Experimental evaluation of flame stability and pollutant emissions from a multi-tube fuel injector
According to US Energy Information Administration coal is predicted to be the dominant source of power production in the United States until 2035. With fifty percent of the electricity generated in the United States originating from coal, the US produces close to 2 billion tons of CO2 per year from coal-burning power plants. The Integrated Gasification Combined Cycle (IGCC) offers a cleaner way to generate electricity-using coal. IGCC is a process where the feedstock is gasified and converted into to syngas (CO-H 2) which can then be used as a fuel source to power energy-generating gas turbines. Compared to other hydrocarbons, high hydrogen content fuels behave differently because of their much higher specific heat, higher diffusivity, flammability limits and higher laminar flame speed. The design of a fuel injector plays a vital role in terms of mixing which impacts flame stability inside a high-pressure gas turbine combustor (HPTC). The combustor used for experiments in this thesis has the capability to operate at pressures up to 1.5 MPa and temperatures up to 2400 K. A detailed and effective control and ignition system was developed as part of this work to operate with the combustion chamber. The modified ignition system is used to create a pilot flame. A LabVIEW program was introduced to operate the combustor remotely. Stability was of interest for the experiments since when designing combustion devices it is necessary to know the stability regions, this way stable operation can be maintained. For this thesis flame flashback and flame blowout were defined to be outside of the stable operating conditions. The flashback tendency of the flames was determined to be dependent on the flame speed of the hydrogen. It was also observed that due to the boundary layer effect the central injector ports received the maximum flow rates, resulting in premature flashback in the outer injector ports. As the hydrogen concentration was increased, the flame became less susceptible to blowout. The production of NOx pollutant emission increased for increasing fuel percentage reaching a maximum value at a 40%-60% H2-CO concentration.
Hossain, Sarzina, "Experimental evaluation of flame stability and pollutant emissions from a multi-tube fuel injector" (2014). ETD Collection for University of Texas, El Paso. AAI1564677.