Catalytic hydrothermal liquefaction of food waste: Influence of catalysts on bio-crude yield, asphaltenes, and pentane soluble fractions

Low quality wet waste feedstocks like food waste are cheap, abundant and have immense potential to be utilized for the production of liquid/gaseous biofuels and renewable chemicals via thermochemical processes such as hydrothermal liquefaction. The energetics, economics, and upgrading options of these processes are greatly dependent on the yield and quality of the produced bio-crude. Both of which could potentially be enhanced by using heterogeneous catalysts. This study evaluated the effectiveness of commercial Ru/Al2O3, NiMo/Al2O3, Pd/ Al2O3, Pt/Al2O3 and unsupported Fe catalysts in improving the yields and quality of bio-crude produced from food waste. Heteroatom content, HHV, and asphaltenes content were used as indicators of bio-crude quality. The results indicate that the HTL of food waste produces bio-crude yields in the range of 32-58 wt%, bio-crudes HHV's in the range of 36-40 MJ/kg, and asphaltenes content in the range of 12-27 wt% depending on the catalyst type and the operating gas.

Automated summary

This study evaluated the effectiveness of commercial catalysts in improving the yield and quality of bio-crude produced from food waste. The results show that different catalysts and operating gases have an impact on the bio-crude yield, HHV, and asphaltenes content.