Olivine, dolomite and ceramic filters in one vessel to produce clean gas from biomass
Highlights: • Syngas free of particles and with very low amount of tar is produced from biomass gasification. • Combination is tested of primary catalyst in the gasifier fluidized bed with catalytic ceramic candles in its freeboard. • Remarkable process intensification and thermal integration is obtained. • The adoption of catalytic filter candles doesn’t increase the required standard filtration surface in practical applications. - Abstract: Heavy organic compounds produced during almond shells gasification in a steam and/or air atmosphere, usually called tar, are drastically reduced in the product gas by using simultaneously in one vessel a ceramic filter placed in the freeboard and a mixture of olivine and dolomite particles in the fluidized bed of the gasifier. The content of tar in the product gas during a reference gasification test with air, in presence of fresh olivine particles only, was 8600 mg/Nm{sup 3} of dry gas. By gasifying biomass with steam at the same temperature level of 820 °C in a bed of olivine and dolomite (20% by weight), and in the presence of a catalytic ceramic filter inserted in the freeboard of the fluidized bed gasifier, the level of tar was brought down to 57 mg/Nm{sup 3} of dry producct gas, with a decrease of more than two orders of magnitude.