CoMoK／γ－Al_2O_3水煤气变换催化剂的硫化及反硫化

Sulfurization and Desulfurization of Water Gas Shift Catalyst CoMOK/Al2O3

以Ｈ＿２Ｓ和ＣＳ＿２作硫化剂，用ＴＰＳ和ＴＰＤＳ方法研究了水媒气变换催化剂ＣｏＭｏＫ／γ－Ａｌ＿２Ｏ＿３的硫化及反硫化过程。用Ｈ＿２Ｓ／Ｈ＿２硫化时，只发现Ｈ＿２Ｓ的消耗和Ｈ＿２Ｏ的生成，用ＣＳ＿２／Ｈ＿２硫化时，首先生成ＣＯ＿２，然后是ＣＨ＿４，Ｈ＿２Ｏ和Ｈ＿２Ｓ，ＴＰＧ实验表明催化剂表面上有积炭，造成催化剂的活性降低。但积炭在水煤气变换反应进行中逐渐除去。ＴＰＤＳ实验表明Ｎ＿２不起反硫化作用，Ｈ＿２和ＣＯ也没有明显反硫化作用，Ｈ＿２Ｏ对ＣｏＭｏＫ／γ－Ａｌ＿２Ｏ＿３催化剂有根强的反硫化作用。Ｏ＿２能使催化剂部分永久性失活。ＸＰＳ测试表明反硫化的催化剂中低价的Ｍｏ￣（４＋）转变成高价的Ｍｏ￣（５＋）和Ｍｏ￣（６＋），导致其活性下降。

The sulfurization and desulfurization of water gas shift catalyst CoMoK/Al2O3have been investigated by TPS and TPDS techniques, using H_2S and CS_2 as sulfurizingagents. Only H_2S consumption and H_2O formation were found when the catalyst was sulfur-ized with H_2S/H_2. When CS_2/H_2 was used as sulfurizing agent,CO_2 was formed at first,then CH_4,H_2O and H_2S as shown by TPS curves. Carbon deposition on the catalyst duringthe sulfurization with CS_2/H_2 caused lowering of the catalytic activity, but the deposifed car-bon could be reduced in the run of WGS reaction. The results of TPDS indicated that N_2 doesnot act in desulfurization and H_2 or CO also does not give an obvious effect on the desulfur-ization. However,H_2O shows a strong desulfurizing effect. Oxygen caused a permanent lossof the activity in some part of the catalyst. XPS results showed that Mo￣(4+)has been changedto Mo￣(5+)and Mo￣(6+)in desulfurized catalyst,decreasing its activity.