Natural gas burns cleaner and more efficiently than the more traditional petroleum fuel types. It can be used for many of the same amenities we rely on every day and is currently much cheaper than its petroleum counterpart.
Natural gas is something of a wonder. It burns cleaner and more efficiently than the more traditional petroleum fuel types. It can be used for many of the same amenities we rely on every day and is currently much cheaper than its petroleum counterpart. But it shares one significant trait with petroleum.
"Natural gas, as it comes out of the ground, requires processing to produce pipeline-quality natural gas," says Trent Kelsey, an associate chemical engineer at Burns & McDonnell. "And in the case of shale gas with which Burns & McDonnell primarily works, it requires more processing to remove impurities and recover valuable co-products."
While there are various ways to process raw natural gas, a common method is to use a cryogenic gas-liquid separation plant. As natural gas is extracted from the ground, it is typically sent by pipeline to a treatment facility at pressures between 500 and 1,200 pounds per square inch (psi). When gas enters the plant, it is treated for removal of carbon dioxide (CO2) and water (H2O). Next, by dropping the pressure to around 300 psi, the temperature is lowered. This condenses a portion of the gas to recover the natural gas liquids (NGLs) to the bottom of a separation column while the natural gas separates to the top.
Once separated, the gas, now pipeline quality, is recompressed to between 500 and 1,200 psi and sent to a natural gas pipeline. The NGLs are sent to a fractionation facility where they can be further processed for additional products, such as ethane, propane and butanes, to be sold in various markets.
"This is a basic, essential first step to make a premium fuel and to feed chemical production facilities," Kelsey says. "And new and improved methods over the last decade could allow the United States to go from an importer of natural gas products to an exporter in the next few years."
For more information, contact Trent Kelsey, 816-822-3383.