Toward hydrogen production from aqueous phase reforming of polyols on Pt/Al2O3 catalyst

In aqueous phase processing of bio-oil, hydrogen (H-2) is produced in three steps: extraction with water, mild hydrogenation of the aqueous fraction and reforming in the aqueous phase. Polyols are the familiar hydrogenation products of the unsaturated oxygenates present in the bio-oil aqueous fraction. In this work, we decided on studying the aqueous phase reforming of two such polyols, viz. 1,2-propanediol and 1,4-butanediol. Activity trials were performed in a fixed-bed reactor using Pt/A1203 catalyst. Reactions conditions selected for these studies were like so: temperature, 433-493 K, pressure, 0.9-2.67 MPa, polyol concentration, 5-15 wt%, and weight hourly space velocity, 0.08-0.68 1/h. A chemical control regime prevailed at these conditions. The dependency of polyol conversion and H-2 yield on the aforesaid reaction variables was studied. The turnover frequency (TOFH2) was measured and it was found that the activation energy for H-2 production from 1,2-propanediol and 1,4-butanediol was 82.7 and 70.1 kJ/mol. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.