Date of Award

8-2007

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Chemical Engineering

Advisor

Goodwin, James G

Committee Member

Bruce , David A

Committee Member

Walker , Terry

Committee Member

Kitchens , Christopher

Abstract

Biodiesel, defined as 'a fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats', is finding favor commercially worldwide. The objective of this study is to evaluate the use of solid catalysts for triglyceride transesterification and carboxylic acid esterification to produce biodiesel fuel.
Processes using mainly homogeneous alkali catalysts (such as NaOH, KOH, and methoxides) have been shown to be effective for biodiesel synthesis when dealing with virgin oil feedstocks. Use of acid catalysts (e.g., H2SO4) becomes important when processing low quality feedstocks that contain appreciable amounts of free fatty acids, such as restaurant waste grease, and trap greases.
Due to environmental concerns, there has been a strong interest in the use of solid catalysts as a replacement for homogeneous ones. The use of solid catalysts has the potential to improve the technical economic, and environmental aspects of biodiesel synthesis (e.g., ease of separation, continuous processing, reuse of catalyst, less waste generation, less corrosive effects by avoiding the use of mineral acids and methoxydes). In particular, solid acid catalysts are able to catalyze both transesterification and esterification reactions simultaneously.
To evaluate the potential use of solid catalyst for biodiesel applications, knowledge of the reaction mechanism and accurate kinetics for the transesterification and esterification reactions are essential. Therefore, numerous solid catalysts are being investigated with the objective of finding suitable catalyst characteristics and optimum conditions for biodiesel synthesis.

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