Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the invention aims to provide a method for preparing reducing gas for a shaft furnace by catalytic gasification of coal, which has the advantages of low gasification temperature, high gasification efficiency, low requirement on equipment materials and the like.
The method for preparing the reducing gas for the shaft furnace by coal catalytic gasification comprises the following steps:
mixing pulverized coal with a catalyst and then performing ball pressing treatment to obtain pulverized coal particles;
carrying out catalytic gasification reaction on the pulverized coal particles and water vapor in a heat accumulating type pyrolysis furnace so as to generate crude reducing gas containing hydrogen, carbon monoxide, carbon dioxide and hydrogen sulfide;
recovering waste heat of the crude reducing gas so as to generate steam;
purifying the crude reducing gas subjected to the waste heat recovery so as to obtain refined reducing gas,
wherein the total content of hydrogen and carbon monoxide in the refined reducing gas is not less than 88 vol%, and the volume ratio of hydrogen to carbon monoxide is (3.5-1.5): 1; the oxidation degree of the refined reducing gas is less than 5%;
the catalytic gasification reaction is carried out at 650-800 ℃ and 22 KPa.
Therefore, the method for preparing the reducing gas for the shaft furnace by catalytic gasification of coal in the embodiment of the invention is simple and efficient, has low energy consumption, is environment-friendly, can prepare qualified sponge iron reducing gas at low cost, is technically environment-friendly, energy-saving and feasible, and is a method for efficiently utilizing the coal to prepare the reducing gas.
In addition, the method for preparing the reducing gas for the shaft furnace by coal catalytic gasification according to the above embodiment of the invention may further have the following additional technical features:
in some embodiments of the invention, the mass ratio of the pulverized coal, the catalyst and the steam is: (1-4): (0.01-0.08): 1. therefore, the prepared reducing gas can meet the requirement of sponge iron preparation in a gas-based shaft furnace on reduction.
In some embodiments of the invention, the water vapor produced by the waste heat recovery is returned for use in the catalytic gasification reaction. Thereby further energy consumption can be saved.
In some embodiments of the invention, the purification process comprises:
washing the crude reducing gas subjected to waste heat recovery so as to remove residual catalyst and fine ash in the crude reducing gas;
carrying out desulfurization treatment on the washed crude reducing gas so as to remove hydrogen sulfide gas;
compressing the desulfurized crude reducing gas; and
and performing decarburization treatment on the compressed crude reducing gas so as to remove carbon dioxide to obtain the refined reducing gas. Thereby further improving the purity of the reducing gas and improving the volume ratio of hydrogen to carbon monoxide of the reducing gas.
In some embodiments of the invention, the desulfurization and the decarburization are both carried out using N-methyldiethanolamine. Thereby, the desulfurization and decarburization efficiency and effect can be further improved.
Therefore, aiming at the defects of the existing coal gasification technology, the catalytic coal gasification technology is adopted to replace the reducing gas required by the existing coal gasification technology for preparing the gas-based shaft furnace, under the condition of adding the catalyst, the pulverized coal particles can quickly generate gasification reaction at 650-800 ℃, and the generated H in the crude synthesis gas2The ratio of/CO is 3.5-1.5: 1, the requirement of reducing gas of the gas-based shaft furnace is met, and transformation is not needed; the addition of the catalyst reduces the coal gasification temperature, energy consumption and requirements on equipment materials and the like, is very favorable for desulfurization, dust removal, environmental protection and the like, has better selectivity on the coal gas composition in the product, and in addition, because oxygen is not added in the process, the synthetic gas does not contain nitrogen, thereby improving the economical efficiency of industrial production.
According to another aspect of the invention, the invention provides a system for preparing reducing gas for a shaft furnace by coal catalytic gasification.
The system for preparing the reducing gas for the shaft furnace by coal catalytic gasification is characterized by comprising the following steps:
the regenerative pyrolysis furnace is provided with a pulverized coal catalyst particle inlet, a water vapor inlet and a crude reducing gas outlet, and is suitable for catalytic gasification reaction of pulverized coal and water vapor under the action of a catalyst so as to generate crude reducing gas containing hydrogen, carbon monoxide, carbon dioxide and hydrogen sulfide;
the waste heat boiler is provided with a hot reducing gas inlet, a cold reducing gas outlet and a steam outlet, the hot reducing gas inlet is connected with the crude reducing gas outlet, and the waste heat boiler is suitable for performing waste heat recovery on the crude reducing gas so as to generate steam;
and the purification device is connected with the waste heat boiler and is suitable for purifying the crude reducing gas recovered by the waste heat so as to obtain refined reducing gas.
In addition, the system for preparing the reducing gas for the shaft furnace by coal catalytic gasification according to the above embodiment of the invention may further have the following additional technical features:
in some embodiments of the present invention, the steam outlet of the waste heat boiler is connected to the steam inlet of the regenerative pyrolysis furnace so as to use the steam for the catalytic gasification reaction. Thereby further energy consumption can be saved.
In some embodiments of the present invention, the purification apparatus includes a washing device, a desulfurization device, a compression device and a decarburization device, which are connected in series and are adapted to perform a washing process, a desulfurization process, a compression process and a decarburization process on the crude reducing gas subjected to the waste heat recovery.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The method for preparing a reducing gas for a shaft furnace by catalytic gasification of coal according to an embodiment of the present invention will be described with reference to fig. 1-2.
The method for preparing the reducing gas for the shaft furnace by coal catalytic gasification comprises the following steps:
s100: catalytic gasification reaction
Mixing pulverized coal with a catalyst and then performing ball pressing treatment to obtain pulverized coal particles;
the pulverized coal particles are subjected to a catalytic gasification reaction with steam in a regenerative pyrolysis furnace to generate a crude reducing gas containing hydrogen, carbon monoxide, carbon dioxide and hydrogen sulfide.
Therefore, the water vapor is used as a gasifying agent and the catalyst is used for catalytic coal gasification, the gasification reaction temperature can be reduced, the temperature of the gasification furnace is not required to be maintained by burning part of coal with air, so that nitrogen is prevented from being brought into the gasification furnace by air, the synthetic gas does not contain nitrogen, the subsequent nitrogen separation problem is avoided, the processing capacity of equipment units and the applicability of coal types are improved, the energy consumption cost is saved, meanwhile, the nitrogen is prevented from being brought into the gasification furnace by air, the heat loss of the system can be reduced, and the equipment investment and the production cost are reduced. The low-temperature catalytic gasification of coal enables the pulverized coal particles and steam to carry out gasification reaction at a lower temperature under the action of a catalyst, reduces the temperature and energy consumption of coal gasification, meets the requirements on equipment materials and the like, and is very favorable for desulfurization, dust removal, environmental protection and the like.
The reduction gas prepared by the pressed pulverized coal can save an airflow conveying device for configuring the pulverized coal, thereby simplifying the process and reducing the equipment cost. According to the specific embodiment of the invention, the particle size of the pulverized coal particles obtained by the ball pressing treatment can be 10-50 mm. Can increase the area of contact of fine coal and catalyst from this through pressing the ball to handle, and then can show the conversion that improves carbon, it is 10 ~ 50mm fine coal granule not only can save to use air current conveyor to carry fine coal to press the ball to obtain the particle diameter simultaneously, improves steam more easily and fine coal granule area of contact simultaneously. Although the particle size of the pulverized coal is smaller, when the pulverized coal is contacted with steam, the steam hardly comes into contact with all the pulverized coal, and thus the gasification efficiency is not high. However, the pulverized coal and the catalyst are pressed into pellets in advance and then contacted with the steam, so that the contact chance of the steam and the pellets is increased, and further the gasification efficiency can be obviously improved.
According to the specific embodiment of the invention, the mass ratio of the pulverized coal, the catalyst and the water vapor is as follows: (1-4): (0.01-0.08): 1, thereby further improving the gasification efficiency, saving energy consumption and preparing the H of the reducing gas by adopting the proportion2/CO2Can meet the requirement of reducing gas for smelting sponge iron in a gas-based shaft furnace. Therefore, the pulverized coal, the steam and the catalyst are subjected to catalytic gasification reaction according to the mass ratio, so that the gasification reaction efficiency can be further improved, and the yield of the reducing gas can be improved.
According to the specific embodiment of the invention, the addition of the catalyst can gasify the pulverized coal at low temperature, simultaneously methane generated by gasifying the pulverized coal further reacts with steam under the action of the catalyst to produce carbon monoxide and hydrogen, and coal tar generated by pyrolyzing the pulverized coal is subjected to secondary decomposition under the action of the catalyst to generate more reducing gas. The conversion of methane and the secondary decomposition of coal tar are carried out in the same reactor, thereby greatly improving the efficiency of the process, simultaneously, the catalyst can also absorb partial gases such as hydrogen sulfide, carbon dioxide and the like, being beneficial to the low-temperature gasification of coal and the subsequent desulfurization, dust removal and environmental protection, and having better selectivity on the composition of reducing gas.
According to a specific embodiment of the present invention, the catalyst is an oxide or salt of at least one selected from the group consisting of alkali metals, transition metals, and alkaline earth metals, wherein the alkali metal is at least one selected from the group consisting of lithium, sodium, potassium, rubidium, and cerium; the transition metal is at least one of vanadium, chromium, manganese, iron, cobalt, nickel, copper and molybdenum; the alkaline earth metal is at least one of magnesium, calcium and barium; the salt is at least one of carbonate, sulfate, bicarbonate, formate, oxalate, amide, hydroxide, and acetate. Therefore, the addition of the catalyst can further improve the gasification reaction efficiency, reduce the temperature, energy consumption and requirements on equipment materials and the like of pulverized coal gasification, and can absorb part of gases such as hydrogen sulfide, carbon dioxide and the like in the crude product gas, thereby being beneficial to desulfurization, dust removal and environmental protection of the following procedures. And the addition of the catalyst has better selectivity on the composition of the crude reducing gas.
According to another embodiment of the present invention, the catalyst contains 0.1 to 3.0 wt% of an oxide of an alkaline earth metal and/or a salt of an alkaline earth metal. The catalytic efficiency can thereby be increased considerably, for example with a catalyst having the above-mentioned composition the carbon conversion can be increased from 54% to 90% and the content of hydrogen and carbon monoxide from 44% to 89%. According to a specific embodiment of the present invention, the alkaline earth metal may be at least one of magnesium, calcium and barium. Therefore, the catalytic efficiency of the catalyst can be obviously improved, and the carbon conversion rate and the content of the reducing gas can be improved.
According to another embodiment of the present invention, the conditions of the catalytic gasification reaction in the regenerative pyrolysis furnace are not particularly limited, and according to a specific example of the present invention, the catalytic gasification reaction may be performed at 650 to 800 degrees celsius and at a pressure of 22 KPa.
The traditional pulverized coal gasification reaction needs to be carried out at 1200-1500 ℃ and under the pressure of 2-6 MPa, and even if a catalyst is used, the pressure of the gasification reaction is controlled to be 3-4 MPa. Therefore, compared with the existing pulverized coal gasification reaction, the method for preparing the reducing gas for the shaft furnace by catalytic gasification of coal obviously saves energy consumption. According to the embodiment of the invention, the reducing gas prepared by the method can meet the requirement of the gas-based shaft furnace for preparing the sponge iron.
S200: waste heat recovery
According to the embodiment of the invention, the crude reducing gas obtained as described above is subjected to waste heat recovery so as to generate steam. Thus, the crude reducing gas can be cooled while recovering heat.
According to another embodiment of the invention, the water vapour produced in the waste heat boiler can be returned for the catalytic gasification reaction. Thereby saving energy consumption for preparing the water vapor.
S300: purification treatment
According to the embodiment of the invention, the crude reducing gas after waste heat recovery is further subjected to purification treatment so as to obtain refined reducing gas. Thereby improving the purity of the reducing gas and obtaining the reducing gas with proper H2/CO2Refined reducing gas is proportioned.
According to an embodiment of the present invention, as shown in fig. 2, the purification process may further include:
s310: washing treatment
According to the specific embodiment of the invention, the crude reducing gas after waste heat recovery is first subjected to a washing treatment to remove the catalyst and fine ash remaining in the crude reducing gas.
According to a particular example of the invention, the washing treatment can be carried out in particular by mixing the crude reducing gas with water from a chilled water pump via a venturi tube, the fine ash being completely wetted with water, then passing through the downcomer of the washing column into a water bath at the bottom of the washing column, removing the remaining fine ash, then passing through the annular space between the downcomer and the gas duct, entering the tray at the top of the washing column, and separating the entrained water droplets by means of a demister above the tray. The crude reducing gas, which is substantially free of fine ash, exits the scrubber and is sent to the desulfurizer. And (4) enabling acid liquor discharged from the bottom of the washing tower to enter catalyst recovery equipment to recover the catalyst.
S320: desulfurization treatment
According to a specific example of the present invention, the crude reducing gas subjected to the washing treatment is subjected to a desulfurization treatment in order to remove hydrogen sulfide gas.
According to an embodiment of the present invention, the desulfurization treatment may be performed using N-methyldiethanolamine. Thereby further improving the desulfurization effect, specifically, the effect of reducing H in the gas2S is from 4g/m3To 2mg/m3. And the N-methyldiethanolamine is adopted to remove hydrogen sulfide and simultaneously remove a considerable amount of CO2Therefore, the total content of hydrogen and carbon monoxide in the reducing gas can be further improved, and the reducing performance of the reducing gas can be improved. Therefore, the reducing gas prepared by the method for preparing the reducing gas for the shaft furnace by catalytic gasification of coal in the embodiment of the invention can be directly used for smelting sponge iron in the gas-based shaft furnace, and the quality and smelting efficiency of the sponge iron can be obviously improved.
According to a specific example of the present invention, the desulfurization treatment may be performed according to the following steps, wherein the crude reducing gas is washed, dedusted and cooled, enters the bottom of the desulfurization tower, and is contacted with the MDEA solution ((N-methyldiethanolamine)) from top to bottom in the tower in a counter-current manner to absorb most of H2S and part of SO2And COS. The reducing gas out of the desulfurizing tower enters a tower top cooler to be cooled to about 40 ℃, enters a gas-liquid separator to be subjected to gas-liquid separation, MDEA absorption liquid (N-methyldiethanolamine) is recovered,about 22kPa (G) of reducing gas is sent to the compressor 1. The rich liquid discharged from the bottom of the desulfurization tower enters a flash tank for flash evaporation through a rich liquid pump, and flash steam at the top of the flash tank, flash steam at the decarbonization section and overhead gas of the solution regeneration tower are condensed and then enter CO2A separator and a desulfurization tank. After sulfur in the desulfurization tank is treated, sulfur is produced and sold, and the barren solution regenerated at the bottom of the regeneration tower is subjected to heat exchange and cooling by the solution heat exchanger and the solution cooler and then returns to the desulfurization tower and the decarbonization tower for recycling.
S330: compression process
According to a specific embodiment of the present invention, the desulfurized raw reducing gas is subjected to a compression treatment. According to a specific example of the present invention, the reducing gas may be compressed to about 1mpa (g) by a compressor and then introduced into the decarbonization tower.
S340: decarburization treatment
And performing decarburization treatment on the compressed crude reducing gas so as to remove carbon dioxide to obtain the refined reducing gas.
According to an embodiment of the present invention, the decarburization treatment may be performed using N-methyldiethanolamine.
According to a specific example of the present invention, the desulfurization treatment may be performed by feeding the reducing gas from the compressor into the gas inlet and oil remover, and then into the decarbonization tower, wherein the reducing gas is fed downward and discharged upward, and the absorption liquid MDEA is fed upward and discharged downward, and then counter-currently contacted. And (3) discharging the decarbonized gas from the top of the tower, feeding the decarbonized gas into a tower top cooler, cooling the reducing gas heated by absorption to 40 ℃, performing gas-liquid separation through a gas-liquid separator at the outlet of the fine decarbonization tower, and recovering the MDEA absorption liquid. Two MDEA (N-methyldiethanolamine) solutions from a desulfurization tower for desulfurization and a decarbonization tower for decarbonization are mixed and then enter a flash tank. The flash steam coming out from the top of the flash tank and the overhead gas of the regeneration tower enter CO after being condensed2The separator and the desulfurization tank, the sulfur in the desulfurization tank is treated to produce sulfur for sale; the barren solution after regeneration at the bottom of the regeneration tower is cooled by the heat exchange of the solution heat exchanger and the solution cooler and then returns to the dehydration towerThe sulfur tower and the decarbonization tower are recycled.
According to the specific embodiment of the invention, the total content of hydrogen and carbon monoxide in the refined reducing gas prepared by the method is not less than 88% by volume, and the volume ratio of hydrogen to carbon monoxide is (3.5-1.5): 1. therefore, the refined reducing gas can meet the requirement of the sponge iron prepared by the gas-based shaft furnace on the reducing gas. According to an embodiment of the present invention, the refined reducing gas prepared by the above method has an oxidation degree of less than 5% and a pressure of about 1.0MPa (G). Further, the refined reducing gas is used for iron making, so that the metallization rate, the productivity and the energy utilization rate can be further improved, the purity of iron is improved, and the energy consumption is reduced.
The system for preparing the reducing gas for the shaft furnace by catalytic gasification of coal according to the embodiment of the present invention will be described with reference to fig. 3 to 4.
The system 100 for preparing the reducing gas for the shaft furnace by catalytic coal gasification according to the embodiment of the invention comprises: a regenerative pyrolysis furnace 10, a waste heat boiler 20 and a purification device 30.
The regenerative pyrolysis furnace 10 is provided with a pulverized coal catalyst particle inlet 11, a water vapor inlet 12 and a crude reducing gas outlet 13, and is suitable for catalytic gasification reaction of pulverized coal and water vapor under the action of a catalyst so as to generate crude reducing gas containing hydrogen, carbon monoxide, carbon dioxide and hydrogen sulfide;
the waste heat boiler 20 is provided with a hot reducing gas inlet 21, a cold reducing gas outlet 22 and a steam outlet 23, the hot reducing gas inlet is connected with the crude reducing gas outlet, and the waste heat boiler is suitable for performing waste heat recovery on the crude reducing gas so as to generate steam;
the purification device 30 has a cold reducing gas inlet 301 and a refined reducing gas outlet 302, the cold reducing gas inlet 301 is connected with the cold reducing gas outlet 22 of the waste heat boiler, and the purification device is suitable for purifying the crude reducing gas subjected to waste heat recovery so as to obtain the refined reducing gas.
As shown in fig. 4, according to the embodiment of the present invention, the steam outlet 23 of the waste heat boiler is connected to the steam inlet 12 of the regenerative pyrolysis furnace so as to use the steam for the catalytic gasification reaction. Thereby saving energy consumption for preparing the water vapor.
According to an embodiment of the present invention, the purification apparatus further comprises a washing device 31, a desulfurizing device 32, a compressing device 33 and a decarbonizing device 34, which are connected in series and are adapted to perform a washing process, a desulfurizing process, a compressing process and a decarbonizing process on the crude reducing gas subjected to the waste heat recovery. Thus, the crude reducing gas can be purified to obtain a refined reducing gas. According to the specific embodiment of the invention, the total content of hydrogen and carbon monoxide in the refined reducing gas prepared by the system for preparing the reducing gas for the shaft furnace by coal catalytic gasification is not lower than 88 volume percent, and the volume ratio of hydrogen to carbon monoxide is (3.5-1.5): 1. therefore, the refined reducing gas can meet the requirement of preparing sponge iron by a gas-based shaft furnace. According to an embodiment of the present invention, the refined reducing gas has a degree of oxidation of less than 5% and a pressure of about 1.0MPa (G). Further, the refined reducing gas is used for iron making, so that the metallization rate, the productivity and the energy utilization rate can be further improved, the purity of iron is improved, and the energy consumption is reduced.
Example 1
Referring to fig. 5, the method and system for preparing reducing gas for a shaft furnace by catalytic coal gasification for preparing the reducing gas required for sponge iron production comprises the following steps: mixing pulverized coal and a catalyst according to a mass ratio of 2.5: 0.06 of the catalyst is uniformly mixed and is subjected to ball pressing treatment to obtain pulverized coal particles with the diameter of 10-50 mm, and 84 percent K is adopted as the catalyst2CO3-14.5%FeCl3-1.5%Ca(Ac)2(ii) a Adding pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction, so that the pulverized coal particles and the steam are mixed according to the weight ratio of 2.5 kg: 1kg of the mixture ratio is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2A mixed gas of S, etc.).
Go out to holdHigh-temperature crude reducing gas of the thermal pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and acidic water at the bottom of the washing tower enters catalyst recovery equipment to recover a catalyst; the reducing gas (temperature about 40 ℃, pressure 22KPa (G)) washed at the top of the washing tower enters the bottom of the desulfurizing tower and is in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 94%, a hydrogen and carbon monoxide content of 92% and a hydrogen to carbon monoxide ratio of 3.8: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 93%.
Example 2
Referring to fig. 5, the method and system for preparing reducing gas for a shaft furnace by catalytic coal gasification for preparing the reducing gas required for sponge iron production comprises the following steps: mixing pulverized coal and a catalyst according to a mass ratio of 2.5: 0.06 of the catalyst is uniformly mixed and is subjected to ball pressing treatment to obtain pulverized coal particles with the diameter of 10-50 mm, and 84 percent K is adopted as the catalyst2CO3-14.5%FeCl3-1.5%BaCl2(ii) a Adding pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction, so that the pulverized coal particles and the steam are mixed according to the weight ratio of 2.5 kg: 1kg of the mixture ratio is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2A mixed gas of S, etc.).
The high-temperature crude reducing gas discharged from the heat accumulating type pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and acidic water at the bottom of the washing tower enters catalyst recovery equipment to recover a catalyst; the reducing gas (temperature about 40 ℃, pressure 22KPa (G)) washed at the top of the washing tower enters the bottom of the desulfurizing tower and is in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 92%, a hydrogen and carbon monoxide content of 90% and a hydrogen to carbon monoxide ratio of 3.6: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 91%.
Example 3
Referring to fig. 5, the method and system for preparing reducing gas for a shaft furnace by catalytic coal gasification for preparing the reducing gas required for sponge iron production comprises the following steps: mixing pulverized coal and a catalyst according to a mass ratio of 2.5: 0.06 of the catalyst is uniformly mixed and is subjected to ball pressing treatment to obtain pulverized coal particles with the diameter of 10-50 mm, and 84 percent K is adopted as the catalyst2CO3-15%FeCl3(ii) a Adding pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction, so that the pulverized coal particles and the steam are mixed according to the weight ratio of 2.5 kg: 1kg of the mixture ratio is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2A mixed gas of S, etc.).
The high-temperature crude reducing gas discharged from the heat accumulating type pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and acidic water at the bottom of the washing tower enters catalyst recovery equipment to recover a catalyst; the reducing gas (temperature about 40 ℃, pressure 22KPa (G)) washed at the top of the washing tower enters the bottom of the desulfurizing tower and is in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 87%, a hydrogen to carbon monoxide content of 86% and a hydrogen to carbon monoxide ratio of 2.7: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 88%.
Example 4
Referring to fig. 5, the method and system for preparing reducing gas for a shaft furnace by catalytic coal gasification for preparing the reducing gas required for sponge iron production comprises the following steps: mixing pulverized coal and a catalyst according to a mass ratio of 2.5: 0.08, uniformly mixing and performing ball pressing treatment to obtain pulverized coal particles with the diameter of 10-50 mm, wherein 84% K is adopted as a catalyst2CO3-14.5%FeCl3-1.5%Ca(Ac)2(ii) a Adding pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction, so that the pulverized coal particles and the steam are mixed according to the weight ratio of 2.5 kg: 1kg of the mixture ratio is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2A mixed gas of S, etc.).
The high-temperature crude reducing gas discharged from the heat accumulating type pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and acidic water at the bottom of the washing tower enters catalyst recovery equipment to recover a catalyst; the reducing gas (temperature about 40 ℃, pressure 22KPa (G)) washed at the top of the washing tower enters the bottom of the desulfurizing tower and is in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 93%, a hydrogen and carbon monoxide content of 91% and a hydrogen to carbon monoxide ratio of 3.4: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 92%.
Example 5
Referring to fig. 5, the method and system for preparing reducing gas for a shaft furnace by catalytic coal gasification for preparing the reducing gas required for sponge iron production comprises the following steps: mixing pulverized coal and a catalyst according to a mass ratio of 2.5: 0.06 of the catalyst is uniformly mixed and is subjected to ball pressing treatment to obtain pulverized coal particles with the diameter of 10-50 mm, and 84 percent K is adopted as the catalyst2CO3-14.5%FeCl3-1.5%Ca(Ac)2(ii) a Adding pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction, so that the pulverized coal particles and the steam are mixed according to the weight ratio of 2.5 Kg: 1.5kg of the mixture ratio is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2Mixed gas of S and the like)。
The high-temperature crude reducing gas discharged from the heat accumulating type pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and acidic water at the bottom of the washing tower enters catalyst recovery equipment to recover a catalyst; the reducing gas (temperature about 40 ℃, pressure 22KPa (G)) washed at the top of the washing tower enters the bottom of the desulfurizing tower and is in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 93%, a hydrogen and carbon monoxide content of 92% and a hydrogen to carbon monoxide ratio of 3.9: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 92%.
Comparative example 1
Referring to FIG. 5, performing ball pressing treatment on pulverized coal to obtain pulverized coal particles with diameters of 10-50 mm; adding the pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction (without using a catalyst), so that the pulverized coal particles and the steam are mixed according to the weight ratio of 2.5 kg: 1kg of the mixture ratio is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2A mixed gas of S, etc.).
The high-temperature crude reducing gas discharged from the heat accumulating type pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and acidic water at the bottom of the washing tower enters catalyst recovery equipment to recover a catalyst; top of washing towerThe washed reducing gas (the temperature is about 40 ℃, the pressure is 22KPa (G)) enters the bottom of the desulfurizing tower to be in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 73%, a hydrogen and carbon monoxide content of 75% and a hydrogen to carbon monoxide ratio of 2.1: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 78%.
Comparative example 2
Referring to fig. 5, the method and system for preparing reducing gas for a shaft furnace by catalytic coal gasification for preparing the reducing gas required for sponge iron production comprises the following steps: mixing pulverized coal and a catalyst according to a mass ratio of 2.5: 0.01 (a small amount of catalyst) is uniformly mixed and is subjected to ball pressing treatment to obtain pulverized coal particles with the diameter of 10-50 mm, and 84% K is adopted as the catalyst2CO3-14.5%FeCl3-1.5%Ca(Ac)2(ii) a Adding pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction, so that the pulverized coal particles and the steam are mixed according to the weight ratio of 2.5 kg: 1kg of the mixture ratio is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2A mixed gas of S, etc.).
The high-temperature crude reducing gas discharged from the heat accumulating type pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and acid water at the bottom of the washing tower enters a catalyst recovery devicePreparing and recovering a catalyst; the reducing gas (temperature about 40 ℃, pressure 22KPa (G)) washed at the top of the washing tower enters the bottom of the desulfurizing tower and is in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 80%, a hydrogen and carbon monoxide content of 79% and a hydrogen to carbon monoxide ratio of 2.5: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 82%.
Comparative example 3
Referring to fig. 5, the method and system for preparing reducing gas for a shaft furnace by catalytic coal gasification for preparing the reducing gas required for sponge iron production comprises the following steps: mixing pulverized coal and a catalyst according to a mass ratio of 2.5: 0.06 of the catalyst is uniformly mixed and is subjected to ball pressing treatment to obtain pulverized coal particles with the diameter of 10-50 mm, and 84 percent K is adopted as the catalyst2CO3-14.5%FeCl3-1.5%Ca(Ac)2(ii) a Adding pulverized coal particles into a regenerative pyrolysis furnace, and introducing steam to perform catalytic gasification reaction, so that the pulverized coal particles and the steam are mixed according to the weight ratio of 1 kg: 1kg (large amount) of the mixture is reacted in a regenerative pyrolysis furnace. The reaction temperature is controlled to be 650-800 ℃, and the pressure is about 22KPa, and the raw reducing gas (CH) is generated by the reaction in a regenerative pyrolysis furnace4、CO2、CO、H2And a small amount of H2A mixed gas of S, etc.).
The high-temperature crude reducing gas discharged from the heat accumulating type pyrolysis furnace enters a washing tower after waste heat is recovered by a waste heat boiler, and the acidity of the bottom of the washing towerWater enters catalyst recovery equipment to recover the catalyst; the reducing gas (temperature about 40 ℃, pressure 22KPa (G)) washed at the top of the washing tower enters the bottom of the desulfurizing tower and is in countercurrent contact with MDEA (N-methyldiethanolamine) solution from top to bottom in the tower to absorb most of H2And (4) S gas. Reducing gas (pressure about 0.02MPa (G)) from the desulfurizing tower, H2S content less than 5ppm) is fed into a tower top cooler, reducing gas heated by absorption is cooled to about 40 ℃ for gas-liquid separation, MDEA absorption liquid is recovered, and the reducing gas is sent into a compressor for pressure increase after being cooled and separated from the gas-liquid. After the pressure of the reducing gas is increased by a compressor (the pressure of the reducing gas is about 1.0MPa (G) and the temperature is about 40 ℃), the reducing gas enters a decarbonizing tower to remove carbon dioxide to obtain refined reducing gas.
The gas product was analyzed by gas chromatography for components with a carbon conversion of 95%, a hydrogen and carbon monoxide content of 91% and a hydrogen to carbon monoxide ratio of 4.3: 1. And cooling the refined reducing gas, separating gas from liquid, heating the refined reducing gas in a tubular furnace to about 900 ℃, and then making iron in a vertical furnace, wherein the metallization rate is 90%.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.