A number of high-pressure pumps from pump and system producer LEWA, which in 2010 will go into service aboard a crude oil processing vessel (FPSO) in the Skarv Idun gas field off the Norwegian coast, first had to be transported via Rotterdam to a shipyard in South Korea. The magnitude of this shipment was very impressive: what is considered ‘compact’ on a gigantic FPSO can be a massive undertaking over a land route. The packaging units required a special low-bed trailer, which, due to its dimensions, was only allowed to travel at night and under escort by police vehicles.
The ‘Skarv Idun’ project
A floating production storage offloading (FPSO) vessel located off the coast of Norway is to be used in the extraction of natural gas. The field contains crude oil and natural gas under elevated pressure. When the natural gas is extracted into a flow line, it expands and cools (the ‘Linde effect’). Problematic here is that solid methane hydrate is produced under certain pressure/temperature conditions, which would plug up the lines. To prevent this, LEWA pumps will be used to inject methanol under high pressure, which serves as an anti-icing agent.
A space- and weight-optimised solution was required for the hydrate inhibitor injection system for the wells, since space is always limited on an FPSO: one square metre of floor space costs approximately $40,000 – each saved ton of material/equipment means a greater load can be taken aboard, i.e. the productivity of the FPSO is increased.
Thanks to its very compact monoblock diaphragm pumps, LEWA is the only company that can deliver the necessary high-performance equipment in the smallest of spaces. The hydrate inhibitor injection system (dimensions: 11.8m x 3.2m) consists of seven space-optimised, triplex high-pressure diaphragm pumps with a total drive power of 500kW at a working pressure of 364bar. Housed separately are two API 674 high-pressure positive displacement pumps (special angular gears save on installation space) with a total drive power of 1,300 kW. The volume of the hydrate inhibitor that is injected into the individual wells is controlled via pressure regulator valves. The systems were built to NORSOK standards (design requirements for technical equipment in offshore applications) and they fulfil strict OSHA requirements (standards related to occupational safety).
That’s just the technology. The logistical effort involved in transporting the pump system to Rotterdam was enormous: packaging units ranged up to 8m in length and 4m in height – with weights of 15, 35 and 50 metric tons. The largest packaging unit was moved out of the production hall using heavy-duty rollers and forklifts, and was then loaded by mobile crane. Since the asphalt outside the building could not support the heavy-duty rollers by itself, 20mm-thick base plates were placed on the pavement.
Only then could the packages be moved onto the low-bed trailer, which was 30m long and equipped with 11 axles.
‘Compact’ is relative – it just depends on the environment.