Gasification of lignocellulosic residues at pilot scale: Evidence of the catalytic effect of its ash

The updraft gasifications of the two residues of biorefinery having different inert content were carried out at the very close operating conditions, namely at almost the same equivalence ratio of air and steam. The temperature inside the autothermal gasifier was monitored and a detailed profile was obtained. The H2/CO ratio and condensable organics produced from the two feedstock were different. The average temperatures in the reactor differed in the two cases of 89°C. Being the process carried out in authothermal mode, it was correlated the different exothermicity and with the reaction kinetics, in particular to a different degree of advancement of the water gas reaction (WGS) that in the case of high ash content feedstock was more favoured. Metals content affected also the content of organic condensable molecules in the producer gas and it was 50% higher in the case of low ash content feedstock.