Performance of direct contact bubble reactor for methane dry reforming over nickel alumina catalyst: In comparison with indirectly heated fixed bed reactor

The catalytic methane reforming with CO₂ to synthesis gas was experimentally investigated over nickel-alumina catalysts. The reforming behavior was performed in two different atmospheric reactors of direct-contact bubble reactor (DCBR) and indirectly heated fixed bed reactor (IHFBR). The reaction temperature was varied between 600 and 900 C. The methane dry reforming proceeds in DCBR containing an alkali carbonate based molten salt system and the suspended Ni-Al₂O₃ powder catalyst. The bubbly flow reactor of DCBR composed of a catalyst/molten salt ratio of 1:10. Carburized Ni-Al₂O₃ catalyst exhibited an improved catalytic activity compared to non-carburized catalyst. Nevertheless, the carburized Ni-Al₂O₃ catalyst is deteriorated by coke removal when introducing to the molten carbonate salt. The catalytic reactions of IHFBR exhibited an excellent catalytic activity, however carbon deposition rate over catalyst's surface was estimated as high as the deactivation is predicted after some period of time. The deactivation of Ni-Al2O3 catalysts can be attenuated by proposing a recycling process between DCBR and IHFBR. In addition to experimental results, a theoretical comparison, between DCBR and IHFBR, in terms of heat transfer and catalytic activity was investigated.