Alstom Gas Turbine Technology Overview: Status 2014

Abstract

Market requirements for the heavy duty gas turbine power generation business have significantly changed over the last few years. With high gas prices in former times, all users have been mainly focusing on efficiency in addition to overall life cycle costs. Today individual countries see different requirements, which is easily explainable picking three typical trends. In the United States, with the exploitation of shale gas, gas prices are at a very low level. Hence, many gas turbines are used as base load engines, i.e. nearly constant loads for extended times. For these engines reliability is of main importance and efficiency somewhat less. In Japan gas prices are extremely high, and therefore the need for efficiency is significantly higher. Due to the challenge to partly replace nuclear plants, these engines as well are mainly intended for base load operation. In Europe, with the mid and long term carbon reduction strategy, heavy duty gas turbines is mainly used to compensate for intermittent renewable power generation. As a consequence, very high cyclic operation including fast and reliable start-up, very high loading gradients, including frequency response, and extended minimum and maximum operating ranges are required. Additionally, there are other features that are frequently requested. Fuel flexibility is a major demand, reaching from fuels of lower purity, i.e. with higher carbon (C2+), content up to possible combustion of gases generated by electrolysis (H2). Lifecycle optimization, as another important request, relies on new technologies for reconditioning, lifetime monitoring, and improved lifetime prediction methods. Out of Alstom’s recent research and development activities the following items are specifically addressed in this paper. Thermodynamic engine modelling and associated tasks are discussed, as well as the improvement and introduction of new operating concepts. Furthermore extended applications of design methodologies are shown. An additional focus is set ono improve emission behaviour understanding and increased fuel flexibility. Finally, some applications of the new technologies in Alstom products are given, indicating the focus on market requirements and customer care.

Study on the Flame Transition Characteristics of a Gas Turbine Combustor

“…Another typical stage fuel combustion system is the GT24/GT26 heavy-duty gas turbines sequential combustion system proposed by Alstom [28,29]. This system features an axial stage combustion design, with the first stage utilizing a premix mode and the second stage integrating a reheat combustor [30,31]. The sequential combustion technology improves both operability and fuel flexibility of gas turbines, consequently facilitating stable combustion and minimizing emissions across a broad range of engine loads [32,33].…”