Type of Document Thesis Author Mulkey, Cynthia E. URN etd-10302003-163346 Title Evaluation of Nitrogen Oxide Emissions During Startup of Simple Cycle Combustion Turbines Degree Master of Science Department Civil and Environmental Engineering, Department of Advisory Committee
Advisor Name Title Andrew A. Dzurik Committee Chair Danuta Leszczynska Committee Member Millard W. Hall Committee Member Keywords
- Nitrogen Oxide Limits
- Nitrogen Oxide Emissions
- Combustion Turbines
Date of Defense 2003-06-09 Availability unrestricted AbstractSince the implementation of the Clean Air Act of 1970, regulations have been put into place to greatly reduce air pollution in this country. There has been much recent interest in startup emissions from combustion turbines largely because of the vast number of such turbines coming on line and the current push by the United Sates Environmental Protection Agency to set emission limits on these turbines during startup. The EPA recommends that state agencies establish Best Available Control Technology to limit carbon monoxide and nitrogen oxides during the startup and shutdown of these turbines. It is suspected that emissions during startup and shutdown periods can be a significant fraction of a combustion turbine's annual emissions, particularly for simple cycle peaking units.
Nitrogen oxides emissions during startup; (which requires the turbine to cycle from no load through to its normal operating rate); are higher than during operation at rated generating capacity, and are not well controlled because of the transient nature of the startup process. The same is true for the shutdown period (that requires cycling from capacity to no load). To be responsive to recommendations for emissions during startup and shutdown periods, the Florida Department of Environmental Protection has attempted to quantify and control these “excess” emissions in the past by limiting the duration of these periods. Because of continuing concerns, future determinations for new combustion turbines may include concentration or mass emission limits for nitrogen oxides, and perhaps carbon monoxide during startup and shutdown.
Limiting the duration of the startup periods, presumably keeps emissions during such times within reason. However, startup emissions may be significant enough to require more elaborate limits. Startup data from several General Electric PG 7241FA (7FA) simple cycle gas turbines are reviewed and analyzed. Maximum nitrogen oxides concentrations and mass emissions during startup are examined and compared as well as the durations of the startup events. Recommendations for reasonable limits during startup are explored including a limit of total pounds of NOx emitted during startup, mass emission rates during the startup period, and mass emission rates during the first hour of operation. The overall significance of startup emissions from these units when compared to total annual emissions of the same units, and emissions of other higher polluting units is also considered.
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