Abstract
Microwave energy based chemical synthesis has several merits and is important from both scientific and engineering standpoints. Microwaves have been applied in numerous inorganic and organic chemical syntheses; perhaps, from the time their ability to work as heat source was discovered. Recent laboratory scale microwave applications in biodiesel production proved the potential of the technology to achieve superior results over conventional techniques. Short reaction time, cleaner reaction products, and reduced separation-purification times are the key observations reported by many researchers. Energy utilization and specific energy requirements for microwave based biodiesel synthesis are reportedly better than conventional techniques. Microwaves can be very well utilized in feedstock preparation, extraction and transesterification stages of the biodiesel production process. Although microwave technology has advanced in other food, pharmaceutical and polymer chemistry related research and industry, it has yet to prove its potential in the biodiesel industry at large scale applications. This paper reviews principles and practices of microwave energy technology as applied in biodiesel feedstock preparation and processing. Analysis of laboratory scale studies, potential design and operation challenges for developing large scale biodiesel production systems are discussed in detail.
Highlights
Renewable energy research is receiving increased attention in recent years
The intention of this review is to provide the basics of microwave energy applications specific to biodiesel preparation and processing, preliminary understanding and explanation of microwave effect on the chemical reactions, update on process utilization and improvements, and information related to different process configurations and reactor designs available for biodiesel production
Microwave-enhanced organic/inorganic synthesis is considered as green chemistry and a preferred method due to several advantages such as lower energy consumption, substantial reduction in reaction times and solvent requirements, enhanced selectivity, and improved conversions with less by-product formation
Summary
Renewable energy research is receiving increased attention in recent years. Main reasons for this evolution are energy, economic and environmental security related concerns. A non-conventional heating method is utilized in biodiesel production in two main stages: 1) oil extraction and 2) chemical transesterification reaction. In conventional extraction the extractability of different components depends mainly on the solubility of the compound in the solvent, mass transfer kinetics of the product and matrix interactions [89], whereas under microwave-assisted extraction localized superheating rate plays an important role in extraction efficiency This heating rate is influenced by factors such as microwave power level, frequency, initial temperature and design of microwave applicator, and can be selected for a particular processing application. Continuous preparation of fatty acid ethyl esters (FAEE) from coconut, rice bran and used frying (palm) oils in a modified conventional microwave oven (800 Watts) were reported by Lertsathapornsuk et al In a continuously mixed batch reactor system, rapid reaction rate and higher conversion yield of FAEE in the presence alkali catalyst of three vegetable oils was observed with excess amounts of alcohol. Radio frequency microwave energy further improves product recovery in the separation of the biodiesel product from alcohol and glycerin in the reaction mixture [124]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
