Alliance Pipeline LP will resume full service of its 3,848-km (2,391-mile) integrated Canadian and US natural gas transmission pipeline this week after an early-August release of hydrogen sulfide into the system caused the operator to declare a force majeure along the mainline (OGJ Online, Aug. 7, 2015).
Alliance said it plans to lift the force majeure and resume full contract firm service on the mainline system on Aug. 13.
The anticipated restart schedule follows progress with recent mitigation efforts designed to safely remove contaminated gas from the line, including flaring activities at Alliance’s Alameda compressor station in Saskatchewan and at a mainline block valve upstream from the Alameda station (OGJ Online, Aug. 10, 2015).
"Our flaring operation is on track and the amount of hydrogen sulfide in the small segment of pipeline is being reduced to a safe level," said Daniel Sutherland, Alliance’s vice-president of commercial operations.
To replace volumes lost during the flaring process, Alliance has asked to purchase up to 400 MMcf of natural gas from existing shippers in order to increase pressure and expedite flow along the line.
The operator plans to begin a controlled restart of the line on Aug. 12 following receipt of the replacement linepack.
Alliance shut down the mainline pipeline on Aug. 7 after discovering hydrogen sulfide had entered its system following an Aug. 5 operational upset at upstream operator Keyera Corp.’s Simonette gas plant, located 57 miles southwest of Valleyview, Alta.