Hydrothermal Liquefaction of Animal By-Products Using a Chromium-Loaded Hβ Zeolite Catalyst

Hydrothermal liquefaction (HTL) is an environmentally friendly technology for converting wet biomass into biocrude, and animal by-products (ABP) are an efficient source of biofuel for recycling and disposal. The hydrothermal liquefaction process directly utilizes ABP biomass in the wet state. Hydrothermal liquefaction experiments of ABP biomass were performed using a high-pressure batch reactor in the presence of a chromium-modified zeolite Hβ catalyst. In this study, the catalyst samples were characterized before and after regeneration, and it was noted that adding chromium increased the peak intensity of the Hβ zeolite and decreased its surface area and pore size. All samples contained a homogeneous spherical crystallinity and a very narrow particle size dispersion to produce the optimum biomass-to-liquid conversion rates, and it is commonly recommended to employ it during the HTL process to upgrade the biocrude. At 250 °C, a catalyst concentration of 10%, and a residence time of 45 min, a maximum biocrude yield of 68% was achieved. To determine the chemical components present in biocrude oil and aqueous phase products through gas chromatography and mass spectrometry (GC–MS), demonstrating that increasing temperature increases the yield of free fatty acids, cyclic compounds, and amides because of protein and triglyceride interactions. The composition of the resulting biocrude differed significantly at 250 °C, and due to lipid hydrolysis, there was a noticeable quantity of glycerol in the aqueous phase.