Catalytic pyrolysis of biomass:: influence of the catalyst pretreatment on gas yields

This experimental study of biomass catalytic pyrolysis at low temperatures (650 and 700 degreesC) was carried out in an installation based on the Waterloo Fast Pyrolysis Process (WFPP) technology, with a Ni/Al coprecipitated catalyst introduced into the reaction bed where the thermochemical decomposition of biomass took place. The influence of the calcination temperature (750-850 degreesC) and the activation conditions (hydrogen flow rate) of the catalyst were analyzed. The calcination temperature significantly influences the properties and performance of the catalyst. For the two reaction temperatures, 650 and 700 degreesC, and with the catalyst calcined at 850 degreesC, higher H(2) and CO yields were obtained with the reduced catalyst (flow rate 3080 cm(3) (STP)/min; WHSV=0.826 h(-1)) than without reduction. However, the catalyst calcined at 750 degreesC without reduction showed a good performance at the reaction temperature of 700 degreesC. Considering the characterization and experimental results, it can be deduced that the catalyst calcined at 750 degreesC is reduced by the reaction atmosphere forming a stable active phase, whereas for the catalyst calcined at 850 degreesC more severe reduction conditions are necessary. (C) 2001 Elsevier Science B.V. All rights reserved.