Study On Fine Desulfurization Technology Of Blast Furnace Gas

Blast furnace gas is the largest combustible gas by-product of iron and steel enterprises,and its existing purification process cannot meet the requirements of ultra-low emission limit.Implementing blast furnace gas fine desulfurization has become the first choice and urgent work to solve this problem.But blast furnace gas sulfide is dominated by organic sulfur,of which carbonyl sulfide(COS)is the main component,accounting for about 70%,and the gas contains more impurities.At present,there is no mature application technology of fine desulfurization at home and abroad.In this paper,starting from two aspects of wet and dry COS removal,an electrochemical cooperative wet absorption desulfurization method is proposed,and a hydrolysis catalyst is developed to lay a scientific foundation for industrial applications.The main results are as follows:(1)Obtained the efficiency law and working condition parameters of electrochemical cooperative wet absorption desulfurization.Take 15%Na2CO3+15%EDTA+EDTA-2Na mixed solution as the absorbing liquid(nEDTA:nEDTA-2Na=1:1),under the electrochemical synergy,the contact time is 160s,the working voltage is 3V,and the current density is 2.50A/mm2,the gas flow rate is 0.0025m/s,and the absorption liquid temperature is 30℃,the COS removal efficiency is increased from 78.28%to 89.81%,an increase of 11.53%.(2)Using FT-IR and acid-base titration methods to explore the reaction process of electrochemical cooperative wet absorption desulfurization.Under the catalysis of the compound solution,COS is hydrolyzed and catalyzed to produce HS-and HCO3-,and in this process,the reaction order of COS is 1.(3)The Al2O3-based modified bimetallic hydrolysis catalyst was developed by the equal volume impregnation method,and its activity was evaluated and the optimal ratio components were selected as follows:the mass fractions of ZnO,MnO,and CoO are 10%,20%,5%.Compared with the Al2O3 hydrolysis catalyst,the modified bimetallic hydrolysis catalyst has an increase of 11.31%in the removal efficiency of COS.(4)The reaction mechanism of the modified bimetallic hydrolysis catalyst is analyzed.XRD,BET,FT-IR and other characterization methods indicate that COS diffuses to the surface of the catalyst,and hydrolyzes inside the catalyst to generate H2S,and H2S is further oxidized to form metal salt compounds attached to the surface of the catalyst.(5)The optimal working conditions for the use of the modified bimetallic hydrolysis catalyst are clarified.The results show that the reaction temperature is 90℃,the space velocity is 1000h-1,the reaction humidity is 32%,the CO concentration is 10%,the CO2 concentration is 4%,and the COS inlet concentration is 240mg/m3.At this time,the COS hydrolysis efficiency reached 99.75%.