* Borescope ports are available tor inspection of five of the compressor stages. * At the front of the air inlet chamber, a door is fitted allowing access to the compressor. * The compressor casing is horizontally split, allowing the top half to be removed tor easy access to the rotor and stator parts. * The combustion chamber can be inspected by removing a burner, through the sight glass or through the bypass at the end of the combustion chamber. ·* An overhead crane is installed inside the gas turbine enclosure to facilitate maintenance and enough space is available to allow operating personnel to walk around the machine. For flexibility, the gas generator can be removed from either side (to be selected) of the installation. A well-established maintenance programme is available tor both GT 10B and GT 1 0C. lnspections and maintenance are carried out at intervals of 10,000 equivalent operating hours and come in five levels, a philosophy which ensures high reliability. The time between major overhauls is 40,000 equivalent hours. Depending on the individual customer requirements, ALSTOM offers a comprehensive service programme, from a simple support agreement up to full responsibility tor preventive as well as corrective maintenance. ALSTOM also stores emergency spares and a spare gas generator tor emergency back up as part of its service agreements. (Figure 4) Leader in environmental technology The combustor is of the annular film-cooled type and is made from welded sheet metal. This design concept has been used tor many years in ALSTOM gas turbines. As early as 1988, recognising the strategic importance of environmental issues, ALSTOM took the lead in the control of gas turbine emissions, introducing the first so-called MAKALE / ARTICLE Fig11re 5: GTJOC AEV bıırner Environmental burner (EV) to the market. The GT10B has 18 such burners. To date, the total accumulated experience with this dry, low-emission (DLE) technology amounts to well over 3 million operating hours tor industrial gas turbines, of which 1.4 million are tor the GT10B, where it is now standard. (Figure 5) With the GT 1 0C, ALSTOM has taken another step in lowering emissions. The combustor has 18 burners of the new Advanced EV (AEV) design, giving the GT 1 0C NOx and CO emissions capabilities below 1 5 ppm (1 5% 02) on natural gas and below 42 ppm (15% 0 2 ) on liquid fuel without the need tor water or steam injection. Dual-fuel dry low emission capability is a built-in feature. (Figure 6) The GT1 O turbines will run on a range of gas and liquid fuels. Two fuel systems are available, tor gas and liquid fuels, which can work independently of each other or in dual-fuel operation, where automatic switch-over between the fuels is possible, in any direction, at full and part load. Cooling and sealing air systems are the same in both turbines. The cooling air is used to cool the compressor turbine rotor, vanes and blades and the sealing air is used to prevent hot gases from entering the bearing housing or oil misi from leaking out from the bearing housings. The auxiliary systems are also largely common to both GT 1 0C and GT10B. Fig11re 6: GTJOC DLE coınbııstor ECOGENERATION WORLD 53
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