Olivine, dolomite and ceramic filters in one vessel to produce clean gas from biomass

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 8600mg/Nm³ 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 57mg/Nm³ of dry producct gas, with a decrease of more than two orders of magnitude.

Keywords: Fluidized bed gasifier; Freeboard catalyst; Hot gas cleaning; Plant intensification; Waste biomass gasification.