CATALYTIC GAS CONDITIONING - APPLICATION TO BIOMASS AND WASTE GASIFICATION

Catalytic gas conditioning is a key step in producing clean syngas via gasification of heterogeneous materials. Our work has focused on the steam re-forming of naphthalene and orthodichlorobenzene as prototypes of polyaromatic hydrocarbons (PAHs) and halogenated aromatics. Subseq uently, we have studied the conversion of tar present in the syngas de rived from biomass and waste gasification. Steam re-forming of naphtha lene was initially studied over a UCI GB-98 commercial catalyst in a f ixed bed reactor operated at atmospheric pressure, in the temperature range 873-1123 K, with residence times of 0.31-0.82 s and steam to nap hthalene molar ratios of 10-22. Although the catalyst is efficient, it suffers from a progressive drop in activity due to coke formation as well as weight loss (35% weight loss after 24 h on stream). To overcom e deactivation and catalyst weight loss, a robust catalyst formulation has been developed. It has demonstrated excellent activity as well as reasonable time-on-stream and easy regeneration without significant l oss of activity. Total conversion of naphthalene and dichlorobenzene h as been observed at 1023 and 1123 K, respectively. The yields of dry g as in both cases have been higher than 90%. After 60 h on stream, the catalyst weight loss is less than 5%. This catalyst has also performed efficiently in the conversion of tar present in the producer gas from air gasification of biomass and mixed wastes.