Hydrothermal liquefaction of representative to Israel food waste model

Abstract

In this study, we examined the hydrothermal liquefaction (HTL) pathway to reduce food waste environmental impacts by converting it into bio-crude and biochar. The yield and properties of these products depend on the composition of the feedstock and process parameters. We developed a model of household food waste based on Israel national waste survey. To investigate the effects of catalysts type, we examined the influence of dolime, dolomite, phosphate and potassium carbonate on products yields and composition. Additionally, we analyzed the role of the process parameters, including solid load, residence time, catalyst concentration, and temperature, on the yield and the properties of the hydrothermal liquefaction reaction products, such as bio-crude, biochar, and aqueous phase solubles. The experimental results show absolute bio-crude yield ranging from 6.61w% to 29.36w% and biochar yield ranging from 12.29w% to 40.73w% from the initial waste. Furthermore, 13.78w% to 33.98w% of the feed material was found in the aqueous phases and 6.15w% to 8.94w% was measured in the gas phase. The addition of catalysts positively influenced the bio-crude yield. A process temperature of 280 °C improved the energy recovery and increased product yield, resulting in a reduction in the oxygen content of the bio-crude. All bio-crudes showed undetectable sulfur levels and exhibited HHVs ranging from 30.24 MJ/kg to 37.94 MJ/kg, while biochar had HHVs of 31.29 MJ/kg to 31.84 MJ/kg. On the Israel national level, the bio-crude derived from food waste demonstrates the potential to meet up to 31.4 % of Israel's marine fuel demand assuming bio-crude yield of 29 %, as achieved in this study.