Three domestically available raw materials — coal, biomass and natural gas — may reduce the country’s dependence on imports and vulnerability to volatile oil prices while addressing the increasing national fuel demand at a low financial and environmental cost.

Christodoulos Floudas in the Department of Chemical and Biological Engineering and his team have come up with a new process that can convert these raw materials into gasoline, diesel and kerosene, crucial fuels for transportation vehicles ranging from cars to rockets. The invention, developed with graduate student Josephine Elia and 2012 Princeton Ph.D. recipient Richard Baliban, includes a complete refinery that first converts the raw materials — also called feedstocks — into gases such as carbon dioxide, carbon monoxide and hydrogen in reactors. The refinery then separates out some of the carbon dioxide and other acidic gases from the main gas stream, recycling these gases back into the reactors and reducing carbon emissions into the atmosphere. The “cleaned-up” gas goes through the reactor to produce the different hydrocarbons that make up key transportation fuels.

Floudas’ process includes a quantitative framework for ensuring that the refinery uses the best combination of the three feedstocks for minimal production costs, which include operation and maintenance as well as feedstock purchase and delivery. This framework also assists in limiting greenhouse gas emissions from the process.

The next move, Floudas said, is to form collaborations with companies and government entities interested in pursuing alternative energy options. His team has already partnered with security and aerospace company Lockheed Martin.

Floudas, the Stephen C. Macaleer ’63 Professor in Engineering and Applied Science, has also pursued a different avenue of carbon emissions reduction. With graduate student Eric First and Postdoctoral Research Associate Faruque Hasan, Floudas has created methods for engineers to characterize which materials are best for separating carbon dioxide from the gas streams of various sources, such as natural gas and coal-based power plants and cement manufacturers. His strategy focuses on zeolites and metal-organic frameworks, which are both porous structures that can extract specific gases using processes such as adsorption, in which molecules bind to a surface, or membrane structures with different pore sizes.

With his invention, Floudas can combine the materials’ properties and separation processes to figure out which is the best solution for a given scenario. This can yield information not found by other means. “We have found out that what was proposed to be the best adsorber based on material properties is not necessarily the lowest cost,” he said. “So there’s a tradeoff.”