Performance modeling of aeroderivative steam-injected gas turbines and combined cycles fueled from fixed or fluid-bed biomass gasifiers

First-generation biomass integrated-gasifier/gas turbine (BIG/CT) technology, based on combined cycles and fluid-bed gasifiers, is likely to be commercially ready by the turn of the century, with ten or more commercially-oriented demonstration projects presently ongoing worldwide. In development and demonstration efforts to date, relatively little attention has been given to alternative cycle configurations or gasifier designs. Performance modeling is described here for steam-injected and combined cycle systems built around gas turbines resembling the GE LM2500, with fuel delivered from integrated fluid- or fixed-bed gasifiers. Some features of fixed-bed gasification appear to offer benefits, particularly for steam-injected cycles. A primary motivation for examining steam injection is expected capital cost savings compared to combined cycles, especially at total power plant capacities below 100 MW, (due to scale economies associated with steam bottoming cycles). Because of the inherently dispersed nature of biomass production, first-generation BIG/CT applications in the sub-100 MW, range will be common.