Catalytic pyrolysis of biomass for transportation fuels

Application of heterogeneous catalysis in biomass pyrolysis seems to be one of the most promising methods to improve bio-oil quality by minimizing its undesirable properties (high viscosity, corrosivity, instability, etc.) and producing renewable crude (bio-crude). This bio-crude could finally lead to transportation fuels using existing refinery processes (such as hydrotreating). A plethora of catalytic materials have been investigated in the literature as catalysts for the biomass catalytic pyrolysis process. Among them, microporous (zeolitic) or mesoporous (Al-MCM-41) acid materials have been tested, either promoted or not with several transition metals. Lately, basic materials are also suggested. For this process, a circulating fluid bed reactor seems to be the most effective technology, since it offers continuous catalyst regeneration. The research till today shows that catalysts based on ZSM- are the most promising. With these catalysts, bio-oil yield up to about 30 wt% (on dry biomass) with about 21 wt% oxygen can be produced. However, tailoring of catalyst properties such as acidity/basicity and porosity characteristics is still needed to develop an optimized catalyst.