This Small Business Innovation Research Phase I project will establish the feasibility of a tandem process for higher alcohol (C4+) synthesis (HAS) and water separations that is cost effective and has high conversion efficiency. This process is intended to address the shortcomings in: (i) Fischer-Tropsch (F-T) synthesis, that is part of gasification of non-food feedstocks to create syngas, where expensive catalysts are needed and the products have non-ideal distribution; and (ii) grain-ethanol processes for gasoline replacement, which are faced with feedstock limitations (i.e. edible carbohydrates) and entail difficult, energy-intensive product-water separations. This project seeks to demonstrate a process with syngas and dilute ethanol as co-reactants that will use lower-cost catalysts and milder process conditions than F-T to deliver superior fuel products relative to ethanol. The work plan includes synthesis of new catalysis, their assessment under an expanded range of operating conditions and modeling of process economics. Demonstration and practical integration of these process advantages are targeted.
The broader/commercial impact of this project begins with a beneficial offering to current ethanol manufacturers in a retrofit scenario. Implemented as a "bolt-on", the process can potentially increase biofuel volumetric production and fuel energy output by two fold or more. If successful, lower feedstock costs and reduced energy needs will dramatically improve economics while reducing the negative impacts of corn and energy price fluctuations. This technology has the potential to increase alternative fuel capacity from the current ~11B gpy to ~20B gpy, while delivering a more energy-dense fuel. The process promises to reduce fuel prices (due to lower feedstock costs, lower energy costs, and transportation savings related to pipeline distribution), and to cut greenhouse gas emissions by >50%. Fully implemented at existing bio-refineries, the technology could also reduce annual natural gas consumption by an estimated 256,000,000 MMBTUs (~$1B) and displace an incremental 178MM barrel of crude oil each year. This project has the potential to deliver a breakthrough approach sought by recent federal legislation (2007 EISA) with its mandate for 21B gpy of "advanced" alternative fuels to be available by 2022.
Intellectual Merit: The Higher Alcohol Synthesis (HAS) process being developed by Pennsylvania Sustainable Technologies, LLC (PST) uses a catalytic process to convert wet bio-ethanol with cellulosic feedstock-derived syngas via gasification to generate a low-water mixture of heavier alcohols and hydrocarbons. Most of the water contained in the ethanol feedstock (e.g., 80% ethanol and 20% water) is consumed in the HAS reactor and thus, the liquid product containing heavy alcohols and hydrocarbons is nearly water-free (i.e., <2% water). The product mixture has a significantly higher energy density than the ethanol feedstock and can serve as a major additive to gasoline. The basic chemistry has been demonstrated in the Phase I NSF-SBIR program; having the carbon utilization higher than the targeted 18% with the catalyst’s activity greater than the targeted 180 g/kg catalyst/hour. Broader Impacts: Current bioethanol economics are seriously impeded by the inferiority of ethanol as fuel (lower energy density and hygroscopic) and the efficiency of feedstock utilization (no use of the cellulosic component). The PST’s HAS process has significant potential to address these problems. HAS can reduce the energy usage in a current ethanol production facility by providing a more efficient drying process. The liquid output products have higher energy density than ethanol. The gasoline additives produced by the HAS reactive separation process have the potential to overcome the largest hurdle in pipeline transportation of biofuels, the water absorption.? Finally, it incorporates the cellulosic component through the production and utilization of syngas, increasing feedstock utilization and decreasing the use of foodstuffs as feedstock. The resulting process requires much lower energy input than the current ethanol production.
