Biodiesel: Alternative Fuel

Over these few decades, fossil fuel reserves are depleting in a fast rate due to continue usage and the rising price of crude oil have triggered the energy crisis all over the world. However, in order to overcome this problem, biomass which is derived from renewable materials has become a new alternative of fuel to replace the traditional fossil fuels. Biodiesel or fatty acid methyl ester (FAMEs) which is derived from vegetables oil or animal fats is considered one of the best biomass-fuel to replace fossil fuel. Biodiesel is a renewable energy, lack aromatic compounds, highly biodegradable, and also has low SOx emission (Nyoman Puspa Asri, 2012).

Biodiesel has gained the attention internationally as an alternative fuel since it is highly

In order to minimize the cost of purification process, heterogeneous solid catalyst such as metal oxides, zeolites, hydroalcites, and γ-alumina have been used recently. Some of these catalysts are promising but some still have low performance compared to homogeneous catalyst in term of FAME yield and activity. The advantages of using heterogeneous are these catalysts can be separated easily from the reaction mixture and can be reuse. Most of these catalysts are alkali or alkaline oxides supported on materials with a large surface and they are more active than solid acid catalysts (Thanh, Okitsu, Boi, & Maeda,

One of the ways is to use structure promoters or catalyst supporters to overcome this mass transfer problem. They can react with large triglyceride molecules by providing more specific surface area and pores for active species. (Zabeti et al. 2009). Different types of supports such as aluminium and zinc oxide have been used in the heterogeneous transesterification and they showed favorable support properties for alkali catalysts in biodiesel production process. The potassium hydroxide catalyst supported on palm shell activated carbon used in this work showed high performance to produce biodiesel from palm oil. (Saeid Baroutian,