January 2015, Vol. 242, No. 1

TechNotes

Glycol Dehydrator Fits Schools Needs To A T

At 35-foot tall and equally as wide, a glycol dehydrator may be big, but this gift is a perfect fit just the same. The device, which is used to remove water from natural gas before compression and distribution, is now nestled snugly into one corner of the Susquehanna County, PA site of Lackawanna College’s School of Petroleum & Natural Gas.

The dehydrator is the gift from Williams Midstream to the school, which offers associate’s degrees in petroleum and natural gas technologies.

Williams operates compressor and gas processing stations, gathering pipelines and other facilities within miles of the School of PNG, which is in Pennsylvania’s Marcellus Shale region, and saw the gift as a way of achieving two important goals: making it clear that Williams wants to continue being a good neighbor and helping to build a competent, reliable workforce in the region to meet its technical employment needs.

“Our employees are technicians who spend a lot of time on computers,” said Williams’ spokesman Ryan Stalker. “Most of the people coming for jobs with us are from nearby communities, so helping this school train them just makes good sense.”

Stalker, a native of northeastern Pennsylvania, says dehydrators like this are found at 95% of the natural-gas compressor installations in the region, and industry sources say thousands of these units are in daily use across the nation.

A glycol dehydrator is comprised of two key components: a “contact tower” (a vertical steel cylinder) and a “glycol reboiler” (a horizontal cylinder), which is basically a kind of still. The system uses the chemical triethylene glycol (TEG) as a dehydrating agent.

The wet gas collected from wells enters the base of the contact tower and ascends ascends, contacting the TEG, which absorbs water. The dry gas then enters the pipeline. The TEG is pumped to the reboiler where it’s heated sufficiently to boil off the water it has absorbed. The TEG is then pumped back to the tower to be reused in an endless cycle.

The unit at the college will be non-operational, Stalker said, but all the piping and other hardware needed to operate such a unit will be installed so students can see how an actual dehydrator works and become thoroughly familiar with it.

In addition to the unit, Williams has given the college $10,000 to cover the costs of acquiring and installing the necessary controllers, regulators, valves and piping. New glycol hydrators cost between $80,000-100,000.