Deactivation of a CoMo Catalyst during Catalytic Hydropyrolysis of Biomass. Part 1. Product Distribution and Composition

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Deactivation of a sulfided CoMo/MgAl2O4 catalyst during fluid bed catalytic hydropyrolysis of biomass (beech wood) was studied. The stability of the catalyst was investigated by converting approximately 4.4 kg of biomass and collecting the liquid and solid products for every 1 kg fed, using the same catalyst load. The total time on stream was 16.2 h. A secondary hydrotreating reactor with a sulfided NiMo/Al2O3 catalyst was used after the fluid bed to further deoxygenate the vapors. The condensed organics and C4+ gases yield for each 1 kg fed was 22.2 ± 1 wt %, which was variations within the experimental uncertainty. The CO and CO2 yield during the experiment increased from 14.9 to 18.2 wt % daf, while the aqueous phase yield decreased from 38.0 to 35.1 wt % daf. The change in CO, CO2, and aqueous phase yields was ascribed to a decrease in hydrodeoxygenation activity of the used catalysts. The concentration of oxygen in the condensed organic phase increased from 40 to 2832 ppm, indicating that deactivatio...