Current gas turbine expansion starters use pressurized pipeline gas regulated down to relatively low pressures (e.g. 150-200 psig) and expand the gas to atmospheric pressure through a small expansion turbine or helical screw and transmit the resulting horsepower to the gas turbine to accelerate it to light-off and self-sustaining speeds. Although the expansion starter is fairly inexpensive, the large quantity of gas required to start the turbine is vented to the atmosphere and results in high operating costs (particularly for large turbines with long purge cycles) and significant greenhouse gas emissions.
This project was contracted with Southwest Research Institute to identify alternative starter concepts and classify them according to their readiness and suitability for use with a pipeline gas turbine in typical applications. A multi-industry search of methods for generating auxiliary shaft horsepower at the scale of pipeline gas turbines was performed to identify and evaluate any possible concepts for starting gas turbines. The search identified over 30 potential concepts that were classified as either “readily available,” “adaptable,” or “new.” Detailed cost and performance information was gathered for the readily available concepts to perform a quantitative concept comparison for various pipeline application scenarios.
A proposed 2010 project is aimed at performing an engineering feasibility study on several specific hardware configurations that appear to be practical to implement, to determine which is optimal for pipeline operations.