The Effect of Added Carbon Dioxide on the Relationship between Chemiluminescence and Flame Heat Release in Premixed Natural Gas Combustion Systems

Open Access
Author:
Mulvaney, Kathleen Mara
Area of Honors:
Engineering Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Domenic Adam Santavicca, Thesis Supervisor
  • Barbara Shaw, Honors Advisor
  • Judith A Todd, Faculty Reader
Keywords:
  • combustion
  • natural gas
  • chemiluminescence
  • stationary gas turbines
  • exhaust gas recirculation
  • laminar premixed combustion
Abstract:
Stationary gas turbines that operate with natural gas as fuel generate about one quarter of the country’s electricity each year. Nitrogen oxide (NOx) emissions from these devices are regulated by the Environmental Protection Agency. In order to minimize NOx emissions, the gas turbine combustor flame temperature should be as low as possible while maintaining stable combustion. This is done by operating the combustor with lean premixed fuel and air.Gas turbine combustors that run with lean premixed fuel and air are susceptible to combustion instabilities. Combustion instabilities create a feedback loop in which heat release, pressure, and fluid particle velocity fluctuate. These fluctuations can couple with natural frequencies of the equipment, causing failure of the gas turbine. A proposed method for further reducing pollutant emissions from gas turbines is exhaust gas recirculation (EGR). Additionally, EGR concentrates carbon dioxide in the exhaust, increasing the efficiency of carbon capture technologies. Before EGR can be used in commercial gas turbine systems, it is necessary to understand the effect of recirculated exhaust gases on combustion instabilities. One way that combustion instabilities can be studied to gain knowledge of the effect of EGR on a natural gas combustion flame is by monitoring the flame’s heat release using chemiluminescence emitted by the flame. This study simulates exhaust gas recirculation by mixing carbon dioxide with natural gas and air in a research combustor. Chemiluminescence emission is measured over a range of operating conditions to determine the effect of carbon dioxide addition on the relationship between chemiluminescence intensity and the rate of heat release.