Valorizing argan residues into biofuels and chemicals through slow pyrolysis

Abstract

Today's world needs bioresource-derived substitutes for petroleum, chemicals, and fuels. Bio-oil, primarily produced from biomass pyrolysis, is one alternative. However, residues from the production process of the well-known argan oil have not been thoroughly investigated for their potential in pyrolysis. Energy and chemical valorization could improve their commercial value and contribute to regional environmental and socio-economic development. In the present work, the ultimate and proximate analyses of argan nut shells (ANS), argan pulps (AP), and argan press cakes (APC) were first conducted. Then, pyrolysis experiments were performed in a fixed-bed reactor, and the produced bio-oils were characterized using GC-MS analysis. The obtained bio-oil yields are 28, 25, and 19 wt% from ANS, APC, and AP, respectively. ANS bio-oil contains valuable chemicals mainly used in the pharmaceutical, food, and chemical industries. APC-derived bio-oil can produce pollutants during combustion as it contains highly nitrogenated compounds. Thus, it cannot be used directly as biofuel, but it can also be exploited for valuable chemical production. The AP organic bio-oil contains the highest quantity of hydrocarbons and has a HHV value estimated to 37 MJ kg−1. Hence, it has high potential to be used as biofuel for bioenergy generation purposes.