Turning Natural Gas Green

A new process extracts high-value carbon black from methane.

Coal may be the dirty man of the energy world, but it isn't the only fossil fuel trying to clean up its act. A Canadian startup says that it has developed a way to strip carbon out of methane, resulting in hydrogen-enriched natural gas that burns cleaner and more efficiently.

Green gas: Atlantic Hydrogen's plasma reactor (shown here) separates hydrogen and solid carbon from a natural-gas stream using pulsing electrical charges. Credit: Atlantic Hydrogen

Atlantic Hydrogen, based in the Canadian province of New Brunswick, is betting that its "greener" natural gas will appeal to utilities and industrial customers looking to reduce greenhouse-gas emissions under an impending cap-and-trade regime. But an added financial benefit would come from the powdery carbon black that's extracted from the gas stream. "If we can get a value for the carbon that's even in the thousands of dollars per ton range, then we have a very compelling economic model," says David Wagner, president of the seven-year-old company.

Carbon black is used as a pigment in inks and plastics and to reinforce rubber products, such as tires and industrial-strength hoses. It's typically made by partially combusting heavy oil over a high flame and filtering out the carbon particles in the resulting black smoke. This process, on average, emits an estimated 2.4 tons of carbon dioxide per ton of carbon black.

Atlantic Hydrogen says that it can produce high-purity carbon black with a fraction of the emissions, and at the same time partially reduce the carbon content of natural gas. The approach, which the company is calling "carbon capture and utilization," uses less energy than is typically associated with carbon capture and storage technologies.

The heart of its approach is a plasma reactor system that the company calls CarbonSaver; it operates at between 1,500 and 2,500 °C and can be positioned at various points along a pipeline: at compressor stations, at underground storage sites, at the city gateways that bring gas to homes and businesses, and at power plants and industrial sites that receive natural gas.

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Inside the reactor, a proprietary plasma torch pulses a charge as the natural gas flows through, separating hydrogen from the methane and turning the carbon into a solid that's similar to photocopier toner. The hydrogen then rejoins and bonds with the methane stream, resulting in the enriched natural gas. The process can be tuned to blend a 10 to 20 percent mix of hydrogen--any more, and the natural gas is at risk of causing pipelines and equipment to become brittle and unstable.

A three-year, $5.7 million pilot project completed in March supplied 75 kilowatts of power, showing promising results.The system produced about 25 cubic meters of natural gas per hour with a 10 percent blend of hydrogen. Tests found that the engine used operated 5 percent more efficiently and that CO₂ emissions fell 7 percent. The increased hydrogen content in the natural gas led to a more complete burn, reducing nitrogen oxides. Atlantic Hydrogen sees the potential to reduce nitrogen oxides by more than 50 percent.