改性分子筛净化气相中的HCN

Removal of HCN by Modified Molecular Sieve in the Gas Phase

以浸渍法制备催化氧化HCN所需催化剂,分别以Ce3+〔Ce(NO3)3〕、Fe3+〔Fe(NO3)3〕、Cu2+〔Cu(NO3)2〕、La2+〔La(NO3)2〕为活性组分,以Hβ、HY、5A、ZSM5分子筛作为载体,进行催化剂的优选.以恒温管式反应器作为反应装置,在250℃以下,考察空速、反应温度、φ(O2)对HCN催化氧化过程的影响以及NOx的生成率.结果表明:以0.1 molL Cu(NO3)2溶液浸渍Hβ分子筛,于300℃焙烧所得催化剂CuHβ,在HCN催化氧化过程中具有良好的性能.在空速低于6 000 h-1、反应温度高于100℃时,CuHβ催化剂对HCN的去除率高于95%;反应温度高于200℃时,HCN去除率接近100%.在φ(O2)由1%增至5%时,HCN去除率高于95%;反应温度低于200℃且φ(O2)小于3%时,NOx生成率低于5%.表明铜基改性分子筛催化氧化脱除气相HCN方法所需反应温度低于200℃,受φ(O2)影响小,具有节能、二次污染小的特点.

The catalysts used for catalytic oxidation HCN were prepared by the impregnation method. To optimize the catalyst,Ce3 ＋（ Ce（ NO3）3）,Fe3 ＋（ Fe（ NO3）3）,Cu2 ＋（ Cu（ NO3）2） and La2 ＋（ La（ NO3）2）,were used as active components,while molecular sieves including Hβ,HY,5A and ZSM5 were used as the carrier. The reaction device was a tubular reactor with constant temperature,and effects of space velocity,reaction temperature and O2 concentration during the HCN catalytic oxidation process were investigated. The formation rate of NOxwas calculated under 250 ℃. The results suggested that Hβ zeolite impregnated with 0. 1 molL Cu（ NO3）2solution and calcinated at 300 ℃ performed well in HCN removal experiments. When the space velocity was under 6000 h- 1,the conversion rate of HCN was over 95% above 100 ℃,and the conversion rate reached 100% above 200 ℃. The conversion rate of HCN was higher than95% when φ（ O2） ranged from 1%-5%. The formation rates of NOxwere less than 5% when the reaction temperature was under 200 ℃and φ（ O2） was below 3%. The HCN removal method discussed in the present study showed its advantages such as high conversion under200 ℃,less effect of O2,low NOxformation rate less than 5%,energy saving and little secondary pollution.