Ceramic filter candles, partially filled with pellets of a commercial nickel-based catalyst (about 600 g) for hydrocarbons reforming, were recently tested for in-situ syngas cleaning and conditioning in the freeboard of a fluidized-bed biomass steam gasifier, with positive results (Savuto et al. 2019). To get full insight into the performance of that device, characterizing more accurately the dependence of catalytic activity on the operating conditions, a more focused approach is needed; this work describes an experimental study utilizing a laboratory-scale tubular reactor containing a small packed bed with pellets of the same catalyst (3.9 g), and involving steam reforming tests of tar key-compounds (mixtures of naphthalene and toluene, optionally with the addition of thiophene, vaporized in an inert gas stream together with steam). The experimental data were used to infer a lumped kinetic law, referred to the steam reforming of a pseudo-component representing tars. This law was implemented in a mathematical model of the annular catalytic packed bed inside the filtering candle, obtaining numerical simulations in fair agreement with gasification experiments from Savuto et al. 2019, as far as tar removal from biomass product syngas was concerned.

Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 570-576