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Gasification is among the most prominent thermochemical technologies for converting biomass into renewable fuels and chemicals. Raw syngas from biomass gasification contains several contaminates that must be removed before further processing or utilization. The objective of this research is to develop a process development unit suitable for integrated studies of gas cleaning, including removal of tars, hydrogen chloride (HCl), ammonia (NH3), and hydrogen sulfide (H2S). The approach to this project eliminates costly and hazardous waste streams that are sometimes associated with conventional gas stream clean-up. The tars and particulates are removed with heavy gas oil, which can then serve as additional feedstock in industrial refineries. Hydrogen sulfide is removed using hot fixed-bed adsorption. Water scrubbing is used to remove remaining NH3 and HCl. A final guard bed ensures residual contaminants reach target levels of 0.01g/m3 tar, 20 ppb sulfur, 2 ppb chlorine, 1 ppm ammonia and undetectable particulate matter. The process development unit constructed at Iowa State University employs a 20kg/h steam/oxygen gasification reactor to provide slightly pressurized (~15psig) syngas to the cleaning operations. Comprehensive on-line gas analysis is used to determine contaminant removal efficiency of individual cleanup stages.