FT8-3 Advanced Low Emissions Combustor Design

Pratt and Whitney developed a novel water-injected industrial gas turbine combustor liner design that has demonstrated significant reduction in CO emissions when compared with typical film-cooled combustor designs. The CO reduction demonstrated in a prototype test shows that the CO quenching due to cooler film temperatures near the liner wall is a significant source of CO emissions in a conventional water-injected combustor operating on natural gas fuel. This finding paved the way for a combustor design that reduces CO emissions while still maintaining low levels of $NOx$ emissions. This design also has potential for lower $NOx$ since the low CO emissions characteristic enables increased water injection. This paper presents the emissions characteristic measured on prototype hardware and the design of the engine hardware for future validation. Significant reduction in gaseous emissions was demonstrated with the testing of a prototype at the United Technologies Research Center in East Hartford, CT. This reduction in emissions compared with the baseline film-cooled design for a given operating condition has many benefits to the customer, including the reduced need for exhaust catalyst cleanup and extended operating times while still meeting site permits specified in CO tons per year. Other benefits may include the ability to guarantee lower $NOx$ emissions through increased water injection for the current CO emissions output.