Current Technologies and Future Trends for Biodiesel Production: A Review

Increasing use of rapidly developing technology in daily life, people's commitment to comfortable living and rising prosperity increases the need for energy day by day and makes energy essential for human beings. Today, the level of energy consumption has become an indicator of economic development and power for countries, and the sharing of existing energy resources has been one of the main factors that play a role in the formation of the world politics and conjuncture. The majority of the total energy consumption in the world consists of fossil fuels, which are burned in the internal combustion engines (ICE) in the transport sector. The disadvantages of fossil fuel use in ICEs lead researchers to work on new engine designs that will increase combustion efficiency and reduce harmful emission gas output, and to develop renewable and green fuels that can be used in these engines. Biodiesel is the most suitable alternative to petroleum diesel used as conventional fuel in compression ignition engines (diesel engines), which is the most widely used ICE in the transportation sector. In this review paper, a general view of the biodiesel production technologies is addressed to focus on the most valuable strategy, mainly, for ICEs in transportation industry sector. After reviewing a wide range of data, it has been observed that microwave assisted biodiesel production technology is not well-known in low-income countries and should be emphasized about its RandD technology in these countries. This technology has advantages to solve aforementioned problems. The main objective of this paper is to present and discuss the current and future technologies for biodiesel production. Biofuels, in general, are initially presented, then an emphasis is placed on the processes for obtaining biodiesel, on raw materials origins and characteristics and on biodiesel proprieties when used as fuel. Finally, biodiesel production methods from past to present are discussed. A special focus is given to microwave technology as an emerging solution for biodiesel production.