A GAPING hole in the ABB turbine range has been filled with the launch this summer of a new gas turbine. Lead-developed by ABB Stal in Sweden, the GTX 100 is aimed at the growing 30-60 MW market, a segment traditionally dominated by the frame six turbine.

In 1993 the ABB design team was given a straightforward commission: develop a robust, highly-reliable, simple design turbine. It should be capable of withstanding the rigours of use by industry or by an independent power producer. The 43-MW GTX 100 is the result.

'There has been a clear focus during the design phase to keep the turbine's down-time to a minimum,' says Borje Lundqvist, ABB Stal's regional manager for the Middle East. 'The reliability factor and the low maintenance costs have been two of our primary concerns.'

The new turbine draws heavily on ABB's past experience with turbines and its existing range of components. The compressor is a scaled-down version of one used in the larger GT24/26 units. As in other ABB gas turbines, it uses welded-rotor technology. The GTX 100 is, however, the first gas turbine to incorporate ABB's new advanced EV burner technology, which limits emissions of nitrogen oxides and carbon monoxides to 15 ppm with gas feedstock and 25 ppm on liquid fuels.

ABB says that in a simple cycle application the new turbine has a 37 per cent efficiency rating. In combined cycle operation, where output is 62 MW, the rating rises to 54 per cent. It also fits neatly into the existing ABB product range, filling the gap between the 25-MW GT 10 and the 53-MW GT8C.

The first GTX 100 unit is due to roll off the production line at ABB Stal's Finspong plant in Sweden in mid-1998. The GTX 100 will be the fruit of five years' work and an investment of close to $50 million in development and new workshops. As the global market for 30-60 MW turbines is estimated at 5,000 MW a year, and growing at 10-15 per cent a year, the money should prove well spent.