Research On Coupling Reaction Of Coke Gasification And Iron Ore Reduction Under The Condition Of Rich Hydrogen

In order to reduce the emission of greenhouse gases such as CO₂,Japan's COURSE50 and other new blast furnaces technologies which is like high oxygen enrichment and mixing natural gas or waste plastics have emerged one after another.This type of new blast furnace emission reduction technology uses hydrogen-rich fuel to replace some of the coke and pulverized coal to achieve CO₂ emission reduction in the blast furnace ironmaking process.However,these new technologies have greatly increased the H₂ content in the gas of lower part of the shaft.While accelerating the reduction of iron ore,there is a large amount of water vapor in the gas in the lower part of the furnace body above the furnace waist?1000-1300°C?,which aggravates the loss of coke.At the same time,the dissolving reaction of H₂O and CO₂ with coke produces H₂ and CO,and then H₂ and CO react with iron ore to produce H₂O and CO₂ again.These lead to the coupling reaction of coke loss and iron ore reduction under the condition of hydrogen rich.In order to make a more comprehensive analysis of the coupling reaction between the coke loss and the iron ore reduction under the condition of hydrogen rich with ore and coke mixing,the coupling reaction of ore and coke was studied through the high-temperature gas solid reaction device in different reaction temperature,reaction atmosphere,the ratio of ore to coke.At the same time,it provides a basis for selecting the suitable high temperature metallurgical properties of ore,such as reducibility and droplet performance,for the new process of hydrogen enriched blast furnace.Iron ore with different pre-reduction degrees was used as the research object of the droplet performance,and the influence of pre-reduction degree on the droplet performance of iron ore including softening start temperature T_A,softening ending temperature T_S,dripping temperature T_M,maximum pressure difference?P_Max,softening temperature interval?T_SA and reflow temperature interval?T_MS was studied.The conclusions are as follows:?1?The reaction temperature has great influence on the coupling reaction.When the atmosphere is the lower part of the traditional blast furnace for N₂:H₂:CO:CO₂=50:5:35:10 and the ratio of ore to coke is 4.0,the reaction temperature increases from 900?to 1200?,and the coke dissolution rate is increased from 1%to32.5%.The effect on the reduction degree of sinters for 180 min is phased.The temperature is increased from 900?to 1100?,the reduction degree is increased from50.47%to 55.93%.And the temperature is increased from 1100?to 1200?,and the reduction degree is reduced to 50.06%.?2?The influence on the coupling reaction of ore to coke ratio is relatively weak.When the atmosphere is under the atmosphere of the lower part of the traditional blast furnace for N₂:H₂:CO:CO₂=50:5:35:10,the reaction temperature is 1200?and the ratio of ore to coke increases from 4.0 to 5.5,the coke dissolution rate increases from32.5%to 36.33%,and the reduction degree of the sinter is reduced from 50.06%to47.39%.?3?Compared with the atmosphere of the lower part of the traditional blast furnace for N₂:H₂:CO:CO₂=50:5:35:10,the coke dissolution reaction is more intense and the reduction degree of sinter for 180min is higher in the new oxygen-enriched blast furnace atmosphere for H₂:CO:CO₂=25:60:15.When the reaction temperature is 1200?and the ratio of ore to coke is 4.0,compared with the atmosphere of the lower part of the traditional blast furnace,the coke dissolution rate increased from 32.50%to 48.92%,and the reduction degree of the sinter increased from 51.89%to 84.55%in the atmosphere of the new oxygen-enriched blast furnace atmosphere.?4?When the iron ore pre-reduction degree is 60%-70%,the main mineral component is FeO and other low melting point compounds,such as 2FeO·Si0₂?melting point 1217 C?and CaO_x?FeO?₂-x·Si0₂?X=0.19,melting point 1150?.At this point,iron softening start temperature and softening ending temperature of ore become lower,softening temperature interval widens,the dropping temperature decreases,reflow temperature interval widens,and the maximum pressure difference becomes smaller.