Catalytic Hydroliquefaction of Spruce Wood - Elemental Balance and Effect of Catalyst -

Abstract

Catalytic hydroliquefaction of spruce wood particles (ca. 3 mm), suspended in a process derived slurry oil, has been conducted in a three 1-liter-capacity autoclave system using palladium on active charcoal in concentrations of 1 %, 0.5 % and 0.1 % (based on wood) and red mud (10 %) as a once-through catalyst. In a series of successive experiments the carrier slurry oil was separated from the net product oil (NPO) by trapping in a hot separator in order to recycle it. Decreasing Pd amounts increased viscosities of the carrier. In the presence of Pd, wood conversion rates of 95–97 % were obtained and yields of light-and middle distillate NPO decreased from 34 to 30 % when the amount of catalyst was reduced. The use of red mud gave NPO yields of 20 % and char yield increased to 37–43 %. In experiments with Pd, 4 % hydrogen and with red mud 1.7 % hydrogen (based on wood) was consumed. The NPO's were characterized by determination of asphaltene content, molecular weight distribution, elemental composition and boiling point distribution. In all experiments, the oils obtained with Pd had superior properties to those described in the literature and obtained in runs with red mud. Exemplary gas analyses were carried out to close the material balance. The distribution of carbon, hydrogen and oxygen in the liquefaction products was determined and elemental mass balances of some experiments are presented.