Abstract
From the beginning of the offshore oil & gas industry in Norway in 1969, the applications of thermal turbomachinery did often involve new and innovative conceptual solutions. In some cases they had to be followed by extensive modifications on the offshore platforms afterwards, which have resulted in valuable lessons learned.
The list of offshore challenges for thermal turbomachinery has gradually increased over time. The initial challenges involved very high pressure gas compression, low weight machinery, small footprints, low offshore maintenance needs, reliable and safe operation. Later, it also involved strict environmental regulations, reduced emissions, remote control, subsea and multiphase operations.
This paper reviews major technological milestones for offshore application of thermal turbomachinery over five decades. Further, it presents a collation of the experiences that have been made and discussions of their impact on other applications.
The intension of the paper is to transfer experience, and the target group is young engineers and other engineers working with thermal turbomachinery in oil & gas industry.
Initially, the technological milestones were achieved on improvement of centrifugal compressor instabilities in high pressure application, the shift from large heavy duty gas turbines to aeroderivatives and pioneering work on Norwegian small gas turbines. It was followed by a clear trend from gas turbine to electric motor drive, preferably variable speed drive, and a central gas turbine power plant. In the 1990es and beyond, ambitious efforts were made on reduced emissions of CO2 and NOx from gas turbines. Further, achievements were made on dry running gas seals, active magnetic bearings and currently hermetically enclosed compressors without shaft seals. After 2010, the ultimate solution was achieved with combined compressor and electric motor casing, entailing subsea compression and wet gas compression.
