Hydrogen is seen as an important renewable secondary energy carrier of the future. Today, hydrogen is predominantly produced from fossil fuels. Hydrogen production from biomass via a thermochemical route can be an auspicious alternative for future decarbonized applications, which are based on renewable and carbon dioxide neutral produced hydrogen. Especially the dual fluidized bed (DFB) biomass steam gasification using wood chips as feedstock, seems to be a promising technology. It generates a wood gas with a high calorific value, of up to 12 MJ/m (3)_(N,db) and with a high hydrogen content, of about 40 mol.%_(db). Applying a water gas shift (WGS) unit could even increase the hydrogen yield.- In this thesis, the long term performance of a commercial Fe/Cr based WGS catalyst was investigated. For this purpose, a WGS pilot unit was operated for more than 2330 hours, processing a side stream of tar-rich wood gas, extracted upstream of the RME gas scrubber from the commercial DFB biomass steam gasification plant in Oberwart, Austria. Furthermore, steady partial load operations of the DFB gasification plant as well as of the WGS pilot unit were investigated. Extensive chemical analyses were carried out. CO, CO2, CH4, N2, O2, C2H6, C2H4, C2H2, H2S, COS, and C4H4S were measured. In addition, gas chromatography coupled with a mass spectrometer (GCMS) tar and ammonia analyses were performed. Furthermore, the catalyst's activity was observed by measuring the temperature profiles along the reactors of the WGS pilot unit. A technically immaculate functionality and a steady long term operation of the WGS pilot unit could be achieved. Even partial load operation at the DFB plant did not affect the performance of the WGS pilot unit in a negative way. The WGS pilot unit was operated with a significant excess of steam. At this condition of operation, a carbon monoxide conversion up to 93 % and consequently less than 1.5 mol.%_(db) carbon monoxide was obtained at the WGS pilot unit's outlet. In addition, a significant reduction of detectable GCMS tar components was achieved along the WGS pilot unit. With the present experimental layout, no catalyst deactivation could be observed.