New Natural Gas Catalyst Would Help Capture Methane, Other Emissions

Natural gas in the U.S is estimated to last well into next century and beyond, thanks to the advances in drilling technology. This has renewed the idea of using economical, natively produced natural gas as a transportation fuel.

Largely composed of methane, natural gas is a cleaner burning fuel compared to diesel or gasoline when it comes to nitrous oxides and hydrocarbons, but the unwanted “slip” of unreacted methane can diminish that advantage because methane is a powerful greenhouse gas.

The U.S. Department of Energy has selected a team headed by a chemical engineer from the University of Houston to undertake a $2 million project, which would look into developing and optimizing an economical, more efficient catalyst to eliminate unreacted methane.

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

Natural gas combustion creates far less carbon dioxide (CO₂) than diesel or gasoline combustion.  Methane—the main component of natural gas—was not considered a concern until lately, partially because it hasn’t been connected with the health hazards linked to CO₂. But it is a much more potent greenhouse gas than CO₂, making an effective catalyst essential for extensive acceptance of natural gas vehicles.

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

A crucial aspect of the research is to decrease the use of precious metals, thus bringing down the cost. Traditional vehicle exhaust catalysts depend on platinum, rhodium, and palladium, which are effective but costly.

The new four-way catalyst will examine the use of metal oxides comprising lower-cost elements iron, cobalt, nickel, manganese, copper, and others. Those metals are less effective, as well as not costly, and Harold said the design may still necessitate the use of a small number of precious metals to comply with the emission control targets. CDTi’s Spinel™ technology will be the main element in creating a new group of high-performance catalysts with low quantities of precious metals for natural gas engine emissions control.

The process is expected to include the development of a new material, a task Grabow will take up using atomistic computational modeling, while CDTi’s Steve Golden will undertake the catalyst development and commercialization work.

The project brings together a significant market opportunity with our innovative Spinel materials, coupled with the state-of-the-art characterization and testing capability of the University of Houston and the other key partners.

Steve Golden, CDTi

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

We’re working on something that’s important for the country. We have a surplus of natural gas, and we are helping break down barriers for its expanded use.

Michael Harold, Chairman, UH Department of Chemical and Biomolecular Engineering