Gas Fuel Variability Using Buffer Volume in Aeroderivative Gas Turbines

Abstract

General Electric (GE) DLE gas turbines typically use a Gas Chromatograph (GC) and/or a Wobbe Index Meter (WIM) to monitor changing fuel properties during operation. These conventional fuel sensors experience a significant time lag during operation, so a patented buffer volume device and a software algorithm is used to compensate for this lag and to ensure that the control system including metering valves can react to rapid fuel changes. Computational Fluid Dynamics (CFD) was used to design and analyze the buffer volume device that increases the time and distance taken by the gas to the metering valve. This delay provides the control system time to adjust the metering valves when the fuel transitions at the combustor to maintain gas turbine combustor stability and operation during rapid gas property changes that could otherwise result in a trip or flame-out condition. In GE’s Aeroderivative Gas Turbine Gas Fuel transfer system, the innovative buffer volume was the critical component, and this paper describes its performance in detail.