Experimental investigations of hydrogen production from CO catalytic conversion of tar rich syngas by biomass gasification

摘要

In this paper, the activity of a cobalt/molybdenum (Co/Mo) commercial catalyst for the Water Gas Shift Reaction for hydrogen production was investigated in a three fixed-bed reactor pilot plant using a tar rich synthesis gas from a full-scale biomass gasification plant as feed-stream. A parametric variation study was carried out to assess CO conversion (X-CO) and selectivity for the water gas shift reaction as a function of the operating temperature (T) in the range 300-450 degrees C. The effects of four dry gas hourly space velocities (GHSV), Case A-Case D, two steam to dry synthesis gas ratios (H2O/SG), 56% v/v and 67% v/v, and a H2S concentration in the range 100-220 ppm(v,db) were investigated: the highest CO conversion (similar to 95%) was observed in the base case (Case A GHSV) at 67% v/v H2O/SG, and 450 degrees C, the lower the operating temperature the lower the CO concentration, the lower the gas hourly space velocity the higher the CO conversion and the higher the H2O/SG the higher the CO conversion. The effect of 142S variation on CO conversion was also studied, keeping the operating temperature constant (approximate to 365 degrees C) and using the Case D GHSV: CO conversion increased as the H2S concentration increased and X-CO approximate to 40%. Selectivity was not influenced by the parameters investigated. Finally, the effect of the catalyst on tar removal was studied and a CO conversion close to 85% was found. (C) 2016 Elsevier B.V. All rights reserved.