Thermal gasification of biomass: the IGT RENUGAS process

The Institute of Gas Technology's RENUGAS process is being developed for thermal gasification of biomass to produce medium-calorific value and synthesis gas, with primary support from the US Department of Energy. The process employs a single-stage pressurized, oxygen-blown, fluidized-bed gasifier. Substituting air for oxygen produces a lower calorific value gas suitable for either combined-cycle power generation or direct combustion. The process development unit constructed to develop this process consists of a 29.2 cm ID gasifier, capable of gasifying biomass under adiabatic conditions, at pressures up to 3.55 MPa, at temperatures up to 1255 K, and at biomass feed rates up to 10,150 kg/m/sup 2/-h. Tests conducted with feed rates up to 340 kg/h have shown that pressurized gasification PDU at 2.17 MPa and 1028 to 1172 K, of woody biomass is simple. Analysis of temperature variation test results show that total carbon conversion exceeds 92%, above 1090 K and it could be increased further by recycling the entrained char to the high temperature region of the gasifier. The oxygen requirement at 1090 K is about 0.22 kg/kg of (10% moisture) feed material. Pressurized gasification produces nearly two-thirds of potential methane within the gasifier. The dry gas yield ranged from 0.88more » m/sup 3//kg feed to 1.18 m/sup 3//kg feed and the gross calorific value of the fuel gas ranges from about 13.3 MJ/m/sup 3/ (st) to 10.9 MJ/m/sup 3/ (st) at 1028 and 1245 K, respectively. This medium calorific value gas could be either used on-site or distributed in pipelines for short distances for use as an industrial fuel gas. Based on the measured data the cold gas thermal efficiency varies from 74 to 76% for tests conducted at 1090 K to 1256 K.« less