Vantaa, Finland January 28, 2008 – In October 2007, MAN TURBO of Switzerland announced the successful factory testing of its HOFIM™ compact compressor system, a sub-sea gas compression solution that includes highly tailored basic motor technology from The Switch. This motor is part of a future-oriented project financed by the Åsgard Licence Partners in Norway to develop compression systems for the next generation of oil and gas production. The Switch together with MAN TURBO developed the high-speed motor, based on solid rotor technology, for the compressor system that will be used in a challenging environment of uncleaned wellstream gas.
Successful testing
MAN TURBO’s HOFIM™ compact compressor system is a fully encapsulated design now available with a new developed high-speed motor that has successfully completed factory testing.
According to MAN TURBO, the motor has fulfilled the design duty. Focus was given to robustness, reliability and an easy-to-control manufacturing process. The 10 MW-class machine is running with a maximum speed of 12,500 rpm and is optimized for harsh off-shore and subsea environments. For testing, a dedicated test loop was established, enabling full speed, full power and full temperature testing. The testing of different HOFIM™ configurations started in March and was completed October 2007. Important parameters such as power, maximum and minimum speed, motor temperature, as well as motor cooling gas consumption were varied to investigate the limits of the machine.
Know-how of solid rotor motors
The responsibility of The Switch in this project has been to apply solid rotor technology, which has been used for more than ten years in powers up to 1 MW.
This 10 MW class motor proves that the technology is very easily scalable. This has been proven to be problematic in other motor technologies. Plans call for extending the machine size range up to 32 MW.
“Sour natural gas with sulphur is a really demanding environment for the operation of any compressor,” says Panu Kurronen, Technical Manager of The Switch. “Solid rotor machines for such an application are not commercially available. Therefore, our solution was highly tailored to MAN TURBO’s specifications. The motor is pressurized up to 150 bars. This is the first medium voltage machine for The Switch as well as first with active magnetic bearings. Even the power rating is clearly in its own series.”
The Switch’s 10 MW class motor proves that the solid rotor technology is very easily scalable. This has been proven to be problematic in other motor technologies. Plans call for extending the machine size range up to 32 MW.
Reliability and simplicity
MAN TURBO carried out extensive research on the possible technologies and suppliers in this special field before selecting The Switch in 2004. Based on their initial testing and feedback, the machinery should be simple, robust and compatible with sour and wet hydrocarbon gases. In the end, the most important issue was the reliability and the simplicity of the system. The Switch was the only supplier able to providing solid rotor machines to match their requirements for such a demanding application.
The Switch was the only supplier able to providing solid rotor machines to match MAN TURBO’s requirements for such a demanding application.
“The real innovation, however, is its compatibility with untreated well stream gas,” says Uwe Lauber Head of Engineering & Development of MAN TURBO. “System simplicity is the key to achieving high reliability and minimum maintenance interventions. The HOFIM™ concept uses an intrinsic, instead of an external, cooling system, eliminating numerous auxiliary systems. This improved, unique design offers measurable advantages when applied for subsea gas compression or other remote and demanding applications.”
“Due to the environment and the application, the selection of materials was really challenging. We had a lot of help, however, from StatoilHydro of Norway, which is one of the end customers,” Kurronen continues. “Also other details, including careful material selection, required special attention.”