Team says method strips carbon dioxide from natural gas at wellhead
Rice University chemists say they have discovered how to quickly and cheaply strip carbon dioxide from natural gas at the wellhead, an advance that might someday save gas drillers millions of dollars in potential carbon taxes and, to some degree, help curtail climate change.
The secret: asphalt.
Rice chemistry professor James Tour and his lab worked for six years before coming up with a method using a type of asphalt known as Gilsonite to reduce the carbon dioxide released in natural gas processing, which strips impurities from the gas before it is sold commercially.
Carbon dioxide is so-called gree
nhouse gas that contributes to global warming, and many energy companies expect the U.S. government to impose taxes based on the carbon dioxide released by fossil fuels as part of a worldwide effort to slow climate change.
“They are going to have to stop blowing this stuff into the air,” Tour said. “It hasn’t hit yet, but they see it coming.”
Carbon dioxide is released into the atmosphere when fossil fuels are pumped from the ground and later burned, and carbon capture has become one of the great technological challenges for the energy industry. Companies and researchers are seeking ways to collect carbon dioxide before it is released into the atmosphere.
Before natural gas can be burned at power plants, it must be stripped of impurities, including carbon dioxide, which makes up anywhere from 2 to 10 percent of the gas pulled from the ground. But the process is energy-intensive and expensive. Companies transport the newly mined gas via pipeline to plants, where the gas is passed through fluids called amines, which filter out impurities, and then are heated to temperatures above 250 degrees to release the natural gas.
Amines, however, can only soak up about 15 percent of their weight in carbon dioxide, which requires large amounts of the fluids and higher costs, Tour said. The process vents the carbon dioxide into the atmosphere.
If natural gas producers could find an economical method to separate and capture the carbon dioxide, they would not only reduce their exposure to carbon taxes, but also have a product to sell. Carbon dioxide has industrial uses, including stimulating oil and gas recovery in existing wells.
