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Abstract
Houston-based renewable diesel and biodiesel developer Endicott Biofuels LLC won a patent pertaining to the production of renewable diesel via pyrolysis and esterification. In the present invention, methods of obtaining a renewable diesel product that meets either or both ASTM D396 or ASTM D975 specifications from oils of vegetable and animal origin while eliminating the shortcomings of transesterification, wet chemical esterification, and/or hydrolysis are disclosed. Under US tax law, products derived from animal or vegetable origin that meet ASTM D396 or ASTM D975 specification can be considered to be 'renewable diesel' for tax purposes. According to the invention, renewable diesel as used herein is produced where pyrolysis is advantageously substituted for hydrolysis in order to lower the capital cost from that associated with hydrolysis. In one embodiment, in order to further upgrade products by eliminating any remaining acidity while avoiding reaction equilibrium limitations and sulfur contamination normally associated with esterification, reactive distillation over solid catalysts is performed, according to the inventors of the patent.