Production of renewable diesel by pyrolysis and esterification
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 catalytic and/or non-catalytic pyrolysis followed by esterification. Specifically, the present invention relates to the production of Renewable Diesel having low glycerin, water, and sulfur content.
1. A continuous, industrial process for preparing Renewable Diesel from an oil feedstock of vegetable and/or animal origin comprising:
subjecting the feedstock to pyrolysis in the tubes of a direct fired furnace to produce a pyrolyzed composition;
separating, from the pyrolyzed composition, a liquid composition comprising carboxylic acid;
esterifying said carboxylic acid with alcohol in a counter-current reactive distillation column to yield diesel fuel according to either ASTM D396 or ASTM D975 or both having less than 5 ppm sulfur, a cetane number greater than 47, less than 0.20% by weight total free glycerin, less than 0.15% by weight residual methanol, and less than 300 ppm water.
2. The process of claim 1 , wherein said pyrolysis is carried out in the presence of a solid catalyst.
3. The process of claim 1 or claim 2 , wherein said pyrolysis is carried out in the presence of steam.
4. The process of claim 1 , wherein said esterification is carried out using a solid catalyst.
5. The process of claim 4 , wherein the solid catalyst is an ion exchange resin catalyst comprising —SO 3 H or —CO 2 H functional groups.
6. The process of claim 1 , wherein the alcohol is selected from methanol, t-butanol, isobutanol, or a mixture thereof.