CN212476647U - Flash circulating smelting system for pre-reducing and purifying coal gas - Google Patents
Flash circulating smelting system for pre-reducing and purifying coal gas Download PDFInfo
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- CN212476647U CN212476647U CN202021032390.8U CN202021032390U CN212476647U CN 212476647 U CN212476647 U CN 212476647U CN 202021032390 U CN202021032390 U CN 202021032390U CN 212476647 U CN212476647 U CN 212476647U
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Abstract
The utility model provides a flash cycle smelting system for pre-reducing and purifying coal gas by utilizing coal gas, which comprises a flash metallurgical device, a pre-reducing device, a dust removing component, a fan, a decarbonizing device, a gas storage pressure regulating device and a coal gas heating device which are sequentially communicated through pipelines, wherein a reducing coal gas outlet of the coal gas heating device is connected with a reducing gas inlet of the flash metallurgical device through a pipeline; the system also comprises a first gas diversion pipeline, wherein the inlet end of the first gas diversion pipeline is connected with a pipeline of a main gas pipeline between the fan and the decarburization equipment, and the outlet end of the first gas diversion pipeline is connected with a pipeline of a main gas pipeline between the flash metallurgy equipment and the pre-reduction equipment. The flash circulating smelting system utilizing the coal gas to pre-reduce and purify the coal gas can reasonably utilize the discharged coal gas of the flash smelting process, and the comprehensive energy consumption of the system is reduced.
Description
Technical Field
The utility model belongs to flash smelting technology tapping flue gas treatment field especially relates to a flash circulation system of smelting that utilizes coal gas prereduction and purification coal gas.
Background
Flash metallurgy is traditionally only applied to smelting metal sulfide ores, and is being widely applied to smelting metal oxide ores such as iron ores, laterite-nickel ores and the like.
The basic principle of flash smelting of oxidized ore is to use high-temperature high-concentration reducing gas (mainly containing CO and H)2) Introducing a space specially used for reducing metal oxide ores to realize gas-phase reduction of metal oxides in a high-temperature space, wherein products smelted in the space fall into a molten pool, and reducing residual metal oxides by using fixed carbon in the molten pool. Since metal oxide ores generally contain FeO, a space is required for the effective component (CO + H) of the reducing gas to efficiently reduce FeO2) The concentration of (2) is relatively high, i.e. the excess coefficient is high, which results in a low proportion of reducing gas consumed by the reduction reaction, i.e. the tapping flue gas contains a large amount of reducing gas.
The discharged flue gas of the flash metallurgical equipment for the oxidized ore is mainly derived from gas generated after reduction reaction in a reduction space, and is also partially derived from CO and CO generated after reduction of carbon in a molten pool2Because the smelting adopts high oxygen enrichment or pure oxygen, the main components of the discharged flue gas are CO and CO2、H2、H2O, wherein the unused effective reducing gas (CO + H)2) The content of (A) is up to more than 40%. The conventional tail gas treatment method is to utilize CO and H in flue gas discharged from a gas-fired boiler2The method needs to go through multiple times of chemical energy-heat energy-mechanical energy-electric energyEnergy conversion, the energy conversion efficiency of each time is not high, and the energy finally recovered in the flue gas is less than 40%; on the other hand, at the raw material supply end, a large amount of energy is consumed to produce CO and H again with high concentration2So as to realize the reduction of the metal oxidized ore in the oxidized ore flash metallurgy equipment. In addition, the burned off-gas also causes a large amount of carbon emissions, which may be greater than those of conventional smelting processes. Thus, CO and H in the combustion exhaust gas2The method of performing the waste heat power generation treatment is not preferable.
In conclusion, the prior flash smelting process for the oxidized ore cannot reasonably utilize the discharged coal gas, so that the overall energy consumption of the whole process is high and the carbon emission is large.
Disclosure of Invention
In view of this, the utility model aims at providing an utilize flash circulation smelting system of coal gas prereduction and purification coal gas to solve flash metallurgical equipment and smelt the problem that the tail gas of drawing a furnace of oxidized ore does not obtain reasonable recycle, comprehensive energy consumption height.
In order to achieve the above purpose, the technical scheme of the utility model is realized like this:
a flash circulating smelting system for pre-reducing and purifying coal gas by using coal gas comprises a coal gas main pipeline, wherein the coal gas main pipeline comprises a flash metallurgical device, a pre-reducing device, a dust removal assembly, a fan, a decarburization device, a gas storage pressure regulating device and a coal gas heating device which are sequentially communicated through a pipeline, and a reducing coal gas outlet of the coal gas heating device is connected with a reducing gas inlet of the flash metallurgical device through a pipeline; the system is characterized by further comprising a first gas diversion pipeline, wherein the inlet end of the first gas diversion pipeline is connected with a pipeline of a gas main pipeline between the fan and the decarburization equipment, and the outlet end of the first gas diversion pipeline is connected with a pipeline of a gas main pipeline between the flash metallurgy equipment and the pre-reduction equipment.
The flash metallurgical equipment is all metallurgical equipment constructed by adopting the flash metallurgical principle.
The main function of the pre-reduction equipment is to utilize the reducing tail gas pair of the flash metallurgy equipment to enter the flash metallurgy equipmentThe prepared mineral powder is pre-reduced so as to reduce the pressure of reducing the mineral powder of the flash metallurgical equipment and reduce the comprehensive energy consumption of the system. The basic principle of the operation of the prereduction plant is to introduce reducing offgas (generally containing more than 40% of CO and H) from a flash metallurgical plant2) The solid metal oxide ore powder is fully contacted with solid ore powder in equipment, and the characteristics of large specific surface area and high reaction speed of the contact of ore powder particles and gas are utilized to realize rapid direct reduction (non-melting reduction) of the solid metal oxide ore powder, wherein the reduction rate can generally reach more than 30%. The pre-reduction equipment is provided with a coal gas inlet, a coal gas outlet, a powder inlet and a powder discharge port. In order to prevent the mineral powder from being bonded in the prereduction equipment, the temperature of the flue gas at the coal gas inlet of the prereduction equipment is generally controlled to be lower than 850 ℃. Because the powder may be partially aggregated into a lump in the process of heat exchange and temperature rise, a powder scattering device such as a squirrel cage scattering machine is generally required to be connected behind a discharge port of the pre-reduction equipment. In addition, the pre-reduction equipment has a certain drying effect on the mineral powder, and in some applications, the mineral powder can be reduced and dried, so that the requirement of a flash metallurgy process on raw material pretreatment is met.
The dust removal component is used for removing most of smoke dust in the smoke. If the dust removal component adopts wet dust removal equipment, because the smoke dust contains a large amount of flux CaO, the CaO can form alkaline solution when dissolved in the dust removal water, and can absorb acid gas in the smoke gas, and therefore, some wet dust removal equipment also has certain desulfurization effect.
The fan is used for exhausting air, overcoming the system resistance of flue gas transmission and providing power for flue gas flowing, so that a micro-negative-pressure smelting environment is formed inside the flash smelting equipment.
The decarbonization equipment is used for removing CO in the flue gas2、H2S and the like.
The gas storage and pressure regulation device is mainly used for storing gas and serving as a gas buffer device, so that a flue gas system has elasticity. The gas storage temperature of the gas storage and pressure regulation equipment is usually about 0-70 ℃. The output end of the gas storage pressure regulating device can be provided with a pressure regulating device, such as a booster fan and the like, and the pressure of the output gas is regulated, so that the gas can be conveyed to subsequent equipment at proper air pressure, and the gas pressure finally input into the flash metallurgical equipment is influenced; of course, before the coal gas enters the gas storage and pressure regulation equipment, the coal gas may also need to be regulated to a proper pressure through the pressure regulation device so as to be stored in the gas storage and pressure regulation equipment. In addition, when the temperature of the coal gas exceeds the storage temperature range of the gas storage pressure regulating equipment, the temperature of the coal gas needs to be reduced through a cooling device (such as a heat exchanger, a condenser and the like). It should be noted that: the pressure regulating device arranged at the input or output end of the gas storage and pressure regulating equipment is regarded as a part of the gas storage and pressure regulating equipment; if the temperature of the coal gas needs to be reduced so as to be stored in the gas storage and pressure regulating equipment, the attached cooling device is also regarded as a part of the gas storage and pressure regulating equipment.
The gas heating equipment is used for further increasing the temperature of the reducing gas provided by the main pipeline to be more than 1300 ℃, and then guiding the high-temperature gas serving as the reducing gas into the flash metallurgy equipment. The gas heating equipment can use various fuels, such as coal, natural gas, heavy oil and the like, and can also introduce combustible gas of other gas systems. It should be noted that the gas heating device is provided with a reducing gas inlet and a reducing gas outlet which are communicated with each other, and is also provided with a combustion improver inlet, a gas inlet and a tail gas outlet which are communicated with each other, and the two sets of pipeline systems are mutually isolated and are not communicated with each other.
The two junctions of the first gas diversion pipeline and the main gas pipeline are connected by valves, wherein the junction of the inlet end of the first gas diversion pipeline and the main gas pipeline is connected by a valve with flow control, and the proportion of the returned cold gas is regulated and controlled by the valve, so that the temperature of the flue gas entering the subsequent equipment is controlled, and the dust content of the flue gas is reduced. In addition, a pressurizing device is usually arranged on the first gas branch pipeline to provide power for the returned cool gas.
The system further comprises a coarse dust removal device, wherein the coarse dust removal device is arranged on the gas main pipeline and is positioned between the outlet end of the first gas diversion pipeline and the pre-reduction device.
The coarse dust removing equipment is dust removing facility or equipment capable of normally working at the high temperature of 800-950 ℃, and is used for removing large-particle smoke dust in the smoke and preventing the pipeline from being blocked.
Furthermore, a preheating device is arranged between the gas storage pressure regulating device and a pipeline at the reduced gas inlet end of the gas heating device, and the preheating device preheats the reduced gas output by the gas storage pressure regulating device; and the tail gas outlet end of the coal gas heating equipment is connected with the preheating equipment, and the preheating equipment takes high-temperature tail gas discharged by the combustion of the coal gas heating equipment as a heat source.
Further, the coal gas separator also comprises a second coal gas shunt pipeline; the inlet end of the second gas shunt pipeline is connected with a pipeline of a gas main pipeline between the fan and the decarburization equipment, and the outlet end of the second gas shunt pipeline is connected with the gas inlet end of the gas heating equipment after penetrating through the preheating equipment.
The inlet end of the second gas shunt pipeline is connected with the main gas pipeline through a valve with flow control, and the valve can control the amount of the gas distributed to enter the second gas shunt pipeline.
In addition, on the gas main pipeline between the fan and the decarburization device, the connection position of the inlet end of the second gas diversion pipeline and the gas main pipeline can be superposed with the connection position of the inlet end of the first gas diversion pipeline and the gas main pipeline, and a four-way valve with flow control is shared at the connection position.
The gas preheating device comprises a gas heating device, a preheating device, a combustion improver gas channel and a combustion improver inlet end, and further comprises a combustion improver gas supply pipeline, wherein the combustion improver gas supply pipeline comprises a combustion improver gas supply device, a combustion improver gas channel of the preheating device and a combustion improver inlet end of the gas heating device which are sequentially communicated through pipelines.
The preheating device fully utilizes the waste heat of the high-temperature flue gas exhausted by the coal gas heating device, and is a device for improving the heat exchange performance of the coal gas heating device and reducing the energy consumption. The preheating equipment is generally divided into three types, namely plate type, rotary type and tubular type. The reducing gas provided by the gas storage pressure regulating device on the gas main pipeline or/and the gas provided by the second gas shunt pipeline as fuel or/and the oxygen-containing gas provided by the combustion improver gas supply pipeline are preheated by the preheating device, so that the reducing gas and the gas are heated to a certain temperature and then enter the gas heating device. It should be noted that: the oxygen-containing gas is one of air, oxygen-enriched air or pure oxygen, preferably air, and is blown in by a blower.
And the coal gas provided by the second coal gas shunt pipeline is used as fuel, and the oxygen-containing gas blown in by the blower is used as combustion improver, so that the reduced coal gas is further heated in the coal gas heating equipment.
Furthermore, a valve interface which can be connected with an external gas system is arranged on the second gas shunt pipeline.
The valve of the valve interface is a three-way valve. The valve interface in the direction of communicating the valve with the gas main pipeline is closed, so that fuel, such as natural gas or gas of other gas systems, can be supplemented to the gas heating equipment from the outside; and the valve interface communicated with the direction of the gas heating equipment is turned off, and the gas of an external gas system can be supplemented to the gas main pipeline through external pressurization, so that the decarburization function and potential of the decarburization equipment are fully exerted, and the carbon emission is reduced. In addition, when the system has abnormal conditions such as gas system faults and the like, the interface can be communicated with the diffusion system for emergency treatment.
The coal gas separator further comprises a desulfurization device, wherein the desulfurization device is arranged on the coal gas main pipeline and is positioned between the dust removal assembly and the inlet end of the first coal gas shunt pipeline. It should be noted that: on the main gas pipeline, along the flowing direction of the flue gas, the desulfurization equipment can be arranged in front of the fan or behind the fan.
The desulfurization method adopted by the desulfurization equipment is one of dry desulfurization, wet desulfurization and semi-dry desulfurization, wherein the wet desulfurization comprises ammonia washing neutralization, improved ADA (ammonia-induced oxidation) method, MSQ (minimum shift keying) method, KCS (potassium chloride) method, tannin extract method and other desulfurization technologies, and preferably tannin extract method desulfurization. It should be noted that: if the wet desulphurization equipment is adopted, a gas-water separation device such as an electrified demisting device is generally arranged at the flue gas outlet end, and if the wet desulphurization equipment does not comprise a dehydration device, a dehydration device is additionally arranged at the rear end of the desulphurization equipment, and the dehydration device is regarded as a component of the desulphurization equipment.
In practical application, the dust removal component and the desulfurization equipment can be integrated into a whole, namely, the same equipment can remove dust and play a role in desulfurization, and the equipment comprises but is not limited to a water film desulfurization dust remover, an impact water bath desulfurization dust remover and a dynamic wave scrubber.
The coal gas desulfurization device is characterized by further comprising mineral powder drying equipment, wherein the mineral powder drying equipment is arranged on the coal gas main pipeline and is positioned between the dust removal component and the desulfurization equipment.
The mineral powder drying equipment utilizes the waste heat of the tail gas of the flash metallurgy equipment to dry the metal oxide mineral powder to be smelted, so that the water content of the mineral powder is lower than 0.3 percent. The mineral powder drying equipment is similar to a dividing wall type heat exchanger, smoke and powder are respectively provided with respective flow passages, are not in direct contact with each other, move reversely, and exchange heat through a heat conducting wall surface.
Mineral powder drying equipment includes but is not limited to: fluidized type drying machines, vertical drying machines, rotary drying machines and suspension drying machines.
Further, the flash metallurgical equipment is one of a flash smelting furnace, a flash converting furnace, a top flash furnace, a Kiffield furnace and a copper synthesis furnace.
Further, the pre-reduction equipment is one of a shaft furnace, a fluidized bed, a rotary hearth furnace and a rotary kiln.
Further, the decarbonization equipment is one or a combination of a plurality of kinds of equipment selected from a pressure swing adsorption method, an MDEA method, an NHD method, a carbon-carbon method, a low-temperature methanol washing method, a benzophenanthrel method, an MEA method, a DEA method and a modified hot potash decarburization equipment. The low-temperature methanol washing method is preferably selected, and the decarbonization equipment can remove most of CO in the flue gas2And sulfur-containing acid gas in the flue gas can be removed.
It should be noted that: 1) since the decarbonization operation generally requires a high pressure, the flue gas is pressurized when it enters the decarbonization apparatus, which is considered to be part of said decarbonization apparatus, according to the inlet pressure required by the particular apparatus. 2) If wet decarburization equipment such as an NHD method, low-temperature methanol washing and the like is adopted, most of water vapor and small droplets in the coal gas can be removed; some wet decarburization processes cannot remove water vapor and water mist in coal gas, but a gas-water separation device is arranged at the flue gas outlet end, if the process does not comprise a dehydration device, a dehydration device is additionally arranged at the rear end, and the dehydration device is regarded as a component of the decarburization equipment. 3) The temperature of the inlet flue gas required by the decarburization equipment is generally near normal temperature, and if the actual flue gas temperature is greater than the working range of the decarburization equipment, a flue gas cooling device is added at the front end of the decarburization equipment, and the cooling device is also regarded as a part of the decarburization equipment.
Further, the coarse dust removal equipment is one or a combination of a cyclone dust collector, an inertial dust collector, a dust settling chamber and a settling chamber.
Furthermore, the dust removal component is one or a combination of a plurality of dust settling chambers, electrostatic dust collectors, bag dust collectors, cyclone dust collectors, wet dust collectors and desulfurization dust collectors; preferably a combination of a dust settling chamber and a bag-type dust collector.
The flash circulating smelting system process for pre-reducing and purifying coal gas comprises the following steps:
1. high-temperature flue gas with the temperature of 1200-1600 ℃ enters a coal gas main pipeline from a tail gas outlet of the flash metallurgy equipment;
2. mixing the high-temperature flue gas with the cool coal gas returned by the first coal gas shunt pipeline, and reducing the temperature of the mixed flue gas to below 850 ℃;
3. introducing the mixed flue gas into pre-reduction equipment, pre-reducing the mineral powder in the mixed flue gas, and reducing the temperature of the flue gas to be below 350 ℃ after heat exchange;
4. introducing the cooled flue gas into a dedusting component, and after dedusting, the dust content in the coal gas is lower than 25mg/m3；
5. Sending the dedusted coal gas to the subsequent process through a fan;
6. the coal gas which is divided by a certain proportion through the first coal gas dividing pipeline is pressurized and returned to the tail gas outlet end of the flash metallurgy equipment to be mixed with the high-temperature flue gas so as to reduce the temperature of the flue gas at the outlet of the flash metallurgy equipment, and the rest coal gas enters the subsequent treatment process;
7. decarbonizing equipment for removing most of sulfur-containing compounds and CO from coal gas2To makeThe S compound content in the coal gas is lower than 80mg/m3And make CO in the coal gas2Is less than 5% by volume;
8. sending the decarbonized reduced gas into gas storage pressure regulating equipment for storage;
9. the method comprises the following steps that (1) reduced coal gas stored by a gas storage pressure regulating device is regulated to required pressure and then is sent to a coal gas heating device, oxygen-containing gas and fuel are combusted to provide heat for the device, and the coal gas is heated to above 1300 ℃ after passing through the coal gas heating device and then is input into a flash metallurgy device;
10. flash smelting:
1) dry metal oxide ore powder to be smelted, a flux, oxygen and fuel are added into a reduction space of a flash metallurgical device filled with high-temperature reduction gas. The coal gas required in the reduction space can be completely derived from the coal gas returned after tail gas purification, or part of the coal gas produced by a coal gasification space arranged in the flash metallurgical equipment or coal gasification equipment arranged outside the flash metallurgical equipment, part of the coal gas returned after tail gas purification is supplemented, and the two parts of the coal gas are mixed in the reduction space. It should be noted that: the reducing gas which circularly returns to the flash metallurgical equipment can be sprayed into the flash metallurgical equipment from the top of the reducing space or can be divided into a plurality of strands, and the reducing gas is sprayed into the flash metallurgical equipment from the side wall of the reducing space at a certain angle, so that a rotational flow effect is formed, and the mineral powder and the reducing gas are fully mixed and contacted.
2) After the metal oxide ore powder enters the reduction space, the reduction and melting of the metal oxide to be smelted in the ore powder are rapidly completed through heat transfer, mass transfer and chemical reaction between the metal oxide ore powder and the reducing gas.
3) The melt after reaction falls into a molten pool in a droplet shape, and pulverized coal and oxygen are sprayed into the molten pool through side blowing to provide heat and reducing agent for the molten pool, so that the residual metal oxide is reduced. Gangue components in the mineral powder and the flux have slagging reaction in a molten pool, and molten slag and metal melt form a slag layer and a metal layer from top to bottom due to density difference. It should be noted that: the reducing coal gas which is circularly returned to the flash metallurgical equipment can also be sprayed into a molten pool instead of side blowing of coal powder, on one hand, the reducing coal gas is used as a reducing agent and simultaneously reacts with oxygen to provide heat for the molten pool.
4) Discharging the molten metal formed in the step 3) from a molten pool metal discharge outlet to obtain crude metal or crude steel, discharging slag from a slag discharge outlet, and discharging flue gas from a tail gas outlet after the flue gas enters an uptake flue.
11. Repeating the steps 1-10.
Compared with the prior art, the flash circulating smelting system utilizing the coal gas to pre-reduce and purify the coal gas has the following advantages:
1) by the method of mixing the returned cool coal gas and the high-temperature tail (flue) gas, the temperature of the tail (flue) gas is reduced under the condition of not wasting the energy of the tail (flue) gas, and the service life of subsequent related tail (flue) gas treatment equipment is prolonged.
2) Fully recycling effective components (CO + H) in high-temperature tail (flue gas) discharged by flash metallurgical equipment2) The method has the advantages that the mineral powder is pre-reduced, the reduction rate can reach more than 30%, the pressure of reduction smelting of flash metallurgical equipment is reduced, and meanwhile, the temperature of flue gas is also reduced through heat exchange with the mineral powder.
3) The CO in the high-temperature tail gas (flue gas) discharged by the flash metallurgical equipment is removed by a decarbonization device2S-containing gas, H2O and other gases harmful to reduction smelting lead the effective component (H) in tail gas (flue gas)2And + CO) is recycled, so that the comprehensive energy consumption of the system is greatly reduced, and the production cost is reduced.
Drawings
The accompanying drawings, which form a part hereof, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without undue limitation. In the drawings:
FIG. 1 is a simplified schematic diagram of a flash cycle smelting system for pre-reducing and purifying coal gas according to embodiment 1 of the present invention;
FIG. 2 is a simplified schematic diagram of a flash cycle smelting system for pre-reducing and purifying coal gas according to embodiment 2 of the present invention;
FIG. 3 is a simplified schematic diagram of a flash cycle smelting system for pre-reducing and purifying coal gas according to embodiment 3 of the present invention;
FIG. 4 is a simplified schematic diagram of a flash cycle smelting system for pre-reducing and purifying coal gas according to embodiment 4 of the present invention;
FIG. 5 is a simplified schematic diagram of a flash cycle smelting system for pre-reducing and purifying coal gas according to example 5 of the present invention;
fig. 6 is a simplified schematic diagram of a flash cycle smelting system for pre-reducing and purifying coal gas according to embodiment 6 of the present invention.
Description of reference numerals:
1-a flash metallurgical plant; 2-coarse dust removal equipment; 3-pre-reduction equipment; 4-a dust removal assembly; 5, a fan; 6-a decarbonization device; 7-gas storage and pressure regulation equipment; 8-gas heating equipment; 9-a first gas diversion pipeline; 10-preheating equipment; 11-a second gas shunt line; 12-a combustion improver gas supply line; 13-a oxidant gas supply device; 14-a desulfurization unit; 15-mineral powder drying equipment.
Detailed Description
It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.
The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
Example 1
As shown in fig. 1, a flash-cycle smelting system for pre-reducing and purifying coal gas by using coal gas comprises a coal gas main pipeline, wherein the coal gas main pipeline comprises a flash-cycle metallurgical device 1, a pre-reduction device 3, a dust removal assembly 4, a fan 5, a decarburization device 6, a gas storage pressure regulating device 7 and a coal gas heating device 8 which are sequentially communicated through a pipeline, and a reducing coal gas outlet of the coal gas heating device 8 is connected with a reducing gas inlet of the flash-cycle metallurgical device 1 through a pipeline; the device also comprises a first gas diversion pipeline 9, wherein the inlet end of the first gas diversion pipeline 9 is connected with a pipeline of a gas main pipeline between the fan 5 and the decarburization equipment 6, and the outlet end of the first gas diversion pipeline 9 is connected with a pipeline of a gas main pipeline between the flash-smelting equipment 1 and the pre-reduction equipment 3.
The working process of the flash circulating smelting system for pre-reducing and purifying coal gas in the embodiment comprises the following steps:
1. high-temperature flue gas with the temperature of 1200-1600 ℃ enters a coal gas main pipeline from a tail gas outlet of the flash metallurgy equipment;
2. mixing the high-temperature flue gas with the cool coal gas returned by the first coal gas shunt pipeline, and reducing the temperature of the mixed flue gas to below 850 ℃;
3. introducing the mixed flue gas into pre-reduction equipment, pre-reducing the mineral powder in the mixed flue gas, and reducing the temperature of the flue gas to be below 350 ℃ after heat exchange;
4. introducing the cooled flue gas into a dedusting component, and after dedusting, the dust content in the coal gas is lower than 25mg/m3；
5. Sending the dedusted coal gas to the subsequent process through a fan;
6. the coal gas which is divided by a certain proportion through the first coal gas dividing pipeline is pressurized and returned to the tail gas outlet end of the flash metallurgy equipment to be mixed with the high-temperature flue gas so as to reduce the temperature of the flue gas at the outlet of the flash metallurgy equipment, and the rest coal gas enters the subsequent treatment process;
7. decarbonizing equipment for removing most of sulfur-containing compounds and CO from coal gas2The content of S compounds in the coal gas is lower than 80mg/m3And make CO in the coal gas2Is less than 5% by volume;
8. sending the decarbonized reduced gas into gas storage pressure regulating equipment for storage;
9. the method comprises the following steps that (1) reduced coal gas stored by a gas storage pressure regulating device is regulated to required pressure and then is sent to a coal gas heating device, oxygen-containing gas and fuel are combusted to provide heat for the device, and the coal gas is heated to above 1300 ℃ after passing through the coal gas heating device and then is input into a flash metallurgy device;
10. flash smelting:
1) dry metal oxide ore powder to be smelted, a flux, oxygen and fuel are added into a reduction space of a flash metallurgical device filled with high-temperature reduction gas. The coal gas required in the reduction space can be completely derived from the coal gas returned after tail gas purification, or part of the coal gas produced by a coal gasification space arranged in the flash metallurgical equipment or coal gasification equipment arranged outside the flash metallurgical equipment, part of the coal gas returned after tail gas purification is supplemented, and the two parts of the coal gas are mixed in the reduction space. It should be noted that: the reducing gas which circularly returns to the flash metallurgical equipment can be sprayed into the flash metallurgical equipment from the top of the reducing space or can be divided into a plurality of strands, and the reducing gas is sprayed into the flash metallurgical equipment from the side wall of the reducing space at a certain angle, so that a rotational flow effect is formed, and the mineral powder and the reducing gas are fully mixed and contacted.
2) After the metal oxide ore powder enters the reduction space, the reduction and melting of the metal oxide to be smelted in the ore powder are rapidly completed through heat transfer, mass transfer and chemical reaction between the metal oxide ore powder and the reducing gas.
3) The melt after reaction falls into a molten pool in a droplet shape, and pulverized coal and oxygen are sprayed into the molten pool through side blowing to provide heat and reducing agent for the molten pool, so that the residual metal oxide is reduced. Gangue components in the mineral powder and the flux have slagging reaction in a molten pool, and molten slag and metal melt form a slag layer and a metal layer from top to bottom due to density difference. It should be noted that: the reducing coal gas which is circularly returned to the flash metallurgical equipment can also be sprayed into a molten pool instead of side blowing of coal powder, on one hand, the reducing coal gas is used as a reducing agent and simultaneously reacts with oxygen to provide heat for the molten pool.
4) Discharging the molten metal formed in the step 3) from a molten pool metal discharge outlet to obtain crude metal or crude steel, discharging slag from a slag discharge outlet, and discharging flue gas from a tail gas outlet after the flue gas enters an uptake flue.
11. Repeating the steps 1-10.
Example 2
As shown in fig. 2, in example 1, unlike example 1, a rough dust removing device 2 is provided between the outlet end of the first gas flow-dividing line 9 and the pre-reduction device 3 in the gas main line.
The working process of the flash circulating smelting system for pre-reducing and purifying coal gas in the embodiment comprises the following steps:
1. high-temperature flue gas with the temperature of 1200-1600 ℃ enters a coal gas main pipeline from a tail gas outlet of the flash metallurgy equipment;
2. mixing the high-temperature flue gas with the cool coal gas returned by the first coal gas shunt pipeline, and reducing the temperature of the mixed flue gas to below 850 ℃;
3. introducing the mixed flue gas into coarse dust removal equipment to remove large-particle smoke dust in the flue gas;
4. introducing the flue gas after coarse dust removal into pre-reduction equipment, pre-reducing the mineral powder in the flue gas, and reducing the temperature of the flue gas to be below 350 ℃ after heat exchange;
5. introducing the cooled flue gas into a dedusting component, and after dedusting, the dust content in the coal gas is lower than 25mg/m3；
6. Sending the dedusted coal gas to the subsequent process through a fan;
7. the coal gas which is divided by a certain proportion through the first coal gas dividing pipeline is pressurized and returned to the tail gas outlet end of the flash metallurgy equipment, and is mixed with the high-temperature flue gas, so that the temperature of the flue gas at the outlet of the flash metallurgy equipment is reduced, and the rest coal gas continues to enter the subsequent treatment process;
8. decarbonizing equipment for removing most of sulfur-containing compounds and CO from coal gas2The content of S compounds in the coal gas is lower than 80mg/m3And make CO in the coal gas2Is less than 5% by volume;
9. sending the decarbonized reduced gas into gas storage pressure regulating equipment for storage;
10. reducing coal gas stored in the gas storage pressure regulating device is regulated to required pressure and then is led into a coal gas heating device, oxygen-containing gas and fuel are combusted to provide heat for the device, and the temperature of the coal gas is raised to more than 1300 ℃ after passing through the coal gas heating device and then is input into a flash metallurgy device;
11. flash smelting:
1) dry metal oxide ore powder to be smelted, a flux, oxygen and fuel are added into a reduction space of a flash metallurgical device filled with high-temperature reduction gas. The coal gas required in the reduction space can be completely derived from the coal gas returned after tail gas purification, or part of the coal gas produced by a coal gasification space arranged in the flash metallurgical equipment or coal gasification equipment arranged outside the flash metallurgical equipment, part of the coal gas returned after tail gas purification is supplemented, and the two parts of the coal gas are mixed in the reduction space. It should be noted that: the reducing gas which circularly returns to the flash metallurgical equipment can be sprayed into the flash metallurgical equipment from the top of the reducing space or can be divided into a plurality of strands, and the reducing gas is sprayed into the flash metallurgical equipment from the side wall of the reducing space at a certain angle, so that a rotational flow effect is formed, and the mineral powder and the reducing gas are fully mixed and contacted.
2) After the metal oxide ore powder enters the reduction space, the reduction and melting of the metal oxide to be smelted in the ore powder are rapidly completed through heat transfer, mass transfer and chemical reaction between the metal oxide ore powder and the reducing gas.
3) The melt after reaction falls into a molten pool in a droplet shape, and pulverized coal and oxygen are sprayed into the molten pool through side blowing to provide heat and reducing agent for the molten pool, so that the residual metal oxide is reduced. Gangue components in the mineral powder and the flux have slagging reaction in a molten pool, and molten slag and metal melt form a slag layer and a metal layer from top to bottom due to density difference. It should be noted that: the reducing coal gas which is circularly returned to the flash metallurgical equipment can also be sprayed into a molten pool instead of side blowing of coal powder, on one hand, the reducing coal gas is used as a reducing agent and simultaneously reacts with oxygen to provide heat for the molten pool.
4) Discharging the molten metal formed in the step 3) from a molten pool metal discharge outlet to obtain crude metal or crude steel, discharging slag from a slag discharge outlet, and discharging flue gas from a tail gas outlet after the flue gas enters an uptake flue.
12. Repeating steps 1-11.
Example 3
As shown in fig. 3, on the basis of embodiment 2, different from embodiment 2, a preheating device 10 is arranged on the gas main pipeline between the gas storage pressure regulating device 7 and the gas heating device 8, and the preheating device 10 preheats the reduced gas output by the gas storage pressure regulating device 7; the tail gas outlet end of the coal gas heating device 8 is connected with a preheating device 10, and the preheating device 10 takes the high-temperature tail gas discharged by the combustion of the coal gas heating device 8 as a heat source.
The working process of the flash circulating smelting system for pre-reducing and purifying coal gas in the embodiment comprises the following steps:
1. high-temperature flue gas with the temperature of 1200-1600 ℃ enters a coal gas main pipeline from a tail gas outlet of the flash metallurgy equipment;
2. mixing the high-temperature flue gas with the cool coal gas returned by the first coal gas shunt pipeline, and reducing the temperature of the mixed flue gas to below 850 ℃;
3. introducing the mixed flue gas into coarse dust removal equipment to remove large-particle smoke dust in the flue gas;
4. introducing the flue gas after coarse dust removal into pre-reduction equipment, pre-reducing the mineral powder in the flue gas, and reducing the temperature of the flue gas to be below 350 ℃ after heat exchange;
5. introducing the cooled flue gas into a dedusting component, and after dedusting, the dust content in the coal gas is lower than 25mg/m3；
6. Sending the dedusted coal gas to the subsequent process through a fan;
7. the coal gas which is divided by a certain proportion through the first coal gas dividing pipeline is pressurized and returned to the tail gas outlet end of the flash metallurgy equipment, and is mixed with the high-temperature flue gas, so that the temperature of the flue gas at the outlet of the flash metallurgy equipment is reduced, and the rest coal gas continues to enter the subsequent treatment process;
8. decarbonizing equipment for removing most of sulfur-containing compounds and CO from coal gas2The content of S compounds in the coal gas is lower than 80mg/m3And make CO in the coal gas2Is less than 5% by volume;
9. sending the decarbonized reduced gas into gas storage pressure regulating equipment for storage;
10. the reduced coal gas stored by the gas storage pressure regulating device is adjusted to the required pressure and then is sent to the preheating device, and the high-temperature tail gas discharged by the coal gas heating device is continuously heated by utilizing the waste heat of the high-temperature tail gas;
11. then leading the preheated reducing coal gas into a coal gas heating device, burning oxygen-containing gas and fuel to provide heat for the device, and heating the coal gas to above 1300 ℃ after passing through the coal gas heating device and inputting the coal gas into a flash metallurgy device;
12. flash smelting:
1) dry metal oxide ore powder to be smelted, a flux, oxygen and fuel are added into a reduction space of a flash metallurgical device filled with high-temperature reduction gas. The coal gas required in the reduction space can be completely derived from the coal gas returned after tail gas purification, or part of the coal gas produced by a coal gasification space arranged in the flash metallurgical equipment or coal gasification equipment arranged outside the flash metallurgical equipment, part of the coal gas returned after tail gas purification is supplemented, and the two parts of the coal gas are mixed in the reduction space. It should be noted that: the reducing gas which circularly returns to the flash metallurgical equipment can be sprayed into the flash metallurgical equipment from the top of the reducing space or can be divided into a plurality of strands, and the reducing gas is sprayed into the flash metallurgical equipment from the side wall of the reducing space at a certain angle, so that a rotational flow effect is formed, and the mineral powder and the reducing gas are fully mixed and contacted.
2) After the metal oxide ore powder enters the reduction space, the reduction and melting of the metal oxide to be smelted in the ore powder are rapidly completed through heat transfer, mass transfer and chemical reaction between the metal oxide ore powder and the reducing gas.
3) The melt after reaction falls into a molten pool in a droplet shape, and pulverized coal and oxygen are sprayed into the molten pool through side blowing to provide heat and reducing agent for the molten pool, so that the residual metal oxide is reduced. Gangue components in the mineral powder and the flux have slagging reaction in a molten pool, and molten slag and metal melt form a slag layer and a metal layer from top to bottom due to density difference. It should be noted that: the reducing coal gas which is circularly returned to the flash metallurgical equipment can also be sprayed into a molten pool instead of side blowing of coal powder, on one hand, the reducing coal gas is used as a reducing agent and simultaneously reacts with oxygen to provide heat for the molten pool.
4) Discharging the molten metal formed in the step 3) from a molten pool metal discharge outlet to obtain crude metal or crude steel, discharging slag from a slag discharge outlet, and discharging flue gas from a tail gas outlet after the flue gas enters an uptake flue.
13. Repeating steps 1-12.
Example 4
As shown in fig. 4, the embodiment 3 is different from the embodiment 3 in that a second gas diversion pipeline 11 and an oxidant gas supply pipeline 12 are further included; the inlet end of a second gas shunt pipeline 11 is connected with a pipeline of a main gas pipeline between the fan 5 and the decarburization device 6, the outlet end of the second gas shunt pipeline 11 is connected with the gas inlet end of the gas heating device 8 after passing through the preheating device 10, and the second gas shunt pipeline 11 is provided with a valve interface which can be connected with an external gas system; the oxidant gas supply pipeline 12 comprises an oxidant gas supply device 13, an oxidant gas flow passage of the preheating device 10 and an oxidant inlet end of the gas heating device 8 which are sequentially communicated through pipelines, and the oxidant gas supply device 13 is preferably a blower.
On the gas main pipeline, before the gas enters the decarburization device 6, a certain proportion of gas is branched from the second gas branch pipeline 11 through a valve to be used as fuel for heating the reduction gas which is input into the flash metallurgy device 1 after decarburization on the gas main pipeline. Meanwhile, in order to improve the heating efficiency of the gas heating device 8 and reduce the comprehensive energy consumption of the system, the gas which is branched by the second gas branch pipeline 11 and enters the gas heating device 8 as fuel and the oxygen-containing gas which is provided by the combustion improver gas supply pipeline 12 and serves as combustion improver can be introduced into the preheating device 10 for preheating.
The working process of the flash circulating smelting system for pre-reducing and purifying coal gas in the embodiment comprises the following steps:
1. high-temperature flue gas with the temperature of 1200-1600 ℃ enters a coal gas main pipeline from a tail gas outlet of the flash metallurgy equipment;
2. mixing the high-temperature flue gas with the cool coal gas returned by the first coal gas shunt pipeline, and reducing the temperature of the mixed flue gas to below 850 ℃;
3. introducing the mixed flue gas into coarse dust removal equipment to remove large-particle smoke dust in the flue gas;
4. introducing the flue gas after coarse dust removal into pre-reduction equipment, pre-reducing the mineral powder in the flue gas, and reducing the temperature of the flue gas to be below 350 ℃ after heat exchange;
5. introducing the cooled flue gas into a dedusting component, and after dedusting, the dust content in the coal gas is lower than 25mg/m3；
6. Sending the dedusted coal gas to the subsequent process through a fan;
7. the coal gas which is divided by a certain proportion through the first coal gas dividing pipeline is pressurized and returned to the tail gas outlet end of the flash metallurgy equipment, and is mixed with the high-temperature flue gas, so that the temperature of the flue gas at the outlet of the flash metallurgy equipment is reduced, and the rest coal gas continues to enter the subsequent treatment process;
8. before the coal gas enters the decarburization equipment, the coal gas is branched out from the second coal gas branch pipeline by a certain proportion through a valve to be used as fuel for heating the reduction coal gas input into the flash metallurgy equipment after decarburization on the coal gas main pipeline;
9. decarbonizing equipment for removing most of sulfur-containing compounds and CO from coal gas2The content of S compounds in the coal gas is lower than 80mg/m3And make CO in the coal gas2Is less than 5% by volume;
10. sending the decarbonized reduced gas into gas storage pressure regulating equipment for storage;
11. the method comprises the steps that reduced coal gas stored by a gas storage pressure regulating device is regulated to required pressure and then sent to a preheating device, the reduced coal gas is continuously heated by high-temperature flue gas discharged by a coal gas heating device, and meanwhile, coal gas which enters the coal gas heating device and serves as fuel and oxygen-containing gas which serves as combustion improver and is provided by a combustion improver gas supply pipeline and is provided by a second coal gas shunt pipeline are also introduced into the preheating device for preheating;
12. the preheated reducing coal gas is introduced into a coal gas heating device, oxygen-containing gas and coal gas as fuel are combusted to provide heat for the device, and the coal gas is heated to above 1300 ℃ after passing through the coal gas heating device and is input into a flash metallurgy device;
13. flash smelting:
1) dry metal oxide ore powder to be smelted, a flux, oxygen and fuel are added into a reduction space of a flash metallurgical device filled with high-temperature reduction gas. The coal gas required in the reduction space can be completely derived from the coal gas returned after tail gas purification, or part of the coal gas produced by a coal gasification space arranged in the flash metallurgical equipment or coal gasification equipment arranged outside the flash metallurgical equipment, part of the coal gas returned after tail gas purification is supplemented, and the two parts of the coal gas are mixed in the reduction space. It should be noted that: the reducing gas which circularly returns to the flash metallurgical equipment can be sprayed into the flash metallurgical equipment from the top of the reducing space or can be divided into a plurality of strands, and the reducing gas is sprayed into the flash metallurgical equipment from the side wall of the reducing space at a certain angle, so that a rotational flow effect is formed, and the mineral powder and the reducing gas are fully mixed and contacted.
2) After the metal oxide ore powder enters the reduction space, the reduction and melting of the metal oxide to be smelted in the ore powder are rapidly completed through heat transfer, mass transfer and chemical reaction between the metal oxide ore powder and the reducing gas.
3) The melt after reaction falls into a molten pool in a droplet shape, and pulverized coal and oxygen are sprayed into the molten pool through side blowing to provide heat and reducing agent for the molten pool, so that the residual metal oxide is reduced. Gangue components in the mineral powder and the flux have slagging reaction in a molten pool, and molten slag and metal melt form a slag layer and a metal layer from top to bottom due to density difference. It should be noted that: the reducing coal gas which is circularly returned to the flash metallurgical equipment can also be sprayed into a molten pool instead of side blowing of coal powder, on one hand, the reducing coal gas is used as a reducing agent and simultaneously reacts with oxygen to provide heat for the molten pool.
4) Discharging the molten metal formed in the step 3) from a molten pool metal discharge outlet to obtain crude metal or crude steel, discharging slag from a slag discharge outlet, and discharging flue gas from a tail gas outlet after the flue gas enters an uptake flue.
14. Repeating steps 1-13.
Example 5
As shown in fig. 5, in example 4, unlike example 4, a desulfurization device 14 is provided between the dust-removing assembly 4 and the inlet end of the first gas bypass line 9 in the gas main line, and the gas is returned after being desulfurized, so that the possibility of corrosion of the relevant devices by sulfur-containing acidic substances can be reduced. It should be noted that: on the main gas pipeline, along the flowing direction of the flue gas, the desulfurization device 14 can be arranged in front of the fan 5 or behind the fan 5.
The working process of the flash circulating smelting system for pre-reducing and purifying coal gas in the embodiment comprises the following steps:
1. high-temperature flue gas with the temperature of 1200-1600 ℃ enters a coal gas main pipeline from a tail gas outlet of the flash metallurgy equipment;
2. mixing the high-temperature flue gas with the cool coal gas returned by the first coal gas shunt pipeline, and reducing the temperature of the mixed flue gas to below 850 ℃;
3. introducing the mixed flue gas into coarse dust removal equipment to remove large-particle smoke dust in the flue gas;
4. introducing the flue gas after coarse dust removal into pre-reduction equipment, pre-reducing the mineral powder in the flue gas, and reducing the temperature of the flue gas to be below 350 ℃ after heat exchange;
5. introducing the cooled flue gas into a dedusting component, and after dedusting, the dust content in the coal gas is lower than 25mg/m3；
6. Sending the dedusted coal gas into a desulfurization device through a fan;
7. the desulfurization equipment removes most of sulfur-containing compounds in the coal gas to ensure that the content of S-containing compounds is less than 80mg/m3；
8. After the gas is desulfurized, the gas which is divided by a certain proportion by the first gas dividing pipeline is pressurized and returned to the outlet end of the tail gas of the flash metallurgical equipment and is mixed with the high-temperature flue gas so as to reduce the temperature of the flue gas at the outlet of the flash metallurgical equipment, and the rest of the gas continuously enters the subsequent treatment flow;
9. before the coal gas enters the decarburization equipment, the coal gas is branched out from the second coal gas branch pipeline by a certain proportion through a valve to be used as fuel for heating the reduction coal gas input into the flash metallurgy equipment after decarburization on the coal gas main pipeline;
10. removing most of sulfur compounds and CO in the coal gas by a decarbonization device2The content of S compounds in the coal gas is lower than 80mg/m3And make CO in the coal gas2Is less than 5% by volume;
11. sending the decarbonized reduced gas into gas storage pressure regulating equipment for storage;
12. the method comprises the steps that reduced coal gas stored by a gas storage pressure regulating device is regulated to required pressure and then sent to a preheating device, the reduced coal gas is continuously heated by high-temperature flue gas discharged by a coal gas heating device, and meanwhile, coal gas which enters the coal gas heating device and serves as fuel and oxygen-containing gas which serves as combustion improver and is provided by a combustion improver gas supply pipeline and is provided by a second coal gas shunt pipeline are also introduced into the preheating device for preheating;
13. the preheated reducing coal gas is introduced into a coal gas heating device, oxygen-containing gas and coal gas as fuel are combusted to provide heat for the device, and the coal gas is heated to above 1300 ℃ after passing through the coal gas heating device and is input into a flash metallurgy device;
14. flash smelting:
1) dry metal oxide ore powder to be smelted, a flux, oxygen and fuel are added into a reduction space of a flash metallurgical device filled with high-temperature reduction gas. The coal gas required in the reduction space can be completely derived from the coal gas returned after tail gas purification, or part of the coal gas produced by a coal gasification space arranged in the flash metallurgical equipment or coal gasification equipment arranged outside the flash metallurgical equipment, part of the coal gas returned after tail gas purification is supplemented, and the two parts of the coal gas are mixed in the reduction space. It should be noted that: the reducing gas which circularly returns to the flash metallurgical equipment can be sprayed into the flash metallurgical equipment from the top of the reducing space or can be divided into a plurality of strands, and the reducing gas is sprayed into the flash metallurgical equipment from the side wall of the reducing space at a certain angle, so that a rotational flow effect is formed, and the mineral powder and the reducing gas are fully mixed and contacted.
2) After the metal oxide ore powder enters the reduction space, the reduction and melting of the metal oxide to be smelted in the ore powder are rapidly completed through heat transfer, mass transfer and chemical reaction between the metal oxide ore powder and the reducing gas.
3) The melt after reaction falls into a molten pool in a droplet shape, and pulverized coal and oxygen are sprayed into the molten pool through side blowing to provide heat and reducing agent for the molten pool, so that the residual metal oxide is reduced. Gangue components in the mineral powder and the flux have slagging reaction in a molten pool, and molten slag and metal melt form a slag layer and a metal layer from top to bottom due to density difference. It should be noted that: the reducing coal gas which is circularly returned to the flash metallurgical equipment can also be sprayed into a molten pool instead of side blowing of coal powder, on one hand, the reducing coal gas is used as a reducing agent and simultaneously reacts with oxygen to provide heat for the molten pool.
4) Discharging the molten metal formed in the step 3) from a molten pool metal discharge outlet to obtain crude metal or crude steel, discharging slag from a slag discharge outlet, and discharging flue gas from a tail gas outlet after the flue gas enters an uptake flue.
15. Repeating steps 1-14.
Example 6
As shown in fig. 6, in example 5, unlike example 5, a fine ore drying device 15 is provided on the gas main line between the dust-removing unit 4 and the desulfurization device 14, and the fine ore drying device 15 can be used to dry fine ore. It should be noted that: the position of the fan 5 is relatively flexible, and the fan can be arranged between the dust removal component 4 and the mineral powder drying device 15, between the mineral powder drying device 15 and the desulfurization device 14, or between the desulfurization device 14 and the inlet end of the first gas diversion pipeline on the main gas pipeline.
The working process of the flash circulating smelting system for pre-reducing and purifying coal gas in the embodiment comprises the following steps:
1. high-temperature flue gas with the temperature of 1200-1600 ℃ enters a coal gas main pipeline from a tail gas outlet of the flash metallurgy equipment;
2. mixing the high-temperature flue gas with the cool coal gas returned by the first coal gas shunt pipeline, and reducing the temperature of the mixed flue gas to below 850 ℃;
3. introducing the mixed flue gas into coarse dust removal equipment to remove large-particle smoke dust in the flue gas;
4. introducing the flue gas after coarse dust removal into pre-reduction equipment, pre-reducing the mineral powder in the flue gas, and reducing the temperature of the flue gas to be below 350 ℃ after heat exchange;
5. introducing the cooled flue gas into a dedusting component, and after dedusting, the dust content in the coal gas is lower than 25mg/m3；
6. Introducing the dedusted coal gas into mineral powder drying equipment, and cooling the coal gas to below 180 ℃ after passing through the mineral powder drying equipment;
7. the coal gas is sent into a desulfurization device through a fan, and the desulfurization device removes most of sulfur-containing compounds in the coal gas to ensure that the content of the S-containing compounds is lower than 80mg/m3；
8. After the gas is desulfurized, the gas which is divided by a certain proportion by the first gas dividing pipeline is pressurized and returned to the outlet end of the tail gas of the flash metallurgical equipment and is mixed with the high-temperature flue gas so as to reduce the temperature of the flue gas at the outlet of the flash metallurgical equipment, and the rest of the gas continuously enters the subsequent treatment flow;
9. before the coal gas enters the decarburization equipment, the coal gas is branched out from the second coal gas branch pipeline by a certain proportion through a valve to be used as fuel for heating the reduction coal gas input into the flash metallurgy equipment after decarburization on the coal gas main pipeline;
10. removing most of sulfur compounds and CO in the coal gas by a decarbonization device2The content of S compounds in the coal gas is lower than 80mg/m3And make CO in the coal gas2Is less than 5% by volume;
11. sending the decarbonized reduced gas into gas storage pressure regulating equipment for storage;
12. the method comprises the steps that reduced coal gas stored by a gas storage pressure regulating device is regulated to required pressure and then sent to a preheating device, the reduced coal gas is continuously heated by high-temperature flue gas discharged by a coal gas heating device, and meanwhile, coal gas which enters the coal gas heating device and serves as fuel and oxygen-containing gas which serves as combustion improver and is provided by a combustion improver gas supply pipeline and is provided by a second coal gas shunt pipeline are also introduced into the preheating device for preheating;
13. the preheated reducing coal gas is introduced into a coal gas heating device, oxygen-containing gas and coal gas as fuel are combusted to provide heat for the device, and the coal gas is heated to above 1300 ℃ after passing through the coal gas heating device and is input into a flash metallurgy device;
14. flash smelting:
1) dry metal oxide ore powder to be smelted, a flux, oxygen and fuel are added into a reduction space of a flash metallurgical device filled with high-temperature reduction gas. The coal gas required in the reduction space can be completely derived from the coal gas returned after tail gas purification, or part of the coal gas produced by a coal gasification space arranged in the flash metallurgical equipment or coal gasification equipment arranged outside the flash metallurgical equipment, part of the coal gas returned after tail gas purification is supplemented, and the two parts of the coal gas are mixed in the reduction space. It should be noted that: the reducing gas which circularly returns to the flash metallurgical equipment can be sprayed into the flash metallurgical equipment from the top of the reducing space or can be divided into a plurality of strands, and the reducing gas is sprayed into the flash metallurgical equipment from the side wall of the reducing space at a certain angle, so that a rotational flow effect is formed, and the mineral powder and the reducing gas are fully mixed and contacted.
2) After the metal oxide ore powder enters the reduction space, the reduction and melting of the metal oxide to be smelted in the ore powder are rapidly completed through heat transfer, mass transfer and chemical reaction between the metal oxide ore powder and the reducing gas.
3) The melt after reaction falls into a molten pool in a droplet shape, and pulverized coal and oxygen are sprayed into the molten pool through side blowing to provide heat and reducing agent for the molten pool, so that the residual metal oxide is reduced. Gangue components in the mineral powder and the flux have slagging reaction in a molten pool, and molten slag and metal melt form a slag layer and a metal layer from top to bottom due to density difference. It should be noted that: the reducing coal gas which is circularly returned to the flash metallurgical equipment can also be sprayed into a molten pool instead of side blowing of coal powder, on one hand, the reducing coal gas is used as a reducing agent and simultaneously reacts with oxygen to provide heat for the molten pool.
4) Discharging the molten metal formed in the step 3) from a molten pool metal discharge outlet to obtain crude metal or crude steel, discharging slag from a slag discharge outlet, and discharging flue gas from a tail gas outlet after the flue gas enters an uptake flue.
15. Repeating steps 1-14.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A flash circulating smelting system for pre-reducing and purifying coal gas is characterized in that: the device comprises a gas main pipeline, wherein the gas main pipeline comprises a flash metallurgy device (1), a pre-reduction device (3), a dust removal assembly (4), a fan (5), a decarburization device (6), a gas storage pressure regulating device (7) and a gas heating device (8) which are sequentially communicated through a pipeline, and a reduction gas outlet of the gas heating device (8) is connected with a reduction gas inlet of the flash metallurgy device (1) through a pipeline; the device is characterized by further comprising a first gas distribution pipeline (9), wherein the inlet end of the first gas distribution pipeline (9) is connected with a pipeline of a gas main pipeline between the fan (5) and the decarburization equipment (6), and the outlet end of the first gas distribution pipeline (9) is connected with a pipeline of a gas main pipeline between the flash metallurgy equipment (1) and the pre-reduction equipment (3).
2. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 1, wherein: the system is characterized by further comprising a coarse dust removal device (2), wherein the coarse dust removal device (2) is arranged on the gas main pipeline and is positioned between the outlet end of the first gas diversion pipeline (9) and the pre-reduction device (3).
3. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 2, wherein: a preheating device (10) is arranged between the gas storage pressure regulating device (7) and a pipeline at the reducing gas inlet end of the gas heating device (8), and the preheating device (10) preheats the reducing gas output by the gas storage pressure regulating device (7); the tail gas outlet end of the coal gas heating device (8) is connected with the preheating device (10), and the preheating device (10) takes high-temperature tail gas discharged by the combustion of the coal gas heating device (8) as a heat source.
4. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 3, wherein: the coal gas separator also comprises a second coal gas shunt pipeline (11); the inlet end of the second gas shunt pipeline (11) is connected with a pipeline of a main gas pipeline between the fan (5) and the decarburization device (6), and the outlet end of the second gas shunt pipeline (11) is connected with the gas inlet end of the gas heating device (8) after penetrating through the preheating device (10).
5. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 4, wherein: the gas preheating device is characterized by further comprising a combustion improver gas supply pipeline (12), wherein the combustion improver gas supply pipeline (12) comprises a combustion improver gas supply device (13), a combustion improver gas flow passage of the preheating device (10) and a combustion improver inlet end of the coal gas heating device (8) which are sequentially communicated through pipelines.
6. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 4, wherein: and a valve interface which can be connected with an external gas system is arranged on the second gas shunt pipeline (11).
7. Flash cycle smelting system with gas pre-reduction and purification according to any of the claims 1 to 6, characterized by: the coal gas dust removal device is characterized by further comprising a desulfurization device (14), wherein the desulfurization device (14) is arranged on the coal gas main pipeline and is positioned between the dust removal assembly (4) and the inlet end of the first coal gas shunt pipeline (9).
8. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 7, wherein: the coal gas desulfurization and dedusting system is characterized by further comprising mineral powder drying equipment (15), wherein the mineral powder drying equipment (15) is arranged on the coal gas main pipeline and is positioned between the dedusting assembly (4) and the desulfurization equipment (14).
9. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 1, wherein: the pre-reduction equipment (3) is one of a shaft furnace, a fluidized bed, a rotary hearth furnace and a rotary kiln.
10. The flash cycle smelting system for pre-reducing and purifying coal gas using coal gas as claimed in claim 1, wherein: the decarbonization equipment (6) is one or a combination of a plurality of kinds of equipment selected from pressure swing adsorption method, MDEA method, NHD method, carbon-carbon method, low-temperature methanol washing, benzophenanthrel method, MEA method, DEA method and modified hot potash method.
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