Advanced Combustion Systems for Next Generation Gas Turbines

Download or read book Advanced Combustion Systems for Next Generation Gas Turbines written by Joel Haynes and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Next generation turbine power plants will require high efficiency gas turbines with higher pressure ratios and turbine inlet temperatures than currently available. These increases in gas turbine cycle conditions will tend to increase NOx emissions. As the desire for higher efficiency drives pressure ratios and turbine inlet temperatures ever higher, gas turbines equipped with both lean premixed combustors and selective catalytic reduction after treatment eventually will be unable to meet the new emission goals of sub-3 ppm NOx. New gas turbine combustors are needed with lower emissions than the current state-of-the-art lean premixed combustors. In this program an advanced combustion system for the next generation of gas turbines is being developed with the goal of reducing combustor NOx emissions by 50% below the state-of-the-art. Dry Low NOx (DLN) technology is the current leader in NOx emission technology, guaranteeing 9 ppm NOx emissions for heavy duty F class gas turbines. This development program is directed at exploring advanced concepts which hold promise for meeting the low emissions targets. The trapped vortex combustor is an advanced concept in combustor design. It has been studied widely for aircraft engine applications because it has demonstrated the ability to maintain a stable flame over a wide range of fuel flow rates. Additionally, it has shown significantly lower NOx emission than a typical aircraft engine combustor and with low CO at the same time. The rapid CO burnout and low NOx production of this combustor made it a strong candidate for investigation. Incremental improvements to the DLN technology have not brought the dramatic improvements that are targeted in this program. A revolutionary combustor design is being explored because it captures many of the critical features needed to significantly reduce emissions. Experimental measurements of the combustor performance at atmospheric conditions were completed in the first phase of the program. Emissions measurements were obtained over a variety of operating conditions. A kinetics model is formulated to describe the emissions performance. The model is a tool for determining the conditions for low emission performance. The flow field was also modeled using CFD. A first prototype was developed for low emission performance on natural gas. The design utilized the tools anchored to the atmospheric prototype performance. The 1/6 scale combustor was designed for low emission performance in GE's FA+e gas turbine. A second prototype was developed to evaluate changes in the design approach. The prototype was developed at a 1/10 scale for low emission performance in GE's FA+e gas turbine. The performance of the first two prototypes gave a strong indication of the best design approach. Review of the emission results led to the development of a 3rd prototype to further reduce the combustor emissions. The original plan to produce a scaled-up prototype was pushed out beyond the scope of the current program. The 3rd prototype was designed at 1/10 scale and targeted further reductions in the full-speed full-load emissions.