Preparation And Mechanism Of Fine Desulfurization Catalyst For Blast Furnace Gas

The iron smelting in China’s iron and steel industry is mainly blast furnace smelting.The by-product blast furnace gas produced in the smelting process has a serious pollution to the atmospheric environment because it contains a large amount of carbonyl sulfur(COS).In order to promote the improvement of atmospheric environmental quality,China Environmental Association has put forward the requirements for ultra-low emission in the iron and steel industry.At present,conventional desulfurization technologies are difficult to meet ultra-low emission requirements,but source treatment technology has become the object of much attention and is expected to meet ultra-low emission requirements.The key point is how to develop an efficient and durable hydrolysis catalyst.Therefore,based on the characteristics of low cost,easy polymerization and high aromatization of industrial glucose,a new way to develop high-efficiency hydrolysis catalysts with glucose as a precursor was explored to provide a theoretical basis for the research and application of COS hydrolysis catalysis in blast furnace gas.In this paper,using glucose as the raw material to prepare carbon spheres,the effects of reaction temperature and reaction time during the synthesis of carbon spheres on their morphology and chemical properties were investigated.On this basis,using carbon spheres as templates and urea as precipitants,the effects of water alcohol ratio and calcination temperature on the structural characteristics of Al2O3 hollow spheres were investigated.At the same time,the addition amount of aluminum nitrate was changed to explore the effect of γ-Al2O3 hollow sphere hydrolysis catalysts with different additions on the catalytic performance of COS hydrolysis.By loading different proportions of zirconium nitrate on the surface of the γ-Al2O3 hollow sphere hydrolysis catalyst,the effect of the formed ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst on the catalytic performance of COS hydrolysis was investigated.The optimal ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst was screened out,and its performance in removing COS at different reaction temperatures,relative humidity and reaction space velocity was explored,and the optimal ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst was determined.Use conditions.And the anti-poisoning performance and sulfur imbalance degree of ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst were analyzed and studied.The results of the study are as follows:(1)The influencing factors and mechanism of the preparation process of carbon spheres are studied.The results are:When the reaction temperature is 220℃,the proportion of carbon spheres with a particle size of about 1.35 μm can reach 75%.When the reaction time was 4 h,the proportion of carbon spheres with a particle size of about 1.31 μm could reach 78.29%.In addition,the formed carbon spheres are dispersed,uniform in size,and have no cross-linking phenomenon,which is favorable for the carbon spheres to be used as templates for subsequent application research.(2)The catalytic performance of the COS hydrolysis catalyst was studied,and the results showed that:①The Al2O3 crystal phase calcined at 950℃ was mostly γ-Al2O3 with a particle size between 100～150 nm,which was different from the composite carbon spherical phase before calcination.The particle size of Al2O3 hollow spheres is reduced by 90%.②The conversion efficiency of removing COS by the hollow sphere hydrolysis catalyst with the addition amount of 40 mmol is 68%,and the conversion amount is 120 mg/m3.The overflow rate of H2S is 42%,and the overflow amount is 80 mg/m3.③The ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst loaded with Zr and calcined at 500℃ had a conversion efficiency of 81%and a conversion rate of 148 mg/m3.The overflow rate of H2S is 55%,and the overflow amount is 104 mg/m3.④The conversion efficiency of ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst with a loading of 6%was 86.5%,and the conversion amount was 181 mg/m3.The overflow rate of H2S is 74.6%,and the overflow amount is 156 mg/m3.(3)The process conditions,anti-toxicity and sulfur imbalance degree were studied,and the results were as follows:①Under the conditions of reaction temperature of 80℃,reaction space velocity of 1000h-1 and reaction humidity of 38%,ZrO2@γ-Al2O3 hollow spheres were hydrolyzed The catalyst has a good effect on the removal of COS.②Taking dust with a concentration of 10 mg/m3 as the research object,in the presence of dust,the efficiency of ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst remained above 85%after hydrolysis and catalysis for 30min.When 0.01 mol/L HCl was blown into the low temperature reaction system,the hydrolysis catalysis efficiency of ZrO2@γ-Al2O3 hollow sphere catalyst with HCl in the first 50min also maintained above 71%.③In the sulfur balance analysis,when the hydrolysis reaction took 70min,the cumulative sulfur imbalance rate of ZrO2@γ-Al2O3 hollow sphere hydrolysis catalyst was only 11.9%compared with γ-Al2O3 hollow sphere hydrolysis catalyst,mainly because H2S was adsorbed on the surface of the catalyst.and some H2S molecules are catalytically deposited on the catalyst surface.