The Karsto gas processing plant near Haugesund on Norway's west coast is currently undergoing a major upgrade. The plant exports about 30% of Norway's continental shelf gas production and came on stream in 1985.
In 2009, export from the plant amounted to 24.1 billion cu m of dry gas and 7.36 million tonnes of liquid products. The plant's capacity is about 90 million cu m/day.
Rich gas from about 30 fields enters Karsto through the 42-in. Asgard pipeline and the 30-in. Statpipe. Karsto also receives about 200,000 b/d of nonstabilized Sleipner condensate through a 20-in. pipeline.
The plant exports about 20 million cu m/day of dry sales gas through the 28-in. Statpipe via the Draupner riser platforms and Norpipe to Emden, Germany, and 72 million cu m/day through the 42-in. Europipe II to Dornum, Germany.
Karsto has a dedicated plant to stabilize and fractionate the condensate from Sleipner. The fractionation removes ethane, propane, iso-butane, and normal butane. Ships export the stabilized condensate and NGLs to various customers worldwide.
Karsto's NGL capacity is about 10 million tonnes/year. This capacity consists of 112 tonnes/hr (tph) of ethane, 385 tph of propane, 76 tph of i-butane, 145 tph of n-butane, 106 tph of naptha, and 351 tph of condensate. The plant notes that it is ranked as the world's third-largest LPG producer.
At the site, two rock caverns have a capacity to store 250,000 cu m of propane.
At startup 25 years ago, the plant only processed gas from Statpipe. The Sleipner condensate plant was added in 1993, the Asgard plants in 2000, the Mikkel plant in 2003, and the Kristin plants in 2005.
The current upgrade aims to increase Karsto's utilization capacity, extend its life, and meet current safety standards. The work also will replace the NGL metering stations and add facilities to ensure sales gas meets carbon dioxide specifications.
Engineering for the expansion started in 2007 with construction starting in 2008. The work is scheduled for completion in 2012.
Karsto ownership
Karsto is one of the facilities in the Gassled partnership that in 2003 merged nine gas transport systems into one. Partners in Gassled include Petoro 34.459%, Statoil 32.102%, Total E&P 7.783%, Njord Gas Infrastructure 9.428%, Shell 5.319%, Norsea Gas 2.726%, ConocoPhillips 1.996%, Eni 1.525%, and Dong E&P 0.662%.
Njord Gas Infrastructure acquired its Gassled interest early this year from ExxonMobil and is a unit of a holding company owned by UBS International Infrastructure Fund 82% and CDC Infrastructure SA 18%.
ExxonMobil retained its capacity rights to transport gas through the Gassled transport and processing network.
To allow open access to all fields off Norway, Karsto and the Gassled pipeline network is operated by Gassco, a Norwegian state-owned not for profit company. Gassco took over the operations of all gas transport from the Norwegian continental shelf to other countries on Jan. 1, 2002.
The Gassco operated infrastructure includes a 7,800-km pipeline network as well as the Kollsnes and Karsto processing plants. Statoil is the technical service provider for the network.
CO2 sequestration
Karsto also is one of the sites for a Norwegian and UK initiative for studying ways to reduce the costs for CO2 capture and sequestration.
The study involves capturing about 1.1 million tpy of CO2 from the Naturkraft gas-fired power plant and from Karsto's gas processing emissions and transporting the CO2 through a 12-in., 240-km pipeline to an offshore injection site. The pipeline's estimated maximum CO2 capacity will be 3.5 million tpy.
Karsto is the only site in Norway with a gas-fired power plant.
Another site for studying CO2 capture and sequestration in Norway is at the Mongstad refinery. Under construction at the site is a plant that will test amine and chilled ammonia technology for capturing CO2.
The plans for the full-scale project at Mongstad include the capture of 2.2 million tpy of CO2 and studies are under way to evaluate storage locations in the Troll area off Norway. The project may start up in 2014.
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