A review on non-edible oil as a potential feedstock for biodiesel: physicochemical properties and production technologies

Abstract

There is increasing concern regarding alleviating world energy demand by determining an alternative to petroleum-derived fuels due to the rapid depletion of fossil fuels, rapid population growth, and urbanization. Biodiesel can be utilized as an alternative fuel to petroleum-derived diesel for the combustion engine. At present, edible crops are the primary source of biodiesel production. However, the excessive utilization of these edible crops for large-scale biodiesel production might cause food supply depletion and economic imbalance. Moreover, the utilization of edible oil as a biodiesel feedstock increases biodiesel production costs due to the high price of edible oils. A possible solution to overcome the existing limitations of biodiesel production is to utilize non-edible crops oil as a feedstock. The present study was conducted to determine the possibility and challenges of utilizing non-edible oil as a potential feedstock for biodiesel production. Several aspects related to non-edible oil as a biodiesel feedstock such as overview of biodiesel feedstocks, non-edible oil resources, non-edible oil extraction technology, its physicochemical and fatty acid properties, biodiesel production technologies, advantages and limitation of using non-edible oil as a feedstock for biodiesel production have been reviewed in various recent publications. The finding of the present study reveals that there is a huge opportunity to utilize non-edible oil as a feedstock for biodiesel production.

Fig. 1. World biodiesel consumption in 2016 (source: U.S. Energy Information Administration, 2019).

Fig. 2. Biodiesel production from various feedstocks.

Fig. 3. Transesterification reaction of triglycerides for the production of biodiesel from non-edible oil.

Fig. 4. Schematic diagram for the commercial scale biodiesel production via catalytic transesterification process.

Fig. 5. Soap formation during alkaline catalytic transesterification of non-edible oil containing excessive amount of FFAs.

Fig. 6. Pretreatment of non-edible oil containing excessive amount of FFAs before biodiesel production.

Fig. 7. Schematic diagram non-catalytic transesterification process for the commercial scale biodiesel production from non-edible oil.

Marwan Abdul Hakim Shaah

Md. Sohrab Hossain

Faisal Aboelksim Salem Allafi

Alyaa Alsaedi

Norli Ismail

Mohd Omar Ab Kadir

Mardiana Idayu Ahmad