Green diesel production from upgrading of cashew nut shell liquid

In recent years, there has been a strong global interest in developing technologies for converting renewable and low-cost raw materials into green diesel and bio-jet fuel, which are made of hydrocarbons. In this work, cashew nut shell liquid (CNSL), which is an industrial waste, was used as a feedstock to produce green diesel. Different reaction conditions during the upgrading process (deoxygenation, hydrogenation and cracking) were evaluated using palladium over activated charcoal (Pd/C) as a catalyst. The catalyst was characterized by X-ray diffraction and specific surface area analysis. The influences of the reaction parameters, such as temperature (180, 250 and 300 degrees C), time (5 and 10 h) and pressure (10, 20, 30 and 40 bar), were investigated using 10% w/w Pd/C. The composition of the products was determined using gas chromatography coupled with mass spectrometry and infrared spectroscopy. Higher pressures and temperatures led to a higher degree of deoxygenation and hydrogenation. In contrast, lower pressures or temperatures resulted in higher degrees of cracking. From the optimization experiments, a 98% yield of hydrocarbons corresponding to the diesel range was obtained under a 40 bar H-2 atmosphere at 300 degrees C, 10 h, and 500 rpm (in a batch reactor). Of these hydrocarbons, 89% were saturated alkanes, 3% were aromatic compounds and 6% were oxygenated compounds. This new and sustainable route is promising because it involves the conversion of a low-value residue into green diesel using mild experimental conditions. Biofuel production from CNSL allows the total valorization of the residues in the cashew-nut agroindustrial chain and has potential industrial applications in many countries.