Abstract
The catalytic performance of dolomite for the steam reforming of a raw bio-oil/bio-ethanol mixture (80/20 mass ratio) was studied in the 400-700 °C range. Blank runs (without dolomite) under the same operating conditions were also performed in order to differentiate the catalytic performance of dolomite from the thermal effect. Below 500 °C, dolomite mainly promotes inter-conversion reactions between the bio-oil oxygenates, contributing to a noticeable increase in the amount of ketones and phenols, whereas the ethanol conversion is low, once dolomite is saturated with CO2, and a H2 yield below 10 % is obtained. Above 600 °C, dolomite is active for reforming reactions of ethanol and bio-oil oxygenates, and almost steady values of ethanol conversion (100 %), bio-oil conversion (~83 %) and H2 yield (~45 %) are obtained at 700 °C throughout 4 h. Cracking reactions of oxygenates are enhanced with the increase in temperature, which involves the formation of gaseous by-products (mainly CH4, with lower amounts of CO and hydrocarbons). The CO2 capture at 600 °C shifts the WGS and reforming reactions, providing high ethanol and bio-oil conversion (100 % and 90 %, respectively) and H2 yield (40 %) at zero time on stream, but these reaction indices rapidly decrease when dolomite is saturated.
