Fractional distillation of hydrothermal liquefaction (HTL) biocrude

The sources of our energy resources have become a major issue due to global warming and pollution. Transportation will rely on liquid fossil fuels for at least the next 10 years, which makes alternate liquid biofuels attractive. Subsequently, to make renewable resources such as biomass (plants) into biofuels, they should be easily integrated with the current fossil fuel supply chain to be cost-effective. Hydrothermal liquefaction (HTL) is an efficient thermochemical method for biomass conversion into biocrude which could be operated with a wide range of feedstock resources. However, HTL biocrude characteristics including viscosity, density, heating value, composition and stability are not comparable with conventional products. The current focus for upgrading mainly relates to catalytic and hydrogenation processes; however, physical processes are cheaper and more reliable. Fractional distillation has the potential as a cost-efficient physical technique for biocrude upgrading or even co-processing with crude oil in a refinery.

This project plans to summarise and discuss changes in the physical and chemical properties of biocrude using fractional distillation. In addition, it will also investigate how well distillation will impact biocrude storage stability and co-processing capability with current fossil fuels. The impact of distillation on HTL biocrude mixture modelling will also be another outcome of this project.

Outcomes

The fractional distillation showed significant improvement in biocrude physical and chemical properties. It also improved the storage stability of biocrude. More importantly, distillation eased the co-processing of biocrude with conventional fuels such as diesel by significant improving miscibility. The experimental information obtained by GC-MS analysis of distilled biocrude was helpful in more accurate modelling of biocrude mixture using non-dominated sorting genetic algorithm (NSGA-II).