Gas Turbine Developments
Author: Chris W. Maude and Andrew T. Kirchner
Date: September 1995
Abstract: This report aims to identify gas turbine features which may influence the design and performance of emerging coal-based combined cycle systems for power generation. Improved performance is obtained most readily from increased turbine entry temperature. Several manufacturers are developing improved combustion systems which limit NOx production without the need for additional gas treatment.
These developments may impose a limit on the maximum acceptable cycle temperature. Developers are also exploring alternative methods of boosting performance. These include cycle modifications such as compression intercooling, exhaust gas recuperation and turbine gas reheat.
Modern gas turbines are often designed to operate with high quality gaseous fuels. This approach is expected to favor developments of IGCC systems with inherent ability to meet stringent gas quality requirements. However, various systems intended for direct coal combustion, which may be less complex, are also being developed. Pressurized fluidised bed combustion, with a specially adapted gas turbine system, has reached a stage of commercial application. Developments in material technology, which are essential requirements for improved performance and service lives in gas turbines, are also reviewed.