CN116904685A - Iron-making system and process of reduction shaft furnace - Google Patents
Iron-making system and process of reduction shaft furnace Download PDFInfo
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- CN116904685A CN116904685A CN202310879156.0A CN202310879156A CN116904685A CN 116904685 A CN116904685 A CN 116904685A CN 202310879156 A CN202310879156 A CN 202310879156A CN 116904685 A CN116904685 A CN 116904685A
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 239000007789 gas Substances 0.000 claims abstract description 221
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 88
- 230000001603 reducing effect Effects 0.000 claims abstract description 80
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 63
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000001301 oxygen Substances 0.000 claims abstract description 50
- 229910052742 iron Inorganic materials 0.000 claims abstract description 41
- 229910002091 carbon monoxide Inorganic materials 0.000 claims abstract description 28
- 239000000203 mixture Substances 0.000 claims abstract description 22
- 238000002347 injection Methods 0.000 claims abstract description 21
- 239000007924 injection Substances 0.000 claims abstract description 21
- 239000000463 material Substances 0.000 claims abstract description 9
- 238000007664 blowing Methods 0.000 claims abstract description 8
- 238000011946 reduction process Methods 0.000 claims abstract description 7
- 238000002156 mixing Methods 0.000 claims abstract description 6
- 238000009833 condensation Methods 0.000 claims abstract description 4
- 230000005494 condensation Effects 0.000 claims abstract description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 18
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 16
- 239000003345 natural gas Substances 0.000 claims description 8
- 239000002912 waste gas Substances 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 5
- 238000000746 purification Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 238000003786 synthesis reaction Methods 0.000 claims description 3
- 238000000926 separation method Methods 0.000 abstract description 10
- 238000005265 energy consumption Methods 0.000 abstract description 6
- 238000011065 in-situ storage Methods 0.000 abstract description 5
- 239000000126 substance Substances 0.000 abstract description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 8
- 238000001816 cooling Methods 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000003546 flue gas Substances 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000003034 coal gas Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 238000004523 catalytic cracking Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910052595 hematite Inorganic materials 0.000 description 2
- 239000011019 hematite Substances 0.000 description 2
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 2
- 238000010310 metallurgical process Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000002918 waste heat Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000002407 reforming Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Iron (AREA)
Abstract
The invention belongs to the technical field of metallurgy-iron making, and discloses a reduction shaft furnace iron making system and a process, wherein a newly added gas phase outlet is arranged in the middle of a reduction section of the system, and an oxygen injection device is arranged above the newly added gas phase outlet; the process is that the iron-containing furnace material is sent into a shaft furnace, and hot reducing gas is continuously introduced into the bottom of a reduction section to reduce the iron-containing furnace material; in the reduction process, partial gas is discharged through a newly added gas phase outlet, oxygen is blown into the gas phase outlet through an oxygen blowing device, the oxygen and the rest reducing gas are combusted to release heat, and all the reducing gas is oxidized, so that the temperature of a reduction section is maintained; the gas discharged from the newly added gas phase outlet removes H 2 O and CO 2 Then mixing the mixture with hot reducing gas and re-introducing the mixture into a reducing section; separation of H from top gas by condensation 2 O, CO 2 And (5) collecting. The invention realizes the full application of the chemical energy of the top gas and CO in the tail gas 2 In-situ capture of CO in the presence of direct reduction of shaft furnace 2 High separation energy consumption.
Description
Technical Field
The invention belongs to the technical field of metallurgy-iron making, and particularly relates to a reduction shaft furnace iron making system and a reduction shaft furnace iron making process.
Background
Greenhouse gas emission causes increasingly severe climate change, and energy conservation and emission reduction have become common knowledge of all people. Among them, the steel industry extremely depends on fossil energy, and the carbon emission is extremely large. In order to reduce the emission of carbon dioxide, the technical innovation of the high-emission steel industry is not slow. Currently, the adoption of a shaft furnace direct reduction short-process technology to replace the conventional blast furnace long-process technology has become a development trend of industrial iron making in the future.
75% of the world's direct reduced iron is produced by gas-based shaft furnaces, the most widely used gas-based shaft furnace technologies currently being the Midrex and HYL processes. The Midrex process uses a natural gas reforming process to produce a reducing gas which is fed from a central air inlet of the shaft furnace and reduces iron oxide pellets and lump iron ore added from the top into sponge iron in a convective motion. The top gas contains CO and H 2 About 60-70%, and a part of the top gas is pressurized and sent into a mixing chamber to be uniformly mixed with equivalent natural gas. The mixed gas is converted into reducing gas after catalytic cracking reaction, the temperature of the reducing gas is 850-900 ℃, and CO and H are obtained 2 The content is about 95%. The rest of the top gas is used as fuel to be sent out of the reaction tube of the reformer after a small amount of natural gas is added, so as to provide heat for the catalytic cracking reaction of the natural gas. Meanwhile, the flue gas of the reformer enters a heat exchanger to preheat the mixed raw gas and combustion air, and the heat is further recycled. The process adopts an external reformer, increases investment, consumes a large amount of Ni-based and other noble metal catalysts, and has higher operation cost. And the flue gas contains a large amount of CO 2 Further treatment is required before discharge. The HYL process can directly use synthetic gas such as coke oven gas, coal gas and the like as reducing gas, the iron ore reduction process is similar to Midrex process, and the gas from the furnace top is dehydrated and CO removed 2 Mixing the mixed gas with dehydrated fresh synthetic gas, heating the mixture by a heater, adding a proper amount of oxygen for combustion, and feeding the mixture into an iron reduction shaft furnace. The process has high gas consumption and CO and H in the top gas 2 The content is also higher, the power consumption in the subsequent separation process is higher, and a large amount of CO is discharged in the process 2 Is not consistent with the development route of the current clean green.
In the Midrex and HYL processes, CO and H are found in the top gas 2 The content is higher, the chemical energy of the reduction potential in the coal gas cannot be utilized efficiently, and the direct discharge can cause the waste of the chemical energy in the coal gas. This requires that a portion of the top gas be removedCO 2 After reentering the shaft furnace, CO 2 Too high a content directly affects the quality of the reduced iron. Therefore, a large amount of energy is consumed to separate the CO 2 The operation cost is high. At the same time, the heat demand in the upper part of the shaft furnace is greatly increased due to the reduction heat absorption of hydrogen in the reducing gas, so that the reducing gas at the bottom of the shaft furnace has to be externally heated to meet the heat balance, and a great amount of energy consumption is generated.
Thus, there is an urgent need for a green, clean, low-carbon process for reducing the energy consumption and production costs of the process for reducing iron, which process can simultaneously meet the heat demand of hydrogen reduction in the upper part of a gas-based shaft furnace and the CO of top gas 2 And the energy consumption and equipment investment of the subsequent separation are reduced by trapping.
Disclosure of Invention
To realize the full application of chemical energy of the top gas and CO in the tail gas 2 Is used for in-situ trapping of the circulating gas and reducing CO in the circulating gas 2 The invention provides an iron-making system and process of a reduction shaft furnace.
In order to solve the technical problems, the invention is realized by the following technical scheme:
according to one aspect of the invention, there is provided a reduction shaft furnace ironmaking system comprising a shaft furnace, wherein at least one newly added gas phase outlet is arranged in the middle of a reduction section of the shaft furnace, and at least one oxygen injection device is arranged above the newly added gas phase outlet in the reduction section of the shaft furnace.
Preferably, the newly added gas phase outlets are uniformly distributed along the circumferential direction of the furnace body in the reduction section.
Preferably, the newly added gas phase outlets are uniformly arranged in the reduction section along the longitudinal direction of the furnace body.
Preferably, the oxygen injection devices are uniformly arranged along the circumferential direction of the furnace body in the reduction section.
Preferably, the oxygen injection devices are uniformly arranged in the reduction section along the longitudinal direction of the furnace body.
Further, the newly added gas phase outlet is connected with an inlet of a gas purification device, and an outlet of the gas purification device is connected to a fresh reducing gas pipeline at the bottom of the shaft furnace; top coal of said shaft furnaceThe gas outlet is connected with the inlet of the waste gas condensing device, and the outlet of the waste gas condensing device is used for condensing CO 2 And (5) capturing.
According to another aspect of the invention, there is provided a reduction shaft furnace ironmaking process based on the above system, comprising the following steps:
feeding the iron-containing furnace material into the shaft furnace, and continuously introducing hot reducing gas into the bottom of a reduction section of the shaft furnace to reduce the iron-containing furnace material; in the reduction process, according to the temperature of iron charge materials in a reduction section of the shaft furnace, discharging partial gas through the newly added gas phase outlet, and blowing oxygen into the reduction section of the shaft furnace through the oxygen blowing device, wherein the oxygen and the rest of the reduction gas are combusted and released, and all the reduction gas is oxidized, so that the temperature of the reduction section is maintained at 500-1200 ℃;
the gas discharged from the newly added gas phase outlet enters a gas purifying device, and H is removed 2 O and CO 2 Then mixing the mixture with hot reducing gas and re-introducing the mixture into a shaft furnace reduction section;
the top gas of the shaft furnace enters an exhaust gas condensing device and H is separated by condensation 2 O, CO 2 And (5) collecting.
Further, the hot reducing gas is CO and H 2 、CH 4 Synthesis gas, natural gas, shale gas, water gas or biogas, etc.
Further, the proportion of the exhaust gas from the newly added gas phase outlet accounts for 50% -90% of the reducing gas introduced into the vertical furnace.
Further, the oxygen blown into the shaft furnace by the oxygen blowing device can oxidize all the residual reducing gas in the shaft furnace, so that only H is in the composition of the top gas 2 O and CO 2 。
The beneficial effects of the invention are as follows:
the method comprises the steps of (1) additionally discharging a part of reducing gas in the middle of a reduction section of the shaft furnace, and introducing the reducing gas into the shaft furnace from the bottom after purifying; compared with the prior art that all gases are discharged from the furnace top, a great deal of energy is consumed to separate CO 2 The invention only needs to discharge the middle part of the shaft furnaceThe separation of the separated gas can effectively reduce CO 2 Separation energy consumption.
And part of oxygen is uniformly introduced from the upper part of the reduction section of the shaft furnace, and the oxygen and the reducing gas in the furnace burn to release a large amount of heat, so that the temperature in the shaft furnace can be increased and maintained at 500-1200 ℃, thereby improving the reaction rate in the shaft furnace, the utilization rate of the reducing gas and the conversion rate of direct reduced iron, making up the problem of insufficient heat supply in the metallurgical process, avoiding complicated external heating equipment or adding natural gas to burn to supply heat, and greatly reducing the process investment.
(III) the invention can realize the in-situ CO trapping in the metallurgical process 2 Excess CO and H in the shaft furnace can be consumed by introducing sufficient oxygen into the upper part of the reduction section of the shaft furnace 2 Obtaining a substantially fully converted reducing gas at the top of the shaft furnace, i.e. substantially only carbon dioxide and water vapour in the top gas composition; because the composition of the furnace top flue gas is very simple, CO can be trapped only by recovering heat in the flue gas and condensing water vapor in the flue gas 2 No additional CO is required 2 The trapping device does not need to recycle unconverted reducing gas, so that the process energy consumption is reduced.
Drawings
Fig. 1 is a schematic structural diagram and a process flow diagram of a reduction shaft furnace ironmaking system of the invention.
In the figure: 1: an oxygen injection device; 2: a new gas phase outlet is added; 3: a gas purifying device; 4: a hot reducing gas injection device; 5: a top gas output; 6: and an exhaust gas condensing device.
Detailed Description
As shown in fig. 1, the embodiment provides a reduction shaft furnace ironmaking system capable of extracting gas in the middle part of a reduction section of a shaft furnace, and uniformly introducing reducing gas of oxygen into the middle and upper parts of the reduction section to Directly Reduce Iron (DRI), wherein the reduction shaft furnace ironmaking system comprises an oxygen gas injection device 1, a newly added gas phase outlet 2, a gas purification device 3, a hot reducing gas injection device 4, a top gas output device 5 and an exhaust gas condensing device 6.
The newly added gas phase outlet 2 comprises one or more gas phase outlets which are all arranged in the middle of the reduction section of the shaft furnace and used for discharging part of the reduction gas in the reduction section of the shaft furnace. As a preferred embodiment, the newly added gas phase outlets 2 can be uniformly distributed along the circumferential direction of the furnace body in the reduction section, and can also be uniformly distributed along the longitudinal direction of the furnace body in the reduction section.
The oxygen injection device 1 comprises one or more oxygen injection devices, each arranged in the upper middle part of the reduction section of the shaft furnace and each located above the added gas phase outlet 2. As a preferred embodiment, the oxygen injection device 1 is used for uniform introduction of oxygen into the upper middle part of the reduction zone of a shaft furnace.
The specific structures of the gas purifying device 3, the hot reducing gas blowing device 4, the top gas output device 5 and the waste gas condensing device 6 are all the prior art. In the invention, the gas purifying device 3 is used for separating CO in the gas discharged from the newly added gas phase outlet 2 2 And H 2 O; the hot reducing gas injection device 4 is used for introducing hot reducing gas into the bottom of the reducing section of the shaft furnace; the top gas outlet means 5 for discharging top gas; the waste gas condensing device 6 is used for tail gas waste heat recovery and CO 2 And (5) capturing.
Specifically, the newly added gas phase outlet 2 is connected with the inlet of the gas purifying device 3, and the outlet of the gas purifying device 3 is connected with a fresh reducing gas pipeline at the bottom of the shaft furnace, so that H is removed 2 O and CO 2 The hot reducing gas after mixing with fresh reducing gas is then fed from the hot reducing gas injection device 4 into the shaft furnace. The top gas outlet 5 of the shaft furnace is connected to the inlet of an off-gas condensing device 6, the outlet of the off-gas condensing device 6 being for CO 2 And (5) capturing.
The reduction shaft furnace ironmaking process based on the system provided by the embodiment comprises the following process steps:
s1, feeding the iron-containing furnace burden into a reduction section of the shaft furnace from the top of the shaft furnace, and continuously introducing hot reducing gas into the bottom of the reduction section by the hot reducing gas injection device 4 to reduce the iron-containing furnace burden. The fully reduced iron component enters a cooling section of the shaft furnace, and is discharged from the bottom of the cooling section of the shaft furnace after being cooled.
Wherein the hot reducing gas is a gas having reducing effect after heating, and can be CO or H 2 、CH 4 Synthesis gas, natural gas, shale gas, water gas, biogas, and the like.
It is noted that preheating is required before the reducing gas is introduced into the shaft furnace, and the specific preheating temperature is determined according to the actual reaction conditions.
Wherein the reduction temperature in the vertical furnace needs to be controlled to be 500-1200 ℃ as a whole.
S2, in the reduction process, according to the temperature of the iron charge material in the reduction section of the shaft furnace, a certain amount of gas in the furnace is discharged through a newly added gas phase outlet 2 of the reduction section of the shaft furnace.
Wherein the gas discharged from the newly added gas phase outlet 2 is H 2 、CO、H 2 O、CO 2 A mixture of these gases,
wherein the amount of gas discharged from the newly added gas phase outlet 2 is determined by the temperature in the reduction zone of the shaft furnace. If the temperature in the shaft furnace is higher than the set temperature, increasing the gas discharge amount; if the temperature in the shaft furnace is lower than the set temperature, the gas discharge amount is reduced.
Meanwhile, according to the composition of the reducing gas at the upper part of the shaft furnace, the oxygen injection device 1 injects a certain amount of oxygen into the upper part of the reducing section of the shaft furnace until all the reducing gas is oxidized, and only CO remains in the top gas 2 And H 2 O; the oxygen injection device 1 burns and releases heat to the oxygen injected into the shaft furnace and the unreacted reducing gas, thereby maintaining the temperature of the reduction section of the shaft furnace at 500-1200 ℃.
The amount of oxygen injected by the oxygen injection device 1 depends on the composition of the reducing gas at the upper part of the reducing section of the shaft furnace, and the amount of oxygen introduced into the shaft furnace needs to oxidize all the reducing gas completely. At this time, the composition of the top gas is H only 2 O and CO 2 Does not contain reducing gas and oxygen.
S3, introducing the gas discharged from the newly added gas phase outlet 2 into a gas purifying device 3 to remove H from the hot reducing gas 2 O and CO 2 And then mixed with fresh reducing gas and re-fed from the hot reducing gas injection device 4 into the shaft furnace.
Wherein, the gas purifying device 3 does not need to use all H 2 O and CO 2 Is separated out, and only the purified gas can meet the feeding requirement of the hot reducing gas.
S4, passing the furnace top gas through the furnace topThe gas output device 5 discharges and enters the waste gas condensing device 6 to separate CO by condensation 2 And H 2 O and CO 2 And (5) collecting.
Wherein, the waste heat in the waste gas is recycled after being recovered.
For a further understanding of the nature, features, and effects of the present invention, the following examples are set forth to illustrate, and are to be considered in connection with the accompanying drawings:
example 1
In the embodiment, hematite lump ore with iron taste of 70% is selected as iron-containing furnace burden, part of gas is extracted from the middle part of a reduction section of a shaft furnace in the reduction process of the iron-containing furnace burden, oxygen is uniformly introduced into the middle and upper parts of the reduction section, and hot reducing gas preheated to 900 ℃ is used for preparing direct reduced iron. For the convenience of explanation of the process, the reduction section of the shaft furnace is divided into 8 sections from top to bottom, namely L1 to L8 respectively, iron-containing furnace burden is fed from L1, and hot reducing gas is introduced from L8, and the concrete steps are as follows:
(1) Iron-containing charge is fed from the top (L1) of the shaft furnace to the reduction section of the hydrogen shaft furnace, the iron ore mass flow rate being 821274kg/hr, the temperature being 25 ℃, and the pressure being 2atm. Simultaneously, continuously introducing hot reducing gas (mixed gas of hydrogen and carbon monoxide in the embodiment) with the temperature of 900 ℃ into the bottom (L8) of the shaft furnace reduction section, wherein the volume ratio of the hydrogen to the carbon monoxide is 1:1, the molar flow is 22280kmol/h, and the pressure is 2atm. The iron-containing furnace charge is reacted with a hot reducing gas in a reduction zone.
(2) Partial reducing gas is extracted from the middle part (L4) of the reduction section of the shaft furnace through a gas phase additional outlet, the molar flow rate of the extracted gas is 14705kmol/h, the extracted gas accounts for 66 percent of the total reducing gas flow rate in the shaft furnace, the temperature is 911 ℃, the pressure is 2atm, the composition is 34.6 percent of CO, and the CO 2 15.4% of H 2 Takes up 31.3%, H 2 O accounts for 18.7 percent. The produced gas is purified by a gas purifying device 3 to obtain CO 2 And H 2 After O separation, it is re-introduced from the bottom (L1) of the shaft furnace.
(3) Oxygen is uniformly introduced into the upper parts L1, L2 and L3 of the reduction section of the shaft furnace, wherein the temperature is 25 ℃, and the pressure is 2atm. Wherein the molar flow rate of the oxygen introduced into the L1 part is 580kmol/hr, the molar flow rate of the oxygen introduced into the L2 part is 217kmol/hr, and the molar flow rate of the oxygen introduced into the L3 part is 100kmol/hr. The oxygen and the rest of the reducing gas in the shaft furnace burn to release heat so as to maintain the temperature of the iron charge in the reducing section at 900-1050 ℃.
(4) The reduced high-temperature iron enters a cooling section of the shaft furnace for cooling, and is discharged from an outlet at the bottom of the cooling section to obtain the reduced iron. The top gas is discharged from the top of the shaft furnace, at a temperature of 759 ℃, a pressure of 2atm, a flow rate of 7576kmol/hr, and a composition of CO 2 50% of H 2 O accounts for 50 percent.
(5) The top gas enters an exhaust gas condensing device 6 to condense CO 2 And H 2 O separation to trap pure CO 2 Storage was carried out at a flow rate of 3788kmol/hr and a temperature of 25 ℃.
The specific conditions of each section in the reduction section of the shaft furnace are shown in table 1.
TABLE 1 reducing gas 900 ℃ feed-specific conditions and composition of each stage in the reduction section of the shaft furnace (L1-L8)
As can be seen from Table 1, the gas ratio extracted from the newly added gas phase outlet 2 of the reduction stage of the shaft furnace in this embodiment accounts for 66% of the reducing gas introduced into the shaft furnace, thereby increasing the temperature in the reduction stage of the shaft furnace and realizing CO 2 Is in situ captured.
Example 2
In the embodiment, hematite lump ore with iron taste of 70% is selected as iron-containing furnace burden, part of gas is extracted from the middle part of a reduction section of a shaft furnace in the reduction process of the iron-containing furnace burden, oxygen is uniformly introduced into the middle and upper parts of the reduction section, and hot reducing gas preheated to 500 ℃ is used for preparing direct reduced iron. For the convenience of explanation of the process, the reduction section of the shaft furnace is divided into 8 sections from top to bottom, namely L1 to L8 respectively, iron-containing furnace burden is fed from L1, and hot reducing gas is introduced from L8, and the concrete steps are as follows:
iron-containing charge is fed from the top (L1) of the shaft furnace to the reduction zone of the hydrogen shaft furnace, the iron ore mass flow rate being 821274kg/hr, the temperature being 25 ℃, and the pressure being 2atm. Simultaneously, continuously introducing hot reducing gas (mixed gas of hydrogen and carbon monoxide in the embodiment) with the temperature of 500 ℃ into the bottom (L8) of the shaft furnace reduction section, wherein the volume ratio of the hydrogen to the carbon monoxide is 6:4, the molar flow is 22500kmol/h, and the pressure is 2atm. The iron-containing furnace charge is reacted with a hot reducing gas in a reduction zone.
Part of the reducing gas is extracted from the middle part (L4) of the reducing section of the shaft furnace through a newly added gas phase outlet 2, the molar flow rate of the extracted gas is 13500kmol/h, the extracted gas accounts for 66 percent of the total reducing gas flow rate in the shaft furnace, the temperature is 911 ℃, the pressure is 2atm, the composition is 25.7 percent of CO, and the CO 2 14.3% of H 2 40.5% of H 2 O accounts for 19.5%. The produced gas is purified by a gas purifying device 3 to obtain CO 2 And H 2 After O separation, it is re-introduced from the bottom (L1) of the shaft furnace.
Oxygen is uniformly introduced into the upper parts L1, L2 and L3 of the reduction section of the shaft furnace, wherein the temperature is 25 ℃, and the pressure is 2atm. Wherein the molar flow rate of the oxygen introduced into the L1 part is 1000kmol/hr, the molar flow rate of the oxygen introduced into the L2 part is 200kmol/hr, and the molar flow rate of the oxygen introduced into the L3 part is 180kmol/hr.
The reduced high-temperature iron enters a cooling section of the shaft furnace for cooling, and is discharged from an outlet at the bottom of the cooling section to obtain the reduced iron. The top gas is discharged from the top of the shaft furnace, at a temperature of 1055 ℃, a pressure of 2atm, a flow rate of 9000kmol/hr, and a composition of CO 2 40% of H 2 O accounts for 60 percent.
The top gas enters an exhaust gas condensing device to condense CO 2 And H 2 O separation to trap pure CO 2 Storage was carried out at a flow rate of 3599kmol/hr and a temperature of 25 ℃.
The specific conditions of each section in the reduction section of the shaft furnace are shown in Table 2.
TABLE 2 reducing gas 500 ℃ feed-specific conditions and composition of each stage in the reduction section of the shaft furnace (L1-L8)
As can be seen from Table 2, the ratio of the gas extracted from the newly added gas phase outlet 2 of the reduction section of the shaft furnace in this embodiment accounts for 66% of the reducing gas introduced into the shaft furnace, thereby improving the shaft furnaceTemperature in reduction section of furnace and realize CO 2 Is in situ captured.
Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative, not restrictive, and many changes may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the appended claims, which are to be construed as falling within the scope of the present invention.
Claims (10)
1. An iron making system of a reduction shaft furnace comprises the shaft furnace and is characterized in that at least one newly added gas phase outlet is arranged in the middle of a reduction section of the shaft furnace, and at least one oxygen blowing device is arranged above the newly added gas phase outlet in the reduction section of the shaft furnace.
2. The reduction shaft furnace ironmaking system of claim 1, wherein the added gas phase outlets are uniformly distributed along the circumferential direction of the furnace body in the reduction section.
3. The reduction shaft furnace ironmaking system of claim 1, wherein the added gas phase outlets are uniformly arranged in the reduction section along the longitudinal direction of the furnace body.
4. The reduction shaft ironmaking system of claim 1, wherein the oxygen injection devices are uniformly arranged in the reduction zone along the circumferential direction of the furnace body.
5. The reduction shaft ironmaking system of claim 1, wherein the oxygen injection devices are uniformly arranged in the reduction zone along the longitudinal direction of the furnace body.
6. The reduction shaft furnace ironmaking system according to claim 1, characterized in that the added gas phase outlet is connected with an inlet of a gas purification device, the gas purification deviceIs connected to a fresh reducing gas conduit at the bottom of the shaft furnace; the top gas outlet of the shaft furnace is connected with the inlet of the waste gas condensing device, and the outlet of the waste gas condensing device is used for condensing CO 2 And (5) capturing.
7. The reduction shaft ironmaking process based on the system of any one of claims 1-6, characterized by comprising the following processes:
feeding the iron-containing furnace material into the shaft furnace, and continuously introducing hot reducing gas into the bottom of a reduction section of the shaft furnace to reduce the iron-containing furnace material; in the reduction process, according to the temperature of iron charge materials in a reduction section of the shaft furnace, discharging partial gas through the newly added gas phase outlet, and blowing oxygen into the reduction section of the shaft furnace through the oxygen blowing device, wherein the oxygen and the rest of the reduction gas are combusted and released, and all the reduction gas is oxidized, so that the temperature of the reduction section is maintained at 500-1200 ℃;
the gas discharged from the newly added gas phase outlet enters a gas purifying device, and H is removed 2 O and CO 2 Then mixing the mixture with hot reducing gas and re-introducing the mixture into a shaft furnace reduction section;
the top gas of the shaft furnace enters an exhaust gas condensing device and H is separated by condensation 2 O, CO 2 And (5) collecting.
8. The reduction shaft ironmaking process according to claim 7, characterized in that the hot reducing gas is CO, H 2 、CH 4 Synthesis gas, natural gas, shale gas, water gas or biogas.
9. The reduction shaft ironmaking process of claim 7, wherein the proportion of the fresh gas phase outlet vent gas is 50% -90% of the reducing gas introduced into the shaft furnace.
10. The ironmaking process of a reduction shaft furnace according to claim 7, characterized in that oxygen introduced into the shaft furnace by the oxygen injection device can make the oxygen in the shaft furnaceThe residual reducing gas is oxidized to make H only in the composition of the top gas 2 O and CO 2 。
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| CN202310879156.0A CN116904685A (en) | 2023-07-18 | 2023-07-18 | Iron-making system and process of reduction shaft furnace |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310879156.0A CN116904685A (en) | 2023-07-18 | 2023-07-18 | Iron-making system and process of reduction shaft furnace |
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