Scope and opportunities of using glycerol as an energy source

• Published in: Renewable & sustainable energy reviews 2012-09, Vol.16 (7), p.4551-4556
• Main Authors: Gupta, Mayank, Kumar, Naveen
• Format: Article
• Language: English
• Subjects: Acrolien; Applied sciences; Biodiesel; Blending; burning; Byproducts; Combustion; Crude glycerol; Demand; diesel engines; diesel fuel; ecosystem services; Energy; Etherification; Exact sciences and technology; Fuels; glycerol; Glycerols; Hydrocarbon; Hydrogen; hydrogen production; industry; mixing; Pathways; solid wastes; temperature; toxicity; Triacetin
• ISSN: 1364-0321; 1879-0690
• DOI: 10.1016/j.rser.2012.04.001

Biodiesel is a promising fuel for diesel engines in wake of its renewable nature and environmental benefits. Biodiesel can be produced by different pathways; however, glycerol (or glycerin, glycerin) is a valuable by-product which is formed during this process. As mandates are being enforced by different government worlds over, the demand of biodiesel is likely to go up. With increased demand and production of biodiesel, significant quantity of glycerol shall be available. There is an urgent need to find alternative application area of glycerol so that viability of biodiesel industry can be sustained. In the present study, the focus has been made on the various application areas of using surplus glycerol from biodiesel industries to make them more financially attractive. Amongst the different pathways of using glycerol as a source of energy; direct combustion, mixing with agricultural solid wastes and then burning, blending directly or indirectly with other fuels, hydrogen and hydrocarbon production from glycerol, etherification, etc. are prominent one. The requirement, advantages and limitations of each approach have also been evaluated in the study. Combustion of glycerol if not done properly would result in formation of acrolien which is highly toxic in nature and efforts should be made to use glycerol indirectly to produce energy (i.e. all the pathways expect the direct combustion and the solid fuel method). The production of hydrogen from glycerol via APR appears to be the best solution to the disposal problem since the hydrogen yield via APR is highest. Moreover the process occurs at lower pressure and temperature when compared to steam reforming, and it is a single step process. Etherification, tri-acetylisation, and blending have been found to be useful for improving the performance of automotives by facilitating proper and smooth combustion of fuel.