By Irina Slav
The advantages of natural gas over the other two fossil fuels—coal and crude oil—seem to be indisputable when it comes to carbon emissions. Natural gas is a much less carbon-intensive fuel, which has drawn attention to it as an alternative to oil-derived liquid fuels. However, there have been challenges that now a team of Chinese scientists claim to have come closer to solving.
Natural gas consists mostly of methane and some propane. Methane is a sticking point between the industry and environmentalists because it is a much more powerful greenhouse gas than carbon. But if this methane can be turned into fuel it would be a win-win situation since the byproducts of burning natural gas are water vapors and carbon dioxide.
Processing natural gas into liquid fuel is tricky, Phys.org reports in an article on the Chinese scientists’ breakthrough. This processing involves the introduction of oxygen-hydrogen compounds into the gas, which rearranges its atoms. However, not all atoms react to the oxygen and the hydrogen at the same speed and this could ruin the resulting alcohol that would be used as a fuel.
What the Chinese researchers did, essentially, was increase their control over the conversion process, which allowed them to manipulate the speed at which the carbon and hydrogen in the methane and propane rearranged themselves to create alcohol molecules. This, according to the team, would make gas-derived fuel more economical to produce.
The potential of natural gas as a replacement for gasoline and diesel should not be underestimated especially amid the current abundance of natural gas, notably in the United States, thanks to the shale revolution. “Our conclusion is that natural gas as a transportation fuel has both adequate abundance and cost advantages that make a strong case to focus interest in the technology as a real game changer in U.S. energy security.” This is what one engineer from the Argonne National Laboratory told Talking Points Memo, a news outlet, seven years ago, a few months after the Obama government launched a US$30-million grant program for research into making natural gas a more popular fuel for vehicles.
Since then, however, little progress has been made and part of the reason is that challenging conversion process. A simpler form of natural gas—compressed natural gas or CNG—is already in use for some countries’ public transport vehicles and also in passenger vehicles, but it has yet to become a real challenger for gasoline and diesel. While cheaper and more efficient, CNG gets burned up more quickly, it requires a larger tank, and has less torque than gasoline and diesel.
This is where the potential of liquid natural gas fuels lies. In liquid form, natural gas would probably be more competitive with oil-derived fuels but only after the challenges with its conversion into liquid are overcome.
It’s a positive that scientists are working on this. If research is successful it could eventually motivate oil producers to seek ways to reduce gas flaring, which in the U.S. last year grew by 48 percent driven by the shale boom. That’s a lot of methane being burned for no revenues when it could be captured and turned into fuel at some point in the future.