ke all synthetic fuels, the manufacture of synthetic alcohol begins with gasification of heavy hydrocarbons such as coal, or lighter carbon resources such as natural gas, biomass and organic landfill waste — using a process that involves high temperature and pressure in an oxygen-controlled atmosphere.
Gasification produces a synthesis gas, sometimes called syngas (from synthesis gas), which, after cleaned, consists mostly of molecular hydrogen and carbon monoxide. The syngas is then passed over a catalyst, in a controlled environment, creating synthetic molecules, like the ethanol molecule pictured above left. The actual type of molecule depends on the catalyst used in the process.
Synthetic ethanol is chemically identical to bio-ethanol, the only difference is that bio-ethanol is made from the fermentation of carbohydrate derived sugars, followed by distillation, identical to the process used for making alcoholic beverages such as vodka or whisky; whereas synthetic alcohol is produced through a thermo-chemical process which begins with the creation of syngas from the gasification of a wide range of resources, and therefore not limited to grains and sugars.
Gasification: “To convert a solid or liquid into a gas, or become a gas.” © Microsoft Encarta
Synthesis gas: “A mixture of carbon monoxide and hydrogen, derived from the breakdown of carbon and hydrogen containing materials [hydrocarbons and biomass], used as a raw material for many chemical products.” © Microsoft Encarta
Hydrocarbons: “An organic chemical compound containing only hydrogen and carbon atoms, arranged in rows, rings, or both, and connected by single, double, or triple bonds.
Hydrocarbons constitute a very large group including alkanes, alkenes, and alykynes.” © Microsoft Encarta
Biomass: “Plant and animal material, for example, agricultural waste products, used as a source of fuel.” © Microsoft Encarta
Nanoscale catalysts could tap syngas as cheap source of ethanol
By combining gasification with high-tech nanoscale porous catalysts, researchers at the U.S. Dept. of Energy’s Ames Laboratory and Iowa State University hope to create ethanol from a wide range of biomass, including distiller’s grain left over from ethanol production, corn stover from the field, grass, wood pulp, animal waste, and garbage.
Gasification is a process that turns carbon-based feedstocks under high temperature and pressure in an oxygen-controlled atmosphere into synthesis gas, or syngas. Syngas is made up primarily of carbon monoxide and hydrogen (more than 85 percent by volume) and smaller quantities of carbon dioxide and methane.
|In this transmission electron micrograph of the mesoporous nanospheres, the nano-scale catalyst particles show up as the dark spots. Using particles this small (~ 3nm) increases the overall surface area of the catalyst by roughly 100 times.|
It’s basically the same technique that was used to extract the gas from coal that fueled gas light fixtures prior to the advent of the electric light bulb. The advantage of gasification compared to fermentation technologies is that it can be used in a variety of applications, including process heat, electric power generation, and synthesis of commodity chemicals and fuels.
“There was some interest in converting syngas into ethanol during the first oil crisis back in the 70s,” said Ames Lab chemist and Chemical and Biological Science Program Director Victor Lin. “The problem was that catalysis technology at that time didn’t allow selectivity in the byproducts. They could produce ethanol, but you’d also get methane, aldehydes and a number of other undesirable products.”
A catalyst is a material that facilitates and speeds up a chemical reaction without chemically changing the catalyst itself. In studying the chemical reactions in syngas conversion, Lin found that the carbon monoxide molecules that yielded ethanol could be “activated” in the presence of a catalyst with a unique structural feature.
“If we can increase this ‘activated’ CO adsorption on the surface of the catalyst, it improves the opportunity for the formation of ethanol molecules,” Lin said. “And if we can increase the amount of surface area for the catalyst, we can increase the amount of ethanol produced.”
Lin’s group looked at using a metal alloy as the catalyst. To increase the surface area, they used nano-scale catalyst particles dispersed widely within the structure of mesoporous nanospheres, tiny sponge-like balls with thousands of channels running through them. The total surface area of these dispersed catalyst nanoparticles is roughly 100 times greater than the surface area you’d get with the same quantity of catalyst material in larger, macro-scale particles.
It is also important to control the chemical makeup of the syngas. Researchers at ISU’s Center for Sustainable Environmental Technologies , or CSET, have spent several years developing fluidized bed gasifiers to provide reliable operation and high-quality syngas for applications ranging from replacing natural gas in grain ethanol plants to providing hydrogen for fuel cells.
“Gasification to ethanol has received increasing attention as an attractive approach to reaching the Federal Renewable Fuel Standard of 36 billion gallons of biofuel,” said Robert Brown, CSET director.
“The great thing about using syngas to produce ethanol is that it expands the kinds of materials that can be converted into fuels,” Lin said. “You can use the waste product from the distilling process or any number of other sources of biomass, such as switchgrass or wood pulp. Basically any carbon-based material can be converted into syngas. And once we have syngas, we can turn that into ethanol.”
The research is funded by the DOE’s Offices of Basic Energy Sciences and Energy Efficiency and Renewable Energy.
U.S. Department of Energy and Conoco-Phillips fund ethanol catalyst research
James Spivey, McLaurin Shivers professor of chemical engineering at Louisiana State University (LSU), and Challa Kumar, group leader of nanofabrication at LSU’s Center for Advanced Microstructures and Devices, or CAMD, are working diligently with partners from across the nation to make ethanol fuel an efficient reality.
Together with Clemson University and Oak Ridge National Laboratories, the researchers received $2.9 million in funding from the U.S. Department of Energy, or DOE, and its cost-sharing partner, Conoco-Phillips, the third-largest integrated energy company in the nation.
“We’re working with our project partners to produce ethanol from a coal-derived syngas, a mixture of primarily carbon monoxide and hydrogen. The United States has tremendous reserves of coal, but converting it to affordable, clean fuels is a challenge – one that we are addressing in this DOE-funded project,” said Spivey. “Because ethanol is a liquid, it can be more easily distributed to the end user than gaseous hydrogen. It can be converted into a hydrogen-rich gas at the point of use, such as a fuel cell. The net result is clean energy produced from a domestic resource.”
James Goodwin, chairman of the chemical and biomolecular engineering department at Clemson, and David Bruce, associate professor of chemical and biomolecular engineering at Clemson, are using advanced computational methods to identify new catalysts and test them with techniques such as isotopic labeling.
LSU doctoral students Femi Egbebi and Nachal Subramanian are carrying out research with Spivey in the preparation and testing of these catalysts, determining which ones produce the desired results.
Steve Overbury and Viviane Schwarz at the Oak Ridge National Laboratory will test new catalysts with their specialized equipment while Joe Allison and Vis Viswanathan at Conoco-Phillips will analyze the costs and commercial potential of the overall process.
Kumar is in charge of designing and synthesizing novel nano-structured catalysts using wet-chemical synthesis capabilities available at CAMD in addition to utilizing synchrotron radiation-based X-ray absorption spectroscopy tools. Nanomaterials having unique core-shell architecture that are currently under development at CAMD are anticipated to enhance ethanol production significantly.
“It is CAMD’s vision to be in the forefront of development of nanomaterials for a broad range of applications ranging from catalysis to medical diagnosis and therapy,” said Kumar.
“The DOE is definitely interested in seeing a commercial project come out of this,” said Spivey. “Our project team is committed to making this happen. A successful project will help show that LSU is focused on research that makes sense for the environment and for our country.”
LSU Media Relations
Americans consume about 140 billion gallons of gasoline every year. If all spark ignition engines in the future were optimized for alcohol fuel (alcohol engines), then 140 billion gallons of ethanol per year would give American drivers a similar number of miles on the road as would 140 billion gallons of gasoline.
One hundred billion gallons of synthetic alcohol, plus 30 billion gallons of cellulosic ethanol plus 10 billion gallons of corn ethanol would equal 140 billion gallons. That is possible; what are we waiting for?
Artificial Photosynthesis – U.S. Department of Energy — “After nearly 3 billion years of evolution, nature can effectively convert sunlight into energy-rich chemical fuels using the abundant feedstocks of water and carbon dioxide. All fuels used today to power vehicles and create electricity, whether from fossil or biomass resources, are ultimately derived from photosynthesis… plants and photosynthetic microbes were not designed to meet human energy needs – much of the energy captured from the sun is necessarily devoted to the life processes of the plants. Imagine the potential energy benefits if we could generate fuels directly from sunlight, carbon dioxide, and water in a manner analogous to the natural system, but without the need to maintain life processes. The impact of replacing fossil fuels with fuels generated directly by sunlight would be immediate and revolutionary.”
Turning sunlight into liquid fuels — Using the energy of sunlight to produce pure hydrogen and oxygen from water molecules without electrolysis.
The world needs a source of alternative transportation fuel that can replace gasoline, now, not 30 years from now. AmericanEnergyIndependence.com has published a Plan for American Energy Independence describing in detail how America, and the world, can replace gasoline with non-petroleum alcohol fuels (including bio-alcohol and synthetic alcohol: methanol and ethanol). The resources and technology exist today—all that is needed is political leadership and the determined will of the people.
The Plan also offers a practical solution for controlling CO2 emissions—a technology that will remove carbon directly from the atmosphere, enabling carbon based fuels to be 100% carbon neutral. Application of the carbon neutral technology can be expanded worldwide to neutralize all sources of anthropogenic carbon emissions, and ultimately lower atmospheric CO2 concentrations down to, or below, pre-industrial levels.