Six natural gas fields can be found far out into the Atlantic Ocean, 225 km/140 miles off the east coast of Nova Scotia. The energy installation connected to them delivers between 400 and 500 million m3 and 17,000 million ft3 of natural gas and 20,000 barrels of natural gas liquids per day.
Increasing suction pressures
During construction of the Alma platform, new diaphragm pumps were required. The Alma platform conducts preliminary processing before transmitting the natural gas to a processing facility some 50 km/30 miles away. The platform is positioned in a water depth of 67 m/220 ft. Engineers discussed the possibility of using diaphragm pumps supplied by Milton Roy (a sister company of HMD Kontro), but were warned that these pumps may be subjected to low net positive suction head available (NPSHA) conditions. Booster pumps were required to increase suction pressures. However, as with most offshore platforms, space constraints presented a challenge at the Sable site.
One suggestion was to install a second set of pumps to boost the suction pressure. HMD Kontro GSP pumps were evaluated and selected. Two pumps in 316 stainless steel were installed in 2002, with the platform starting operation in the spring of 2003.
The HMD Kontro GSP pumps meet all standards of API 685 for sealless magnetic drive pumps. They are used for a range of applications in oil and gas installations throughout the world with users benefiting from the minimal maintenance requirements of the sealless design.
Some of the parameters that sealless pumps can now accommodate include temperatures between −100°C and +450°C/840°F, flow rates up to 2000m3/hour/8800 USGPM, differential heads up to 350m/1140 ft and pressure values to 185 bar/2600 PSI. In addition, magnetic drive pumps from HMD Kontro can also accommodate solids up to 5%, with a particle size of 150 microns, 8% and 250 microns with a discharge strainer. The GSP range has full compliance with API685/API610 for use in the strenuous conditions of the oil and gas industry.
New platform construction
At a later stage in the expansion of the site, a new platform, called South Venture, was to be built and engineers required a series of vent drum return pumps. Here, the liquids were much more corrosive, so particularly robust pump materials were required. GSP pumps from HMD Kontro were again selected but this time with all wetted parts in Alloy C-276. These pumps were supplied in 2005 and the South Venture platform commenced operation later that year.
The HMD Kontro GSP pumps have performed successfully and the reports from the end user, Exxon Mobil Canada East are very favourable. The processing system has had the benefit of a steady constant pressure liquid supply and this has resulted in a very successful installation.