It is now possible to produce biofuel using the CO2 contained in industrial stack emissions. Following three years of research under the Vasco2 project, diesel fuel was produced in the lab from a biocrude made using hydrothermal liquefaction of microalgae, a process developed at Liten, a CEA Tech institute.

Microalgae in culture were fed with industrial stack emissions in open basins. The strains were not specially selected in any way and did not undergo any pre-treatment to reduce costs. Centrifugation was then used on the algae paste obtained before it was sent to Liten for hydrothermal liquefaction in a continuous reactor.  The high-temperature, high-pressure process is suitable for material with water content of up to 85%. Despite the variability of the input, the process produced a carbon-rich (73%-78%) biocrude with a lower heating value (LHV) comparable to fossil-based resources. The biocrude was distilled in a lab by Total to produce diesel.

Ultimately, the hydrothermal liquefaction process parameters could be further improved to increase biocrude yields. The next step will be to build an industrial-scale demonstrator. This advance makes the opportunities for creating an environmentally-friendly industrial process very real.