在 Mn- Na2 WO4 / Si O2 催化剂上 ,考察了水蒸汽对乙烷氧化脱氢制乙烯反应的影响 ,结果表明加入适量水蒸汽对提高乙烯选择性有利 .在催化剂装量 10 m L,V( C2 H6)∶ V( O2 )∶V( H2 O) =1∶ 0 .65∶ 3.8,GHSV=160 0 h-1,74 0℃时 ,乙烯收率仍可以稳定在 52 %以上 .过多加入水蒸汽将使催化剂活性很快下降 ,反应后的催化剂经 XRD及 XPS表征表明 ,不仅单层 Na2 WO4有流失 ,而且载体发生相变 ,导致 Mn2 O3流失 . The effect of steam on the ethylene oxidation by ethane dehydrogenation was investigated on Mn-Na2 WO4 / Si O2 catalyst. The results showed that adding appropriate amount of steam could improve ethylene selectivity. When the catalyst loading was 10 m L, V ( C2H6): V (O2): V (H2 O) = 1: 0.65: 3.8, GHSV = 160 h-1,74 ℃, the yield of ethylene can still be stabilized at over 52% Water vapor will make the catalyst activity decreased rapidly, the catalyst after XRD and XPS characterization showed that not only the loss of a single layer of Na2 WO4, and the carrier phase transition, resulting in the loss of Mn2 O3.