Catalytic deoxygenation of palm oil and its residue in green diesel production: A current technological review

Worldwide consumption of energy produced from fossil fuels is forecasted to grow. This trend leads to both environmental pollution and the depletion of fossil fuel resources. Green diesel is a suitable candidate to substitute petroleum based-diesel due to its plentiful raw materials, non-polluting production process, and cost-effectiveness. Green diesel production is seen as simple, efficient, and relatively clean process. Deoxygenation (DO) is crowned as the best available technology to produce green diesel from palm fatty acid distillate (a side product of palm oil production) and other oils using heterogeneous catalysts such as zeolites. The capability of catalysts can be improved by optimizing operating parameters, treating and modifying catalysts and with the use of nano-sized catalytic materials. These activities contribute to stronger and more active Bronsted-Lewis acid-base sites and enlarged crystallite sizes, which improve the DO efficiency, selectivity, and reusability, to produce high-grade green diesel with less oxygen content.