锰铈脱硝催化剂的制备及其再生性能研究

采用等体积浸渍法制备了一系列Mn-Ce-Ox复合氧化物脱硝催化剂用于NH3选择性催化还原(NH3-SCR)NO。考察了Mn/Ce摩尔比、焙烧温度、H2O和SO2对Mn-Ce-Ox复合氧化物脱硝催化剂活性的影响及催化剂中毒再生性能。结果表明:当NH3:NO=1:1,空速为5 000 h-1,550℃焙烧制得的Mn/Ce摩尔比为5∶1的Mn-Ce-Ox复合脱硝催化剂活性最佳,活性温度窗口为100~260℃,在此温度区间内催化剂活性大于90%。200℃时,Mn-Ce-Ox复合催化剂活性最高为97.84%;在10%(V/V)H2O蒸汽和300×10-6SO2共存条件下,200℃时,催化剂活性在开始反应2.5 h内迅速下降至53%左右,并在之后的6 h内没有明显变化;中毒催化剂经常温水洗再生处理、质量分数为3%的硝酸溶液再生处理和550℃焙烧2 h再生处理后200℃活性均能恢复到90%以上,其中中毒催化剂经质量分数为3%硝酸处理后活性恢复率最高。

Preparation of Mn-Ce-O_x Denitration Catalyst and Its Regeneration Performance

Mn-Ce-Ox denitration catalysts were prepared by isovolumetric impregnation method and tested for selective catalytic reduction(SCR) of NO with ammonia.Influences of different Mn/Ce molar ratio and calcinations temperature,H2O and SO2 on NO conversion of the catalyst and its regenerative performance were investigated.Results showed that the conditions of NH3:NO 1:1,space velocity 5 000 h-1,the catalyst of molar ratio of Mn/Ce 5:1 calcinated by 550 ℃ showed higher NO conversion and the activity achieved more than 90% in 100~260 ℃ and the most high activity could achieve 97.84% at 200 ℃.The activity of the catalyst was declined to 53% in 2.5h after the action and not changed evidently in the next 6h within 10%(V/V) H2O steam and 300×10-6 SO2 at 200 ℃.NO conversion of the deactivation catalyst dealt with water or 3(wt)% nitric acid and calcinated by 550 ℃ could recover more than 90% at 200 ℃,among which the activation was the best when treated by 3(wt)% nitric acid.