The US Department of Energy has chosen a team led by a chemical engineer from the University of Houston for a $2-million project to develop and optimize a lower-cost, more efficient catalyst to eliminate unreacted methane in natural gas fuel.

Primarily made up of methane, natural gas is a cleaner burning fuel than gasoline or diesel when it comes to hydrocarbons and nitrous oxides, but the undesired “slip” of unreacted methane can reduce that advantage because methane is a potent greenhouse gas.

Michael Harold, chairman of the UH Department of Chemical and Biomolecular Engineering, will work with Lars Grabow, associate professor of chemical and biomolecular engineering at UH, and researchers from the Oak Ridge National Laboratory, the University of Virginia and CDTi Inc., an emissions technology company based in Oxnard, Calif.

Harold, an expert in catalytic reaction engineering, said the team will focus on the so-called “four-way catalyst,” building on the three-way catalysts used with gasoline and diesel engines. Those simultaneously convert non-methane hydrocarbons, carbon monoxide and nitrogen oxides. The new catalyst will also convert methane.

A critical aspect of the work is to reduce the use of precious metals, lowering the cost. Traditional vehicle exhaust catalysts rely on platinum, palladium and rhodium, which are effective but expensive.

The new four-way catalyst will test the use of metal oxides containing lower-cost elements iron, cobalt, copper, manganese, nickel and others. Those metals are less effective, as well as less expensive, and Harold said the design may still require the use of a small amount of precious metals to meet emission control targets.

CDTi’s Spinel technology will be a key element in developing a new class of high-performance catalysts with low levels of precious metals for natural gas engine emissions control. (Earlier post.)

Spinel was the name initially given to naturally-occurring magnesium aluminate (MgAl₂O₄) and is now used to describe any composition with the same structure. CDTi Spinel technology may employ numerous low-cost metals in the spinel structure enabling use in a wide range of engine and vehicle applications, both gasoline and diesel, as well as other potential vertical markets.

The Spinel technology utilizes various base metals which, when combined together in a common structure, achieve unusual and very effective catalytic conversion activity. Spinel technology is suited for the coating of catalytic converters as an alternative to those utilizing costly platinum group metals (PGMs) and rare earth materials.

The process is likely to involve the development of a new material, work Grabow will pursue using atomistic computational modeling, while CDTi’s Steve Golden will lead the catalyst development and commercialization effort.

Once a prototype has been synthesized and tested with simulated exhaust, Harold said it will be tested at the Texas Center for Clean Engines, Emissions & Fuels, a research, development and testing center based at the UH Energy Research Park.

Resources

• Golden, S., Nazarpoor, Z., and Launois, M. (2015) “Novel Mixed Metal Oxide Structure for Next Generation Three-Way Catalysts,” SAE Technical Paper 2015-01-1007 doi: 10.4271/2015-01-1007