Yu J.
University of Hawaii at Manoa, US
Keywords: bioplastic, CO2 fixation, drop-in fuels, green chemicals, renewable energy
With rapid technology progress and cost reduction, more electrical power is generated from renewable solar radiation and wind. Because of the intrinsic intermittency, however, the renewable power posts a great challenge to grid stability, and many times has to be restricted or wasted. A green technology is developed to use the renewable power and produce a bioplastic and drop-in liquid fuels from CO2. Through the green process, the intermittent electricity is first used to split water into hydrogen and oxygen via electrolysis. The clean hydrogen, as a stable energy carrier, is then used by a hydrogen-oxidizing bacterium to fix CO2. Under autotrophic growth conditions, CO2 was reduced to biomass at 0.8 g L-1 hr-1, about 10 times faster than that of a typical oil-producing microalga (Neochloris Oleoabundans). More importantly, a large portion of the reduced carbon is stored in polyhydroxybutyrate (PHB), accounting for 60% of dry cell mass. The productivity of the biopolyester (5.3 g L-1 d-1) is much higher than that of microalgal oil (0.13 g L-1 d-1). PHB is a biodegradable thermoplastic that can find a variety of environmentally friendly applications. Under a solid acid catalysis, the biopolyester can also be reformed into a hydrocarbon oil (C6-C18) from which a gasoline-grade fuel (77 wt% oil) and a biodiesel-grade fuel (23 wt% oil) are obtained. Aromatics and alkenes are the major compounds of the oil, depending on the catalyst and reaction conditions. This work demonstrates that drop-in transportation fuels can be directly produced from carbon dioxide, water and renewable energy.
Journal: TechConnect Briefs
Volume: 2, Materials for Energy, Efficiency and Sustainability: TechConnect Briefs 2018
Published: May 13, 2018
Pages: 187 - 190
Industry sector: Energy & Sustainability
Topic: Carbon Capture & Utilization
ISBN: 978-0-9975117-9-6