A Comprehensive Review on Biofuels from Oil Palm Empty Bunch (EFB): Current Status, Potential, Barriers and Way Forward

Abstract

Biomass is an important renewable energy resource which primarily contributes to heating and cooling end use sectors. It is also a promising alternative source of biofuels to replace the depleting supply of fossil fuels. Surprisingly, few writers have been able to draw on the feedstock significance for oil palm empty fruit bunch (EFB) as the biomass resource for biofuels compared to the other types of biomass waste. Therefore, this paper presents a comprehensive review of EFB as a biomass resource presented in four major parts. First, the introduction covers the demand for bio-oil and describes the different kinds of feedstock, the relevance and potential of EFB biomass. Second, the characteristics of biomass are explained before it is upgraded as biofuel, drawing similarities and contrasts between EFB and other sources of biomass. Pyrolysis processes and reactors used for EFB conversion are described, and the factors affecting the bio-oil yield and quality are discussed. Major reactor parameters are summarized and reactor optimization is discussed. Third, comparison on the properties of the bio-oil vs. petroleum in transportation, power generation, and heating are compared followed by prioritizing the bio-oil properties from the most to least critical, revealing the most promising methods for upgrading. Fourth, the environmental impact, including CO2 emission, of the use of EFB as a promising renewable energy resource and a cleaner alternative fuel is recommended. This paper has comprehensively reviewed the conversion of oil palm empty fruit bunches into biofuels, including the similarities and differences between biomasses, the best reactors, its comparison with fossil fuels, and bio-oil upgrading methods. The upgrading mapping matrix is created to present the best upgrading strategies for the optimum quality of biofuels. This paper serves as a one-stop center for EFB conversion into biofuels.