Forced composition cycling of a novel thermally self-sustaining fluidised-bed reactor for methane reforming

Abstract

The novel coupling of methane oxidation and steam reforming via periodic composition forcing can be used to operate a thermally self-sustaining fluidised-bed reactor. The autothermal reaction was carried out over an alumina-supported Co–NiO catalyst. The catalyst exhibited synergism for the steam reforming reaction although extent of synergy decreased from 3.2 at 773 K to 1.4 at 873 K. Analysis of steady-state oxidation and steam reforming rates showed that the bifunctional catalyst would favour H 2 production in a well-mixed reactor at the lowest temperature permissible (773 K). Cycle symmetry, S OX , has to be greater than 0.3 to achieve thermal self-sustainability. However, time-average rate and H 2 yield increased with cycle frequency. Interestingly, even at the relatively low H 2 O:CH 4 molar ratio of 1, coking was practically non-existent probably due to carbon gasification via reaction with O 2 and H 2 O in the periodically-operated FBR. This investigation shows that the coupling of energetics, kinetics and reactor operation may lead to serendipity in reactor performance. Keywords Periodic operation Thermally self-sustaining Fluidised-bed reactor Methane reforming Co–NiO catalyst Syngas production