Bagasse gasification in a 100 kWth steam-oxygen blown circulating fluidized bed gasifier with catalytic and non-catalytic upgrading of the syngas using ceramic filters

Gasification of pelletized sugar cane bagasse, the waste residue from sugar cane, was carried out using an atmospheric pressure 100 kWth steam-oxygen blown circulating fluidized bed gasifier (CFBG). The purification of the syngas produced was carried out using a high temperature filter unit which contains 3 rigid ceramic candles with an outer diameter of 60 mm and a length of 1500 mm. Keeping the gasification temperature in the range of 800°-860°C and using magnesite M85 as the bed material, the effects of operational conditions (e.g. steam to biomass ratio (SBR) and oxygen to biomass stoichiometric ratio (ER)) and of catalytic and non-catalytic filtration on the composition distribution of the product gas and tar formation were investigated. Higher temperature and SBR values were favorable for increasing the mole ratio H2 to CO and decreasing the tar compound (PAH) concentration on dry basis, measured via solid phase adsorption (SPA) sampling and subsequent GC analysis varying from approximately 2 to 6 g/mn 3. At the same operational conditions, in the downstream filter, the conversion of tar content obtained using catalytic filter candles increased by a factor of 2.8 compared to the one with non-catalytic filter elements. The specification and distribution of major ash forming elements were investigated by SEM-EDS. Experimental results showed that bagasse is an interesting fuel for syngas production via the gasification process, both from a gas composition and from a tar production point of view.