Chemical Engineering Professor Studies Reducing Greenhouse Gas Emissions in Coal Mining

Coal is one of the biggest energy sources in the country. It’s also one of the dirtiest. With the rise of power generated by the sun, wind and natural gas, coal may feel like an fading tie to a past era – but coal still drives the energy sector: Coal generates 30 percent of all the electricity in the United States (U.S. Energy Information Administration). That’s nearly double the production of all renewable energy sources combined.

With a chunk of national electricity that size, coal isn’t going away any time soon. But the way we get this coal can be refined to be less harmful to the environment. The coal industry can invest in clean coal technology, or technology that aims to reduce the carbon footprint of coal-mining operations.

Coal’s dirty reputation is rooted in the emissions released in the coal mining and burning process. When companies mine for the coal that eventually provides steam for generating electricity, the process releases several types of greenhouse gases – gases that, when released into the atmosphere, trap heat from the sun and eventually warm the planet. These emissions trap heat in different ways, varying in impact depending on their chemical makeup.

Carbon dioxide (CO2) is the most frequently mentioned greenhouse gas. Though carbon dioxide is the most abundant greenhouse gas, it isn’t the most damaging to the environment. That honor belongs to methane.

“Even though emissions of methane are smaller globally than carbon dioxide, methane has a large environmental impact because it is 25 times more potent,” says University of Cincinnati Chemical Engineering Professor Vadim Guliants.

Guliants is researching a catalyst that converts this methane into a less potent and, therefore, less harmful gas like CO2. Guliants recently received a two-year $160,000 grant from the Ohio Development Services Agency for his project, “Novel Catalysts for Total Combustion of Ventilation Air Methane Emitted in Underground Coal Mines.”

Coal forms over millions of years as water and dirt compress plant matter into the ground. Pressure and heat initiate physical and chemical changes in the plant matter. When miners mine for coal, they expose this ancient plant matter to oxygen for the first time in millions of years, triggering a release of greenhouse gases like methane. Guliants is attempting to collect this methane and convert it into carbon dioxide through using a palladium-based catalyst at elevated temperatures.

For coal-mining operations, using more energy means netting less profit. Palladium is a metal with very active catalytic properties that can be entirely sustained by the heat of methane combustion, thus eliminating energy costs.

Additionally, given the condition of underground coal mines, the catalyst needs to work in a moist environment. Current palladium-based catalysts perform methane combustion effectively in a moisture-free environment; however, with water vapor in the air, as it would be in a methane ventilation process, palladium-based catalysts are far less effective. Guliants is addressing this problem by adding a second metal, as well as special additives, that can make the catalyst more resistant to the effects of water vapor present in underground mines.

Guliants eventually hopes to find a palladium-based catalyst that can convert at least 95 percent of methane emitted during the coal mining process into CO2 powered entirely by the heat of methane combustion. Though this particular grant is limited to bench-scale research, if Guliants achieves a proof of concept for this catalyst, he can propose a large-scale effort with industry collaboration.

Converting methane into carbon dioxide is one step forward in the complicated world of clean coal technology, which can lead to more efficient and environmentally conscious practices.