(689f) Novel Reactors with Intensified Catalytic Properties for Renewable Diesel Production

Before feedstocks derived from renewable organic material can be used in conventional automobile engines and distributed using existing fuel infrastructure, it is desirable to convert the material into hydrocarbons whose composition resembles that of petroleum-derived fuels. A well-established method is the conversion of vegetable seed oils into green diesel by hydrotreating, an exothermic process involving catalytic hydrogenation of the double bonds present in fatty acid chains of triglycerides in the seed oils.

This paper describes the development and use of improved catalysts and reactor design concepts to alleviate the mass transfer limitations in conventional fixed bed reactors, enable very careful control of reaction temperature, and enhanced yields of green diesel.  The focus is on minimising side reactions, and improving selectivity towards C₁₅-C₁₈ alkanes.

Two reactor concepts have been developed and fabricated: a tubular foam reactor designed to allow staged hydrogen addition, and a membrane reactor.

Experimental work was carried out in the temperature range of 280-325^oC, pressures of 30-50 bar using rapeseed and Jatropha oils. The results show that the reactor designs enable better control of temperature, with improved mixing, mass and heat transfer, leading to an increased selectivity of the hydrogenation process compared to published data.