iPaper - Page 1

FPSO News No. 3 · March 2003 Trends in boiler design for FPSOs/FSOs Aalborg Industries offers boiler solutions for both gas turbine and diesel engine installations onboard offshore installations - and solutions for both boiler/burner conversion and new supply. General Aalborg Industries is one of the leading suppliers of marine boilers for the world’s commercial fleet as well as for FPSOs and FSOs. Our wide range of products and a strong after sales organization provide a solid platform to work from. Some of the boilers for FPSOs and FSOs are installed in safe area engine rooms, but most of them have been installed on open deck in hazardous areas. seems clear - the alternative with steam turbines after steam boilers is the best option. For higher capacities, where few brands of gas turbines are available and it can be hard to find a gas turbine with exactly the required capacity, the total investment for the gas turbine installation can easily be as much as four to five times higher than for the steam alternative. For lower capacities where a better selection of gas turbines in suitable sizes is available on the market, and at more reasonable prices, the total cost for the gas turbine alternative might be only twice as high as for the steam alternative. The difference between the two investment alternatives is even more apparent when it comes to the costs of operation, maintenance and downtime. A gas turbine needs to be stopped a few days per year for maintenance and once every 4-5 years for a larger overhauls. The cost of maintenance is high, but as the turbine must be stopped for a few days, the total costs are even higher, much higher. Steam boilers and steam turbines are known to run day in and day out, more or less without supervision or maintenance. With correct water quality in the system and with normal maintenance procedures, the boiler and turbine can run continuously for months, even years. “ESPOIR FPSO” out on the field Gas or steam as power source? In recent years, a number of gas turbines have been installed for power production onboard FPSOs. In many cases, heat recovery boilers have been installed after the gas turbines for production of steam or hot-water for the process. To make the steam system even more reliable, Aalborg Industries pay special attention to the design of the system. Experience from industrial boiler systems is combined with extensive experience from marine main propulsion and auxiliary boiler systems. The MISSION™ boilers are designed to withstand rough seas, even on deck where the g-forces are higher than for the same boilers below deck. Our standard designs for steam and hot-water boilers are based on using heating surfaces extended by means of pins. The pins are welded on tubes resulting in a highly effective surface, which also results in a very compact boiler that can be installed in narrow spaces. Due to the turbulent gas flow around the pins, the self-cleaning effect is high. This type of extended surface has been used in thousands of boilers worldwide! “NORTH SEA PRODUCER” with heat recovery boilers after gas turbines But which is the better solution? A system based on gas turbines with heat recovery boilers, or gas fired steam boilers feeding steam to steam turbines? The answer has at least two dimensions - facts and company culture. But as far as facts are concerned, the best choice

Page 2