Pressurized pyrolysis of dried distillers grains with solubles and canola seed press cake in a fixed-bed reactor

• Biomass waste was pyrolyzed in a fixed bed reactor at different pressures.
• Pressure had a significant effect to the product yield and compositions.
• Bio-oils had significant fatty acids and their amount was increased by pressure.
• The elemental composition of products was affected by the operation pressure.
• Surface area of chars was lower during pyrolysis under higher pressure.

Pressurized pyrolysis of biomasses was carried in a fixed bed reactor to obtain gases, bio-oils and chars at elevated temperatures. The products were characterized by GC–MS, FTIR, viscometer, SEM, BET and EDXRFS methods. Experiments were performed at 1, 5 and 10 bar pressure and 400, 500 and 600 °C temperatures. The experimental results show that in all the experimental condition the yield of bio-oil from DDGS as higher than that of canola. Yield of non-condensable gases and chars increased, while that of liquid products decreased by pressure. Increasing pressure favoured the formation of low molecular weight gas, such as H2. Maximum surface area of chars was obtained at atmospheric pressure and the surface areas decreased rapidly with increasing pressure. GC/MS results shows that the amount of fatty acids in bio-oils was increased by increasing pressure and bio-oils showed non-Newtonian behavior. Based on EDXRFS results, bio-oils and char contained lots of elements.