Isobutanol from glycerine – A techno-economic evaluation of a new biofuel production process

The paper presents a new thermochemical process for the production of isobutanol, which is an excellent biobased gasoline blendstock. The main feedstock for the process is glycerine, obtained as a byproduct in biodiesel production, being used together with methanol. The process was modeled in Aspen Plus. The process design is characterized by a high level of process integration, pinch analysis being used to optimize the process from the start. A techno-economic evaluation of the process, both in a stand-alone plant and in a plant integrated with an existing petro-refinery was conducted, the estimates for the production cost of isobutanol obtained being 892 $/m3 for a refinery-integrated case and 1017 $/m3 for a stand-alone case. A sensitivity analysis using Monte Carlo methodology showed the production cost estimates to be highly robust. Use of isobutanol rather than fossil gasoline was found to result in 53% reduction in GHG emissions.