Vacuum Distillation Process
The present invention relates to a process and apparatus for the production of diesel fuel from feedstocks containing fatty acids, glycerated fatty acids, and glycerin by vacuum distillation followed by esterification. Specifically, the present invention relates to the production of Renewable Diesel having low glycerin, water, and sulfur content. Operation of the distillation system enables production of esters including biodiesel and other biofuels in an economically advantageous manner. The vacuum distillation system is optionally located upstream of an esterification unit or other biodiesel production facility for improvement in production economy.
1 . A process for preparing Renewable Diesel comprising the step of vacuum distillation of oil of vegetable and/or animal origin followed by the step of esterification to yield diesel fuel according to either ASTM D396 or ASTM D975 or both.
2 . The process of claim 1 , wherein the oil of vegetable and/or animal origin is selected from Palm Fatty Acid Distillate (PFAD), Palm Acid Oil (PAO), Acid Oil (Acidulated Soap Stock), and mixtures thereof.
3 . The process of claim 2 , wherein the oil further comprises up to about 20% pre-split tallow and/or up to about 5% tall oil fatty acid.
4 . The process of claim 2 , wherein the oil is essentially free of tallow or poultry fat.
5 . The process of claim 1 , wherein esterification is carried out by reactive distillation using a solid catalyst.
6 . The process of claim 5 , wherein the solid catalyst is an ion exchange resin catalyst comprising —SO 3 H or —CO 2 H functional groups.
7 . The process of claim 1 , wherein the process is carried out on an industrial scale.
8 . The process of claim 1 , wherein the Renewable Diesel is high value and low acidity.
9 . The process of claim 1 , wherein the process is continuous.
10 . The process of claim 1 , wherein the step of esterification is performed with an alcohol selected from methanol, t-butanol, isobutanol, or a mixture thereof.