invention, the iron ore is sintered by utilizing microwave electric heating to obtain high-temperature furnace charge, then the heat required in the reduction process is provided by the high temperature of the high-temperature furnace charge to obtain the prereduced furnace charge with the metallization rate of 40-66%, so that three technical problems of high pollutant discharge, low utilization rate of direct reduction hydrogen reduction and high energy consumption in the sintering reduction process caused by fossil fuel combustion in the traditional iron ore agglomeration process are solved, the carbon discharge of the traditional steel process is reduced, and a favorable condition is created for green development of the traditional process;
2. according to the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method provided by the invention, the iron ore oxidizing roasting process is organically combined with the furnace charge reduction process, the furnace charge cooling and direct reduction furnace charge heating process is canceled, pure hydrogen or hydrogen-rich gas is utilized for cooling reduction, the flow is simpler, and the energy utilization efficiency is improved;
3. according to the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method provided by the invention, the physical heat of the high-temperature furnace charge is utilized to meet the heat required by hydrogen reduction and gas heating, so that the thermodynamic conditions of hydrogen reduction are more reasonable, and the hydrogen utilization rate can be greatly improved;
4. the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method provided by the invention utilize the characteristics of large microwave penetration depth, good temperature uniformity and integral heating, are used for furnace burden drying, preheating and high-temperature roasting, thoroughly eliminate pollutants and greenhouse gases generated by fuel combustion in the iron ore oxidation roasting process, and are more environment-friendly;
5. according to the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method provided by the invention, the whole flow adopts the modes of microwave electric heating and pure hydrogen or hydrogen-rich gas reduction, so that the carbon-free production of pre-reduced furnace burden can be realized; the prereduced furnace burden is used in traditional blast furnace or converter, and can reduce carbon emission in steel process greatly.
6. The iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method provided by the invention can simplify a hydrogen-based shaft furnace gas treatment system, improve the hydrogen utilization rate, and can greatly reduce the fuel consumption and carbon emission of a blast furnace by taking the prepared pre-reduced furnace charge as the blast furnace charge, thereby being a low-carbon and green iron ore sintering reduction process.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
fig. 1 is a schematic structural view of an iron ore microwave high-temperature sintering hydrogen-cooled reduction device according to the present invention.
Detailed Description
In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below with reference to the accompanying drawings and examples.
Referring to FIG. 1, the iron ore microwave high-temperature sintering hydrogen-cooled reduction device provided by the invention comprises a continuous belt roasting system 1 and a hydrogen-based shaft furnace reduction system 2;
referring to fig. 1, a continuous belt roasting system 1 is used for drying, preheating and roasting iron ore-containing raw materials; the continuous belt type roasting system 1 adopts microwave electric heating, and is sequentially provided with a drying section A, a preheating section B and a high-temperature roasting section C along the moving direction of the iron-ore-containing raw material; in a further preferred scheme, an air inlet is arranged above the high-temperature roasting section C of the continuous belt roasting system 1, and an air outlet is arranged above the drying section A; the exhaust port is connected with a bag-type dust collector 12 through a fan 11; the high-temperature furnace burden obtained after roasting in the continuous belt roasting system 1 is conveyed into the feeding system 21 through a high-temperature resistant charging bucket.
Referring to fig. 1, a hydrogen-based shaft furnace reduction system 2 is used for reducing a high-temperature charge obtained by roasting in a continuous belt roasting system 1; the hydrogen-based shaft furnace reduction system 2 comprises a hydrogen-based shaft furnace 22, a feeding system 21, a reducing gas system 23, a cooling system 24 and a discharging system; the feeding system 21 is arranged at the upper part of the hydrogen-based shaft furnace 22; the reducing gas system 23 is used for providing reducing gas required in the reduction reaction, and in addition, the reducing gas system 23 can also treat flue gas generated in the reduction reaction; the cooling system 24 is used for cooling the reduced pre-reduced furnace burden, providing cooling gas required by the cooling treatment, and further processing the mixed gas generated after cooling; the blanking system is arranged at the bottom of the hydrogen-based shaft furnace 22.
As shown in connection with fig. 1, the loading system 21 comprises an upper hopper 211, a middle hopper 212 and a lower hopper 213; valves are arranged among the upper hopper 211, the middle hopper 212 and the lower hopper 213 in order to facilitate the maintenance of a closed environment in each part of the hoppers; in a specific embodiment, after the high-temperature furnace burden (about 1200 ℃) is filled in the upper hopper 211, in order to ensure that the oxygen content in the upper hopper 211 is less than or equal to 1%, the upper hopper 211 is further provided with a ventilation pipeline, so that high-temperature high-pressure steam or high-temperature high-pressure nitrogen can be conveniently introduced to replace oxygen in the air. In order to ensure the pressure equalization in the middle hopper, a pressure equalizing device is arranged on the middle hopper 212, and the pressure equalizing process can be completed by adopting the gas with the same composition as the gas on the inner top of the shaft furnace. To facilitate the distribution of the high temperature charge into the hydrogen-based shaft furnace 22, a universal distributor is provided below the lower hopper 213.
As shown in connection with fig. 1, the reducing gas system 23 is for providing reducing gas required in the reduction reaction, and includes a waste heat boiler/tubular heat exchanger 231, a first scrubber 232, a circulating fan 233, and a pressurizing fan 234; one end of the waste heat boiler/tubular heat exchanger 231 is connected with a flue gas outlet at the top of the hydrogen-based shaft furnace 22, and the other end of the waste heat boiler/tubular heat exchanger is connected with an air inlet of the first scrubber 232; one end of the circulating fan 233 is connected with the air outlet of the first scrubber 232, and the other end of the circulating fan 233 is communicated with an annular air port in the middle of the hydrogen-based shaft furnace 22; the pressurizing fan 234 pressurizes the reducing gas from the circulating fan 233; in specific use, the reducing gas enters from the annular tuyere of the hydrogen-based shaft furnace 22, contacts with the high-temperature furnace burden from the charging system 21 in the middle of the hydrogen-based shaft furnace 22, is heated by the high-temperature pellets (absorbs the temperature of the high-temperature furnace burden and cools the high-temperature furnace burden) and undergoes a reduction reaction with the high-temperature furnace burden, and after the reaction, the reducing gas is recycled from the flue gas outlet at the top of the hydrogen-based shaft furnace 22, preheated through the waste heat boiler/tubular heat exchanger 231, washed by the first scrubber 232, and then participates in the reduction reaction through the annular tuyere under the action of the circulating fan 233 and the pressurizing fan 234.
As shown in connection with fig. 1, the cooling system 24 includes an oxygen supplementing combustion unit 241, a waste heat recovery unit 242, a second scrubber 243, and a cooling fan 244; the oxygen supplementing combustion unit 241 is connected with an air outlet at the lower part of the hydrogen-based shaft furnace 22; one end of the waste heat recovery unit 242 is connected with the oxygen supplementing combustion unit 241, and the other end is connected with the air inlet of the second scrubber 243; one end of the cooling fan 244 is connected with the air outlet of the second scrubber 243, and the other end is communicated with the air inlet at the lower part of the hydrogen-based shaft furnace 22; wherein the air outlet is arranged at the upper part of the air inlet; when the device is specifically used, cooling gas enters from the air inlet at the lower part of the hydrogen-based shaft furnace 22, the prereduced furnace burden after the reduction reaction is cooled at the lower part of the hydrogen-based shaft furnace 22, and the cooled mixed gas is subjected to oxygen-supplementing combustion by the oxygen-supplementing combustion unit 241, recovered and preheated by the waste heat recovery unit 242 and washed by the second scrubber 243, and then is subjected to cooling treatment through the air inlet at the lower part of the hydrogen-based shaft furnace 22 under the action of the cooling fan 244.
And the discharging system is used for discharging the cooled pre-reduced furnace burden or hot-pressed iron HBI.
Referring to fig. 1, the microwave high-temperature sintering hydrogen-cooled reduction method for iron ore provided by the invention uses the microwave high-temperature sintering hydrogen-cooled reduction device for iron ore, and comprises the following steps: the iron ore-containing raw materials in the continuous belt roasting system 1 are directly sent into the hydrogen-based shaft furnace reduction system 2 for reduction after being roasted at high temperature by microwave electric heating; the method specifically comprises the following steps:
(1) Adding dolomite, limestone and quicklime/slaked lime into the iron ore raw materials, adding water, and mixing, granulating or mixing and briquetting to obtain iron ore-containing raw materials;
the specific process is as follows: one or more of magnetite, hematite and limonite are matched to obtain iron ore raw materials, then flux such as dolomite, limestone, quicklime/slaked lime and the like is added, the alkalinity and MgO content are adjusted to be suitable (the adding amount of the dolomite, the limestone and the quicklime/slaked lime is adjusted according to the slag making requirement of a blast furnace), water is added, and the iron ore raw materials (mixture or briquette) with uniform granularity are obtained through mixing granulation or mixing briquetting.
(2) Loading iron ore-containing raw materials into a continuous belt roasting system 1 with a bed charge, and drying, preheating and high-temperature roasting by utilizing microwave electric heating to obtain a high-temperature furnace charge;
the specific process is as follows: the method comprises the steps of (1) paving the iron ore-containing raw materials prepared in the step (1) on a trolley of a continuous belt roasting system 1, controlling the thickness of the base material to be 20-50mm, and after the iron ore-containing raw materials are filled, enabling the total height of a material layer to be 200-300mm, wherein the base material adopts hematite powder with granularity less than 5mm and melting point greater than 1300 ℃; then the iron ore-containing raw material is dried, preheated and roasted at high temperature by adopting microwave electric heating to obtain high-temperature furnace burden, in the microwave electric heating process, no air flow penetrates through the material layer to maintain the medium-high temperature state of the material layer, if magnetite is added into the iron ore-containing raw material to ensure complete oxidation of the iron ore-containing raw material, a small amount of air is supplemented into the upper part of the material layer to ensure that the oxygen content is more than 14%, the iron oxide is utilized to have strong wave absorption and microwave penetrability, so that the iron ore-containing raw material is quickly heated on a trolley, the high-temperature roasting temperature is controlled to be 1250-1350 ℃, the high-temperature maintaining time is 5-10min, and the high-temperature furnace burden (sintered ore or agglomerate) is cooledThe aim is that the drum strength is more than 75%, and the microwave power is regulated, so that the roasting temperature and the roasting time are regulated; in the microwave electric heating process, a small amount of water vapor and CO are removed from the iron ore-containing raw material 2 And the waste gas enters into a fan 11, is dedusted by a bag-type dust remover 12, and is discharged through a chimney 13 after meeting the ultra-low emission standard.
(3) The high-temperature furnace burden enters a hydrogen-based shaft furnace reduction system 2 to undergo a reduction reaction with reducing gas, and then is subjected to cooling treatment by cooling gas to obtain pre-reduced furnace burden or hot-pressed iron: the high-temperature furnace charge enters a feeding system 21 of the hydrogen-based shaft furnace reduction system 2 through a high-temperature resistant charging bucket, then enters a hydrogen-based shaft furnace 22 of the hydrogen-based shaft furnace reduction system 2 through the feeding system 21, performs a reduction reaction at the middle part of the hydrogen-based shaft furnace 22, and performs cooling treatment at the lower part of the hydrogen-based shaft furnace 22 after the reduction reaction to obtain pre-reduced furnace charge; the flue gas after the reduction reaction enters a reducing gas system 23 from a flue gas outlet at the top of the hydrogen-based shaft furnace 22, and enters the middle part of the hydrogen-based shaft furnace 22 to participate in the reduction reaction through the reducing gas system 23 after waste heat recovery and washing; the mixed gas after cooling treatment enters a cooling system 24 from an air outlet at the lower part of the hydrogen-based shaft furnace 22, and enters the lower part of the hydrogen-based shaft furnace 22 to participate in cooling treatment after oxygen supplementing combustion, waste heat recovery and washing by the cooling system 24; the specific process is as follows:
(3.1) cloth: the high-temperature furnace burden prepared in the step (2) enters a feeding system 21 of a hydrogen-based shaft furnace reduction system 2 through a high-temperature resistant charging tank, sequentially enters an upper hopper 211, a middle hopper 212 and a lower hopper 213 of the feeding system 21, and then is distributed into the hydrogen-based shaft furnace 22, after the high-temperature furnace burden is filled into the upper hopper 211 in the process, high-temperature high-pressure steam or high-temperature high-pressure nitrogen is introduced for replacement, after the oxygen content in the upper hopper 211 is less than or equal to 1%, a valve below the upper hopper 211 is opened, after the high-temperature furnace burden enters the complete middle hopper 212, a valve below the upper hopper 211 is closed, a pressure equalizing process is completed by adopting gas with the same composition as the top gas in the hydrogen-based shaft furnace 22, after pressure equalizing is completed, the valve below the middle hopper 212 is opened, after the high-temperature furnace burden completely enters the lower hopper 213, the valve below the middle hopper 212 is closed, the valve below the lower hopper 213 is opened, and the high-temperature furnace burden is distributed into the hydrogen-based shaft furnace 22 through a universal distributor.
(3.2) reduction reaction: the high-temperature furnace burden performs a reduction reaction in the middle of the hydrogen-based shaft furnace 22, wherein the reducing gas adopts pure hydrogen or coke oven gas, preferably pure hydrogen; the reducing gas enters from the annular air port in the middle of the hydrogen-based shaft furnace 22, contacts with the hot high-temperature furnace burden at about 500 ℃, and is heated by the high-temperature pellets (absorbing the temperature of the high-temperature furnace burden and cooling the high-temperature furnace burden) while undergoing a reduction reaction with the high-temperature furnace burden, and the concentration of the reducing gas gradually decreases along with the rising of the gas, but the reduction reaction is continuously performed because the temperature of the high-temperature furnace burden gradually increases, the flue gas after the reduction reaction is discharged from the flue gas outlet at the top of the hydrogen-based shaft furnace 22, the temperature of the flue gas after the reduction reaction is heated to more than 1000 ℃, the waste heat is recovered through a tubular heat exchanger or a waste heat boiler, the physical heat in the top gas is utilized, and then the H in the flue gas is removed by the first scrubber 232 2 O and dust, or a small amount of ammonia water is sprayed into the first scrubber 232 according to the process requirement to remove CO in the flue gas 2 And SO 2 So that the flue gas becomes H after simple washing treatment 2 And CO is the main high reduction potential gas, and the reduction gas is recycled to the reduction reaction through the circulating fan 233; in the course of reduction reaction the consumption of reducing gas is 800-1200m 3 And/t, the reduction reaction time is 40-100min, and the pressure of the hydrogen-based shaft furnace 22 of the hydrogen-based shaft furnace reduction system 2 is 200-250kPa.
(3.3) cooling treatment: the high-temperature furnace burden is subjected to reduction reaction and then is subjected to cooling treatment by adopting cooling gas at the lower part of the hydrogen-based shaft furnace 22, the mixed gas after the cooling treatment enters a cooling system 24 from a gas outlet at the lower part of the hydrogen-based shaft furnace 22, and the mixed gas is subjected to oxygen-supplementing combustion, waste heat recovery and washing and then enters the cooling treatment through a gas inlet at the lower part of the hydrogen-based shaft furnace 22 by the cooling system 24; in the cooling treatment, nitrogen and a small amount of natural gas are adopted, and the reduced material contains sponge iron (DRI) which can catalyze CH4 to crack and form a small amount of Fe3C when being cooled, so that the carburizing process is finished to prevent the DRI from being oxidized again; in the above process, the cooling air flow is 1200-1800m 3 T; the final hydrogen-based shaft furnace 22 is discharged into pre-reduced furnace burden or hot-pressed iron, and the discharging temperature thereofAnd determining the metallization rate of the product according to the requirement of the subsequent working procedure at a temperature lower than 150 ℃.
In the microwave high-temperature sintering hydrogen-cooled reduction method of the iron ore, the metallization rate of the prepared pre-reduced furnace burden or hot-pressed block iron is more than or equal to 40%, and the hydrogen utilization rate is more than 40%. In a further scheme, the metallization rate of the pre-reduced furnace burden or the hot-pressed block iron is 40-66%, and the hydrogen utilization rate is more than 50%.
The iron ore microwave high-temperature sintering hydrogen-cooled reduction device and the method are further described below by combining specific examples; the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method adopt the device and the method;
examples 1 to 5
The iron ore raw materials in examples 1 to 5 are shown in table 1, and after adding dolomite, limestone and quicklime/slaked lime, adding water, mixing, granulating or briquetting to obtain iron ore-containing raw materials, and then transferring into a continuous belt type roasting system to prepare high-temperature furnace materials after drying, preheating and high-temperature roasting, wherein the roasting parameters are shown in table 1;
TABLE 1 iron ore raw materials and high temperature roasting parameters
Transferring the high-temperature furnace burden into a hydrogen-based shaft furnace reduction system for reduction, adopting pure hydrogen or coke oven gas for reduction, and cooling and carburizing by nitrogen and methane to obtain pre-reduced furnace burden or hot-pressed block iron, wherein the reduction parameters are shown in table 2;
TABLE 2 high temperature burden and reduction parameters
In the embodiment 1, the alkalinity of the iron ore-containing raw material is 1.8, the iron ore-containing raw material is manufactured in a briquetting mode, the size of the briquettes is 35-50-20 mm ellipsoids, the briquettes are roasted for 12min at 1350 ℃, the cold drum strength of the obtained high-temperature furnace burden is 76%, the high-temperature furnace burden is reduced by pure hydrogen, the hydrogen utilization rate is 54%, and the metallization rate of the pre-reduced furnace burden obtained after cooling can reach 66%.
In example 2, the alkalinity of the iron ore-containing raw material is 1.9, the raw material is mixed and granulated by adopting a strong mixer/cylinder mixer, the raw material is roasted for 10min at 1320 ℃, the cold state drum strength of the obtained high-temperature furnace burden reaches 78%, the high-temperature furnace burden is reduced by introducing hydrogen, the hydrogen utilization rate is 62%, and the metallization rate of the pre-reduced furnace burden obtained after cooling is 51%.
In example 3, the alkalinity of the iron ore-containing raw material is 0.9, the iron ore-containing raw material is manufactured in a briquetting mode, the size of the briquettes is 35-50-20 mm ellipsoids, the briquettes are roasted for 11min at 1300 ℃, the cold drum strength of the obtained high-temperature furnace burden reaches 77%, the high-temperature furnace burden is reduced by pure hydrogen, the hydrogen utilization rate is 65%, and the metallization rate of the pre-reduced furnace burden obtained after cooling is 64%.
In example 4, the alkalinity of the iron ore-containing raw material is 1.8, the raw material is mixed and granulated by adopting a strong mixer/cylinder mixer, roasting is carried out for 9min at 1280 ℃, the cold drum strength of the obtained high-temperature furnace burden reaches 75%, the high-temperature furnace burden is reduced by introducing hydrogen, the hydrogen utilization rate is 45%, and the metallization rate of the pre-reduced furnace burden obtained after cooling is 53%.
In example 5, the alkalinity of the iron ore-containing raw material is 1.9, the raw material is mixed and granulated by adopting a strong mixer/cylinder mixer, the raw material is roasted for 12min at 1310 ℃, the cold state drum strength of the obtained high-temperature furnace burden reaches 79%, the high-temperature furnace burden is reduced by introducing hydrogen-rich gas, the hydrogen utilization rate is 43%, and the metallization rate of the pre-reduced furnace burden obtained after cooling is 52%.
In summary, the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and the method organically combine the iron ore oxidizing roasting process with the furnace charge reduction process, firstly utilize microwave electric heating to sinter the iron ore to obtain high-temperature furnace charge, then utilize the high temperature of the high-temperature furnace charge to provide heat required by the reduction process to obtain pre-reduced furnace charge with the metallization rate of 40-66%, solve the three technical problems of high pollutant discharge amount, low utilization rate of direct reduction hydrogen reduction and high energy consumption in the sintering reduction process caused by the combustion of fossil fuel in the traditional iron ore agglomeration process, reduce the carbon discharge of the traditional steel process, and create favorable conditions for the green development of the traditional process; the iron ore oxidizing roasting process is organically combined with the furnace charge reduction process, the furnace charge cooling and direct reduction furnace charge heating process is canceled, pure hydrogen or hydrogen-rich gas is utilized for cooling and reduction, the flow is simpler, and the energy utilization efficiency is improved; according to the iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method, the physical heat of high-temperature furnace charge is utilized to meet the heat required by hydrogen reduction and gas heating, so that the thermodynamic conditions of hydrogen reduction are more reasonable, and the hydrogen utilization rate can be greatly improved; the method has the advantages that the characteristics of large microwave penetration depth, good temperature uniformity and integral heating are utilized, the method is used for drying, preheating and high-temperature roasting of furnace charges, pollutants and greenhouse gases generated by fuel combustion in the iron ore oxidizing roasting process are thoroughly eliminated, and the method is more environment-friendly; the whole process adopts the modes of microwave electric heating and pure hydrogen or hydrogen-rich gas reduction, and can realize the carbon-free production of pre-reduced furnace burden; the prereduced furnace burden is used in traditional blast furnace or converter, and can reduce carbon emission in steel process greatly. The iron ore microwave high-temperature sintering hydrogen-cooled reduction device and method can simplify a hydrogen-based shaft furnace gas treatment system, improve the hydrogen utilization rate, take the prepared pre-reduced furnace charge as a blast furnace charge, greatly reduce the fuel consumption and carbon emission of the blast furnace, and are a low-carbon and green iron ore sintering reduction process.
It will be appreciated by persons skilled in the art that the above embodiments are provided for illustration only and not for limitation of the invention, and that variations and modifications of the above described embodiments are intended to fall within the scope of the claims of the invention as long as they fall within the true spirit of the invention.
Claims (7)
1. The iron ore microwave high-temperature sintering hydrogen-cooled reduction device is characterized by comprising a continuous belt roasting system and a hydrogen-based shaft furnace reduction system;
the continuous belt roasting system is used for drying, preheating and roasting the iron ore-containing raw materials; the continuous belt type roasting system is electrically heated by microwaves and is provided with a drying section, a preheating section and a high-temperature roasting section along the moving direction of the iron-ore-containing raw materials;
the hydrogen-based shaft furnace reduction system is used for reducing high-temperature furnace burden obtained by roasting by the continuous belt roasting system; the hydrogen-based shaft furnace reduction system comprises a hydrogen-based shaft furnace, a feeding system, a reducing gas system, a cooling system and a discharging system; the feeding system is arranged at the upper part of the hydrogen-based shaft furnace; the reducing gas system is used for providing reducing gas required by reduction treatment; the cooling system is used for cooling the reduced pre-reduced furnace burden; the blanking system is arranged at the bottom of the hydrogen-based shaft furnace,
the reducing gas system comprises a waste heat boiler/tubular heat exchanger, a first scrubber, a circulating fan and a pressurizing fan; one end of the waste heat boiler/tubular heat exchanger is connected with a flue gas outlet at the top of the hydrogen-based shaft furnace, and the other end of the waste heat boiler/tubular heat exchanger is connected with an air inlet of the first scrubber; one end of the circulating fan is connected with the air outlet of the first scrubber, and the other end of the circulating fan is communicated with the annular air port in the middle of the hydrogen-based shaft furnace; the pressurizing fan pressurizes the reducing gas from the circulating fan;
the cooling system comprises an oxygen supplementing combustion unit, a waste heat recovery unit, a second scrubber and a cooling fan; the oxygen supplementing combustion unit is connected with an air outlet at the lower part of the hydrogen-based shaft furnace; one end of the waste heat recovery unit is connected with the oxygen supplementing combustion unit, and the other end of the waste heat recovery unit is connected with the air inlet of the second scrubber; one end of the cooling fan is connected with the air outlet of the second scrubber, and the other end of the cooling fan is communicated with the air inlet at the lower part of the hydrogen-based shaft furnace; the air outlet is arranged at the upper part of the air inlet,
the iron ore microwave high-temperature sintering hydrogen-cooled reduction device executes the following iron ore microwave high-temperature sintering hydrogen-cooled reduction method, which comprises the following steps:
(1) Adding dolomite, limestone and quicklime/slaked lime into the iron ore raw materials, adding water, and mixing, granulating or mixing and briquetting to obtain the iron ore-containing raw materials;
(2) The iron ore-containing raw materials are put into a continuous belt roasting system with the bed charge well paved, and are dried, preheated and roasted at high temperature by utilizing microwave electric heating to obtain high-temperature furnace charge,
in the high-temperature roasting process, the high-temperature roasting temperature is controlled to be 1250-1350 ℃, and the high-temperature roasting time is controlled to be 5-10min;
(3) The high-temperature furnace burden enters a hydrogen-based shaft furnace reduction system to undergo a reduction reaction with reducing gas, and then is subjected to cooling treatment by cooling gas to obtain pre-reduced furnace burden or hot-pressed iron,
in the step (3), the pressure of the hydrogen-based shaft furnace reduction system is 200-250kPa;
the reducing gas adopts pure hydrogen; in the course of said reduction reaction, the consumption of said reducing gas is 800-1200m 3 And/t, the reduction reaction time is 40-100min, and the hydrogen utilization rate reaches more than 55%;
the cooling gas adopts nitrogen and a small amount of natural gas; in the cooling treatment process, the cooling air flow is 1200-1800m 3 /t；
The discharging temperature of the pre-reduced furnace burden or the hot-pressed block iron is lower than 150 ℃;
the metallization rate of the pre-reduced furnace burden or hot-pressed block iron is 40-66%.
2. The iron ore microwave high-temperature sintering hydrogen-cooled reduction device according to claim 1, wherein an air inlet is arranged above a high-temperature roasting section of the continuous belt roasting system, and an air outlet is arranged above the drying section; the exhaust port is connected with the bag-type dust collector through a fan;
the feeding system comprises an upper hopper, a middle hopper and a lower hopper; valves are arranged among the upper hopper, the middle hopper and the lower hopper.
3. The iron ore microwave high-temperature sintering hydrogen-cooled reduction device according to claim 2, wherein a ventilation pipeline is arranged on the upper hopper; the middle hopper is provided with a pressure equalizing device; the lower hopper is provided with a universal distributing device.
4. A microwave high-temperature sintering hydrogen-cooled reduction method for iron ores is characterized in that the microwave high-temperature sintering hydrogen-cooled reduction method for iron ores uses the microwave high-temperature sintering hydrogen-cooled reduction device for iron ores according to any one of claims 1-3, the microwave high-temperature sintering hydrogen-cooled reduction method for iron ores is characterized in that iron ore-containing raw materials are loaded into a continuous belt type roasting system, high-temperature roasting is carried out through microwave electric heating, and then the raw materials are directly sent into a hydrogen-based shaft furnace reduction system for reduction,
the iron ore microwave high-temperature sintering hydrogen-cooled reduction method comprises the following steps:
(1) Adding dolomite, limestone and quicklime/slaked lime into the iron ore raw materials, adding water, and mixing, granulating or mixing and briquetting to obtain the iron ore-containing raw materials;
(2) The iron ore-containing raw materials are put into a continuous belt roasting system with the bed charge well paved, and are dried, preheated and roasted at high temperature by utilizing microwave electric heating to obtain high-temperature furnace charge,
in the high-temperature roasting process, the high-temperature roasting temperature is controlled to be 1250-1350 ℃, and the high-temperature roasting time is controlled to be 5-10min;
(3) The high-temperature furnace burden enters a hydrogen-based shaft furnace reduction system to undergo a reduction reaction with reducing gas, and then is subjected to cooling treatment by cooling gas to obtain pre-reduced furnace burden or hot-pressed iron,
in the step (3), the pressure of the hydrogen-based shaft furnace reduction system is 200-250kPa;
the reducing gas adopts pure hydrogen; in the course of said reduction reaction, the consumption of said reducing gas is 800-1200m 3 And/t, the reduction reaction time is 40-100min, and the hydrogen utilization rate reaches more than 55%;
the cooling gas adopts nitrogen and a small amount of natural gas; in the cooling treatment process, the cooling air flow is 1200-1800m 3 /t；
The discharging temperature of the pre-reduced furnace burden or the hot-pressed block iron is lower than 150 ℃;
the metallization rate of the pre-reduced furnace burden or hot-pressed block iron is 40-66%.
5. The method of microwave high-temperature sintering hydrogen-cooled reduction of iron ore according to claim 4, wherein in the step (1), the iron ore raw material is selected from one or more of magnetite, hematite and limonite; and/or
In the step (2), the thickness of the bottom material is 20-50mm, and the total height of the material layer is 200-300mm after the iron ore-containing raw materials are filled in the bottom material; and/or
The bed charge adopts hematite powder with granularity smaller than 5mm and melting point larger than 1300 ℃; and/or
When magnetite is contained in the iron-ore-containing raw material, air is supplemented above the iron-ore-containing raw material, and the oxygen content is controlled to be more than 14%; and/or
In the high-temperature roasting process, the high-temperature roasting temperature is controlled to be 1250-1350 ℃, and the high-temperature roasting time is controlled to be 5-10min.
6. The method for microwave high-temperature sintering hydrogen-cooled reduction of iron ore according to claim 4, wherein in the step (3), the hydrogen utilization rate is up to 60% or more in the course of the reduction reaction; and/or
The high-temperature furnace burden enters a feeding system of the hydrogen-based shaft furnace reduction system through a high-temperature resistant charging bucket, is distributed by the feeding system and enters a hydrogen-based shaft furnace of the hydrogen-based shaft furnace reduction system, and participates in reduction reaction in the middle of the hydrogen-based shaft furnace;
the reducing gas participates in the reduction reaction through a reducing gas system, and flue gas after the reduction reaction enters the reducing gas system from a flue gas outlet at the top of the hydrogen-based shaft furnace, and enters the middle part of the hydrogen-based shaft furnace to participate in the reduction reaction after waste heat recovery and washing;
the cooling gas participates in cooling treatment through a cooling system, and the mixed gas after cooling treatment enters the cooling system from a gas outlet at the lower part of the hydrogen-based shaft furnace, and enters the lower part of the hydrogen-based shaft furnace to participate in cooling treatment after oxygen supplementing combustion, waste heat recovery and washing.
7. The method for microwave high-temperature sintering hydrogen-cooled reduction of iron ore according to claim 4, wherein in the step (3), the material distribution mode of the material feeding system is as follows:
after entering the feeding system, the high-temperature furnace burden sequentially passes through an upper hopper, a middle hopper and a lower hopper of the feeding system and then is distributed into the hydrogen-based shaft furnace;
after the high-temperature furnace burden is filled into the upper hopper, high-temperature high-pressure steam or high-temperature high-pressure nitrogen is introduced to replace the high-temperature high-pressure steam or high-temperature high-pressure nitrogen, after the oxygen content in the upper hopper is less than or equal to 1%, the valve below the upper hopper is opened, after the high-temperature furnace burden completely enters the middle hopper, the valve below the upper hopper is closed, the pressure equalizing process is completed by adopting gas with the same composition as the gas on the inner top of the hydrogen-based shaft furnace, after the pressure equalizing is completed, the valve below the middle hopper is opened, after the high-temperature furnace burden completely enters the lower hopper, the valve below the middle hopper is closed, the valve below the lower hopper is opened, and the high-temperature furnace burden is distributed into the hydrogen-based shaft furnace.
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| CN101592441A (en) * | 2009-04-24 | 2009-12-02 | 江苏大学 | Grate bed tempertaure field and field of pressure integrated control method and control system thereof |
| CN105408500A (en) * | 2013-07-31 | 2016-03-16 | 米德雷克斯技术公司 | Reducing iron oxide to metallic iron using natural gas |
| CN108004362A (en) * | 2017-12-14 | 2018-05-08 | 江苏省冶金设计院有限公司 | Troilite prepares sulfuric acid and the method and system of direct reduced iron |
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| CN101592441A (en) * | 2009-04-24 | 2009-12-02 | 江苏大学 | Grate bed tempertaure field and field of pressure integrated control method and control system thereof |
| CN105408500A (en) * | 2013-07-31 | 2016-03-16 | 米德雷克斯技术公司 | Reducing iron oxide to metallic iron using natural gas |
| CN108004362A (en) * | 2017-12-14 | 2018-05-08 | 江苏省冶金设计院有限公司 | Troilite prepares sulfuric acid and the method and system of direct reduced iron |
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