Contaminant Estimates and Removal in Product Gas from Biomass Steam Gasification

Permanent gas species, tar compounds, sulfur compounds, and ammonia produced from a bench-scale (∼1 kg/h) fluidized-bed biomass gasifier were analyzed. Two commercial Ni-based catalysts and one commercial ZnO sorbent were evaluated under varied conditions by quantifying contaminants from the reactor inlet and outlet with specific sampling and analysis methods. The Ni catalysts targeted tar destruction and ammonia reduction, and the ZnO sorbent was selected for sulfur compound removal. Tar components were identified by gas chromatography−mass spectrometry (GC−MS) and quantified by GC−flame ionization detector (FID). A total of 13 compounds (≥C6) were identified in raw product gas, principally “lighter tar” species with an average concentration of 15.5 g m−3 (dry gas basis). For tar species that were not detected by GC, a gravimetric method was used to quantify the portion of “heavier tar” (5.3 g m−3 dry gas basis). These data are raw gas tar concentrations for the gasifier-operating conditions used for the...