Renewable diesel production from rapeseed oil with hydrothermal hydrogenation and subsequent decarboxylation

Abstract

Hydrocarbon (renewable diesel) production from rapeseed oil was studied with hydrothermal hydrogenation and subsequent decarboxylation in a batch-type reaction vessel. An appropriate reaction condition for hydrothermal hydrogenation was found to be 270 °C/5 MPa (H2 pressure) with water and Pd/C catalyst for 60 min, under which triglycerides were simultaneously hydrolyzed and hydrogenated into saturated fatty acids in a yield of 98.4 mol%. The obtained saturated fatty acids were then decarboxylated to hydrocarbons under the condition of 300 °C/1 MPa (H2 pressure) with Pd/C for 120 min in a yield of 91.5 mol% on rapeseed oil. In addition, the composition of the obtained hydrocarbons corresponded nearly to that of the fatty acid in rapeseed oil. Such a result indicates that the composition of hydrocarbons produced in this proposed process can be foreseen from fatty acid composition of the feedstock triglycerides. By blending the obtained hydrocarbons from rapeseed oil with an adequate amount of fossil diesel, the blended fuel could satisfy the specification standard of fossil diesel in Japan.