Research On Removal Technology Of Carbonyl Sulfur In Blast Furnace Gas

With the implementation of the "Opinions on Promoting the Implementation of UltraLow Emissions in the Iron and Steel Industry"(Huan Daqi[2019]No.35),the desulphurization of blast furnace gas(BFG)has become an urgent problem for iron and steel enterprises.COS accounts for about 60%to 80%of sulfide in BFG,and COS is the most difficult component to remove.Therefore,a series of new absorbents were prepared and their chemical absorption performance for COS was studied.First of all,three organic strong base absorbents,DBN,DBU and TMG,were screened out,and their absorption performance for COS was studied on a dynamic absorption device,at normal pressure and at 25 ?,the COS+N2 mixture with the initial COS concentration of 420 mg/m3 was desulfurized.The sulfur removal efficiency of the three absorbents were all above 95%.After 240 minutes of continuous feeding,the sulfur concentration in the off-gas was 1.7 mg/m3,1.7 mg/m3,and 10.0 mg/m3 are all smaller than 35 mg/m3.NMR and FTIR of desulfurization products show that COS and a strong base DBN,DBU,TMG can form zwitterionic ions.Secondly,in order to solve the problem of the solid products produced by the above three strong organic bases after absorbing COS,the organic strong bases(DBN,DBU or TMG),amines(DIPA,MOR and or MDEA)and SUL were compounded to obtain 9 types of three-types compound absorption system.The absorption effect of 60 w%DBN+20 w%DIPA+20 w%SUL is the best,under normal pressure,At 35 ?,the sulfur concentration in the off-gas is 21.2 mg/m3,and the absorption effect is basically unchanged after the absorbent is recycled for 5 times.Then,this article studies[DBU][Ace],[DBU][n-Pr],[DBU][n-Bu],[DBN][Ace],[DBN][n-Pr]and[DBN][n-Bu].The absorption performance of these six ionic liquids for COS at normal pressure and at 60?,the sulfur concentration in the off-gas can be reduced from 230 mg/m3 to 38.6 mg/m3,22.7 mg/m3,13.2 mg/m3,37.5 mg/m3,8.3 mg/m3,3.5 mg/m3,respectively.The absorption of COS effect[DBU]<[DBN],[Ace]<[n-Pr]<[n-Bu].[DBN][n-Bu]has good regeneration cycle performance.Finally,foaming and corrosion experiments show that the foaming performance of 60 w%DBN+20 w%DIPA+20 w%SUL compound absorbent and[DBN][n-Bu]ionic liquid has reached h<5 cm,t<10 s industry standard;at 120?,the corrosion rates of stainless steel in these two absorbents are 0.00098 mm/a and 0.00062 mm/a,respectively,which has relatively low corrosivity.The compound absorbent and ionic liquid absorbent prepared in this article both show good absorption performance for COS,which establishes an experimental and theoretical basis for the development of new technologies for blast furnace gas desulfurization.