Development of High Density Circulating Fluidized Beds for Steam Gasification of Coal or Biomass

In order to increase the power generation efficiency, it is possible to use an advanced-integrated gasification combined cycle (A-IGCC) or advanced-integrated gasification fuel cell (A-IGFC) system making use of exergy recuperation technology for recycling of waste heat from gas turbine or fuel cells for steam gasification of coal and biomass. In this system, using a circulating fluidized bed (CFB) gasifier with high solid mass flux and large solid holdup to take the place of traditional fluidized bed gasifiers such as spouted bed gasifier is expected to more effectively utilize the heat energy produced by the combustion of the tar in the riser or from the waste steam for the pyrolysis and gasification of coal and biomass. In this study, a novel circulating fluidized bed (CFB) system, which composed of a downer (as a pyrolyzer), a bubbling fluidized bed ( as a gasifier), and a riser ( as a combustor), was set up and the fundamental characteristics were investigated. The objective is to find the optimum operation conditions and structure to realize a particle circulating with a high density and a high flux in the CFB system.