钠盐对碳酸氢铵SNCR的低温增效性能OA

In response to the narrow temperature window and low denitration efficiency of the selective non-catalytic reduction(SNCR)technology at low temperatures,this paper investigates the characteristics of the ammonium bicarbonate denitration reaction and selects sodium salts as additives for denitration efficiency enhancement experiments in a tubular furnace.Based on the Chemkin-Pro software,the yield and sensitivity analysis of key free radicals are carried out,and the low-temperature enhancement mechanism of sodium carbonate and sodium acetate on the SNCR technology is explored with the experimental results.The results show that adding sodium salts at a low temperature of 750℃can improve denitration efficiency to varying degrees at different ammonia-to-nitrogen molar ratios(normalized stoichiometric ratio,NSR),and the reductant utilization reaches its peak at NSR=1.7.Adding 50 μmol/mol of Na2CO3 and CH3COONa to the reaction system at NSR of 1.7 reduces the lower limit of the denitration temperature window to 785 and 776℃,respectively,and the average low-temperature denitration rate increases from 12.5%to 42.57%and 44.25%,respectively.CH3COONa shows a more pronounced improvement in low-temperature denitration performance.Simulation analysis indicates that after adding CH3COONa,·NH2 and·OH radicals exhibit two"generation peaks,"with sodium and acetate ions jointly enhancing low-temperature SNCR efficiency.In contrast,Na2CO3 only strengthens the formation pathway of the intermediate radical NNH under the influence of sodium ions,thereby accelerating its reduction with NO;thus,its improvement on low-temperature denitration performance is less significant than that of CH3COONa.