Biocrude production from orange (Citrus reticulata) peel by hydrothermal liquefaction and process optimization

Abstract

Hydrothermal liquefaction is a promising anaerobic thermochemical process for the conversion of wet biomass into an energy dense biocrude. In this study, the suitability of orange peel for biocrude production was investigated. The study was carried out at varying temperatures (200 to 300 °C), reaction time (20 to 60 min), and total solids loading (15 to 25%). The optimum operating conditions for recovering maximum biofuel from biomass (28.4 wt%) were found to be 275 °C temperature, 40-min reaction time, and 25% total solids loading. The Box-Behnken design of response surface methodology was used to examine the effect of reaction parameters on biocrude yield and its byproducts and resulted the temperature to be the most effective followed by reaction time and total solids loading. The heating value of biocrude was 32 MJ/kg with flash point of about 93 °C. The obtained biocrude had comparable fuel properties with those of diesel and bio-diesel standards. The GC-MS and FTIR analyses proved biocrude as a complex mixture of alkanes, alkenes, aliphatic and aromatic acids, and alcohols and aqueous phase byproduct as a rich chemical source consisting of esters, alcohols, and ketones which provides a futuristic approach to drop in advanced fuels and chemicals from biocrude.