Natural Gas Infrastructure: Compressor Stations and Underground Storage Part 2
Posted: September 18, 2011
If you read my last post, I had just completed a tour of the Dominion Energy facility in western PA and hope I was able to give you an idea of what a natural gas storage facility is all about. This time, I’m going to tell a little about the compression component of this operation.
Let me start by saying it’s big. How big? Well, our tour guide liked to describe the engines that are used to increase the pressure on the gas as similar to our car engines. That comparison is only accurate as it relates to the basic concept of an engine. While my car has a 290 horsepower V-6 gasoline-powered engine, this facility has 2500 horsepower V-10 engines powered by natural gas (of course!). While my car engine has pistons about 3” across, these engines have pistons about 18” across. These engines - 10 of them, each standing 15’ tall - sit side by side in a large building, and they’re loud; very loud. There are three electric engines in another building to complement the gas engines that are about as big, but they’re quiet; very quiet.
As a crossroads for interstate pipelines, the job of this facility is to monitor gas flow and to make sure it is at a high enough pressure to continue its journey to customers on the East Coast. The engines and compressors run as needed and generally help to maintain a pressure of about 800 psi in the pipeline.
A control room operator in another building on the site can remotely start and shut down each engine as needed.
Safety is a constant and was evident everywhere we walked on these grounds. Redundant systems to detect leaks and suppress a fire are installed. Multiple valves to control and direct the flow of gas are everywhere and marked.
One area is reserved for the “pig launchers.” Pig launchers are large pipes plumbed into the pipeline above ground designed to accept a “pig.” A pig comes in many varieties; a standard pig and a “smart pig.” The run-of-the-mill standard pig is an oblong shaped, 3- to 30-foot long device that travels through the pipeline to evacuate accumulated water and dirt by pushing it ahead of itself to its exit. Varieties of smart pigs may be equipped with enough electronics to determine the thickness of the pipe and to check for dents, unauthorized pipe tap-ins, and leaks. They can inspect anywhere from 5 to 40 miles at a time. As pipelines are required to be inspected every 7 years, pigs are kept busy.
This facility is just another piece of western Pennsylvania infrastructure that was already in place when Marcellus Shale production began and benefits this new production.
Jon Laughner, Penn State Extension, Beaver County