Effects of MgO and CaO on properties of Ni/γ-Al2O3 catalyst for the reforming of methane and steam
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摘要: 采用固定床装置，考察了以共浸方式引入的助剂MgO、CaO对Ni/γ-Al2O3催化剂在甲烷水蒸气催化重整中的催化反应性能的影响。结果表明，在H2O/CH4/N2的摩尔比为2.86/1/3.28，GHSV为1800h－1，反应温度为700℃下，催化剂Ni-CaO/Al2O3催化性能最好；反应初期甲烷转化率可达到96.95%、CO选择性可达68.93%、H2收率可达73.58%。XRD和H2-TPR结果表明，CaO的存在使催化剂中的活性NiO组分增多，还原性和分散性能较好。利用热分析技术对积炭进行考察发现反应10h后的Ni-CaO/Al2O3催化剂上并未出现导致催化剂失活的炭物种。Abstract: Three Ni-based catalysts with or without MgO or CaO promoters were prepared by co-impregnation method and their properties for methane steam reforming to syngas were studied in a fixedbed reactor. Results showed that CaO promoter on Ni-based catalyst had the best performance with 96.95% methane conversion, 68.93% CO selectivity and 73.58% H2 yield at the condition of n(H2O)/n(CH4)/n(N2)=2.86/1/3.28 with a GHSV 1800h－1 at 700℃. Results from XRD and H2-TPR experiments showed that the addition of CaO enhanced the active component NiO, and had the best reducibility and dispersibility. The type of carbonaceous species Cγ, which may cause catalyst deactivation, wasn't found on the Ni-CaO/Al2O3 catalyst after 10h reaction by using TGA techniques.
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Key words:
- methane /
- steam reforming /
- Ni-based catalyst /
- MgO /
- CaO /
- carbon deposition
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