Analysis and optimisation of a novel ‘almond-refinery’ concept: Simultaneous production of biofuels and value-added chemicals by hydrothermal treatment of almond hulls

For the first time, this work investigates achievability of developing a biorefinery concept around almond hulls by hydrothermal treatment (HTT), thoroughly scrutinising influence temperature (200–300 °C), pressure (100–180 bar), time (20–180 min) and solid loading (5–25 wt%). This process allowed conversion into four main products: gas (2–13%), bio-oil (2–12%), aqueous (4–69%) hydro-char (17–89%). The consisted mix H 2 , CO CH 4 with LHV fluctuating from 1 to 13 MJ/m 3 STP. comprised mixture alkanes, aldehydes, ketones, phenols, furans, benzenes nitrogen compounds HHV between 21 31 MJ/kg. product resembled an energetic material (HHV 21–31 MJ/kg), while effluent value-added chemicals, including saccharides small oxygenated compounds. production biofuels can be maximised at 256 °C 100 bar, using 5 wt% for 157 min, conditions which 43% original feedstock converted elevated energy-filled (11% yield, 30 along high (32% 29 MJ/kg). Regarding up 10% proportion (45%) phenolic species 250 144 bar 167 min. In comparison, sugar-rich (81 C-wt%) solution produced in yield (54%), treating 24 suspension 252 180 153 Therefore, versatility, novelty intrinsic green holistic nature ‘almond-refinery’ exemplify landmark achievement future energy chemicals biomass, might help render complete bio-refinery more cost-effectively ecologically feasible. • Environmentally friendly developed Production high-energy (bio-oil hydro-char) solutions Detailed effect conditions: temperature, pressure, Optimum bio-fuels production: °C, solid, min sugars