Techno-economic analysis of biomass to fuel via the MixAlco process Conference Paper uri icon


  • Because of dwindling fossil fuel resources, there is growing interest in developing cost-effective processes that convert biomass to fuels. MixAlco is a robust process that converts lignocellulose into secondary alcohols (isopropanol and higher), which can be used directly as transportation fuel or converted to hydrocarbons, e.g., gasoline. The process has five main steps, i.e., pretreatment with lime, fermentation with a mixed culture of acid-forming microorganism to obtain carboxylate salts, dewatering with a high-efficiency vapor-compression evaporator, thermal conversion of salts to ketones, and hydrogenation of the ketones to mixed alcohols. Optionally, the alcohols can be oligomerized to hydrocarbons using zeolite catalysts. The process synthesis, simulation, integration, and cost estimation of several process configurations of the MixAlco process are presented. For every step, design alternatives were studied and compared to determine the most profitable and sustainable process design. The configuration in which pretreatment and fermentation were performed in piles was significantly more cost-effective than in conventional tanks. A novel heat exchanger had very high heat transfer coefficients, which allowed the vapor-compression evaporator to operate with very small approach temperatures (0.35F). This evaporator saved both capital and energy, which significantly benefited process economics. Sensitivity analyses were performed to determine process economics under various conditions, such as multiple feedstocks (type and cost), hydrogen (source and price), and plant capacity. This is an abstract of a paper presented at the AIChE 2010 Spring National Meeting (San Antonio, TX 3/21-25/2010).

published proceedings

  • 10AIChE - 2010 AIChE Spring Meeting and 6th Global Congress on Process Safety

author list (cited authors)

  • Pham, V., Granda, C., Holtzapple, M., & El-Halwagi, M.

complete list of authors

  • Pham, V||Granda, C||Holtzapple, M||El-Halwagi, M

publication date

  • August 2010