CN116536469A - System and method for temperature raising and tempering of top gas of direct reduction shaft furnace - Google Patents
System and method for temperature raising and tempering of top gas of direct reduction shaft furnace Download PDFInfo
- Publication number
- CN116536469A CN116536469A CN202310318457.6A CN202310318457A CN116536469A CN 116536469 A CN116536469 A CN 116536469A CN 202310318457 A CN202310318457 A CN 202310318457A CN 116536469 A CN116536469 A CN 116536469A
- Authority
- CN
- China
- Prior art keywords
- gas
- shaft furnace
- oxygen
- direct reduction
- furnace body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000009467 reduction Effects 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 title claims description 23
- 238000005496 tempering Methods 0.000 title claims description 18
- 239000007789 gas Substances 0.000 claims abstract description 158
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 73
- 239000001301 oxygen Substances 0.000 claims abstract description 68
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 68
- 238000002347 injection Methods 0.000 claims abstract description 27
- 239000007924 injection Substances 0.000 claims abstract description 27
- 239000002994 raw material Substances 0.000 claims abstract description 19
- 238000011084 recovery Methods 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 230000003750 conditioning effect Effects 0.000 claims abstract description 4
- 239000000463 material Substances 0.000 claims description 26
- 230000008569 process Effects 0.000 claims description 11
- 239000007787 solid Substances 0.000 claims description 8
- 238000005262 decarbonization Methods 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 238000000746 purification Methods 0.000 claims description 4
- 238000005507 spraying Methods 0.000 claims description 3
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 230000000630 rising effect Effects 0.000 claims description 2
- 235000008331 Pinus X rigitaeda Nutrition 0.000 claims 4
- 235000011613 Pinus brutia Nutrition 0.000 claims 4
- 241000018646 Pinus brutia Species 0.000 claims 4
- 238000010791 quenching Methods 0.000 claims 2
- 230000000171 quenching effect Effects 0.000 claims 2
- 230000008054 signal transmission Effects 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 abstract description 29
- 238000003723 Smelting Methods 0.000 abstract description 5
- 238000009851 ferrous metallurgy Methods 0.000 abstract description 4
- 230000001105 regulatory effect Effects 0.000 abstract description 4
- 238000006722 reduction reaction Methods 0.000 description 37
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 32
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 19
- 238000004519 manufacturing process Methods 0.000 description 11
- 239000008188 pellet Substances 0.000 description 11
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 10
- 229910052742 iron Inorganic materials 0.000 description 8
- 238000001816 cooling Methods 0.000 description 7
- 238000002407 reforming Methods 0.000 description 7
- 238000003756 stirring Methods 0.000 description 7
- 229910052799 carbon Inorganic materials 0.000 description 6
- 239000000571 coke Substances 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 239000003345 natural gas Substances 0.000 description 4
- 238000006057 reforming reaction Methods 0.000 description 4
- 239000002918 waste heat Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000012495 reaction gas Substances 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 239000000112 cooling gas Substances 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 238000005261 decarburization Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000036284 oxygen consumption Effects 0.000 description 2
- 238000010926 purge Methods 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 229910001021 Ferroalloy Inorganic materials 0.000 description 1
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000001465 metallisation Methods 0.000 description 1
- 238000002640 oxygen therapy Methods 0.000 description 1
- 239000011496 polyurethane foam Substances 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 208000024891 symptom Diseases 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 238000005406 washing Methods 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
-
- 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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B1/00—Shaft or like vertical or substantially vertical furnaces
- F27B1/005—Shaft or like vertical or substantially vertical furnaces wherein no smelting of the charge occurs, e.g. calcining or sintering furnaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B1/00—Shaft or like vertical or substantially vertical furnaces
- F27B1/10—Details, accessories, or equipment peculiar to furnaces of these types
- F27B1/20—Arrangements of devices for charging
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B1/00—Shaft or like vertical or substantially vertical furnaces
- F27B1/10—Details, accessories, or equipment peculiar to furnaces of these types
- F27B1/22—Arrangements of heat-exchange apparatus
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B1/00—Shaft or like vertical or substantially vertical furnaces
- F27B1/10—Details, accessories, or equipment peculiar to furnaces of these types
- F27B1/24—Cooling arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B1/00—Shaft or like vertical or substantially vertical furnaces
- F27B1/10—Details, accessories, or equipment peculiar to furnaces of these types
- F27B1/26—Arrangements of controlling devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B1/00—Shaft or like vertical or substantially vertical furnaces
- F27B1/10—Details, accessories, or equipment peculiar to furnaces of these types
- F27B1/28—Arrangements of monitoring devices, of indicators, of alarm devices
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2100/00—Handling of exhaust gases produced during the manufacture of iron or steel
- C21B2100/60—Process control or energy utilisation in the manufacture of iron or steel
- C21B2100/66—Heat exchange
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
Abstract
The invention discloses a gas temperature raising and conditioning system at the top of a direct reduction shaft furnace, which belongs to the technical field of ferrous metallurgy and comprises a receiving system, a loosening device, an oxygen injection valve, a heat recovery system and a control system, wherein the receiving system is arranged above a shaft furnace body, the loosening device and the heat recovery system are both arranged in the shaft furnace body, the loosening device is used for loosening raw materials received by the receiving system, the heat recovery system comprises a gas heat exchanger, an online gas analyzer is arranged on a pipeline of the gas heat exchanger, gas composition signals in the pipeline are acquired through the online gas analyzer, the gas composition signals are transmitted to the control system, and the opening degree of the oxygen injection valve is regulated through the control system. The invention can improve the primary reaction rate of the reformed reducing gas, strengthen smelting strength, improve the utilization coefficient of the shaft furnace and optimize the energy efficiency of the system.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a system and a method for temperature raising and tempering of gas at the top of a direct reduction shaft furnace.
Background
The gas-based direct reduced iron DRI (Direct Reduced Iron) is produced by blowing high-temperature reducing gas (pure H2 or CO+H2 is more than or equal to 90 percent, H2/CO is more than or equal to 1.5) with a certain pressure from an air inlet nozzle in the middle of a furnace body, and iron ore blocks or pellets are reduced into sponge iron with a metallization rate of more than 90 under a solid state condition, and the reduction product can be used as a pure raw material for smelting excellent steel and special steel, and can also be used as an iron-containing raw material for casting, ferroalloy, powder metallurgy and other processes. The direct reduction process does not need coke, the raw materials can be cold-pressed pellets, pellet masses or lump ores, and sintered ores are not used, so that the method is a new high-quality, low-carbon and low-pollution ferrous metallurgy process, and is one of leading-edge technologies of ferrous metallurgy worldwide. The DRI gas-based reduction technology needs to reform and heat natural gas into H2 and CO by adopting a reforming furnace or a tubular heating furnace and the like, blow the heated reducing gas into a shaft furnace for solid-gas reduction reaction, reversely flow ore and reducing gas, and obtain sponge iron (total iron TFe is more than or equal to 90 percent) through reduction. DRI possesses characteristics common to common sponge iron: high purity, low content of harmful impurities, and is beneficial to the production of high-quality steel, and if pure hydrogen smelting is adopted, zero emission of CO2 can be realized.
Since the reaction of H2 and FeOX is a strong endothermic reaction, the temperature of 950 ℃ of furnace gas is reduced to about 800 ℃ after the reaction. And then the temperature of the gas in the furnace is reduced to 600 ℃ to reach the outlet of the furnace top, the gas flow and the lump materials at the feeding port are subjected to mass energy exchange, the temperature is reduced to below 450 ℃ and discharged outside the furnace, and the gas is recycled after purification and decarbonization. The process has temperature change, the primary gas utilization rate is about 30 percent, and the reverse reaction occurs, so that the CH4 content of the top discharged circulating gas is increased. How to improve the primary reaction rate of the reformed reducing gas, strengthen the smelting strength, and reduce the purifying treatment energy of the circulating cooling gas at the furnace top, thereby reducing the energy consumption of the subsequent reducing gas manufacturing process, improving the production efficiency, improving the utilization coefficient of the shaft furnace, optimizing the energy efficiency of the system, reducing the comprehensive cost and improving the DRI shaft furnace process.
Disclosure of Invention
The invention aims to provide a temperature-raising tempering system and method for top gas of a direct reduction shaft furnace, which can improve the primary reaction rate of reformed reducing gas, strengthen smelting strength, reduce purifying treatment energy of circulating cooling gas at the top of the furnace, further reduce energy consumption of subsequent reducing gas manufacturing procedures, improve production efficiency, improve shaft furnace utilization coefficient and optimize system energy efficiency.
In order to achieve the above purpose, the invention provides a gas temperature raising and conditioning system at the top of a direct reduction shaft furnace, which comprises a receiving system, a loosening device, an oxygen injection valve, a heat recovery system and a control system, wherein the receiving system is arranged above a shaft furnace body, the loosening device and the heat recovery system are both arranged in the shaft furnace body, the loosening device is used for loosening raw materials received by the receiving system, the oxygen injection valve is arranged at one side of the loosening device, the heat recovery system comprises a gas heat exchanger, an online gas analyzer is arranged on a pipeline of the gas heat exchanger, gas composition signals in the pipeline are collected through the online gas analyzer, the gas composition signals are transmitted to the control system, and the opening degree of the oxygen injection valve is adjusted through the control system.
Further, the material loosening device is driven by a direct current motor.
Further, the loosener is connected by a connecting rod, so that the loosener can horizontally rotate by 180 degrees.
Further, the material loosening device is integrally in a cylinder, and a plurality of air supply holes are formed in the lower half part of the cylinder.
Further, the plurality of air supply holes are divided into 3 rows which are uniformly distributed, and the interval angle between each row is 30 degrees.
Further, an oxygen conveying pipeline is arranged in the material loosening device and used for conveying oxygen input by the plurality of air supply holes.
Further, the system further comprises: and the purification and decarbonization system is arranged outside the shaft furnace body and is used for purifying and decarbonizing the gas discharged by the shaft furnace body, and then returning the purified and decarbonized gas to the shaft furnace body as reducing gas.
The invention also provides a method for temperature-raising and tempering of top gas of a direct reduction shaft furnace, which uses the direct reduction shaft furnace top gas temperature-raising and tempering system according to any one of claims 1 to 7, comprising the following steps:
s1, feeding solid raw materials into a receiving system, wherein the solid raw materials are processed by the receiving system and then fed into a shaft furnace body, and a control system controls an oxygen injection valve according to data obtained by a pressure detecting instrument in the shaft furnace body so as to control the inflow of oxygen;
s2, feeding high-temperature reducing gas from a reducing gas inlet of the shaft furnace body, so that the high-temperature reducing gas is mixed with oxygen introduced in the step S1;
s3, loosening the raw materials through a loosening device in a feeding preheating section in the process of mixing the raw materials;
s4, uniformly spraying oxygen through the air supply holes on the loosening device.
Further, in the step S3, the feed preheating section is set in a certain temperature interval, and the reduction rate is in a decreasing trend in the temperature interval.
Further, the temperature range is 650-680 ℃.
Compared with the prior art, according to the system and the method for temperature raising and tempering of the top gas of the direct reduction shaft furnace, a loosening device is arranged above the area of injecting the reduction reaction gas into the shaft furnace body at a position of a certain low temperature area (650-680 ℃) and the reduction rate is reduced, namely a feeding preheating section. The loosening device is driven by a direct current motor and is connected in a connecting rod mode, the loosening device can horizontally rotate for 180 degrees left and right, an air supply hole is formed in the lower semi-cylinder of the loosening device, an oxygen conveying pipeline is arranged in the middle of the loosening device, oxygen is uniformly sprayed to a 650-680 ℃ area, and the injection position has higher safety because the temperature is higher than the ignition temperature of reducing gas (coke oven gas: 560 ℃ and methane: 537 ℃). The invention can not only make the oxygen diffuse more uniformly in the area inside the shaft furnace, but also make the material loosening device obtain cooling protection.
On the other hand, before oxygen enters an oxygen conveying pipeline of a material loosening device in the shaft furnace body, the oxygen and the top gas discharged from the shaft furnace are subjected to full heat exchange and waste heat recovery through a top gas heat recovery system, a gas composition signal is fed back through an on-line gas analyzer of the shaft furnace, the opening degree of an oxygen injection valve is regulated and controlled, the oxygen injection amount is controlled, excessive oxygen consumption is prevented, and the furnace top flying temperature and energy stack loss caused by overhigh temperature are avoided. The control system is used for on-line analysis, flexible and accurate adjustment, and can adjust the production condition of the shaft furnace according to the grade of the pellets entering the furnace and the composition of the top gas, thereby ensuring the quality of finished products and stabilizing the operation of the system.
Drawings
FIG. 1 is a schematic diagram of a direct reduction shaft furnace top gas temperature raising tempering system according to one embodiment of the present invention;
FIG. 2 is a schematic view of a fluffer according to one embodiment of the present invention;
FIG. 3 is a functional schematic of a ripper mounting structure according to an embodiment of the present invention;
FIG. 4 is a schematic illustration of the relationship between methanation furnace temperature rise and CO, CO2 concentration in the inlet gas according to an embodiment of the invention.
The main reference numerals illustrate:
(1) reducing reaction gas, (2) reducing gas after top return gas is added, (3) top gas, (4) oxygen (5) entering a buffer tank needs to be injected with quantitative oxygen, (6) a top gas purifying and decarbonizing system, (7) purified gas, (8) a receiving system, (9) direct reduced iron, an on-line gas analyzer,oxygen injection valve->And (5) loosening the material device.
Detailed Description
The following detailed description of specific embodiments of the invention is, but it should be understood that the invention is not limited to specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.
As shown in fig. 1, a direct reduction shaft furnace top gas temperature raising and conditioning system according to a preferred embodiment of the present invention comprises a receiving system 8, a loosening device 12, an oxygen injection valve 11, a heat recovery system and a control system, wherein the receiving system is arranged above a shaft furnace body, the loosening device and the heat recovery system are both arranged in the shaft furnace body, the loosening device is used for loosening raw materials received by the receiving system, the oxygen injection valve is arranged at one side of the loosening device, the heat recovery system comprises a gas heat exchanger, an online gas analyzer 10 is arranged on a pipeline of the gas heat exchanger, gas composition signals in the pipeline are collected through the online gas analyzer 10, and the gas composition signals are transmitted to the control system, and the opening degree of the oxygen injection valve 11 is adjusted through the control system. The invention aims to provide a technical method for further improving quality and regulating temperature of gas at the top of a gas-based direct reduction shaft furnace with low carbon emission and adaptation to a double carbon environment, when natural gas or coke oven gas is adopted as working gas blown into a shaft furnace body, the working gas is required to be reformed and the direct reduction gas 1 is heated to 950 ℃ and then blown into a reactor, so that the energy required by the reaction is provided. The temperature of the reducing gas is heated to 950 ℃ or higher, and as the reduction reaction of the hydrogen-rich and FeOX is endothermic, the temperature of the reducing region can be reduced to about 820 ℃, thereby ensuring the reduction reaction and avoiding the pellet adhesion.
After heat exchange and reduction reaction are carried out on the reducing gas and the pellets, when the temperature of the mixed gas after the reaction is reduced to about 600 ℃, methanation reaction can be carried out to generate CH4 due to the existence of three gases of H2, CO2 and CO. Because of methanation reaction (see the following reaction equations 1-1, 1-2), the chemical process of the effective gas (CO+H2) required by the shaft furnace reduction reaction is backmixed, so that the energy consumption of the subsequent reducing gas manufacturing process is increased, and the gas utilization rate in the shaft furnace is reduced. The optimal reaction result in the shaft furnace is that all carbon is converted into carbon dioxide, all hydrogen is converted into water, and the reducing capability of carbon and hydrogen elements is fully utilized.
The thermal effect of methanation is a strongly exothermic reaction of the formula:
as is known from analysis of the composition of the top gas, methane reforming is a reversible reaction due to the reduced temperature of the reduced top gas, and at this time, methanation, commonly known as "back mixing", occurs in the shaft furnace in which the effective gas (CO+H2) from the reaction zone undergoes methanation in this temperature interval under an environment where the temperature is reduced to about 600 ℃. The methane concentration is raised, the average level is maintained to be about 12-15%, and the methane concentration is higher than the CH4 content in the reducing gas blown into the reaction shaft furnace after reforming. Typical natural gas and coke oven gas are shown in table 1 below as components in the production of DRI as a reducing gas and as components in the top discharge.
TABLE 1 Natural gas and Coke oven gas Process and Top discharge Components
The common process flow adopts the waste heat recovery of the top gas through a waste heat boiler, the top gas enters a top gas washing system for dust removal, the top gas enters a decarburization system for decarburization after being cooled to normal temperature, and the decarburized gas circularly enters a reducing gas heating/reforming system. In the process, the effective gas undergoes methanation reaction in a low-temperature region, and even if the effective gas is exothermic reaction, the effective gas is difficult to obtain sufficient economical recycling due to low temperature and poor energy grade. And methane recycled back to the reducing gas production system needs to consume high grade heat for reforming reactions. Therefore, the mixed gas (CO 2 、CO、H 2 ) Methanation of components is a typical chemical "back mix" and is a source symptom of consumption of effective gases and high-grade energy.
The practical verification shows that: adiabatic temperature rise per 1% CO conversion is 72℃per 1% CO 2 The adiabatic temperature rise for conversion was 60 ℃, and the total temperature rise for the reactor can be calculated from the following formula:
ΔT＝72·[CO] into (I) +60·[CO 2 ] Into (I) (1)
Delta T in the formula (1) -the temperature of the reaction furnace rises, and the temperature is lower than the temperature; [ CO ]]Entering, [ CO ] 2 ]into-CO in the air inlet 2 Concentration of (3) volume%
FIG. 4 shows the methanation furnace temperature rise and CO in the inlet gas 2 The relation between the concentrations of (2) and (1) is used to find the methanation operation.
In some embodiments, the ripper is driven by a dc motor, and the ripper is connected with a connecting rod, such that the ripper can rotate 180 ° horizontally.
In some embodiments, the material loosening device is integrally formed as a cylinder, the lower half part of the cylinder is provided with a plurality of air supply holes, the plurality of air supply holes are divided into 3 rows which are uniformly distributed, and the interval angle between each row is 30 degrees.
In some embodiments, an oxygen delivery conduit is provided inside the fluffer, the oxygen delivery conduit being for delivering oxygen input by the plurality of air feed holes.
In some embodiments, the system further comprises a purge and decarbonizing system disposed outside the shaft furnace body for purging and decarbonizing the gas discharged from the shaft furnace body and then returning the purged and decarbonized gas to the shaft furnace body as a reducing gas.
Therefore, the invention is characterized in that a material loosening device is arranged above a reduction reaction gas injection area of the shaft furnace at a position with a certain low temperature area (650-680 ℃) and a reduction rate being reduced, and a material preheating section is fed. The loosening device is driven by a direct current motor, is connected by a connecting rod and horizontally rotates 180 degrees, an air hole is formed in the lower semi-cylinder of the loosening device, an oxygen conveying pipeline is arranged in the middle of the loosening device, oxygen is uniformly sprayed to a 650-680 ℃ region, and the injection position has higher safety because the temperature is higher than the ignition temperature of reducing gas (coke oven gas: 560 ℃ and methane: 537 ℃). Not only can make the oxygen diffuse more uniformly in the area inside the shaft furnace, but also can make the material loosening device obtain cooling protection. Oxygen diffused into the shaft furnace and reducing gas components with lower reducing capability undergo reforming conversion reaction under the catalysis of iron simple substance.
The complex system mainly comprises CH4, CO2, H2O, H2 and O2. For a typical carbon-chemistry composition, the main reaction network includes the following basic reaction equations:
before oxygen enters a material loosening device pipeline of the shaft furnace, the oxygen and the top gas discharged from the shaft furnace are subjected to full heat exchange and waste heat recovery through a top gas heat recovery system, so that the temperature of the oxygen heat discharging and recovering device is controlled to be 200 ℃, a gas composition signal is fed back through an on-line gas analyzer of the shaft furnace, the opening degree of an oxygen injection valve is regulated and controlled, the oxygen injection amount is controlled, excessive oxygen consumption is prevented, and the temperature of the top of the furnace is prevented from being excessively high, so that the temperature of the top of the furnace is prevented from being increased, and energy stack loss is avoided. Real-time data transmission and feedback are realized through a control system indwelling interface, on-line analysis coupling is flexible and accurate to adjust, the production condition of the shaft furnace can be adjusted according to the pellet grade and the top gas composition, the quality of finished products is ensured, and the system operation is stabilized.
According to the CH4 content in the regional gas at 650-680 ℃ of the shaft furnace, the oxygen injection amount is controlled to be about 10% of the gas volume flow in the furnace, and the oxygen at 200 ℃ is preheated to enable the re-reforming reaction to occur again in the shaft furnace, so that the temperature of the generated reducing gas is controlled to be about 950 ℃, the temperature and the energy grade of the reducing gas entering the furnace are achieved, and meanwhile, carbon precipitation of the lower gas at about 700 ℃ is avoided, the surface of the pellets is coated, and the rapid progress of the reduction diffusion reaction is prevented. Finally, the preheating section is changed into a pre-reduction section with higher utilization efficiency, the reduction reaction section is enlarged, so that the grade of pellets entering the reduction section is higher, the reduction residence time is required to be shorter, the production capacity of unit furnace capacity is improved to a greater extent, the primary utilization rate of reducing gas is improved, the value of the reducing gas is increased to more than 50% from about 35% of the original value, and the productivity is increased by 20% under the conditions of certain equipment volume and productivity, thereby reducing the comprehensive cost.
Fig. 2 to 3 are schematic structural diagrams of a loosening device and schematic installation function diagrams thereof, the loosening device is driven by a direct current motor and is connected by a connecting rod, so that the loosening device can horizontally rotate 180 degrees, the loosening device is integrally in a cylinder, a plurality of air supply holes are formed in the lower half part of the cylinder, the plurality of air supply holes are divided into 3 rows and evenly distributed, the interval angle between the rows is 30 degrees, and an oxygen conveying pipeline is further arranged in the loosening device and is used for conveying oxygen input by the plurality of air supply holes.
The material loosening device is mainly used for cooling and oxygen conveying while stirring, and is provided with sealing flanges which are transversely embedded in a 650-680 ℃ region of the shaft furnace, two ends of the material loosening device are connected by the sealing flanges, supporting bases are additionally arranged on platforms on two sides of the shaft furnace, a water cooling jacket is added in the material loosening device, and an intermediate layer is used as an oxygen channel. The oxygen was only perforated in the lower semicircle of the fluffer column with holes separated by 3 rows at 30 intervals of 15 as above in the plane A-A.
In fig. 3, a pipe 1 is a main stirring pipe, the upper end of the pipe is welded with stirring blades, and the pipe rotates at a low speed in a furnace to stir materials. The pipe 2 is a cooling pipe, one side is sealed by a blocking plate 2, one side is open, a certain gap is reserved between the pipe 1 and the pipe 2, a plurality of supporting blocks are used for supporting, cooling water enters from the open side, overflows outside the cooling pipe after filling the inside of the pipe, enters into the gap between the pipe 1 and the pipe 2, and the pipe wall of the pipe 1 is water-cooled. The pipe 3 is an oxygen transmission pipeline, is processed by a half pipe, is welded with the pipe 1, and is sealed by the blocking plate 3 at two ends to form an independent cavity, and an air hole at the bottom of the oxygen enters the furnace body.
The oxygen and water inlet is composed of a hydraulic driving shaft and a supporting frame, wherein the hydraulic driving shaft is connected with the pipe 1, the driving device drives the driving shaft and the stirring pipe to rotate at a low speed, the supporting frame and the bracket support the stirring pipe, and flexible materials such as polyurethane foam are filled between the inner wall of the supporting frame and the outer wall of the pipe. The furnace body opening is sealed by adopting a stuffing box, so that the materials in the furnace can not leak from the flange when the pipe 1 rotates. The oxygen therapy pipe and the cooling water pipe are in threaded connection with the flange, the threaded tightening range is adjusted according to the stirring range, and the flange is guaranteed not to be locked when rotating.
According to the invention, the method for temperature-raising and tempering of the top gas of the direct reduction shaft furnace, which uses the temperature-raising and tempering system of the top gas of the direct reduction shaft furnace, comprises the following steps:
s1, feeding solid raw materials into a receiving system, wherein the solid raw materials are processed by the receiving system and then fed into a shaft furnace body, and a control system controls an oxygen injection valve according to data obtained by a pressure detecting instrument in the shaft furnace body so as to control the inflow of oxygen;
s2, feeding high-temperature reducing gas from a reducing gas inlet of the shaft furnace body, so that the high-temperature reducing gas is mixed with oxygen introduced in the step S1;
s3, loosening the raw materials through a loosening device in a feeding preheating section in the process of mixing the raw materials;
s4, uniformly spraying oxygen through the air supply holes on the loosening device.
In some embodiments, in the step S3, the feed preheating section is set to a position where the reduction rate decreases in a low temperature region having a temperature ranging from 650 to 680 ℃.
The reducing gas (1) of the working reducing gas heating/reforming unit is mixed with oxygen (2) before entering the shaft furnace, heated and enters a shaft furnace reduction section, and after reforming reaction in the shaft furnace, the reducing gas and the solid pellets are subjected to reduction reaction; the rising steam flow is cooled to about 600 ℃ Dan Duan due to the heat absorption of the reaction, quantitative oxygen is required to be injected from (5) according to the content of CH4 generated by methanation reaction, secondary reforming reaction is promoted, CH4 content is reduced, H2 and CO concentration is increased, the temperature is increased to about 950 ℃, continuous reduction reaction of reducing gas and pellets is ensured, finally, the reducing gas is discharged through top gas (3), the gas enters a gas purification and decarbonization process after cooling, and the decarbonized gas enters the reducing gas (1) again for recycling. The material loosening device is arranged at the section where the quantitative oxygen (5) is required to be injected, the two sections of sealing flange are connected with the furnace body, the oxygen conveying pipeline is arranged inside the material loosening device, and oxygen is uniformly injected, so that the oxygen can be more uniformly diffused inside the shaft furnace, and the material loosening device can be cooled and protected. Oxygen diffused into the shaft furnace and reducing gas components with lower reducing capability undergo reforming conversion reaction under the catalysis of iron simple substance. The injection position has higher safety because the temperature is higher than the self-ignition point of the reducing gas.
Table 1 shows that when the CH4 content is 12.5%, after O2 is blown in, the concentration is reduced to 0.0268%, the concentrations of H2 and CO are respectively converted from 40% and 11% of the instant content to 56.71% and 24.17%, the H2/CO is ensured to be 2.35, and the H2 plus CO is ensured to be 80.88%, so that the basic requirement of the direct reduction reaction is met, and the reaction is promoted to further proceed.
Table 1 shows the material balance after injection of O2 when the CH4 content of the furnace gas is 12.5% in the 600℃section
Table 2 shows that when the CH4 content is 15.0%, after O2 is blown in, the concentration is reduced to 0.035%, the concentrations of H2 and CO are respectively converted from 40% and 11% of the instant content to 62.84% and 26.73%, the H2/CO is ensured to be 2.35, the H2 plus CO is ensured to be 89.57%, the basic requirement of the direct reduction reaction is met, and the reaction is promoted to further proceed.
Table 2 shows the material balance after injection of O2 when the CH4 content of the furnace gas is 15.0% in the 600℃section
Table 3 shows the material balance after injection of O2 when the CH4 content of the furnace gas is 10.0% in the 600℃section
The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application to thereby enable one skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. The utility model provides a gas temperature rising quenching and tempering system at direct reduction shaft furnace top, its characterized in that, including receiving system, pine glassware, oxygen injection valve, heat recovery system and control system, receiving system set up in the top of shaft furnace body, pine glassware with heat recovery system all set up in the inside of shaft furnace body, pine glassware is used for not hard up the raw materials that receiving system accepted, oxygen injection valve set up in one side of pine glassware, heat recovery system includes gas heat exchanger, be provided with on-line gas analyzer on gas heat exchanger's the pipeline, through on-line gas analyzer gathers gas composition signal in the pipeline, and will gas composition signal transmission arrives control system adjusts through control system oxygen injection valve's opening degree.
2. The direct reduction shaft top gas temperature raising tempering system according to claim 1, wherein the de-charging device is driven by a direct current motor.
3. The direct reduction shaft top gas temperature raising tempering system according to claim 1, wherein the loose tooling is connected using a connecting rod such that the loose tooling can rotate 180 ° horizontally.
4. The system of claim 1, wherein the material loosening device is integrally formed as a cylinder, and a plurality of air feed holes are formed in the lower half of the cylinder.
5. The direct reduction shaft top gas temperature raising tempering system according to claim 4, wherein the plurality of gas feed holes are divided into 3 rows which are uniformly distributed, and the interval angle between each row is 30 °.
6. The direct reduction shaft furnace top gas temperature raising and conditioning system according to claim 4, wherein an oxygen delivery pipe is provided inside the material loosening device, and the oxygen delivery pipe is used for delivering oxygen input by the plurality of air feed holes.
7. The direct reduction shaft top gas temperature raising tempering system of claim 1, further comprising: and the purification and decarbonization system is arranged outside the shaft furnace body and is used for purifying and decarbonizing the gas discharged by the shaft furnace body, and then returning the purified and decarbonized gas to the shaft furnace body as reducing gas.
8. A method for tempering a top gas of a direct reduction shaft furnace, characterized in that it uses the direct reduction shaft furnace top gas tempering system according to any one of claims 1-7, comprising the steps of:
s1, feeding solid raw materials into a receiving system, wherein the solid raw materials are processed by the receiving system and then fed into a shaft furnace body, and a control system controls an oxygen injection valve according to data obtained by a pressure detecting instrument in the shaft furnace body so as to control the inflow of oxygen;
s2, feeding high-temperature reducing gas from a reducing gas inlet of the shaft furnace body, so that the high-temperature reducing gas is mixed with oxygen introduced in the step S1;
s3, loosening the raw materials through a loosening device in a feeding preheating section in the process of mixing the raw materials;
s4, uniformly spraying oxygen through the air supply holes on the loosening device.
9. The method according to claim 8, wherein in the step S3, the feed preheating section is set in a temperature range in which the reduction rate is in a decreasing trend.
10. The method for quenching and tempering of top gas of a direct reduction shaft furnace according to claim 9, wherein the temperature range is 650-680 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310318457.6A CN116536469A (en) | 2023-03-28 | 2023-03-28 | System and method for temperature raising and tempering of top gas of direct reduction shaft furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310318457.6A CN116536469A (en) | 2023-03-28 | 2023-03-28 | System and method for temperature raising and tempering of top gas of direct reduction shaft furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116536469A true CN116536469A (en) | 2023-08-04 |
Family
ID=87454989
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310318457.6A Pending CN116536469A (en) | 2023-03-28 | 2023-03-28 | System and method for temperature raising and tempering of top gas of direct reduction shaft furnace |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116536469A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117925934A (en) * | 2024-03-21 | 2024-04-26 | 东北大学 | Reducing gas temperature raising device, hydrogen-based smelting system and reducing gas temperature raising method |
-
2023
- 2023-03-28 CN CN202310318457.6A patent/CN116536469A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117925934A (en) * | 2024-03-21 | 2024-04-26 | 东北大学 | Reducing gas temperature raising device, hydrogen-based smelting system and reducing gas temperature raising method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4054444A (en) | Method for controlling the carbon content of directly reduced iron | |
| EP1036203B1 (en) | Method and apparatus for controlling dri carburization | |
| US5618032A (en) | Shaft furnace for production of iron carbide | |
| CA1043574A (en) | Method and apparatus for producing iron from oxidic iron ores | |
| CN104293998A (en) | Method and system of preparing spongy iron by using gas-based shaft furnace | |
| CN107858471A (en) | A kind of system and method for gas-based shaft kiln production sponge iron | |
| AU2011309835A2 (en) | Method and apparatus for producing direct reduced iron utilizing a source of reducing gas comprising hydrogen and carbon monoxide | |
| CN102037145A (en) | Method for melting raw iron while recirculating blast furnace gas by adding hydrocarbons | |
| US5437708A (en) | Iron carbide production in shaft furnace | |
| CN116536469A (en) | System and method for temperature raising and tempering of top gas of direct reduction shaft furnace | |
| CN106834573A (en) | A kind of full oxygen blast furnace method | |
| CN104087700A (en) | Method and system for preparing sponge iron by using gas-based shaft furnace | |
| CN104087701A (en) | Method and system for preparing sponge iron by using gas-based shaft furnace | |
| CN104087699A (en) | Method and system for preparing sponge iron by using gas-based shaft furnace | |
| CN102010924A (en) | Method for producing directly reduced iron from coal | |
| CN104313228A (en) | Direct reduction process for producing sponge iron by using CH4 non-catalytic oxygen-enriched transformation | |
| US6039916A (en) | Apparatus for producing direct reduced iron with a controlled amount of carbon | |
| CN204039428U (en) | Gas-based shaft kiln prepares the system of sponge iron | |
| CN111304396B (en) | Reaction system and process for producing sponge iron by gas-based direct reduction | |
| CN206256095U (en) | The system that a kind of new gas-based shaft kiln prepares sponge iron | |
| CN206607251U (en) | The system that laterite nickel ore pellet is reduced after gas water steam reformation | |
| CN113816337B (en) | Device and method for preparing hydrogen by reforming natural gas steam based on sensible heat of liquid metallurgical slag | |
| CN104087702A (en) | Method and system for preparing sponge iron by using gas-based shaft furnace | |
| CN115418428A (en) | Direct smelting reduction furnace | |
| CN101818218B (en) | Method for reinforcing blast furnace indirect reduction |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |