High-yield production of fuel- and oleochemical-precursors from triacylglycerols in a novel continuous-flow pyrolysis reactor

Abstract

In this study, conversion of soybean oil was carried out in a continuous pyrolysis system with feed injected through an atomizer. This allowed introduction of micron-sized droplets of oil that could be rapidly vaporized inside the reactor. With this novel design, we were able to achieve feed vapor residence times (τ) of 6–300s without use of carrier gas, which would significantly reduce the overall cost of pyrolysis. Effects of reaction temperature (450<T<500°C) and τ on conversion, product yields and composition were investigated. At the optimum experimental conditions of T=500°C and τ=60s, the yield of pyrolysis liquids was as high as 88% (relative to feed mass). Under these conditions, the identified products consisted of 38% hydrocarbons (22% C5C12 and 16%>C12), 33% long-chain fatty acids (C16C18, but primarily oleic acid) and 15% short-chain fatty acids (C6C12). Upon distillation of the liquid products, the long-chain fatty acids were cleanly separated from the hydrocarbons. Overall, our results demonstrate the feasibility of producing liquid products at high yields, including a wide range of fuels (gasoline, jet and diesel) and enriched oleic acid (for oleochemicals production), using our reactor design for pyrolytic conversion of vegetable oil.