A Novel Catalytic Process for SNG Synthesis

Akira NINOMIYA, Misuzu SATO, Toshio MURAYA, Tatsumi ISHIHARA and Yusaku TAKITA*

Department of Applied Chemistry, Faculty of Engineering, Oita University;
Dannoharu, Oita-shi 870-1192 Japan
Department of Industrial Chemistry, Faculty of Engineering, Nippon Bunri University;
Ichiki, Oita-shi 870-0316 Japan

Methane rich city gas has been synthesized by means of steam reforming of naphtha; however, the produced gas always contains significant concentration of CO and CO2. Therefore, development of a methane production process containing no CO and CO2 removal processes is strongly requested.
Authors reported in the previous paper that C3H8→2CH4+C(1) took place over Ni/SiO2 with 90% selectivity. In this paper, the catalyst supports were studied and found that neutral SiO2 and α-Al2O3 are suitable but the activity was much reduced over Ni supported on acidic SiO2-Al2O3. Catalyst was diluted by various materials to avoid blocking-up by the deposited carbon. Several diluted materials affected the conversion. α-Al2O3 and basic MgO accelerated the reaction which may be due to interaction between Ni and dilution materials with direct contact. Over Ni/SiO2, reaction (1) took place with 90% selectivity, so that the produced gas always contained H2 formed by the C3H8→3C+4H2(2). It has confirmed that H2 in a high concentration of CH4 can be reacted with C3H8 to produce CH4. From these results, a following simple synthesis process can be constituted; the first step is CH4, H2, and solid C formation from C3H8, and the second step is succeeding H2 consumption process of the produced gas in the first step.

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