Advanced Combustion Systems for Next Generation Gas Turbines

Abstract

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 3 rd 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 3 rd prototype was designed at 1/10 scale an...

Active control of combustors after twenty years' efforts

“…One promising possibility being actively pursued by GE and others is the trapped vortex combustor (TVC). A good description of the basic ideas and recent experimental results have been given by Haynes et al [41]. Figure 14a is a drawing of their best device; Fig.…”

“…The TVC: (a) a sketch of the combustor use in GE work [41] and (b) a notion suggestive of a possible axisymmetric installation (AFRL release) gions near surfaces, or in corners and around obstacles may be responsible. Unsteady viscous e¨ects, causing §uctuations of composition and mixture ratio, locally can be signi¦cant.…”

Review of the New Combustion Technologies in Modern Gas Turbines

“…The trapped vortex combustion concept has been under investigation since the early 1990's. The earlier studies of TVC have been concentrated on liquid fuel applications for aircraft combustors [12].…”

Translation and the Visual Predicament of the “JESUS” Film in West Africa

“…While African video film productions fall into a number of different genres, they often follow the conventions of the melodrama (Haynes 2000;Meyer 2004:99-100). They take up local beliefs and practices and deal with culture-specific issues of relationships, both within the family and with invisible powers.…”