Field Experience of the Sequential Combustion System for the GT24/GT26 Gas Turbine Family

Abstract

The first units of the Sequential Combustion System gas turbine family are in commercial operation. The first gas turbine GT24 (60Hz, 165MW-class) started the commercial operation, while the first GT26 (50Hz, 265MW-class) demonstrates its performance at the GT test facility. More engines are presently in the commissioning phase or will be in the near future. These turbines are designed to offer increased output at high GT efficiency. To acheive this, the sequential combustion system, a reheat process with two combustors, has been developed. Whereas the first combustor is based on the proven EV-combustor technology, extensive research and development efforts have been carried out in developing the lean premixed self-igniting second combustor (SEV). This paper is a follow-up of the ASME paper 96-GT-315, which described the basic research work concerning the lean premixing SEV-burners with self-ignition. The present paper reports the experience gained during commissioning of the first engines. The performance of the two combustors, as well as the measured emissions, are discussed and compared with the expected values and rig test results. Finally, the potential of the sequential combustion system to reach low NOx levels is demonstrated by unveiling the results of the extensive testing program during the commissioning phase.

Dynamics and stability of lean-premixed swirl-stabilized combustion

“…In the latter design, the liquid first 8. ABB ALSTOM gas turbine combustion system [64][65][66][67][68][69][70][71][72][73][74][75][76][77][78]. Fig.…”

An insight on intercooling and reheat gas turbine cycles

“…This is because the characteristics and requirements of reheat are very different. Recently, advanced reheated gas turbines have been entering the power generation market (see Joos et al [8]). Even for aeronautical applications, apart from the widely employed afterburner, there is a proposal to adopt interturbine reheat (see Andriani et al [9] and Singh [10]).…”

“…These results indicate that reheat should be installed after the rst turbine stage, if ef ciency is of paramount importance. This is why in advanced reheated gas turbines this layout is adopted (see Joos et al [8]). If speci c power is the objective, it should be installed downstream in the following stages at a lower pressure, as in aeroengines.…”

“…A cycle very similar to that of an existing engine [8] was positioned in Fig. 11, using the ef ciency and speci c power data available in the public domain.…”

A Composite Cycle Engine Concept with Hecto-Pressure Ratio

“…With lean combustion technology such as Lean Direct Injection (LDI) 32 , this factor may be further reduced slightly, although the Joule combustion chamber contributes the minor share to NO x emissions. Potential reduction of NO x concentrations in the Joule/Brayton combustion chamber due to back reaction were neglected, although experience from stationary gas turbines with sequential combustion suggests a significant impact due to the back reaction 33 . Another factor potentially reducing NO x production in the Joule/Brayton combustion chamber originates in the potential for flameless combustion and lower residence times owing to the increased inlet temperature and, hence, better fuel evaporation as well as the presence of oxygen radicals from the first combustion fostering the chemical reactions 34 .…”