Biomass gasification at CRIBE: overview of the experimental activities

Within the last two years CRIBE (Centro di Ricerca Inter-universitario Biomasse da Energia) has carried out experimental works related to biomass gasification. The main core of the activities is a pilot scale downdraft gasifier which is used as a demo facility for testing biomass feedstock and evaluating the performance of the process. This paper resumes the experimental campaigns carried out so far using air as gasifying agent. The first set of tests involved the use of pelletized biomass such as wood sawdust and sunflower pressing cake. The aim was to evaluate the suitability of these materials for this process, since the low moisture content and the homogeneous size distribution make pelletized biomass an attractive feedstock. Despite a fairly good woodgas composition, the experimental tests showed a significant de-rating of the plant throughput and difficult control of the gasifier operation due to very high pressure drops trough the gasifier bed. Ancillary investigations involved the characterization of the gasification solid residues, to point out how to deal with these materials. A further experimental campaign has involved vine clippings as raw feedstock. In this case the experimental set-up was enhanced by measuring the thermal profile inside the gasifier throat and continuously evaluating the gas composition with a FTIR analyzer. The use of the FTIR analyzer allowed for some deeper observation about the gasification process dynamics, such as relationship between the evolutions of different gas species.