Numerical Simulation Of Blast Furnace Gas Separated By Membrane Applied To Blast Furnace Pulverized Coal Injection

Blast furnace gas is a by-product of blast furnace smelting.Due to its low heating value and low utilization rate,the recycling of blast furnace gas has become a breakthrough point in reducing blast furnace energy consumption and emissions.Blast furnace pulverized coal injection is an important method used by modern blast furnaces to adjust the blast furnace condition.If blast furnace gas is screened through a gas separation membrane,a gas with a higher flammable composition is obtained,which is injected as a pulverized coal carrier gas can realize the secondary use of blast furnace gas.Numerical simulation is a commonly used method for studying the internal reaction of a blast furnace.Through numerical simulation,the secondary utilization of blast furnace gas can be studied.In this paper,the blast furnace gas that has been separated with graphene oxide/carbon nanotube molecular sieve membrane is selected as the PCI carrier gas and carbon-based fuel.By constructing a blast furnace belly model,a mathematical model of blast furnace pulverized coal injection is established.The secondary utilization of separated blast furnace gas in blast furnace smelting was numerically simulated,and the model was verified using experimental data.The research results show that when the membrane-separated blast furnace gas is used as pulverized coal carrier gas for blast furnace injection,the gas-solid phase flow is divided into high-speed gas injection and low-speed gas recirculation,and the gas flow velocity in the furnace is significantly increased,which can provide greater blowing kinetic energy is beneficial to blow through the dead stock pile.The formed high temperature area is closer to the blast furnace center than the pulverized coal injection and ordinary blast furnace gas injection.The trajectory of the pulverized coal particles is closer to the deadman zone.The sieved blast furnace gas promotes pulverized coal combustion more significantly,the pulverized coal pyrolysis reaction is advanced,and at the same time,it can provide part of the energy consumption required for blast furnace smelting.The burnout rate of pulverized coal in the raceway shows a"double peak"phenomenon.When the screened blast furnace gas is a carrier gas,a high-temperature region closer to the center of the blast furnace is formed,and the temperature is greatly increased.The temperature reached by A pulverized coal is relatively high,and the high temperature area of C pulverized coal tends to move up the drip zone along the boundary of the deadman zone.When the screened blast furnace gas is a carrier gas,the combustion reaction starts with a blowpipe,and the high temperature generated in the blowpipe may accelerate the burn of the blowpipe.The change of gas phase component content is similar under different pulverized coal.The amount of change is affected by the type of pulverized coal.When gas is involved,this change is exacerbated.The increase of the oxygen-enriched rate increases the temperature in the blast furnace.Compared with the pulverized coal injection alone,when the blast furnace gas is used as a pulverized coal carrier gas,the oxygen-enriched rate has a smaller effect on the temperature increase.However,when the oxygen-enriched rate is increased,the O₂ content in the raceway decreases earlier,while the oxygen consumption increases,which promotes the combustion of residual carbon.At lower oxygen-enriched rates,the trend of slower growth of CO₂ content is more pronounced.This shows that the oxygen-enriched rate has less effect on the combustion of blast furnace gas after screening,and the effect on the combustion performance of pulverized coal is advanced.When the screened blast furnace gas as a pulverized coal carrier gas,the temperature increase is relatively gentle under different pulverized coal particle sizes in the raceway,and the temperature reached by the smaller pulverized coal powder is slightly higher.In the area of 0.1m from the lance tip to the front end of the raceway,the CO₂ content is higher when the coal particle size is larger,and the CO₂ content decreases with the increase of the particle size of pulverized coal.It can be seen that when the blast furnace gas separated by the membrane is injected as a pulverized coal carrier gas,it can provide part of the energy required for blast furnace smelting,promote the combustion of pulverized coal,and realize the secondary utilization of blast furnace gas.