Research Project Summary Information
Optimization of SCR Control Technology for Reduced Nox Emissions(ST10083-1)
Selective catalytic reduction (SCR) is widely employed by the power industry to control NOx emissions. SCR, nevertheless, converts a portion of SO2 to SO3, which can react with excess ammonia to foul heat exchange surfaces with ammonium bisulfate, e.g., in air preheaters, increasing maintenance costs and reducing heat transfer and power generation efficiency. Design and initial operational setup of SCR systems is dictated and constrained by many parameters. Continuous, optimal, long-term operation of the SCR system requires the appropriate balance among the flue gas, reagent, and catalyst, a balance that is rarely achieved in reality. There is also a lack of and deficiency in SCR process instrumentation and control, resulting in deviations from optimal SCR operation and, consequently, increased operation and maintenance (O&M) costs. A comprehensive approach is needed that considers a combined optimization of boiler and SCR operation, working together with reliable upgraded instrumentation and control scheme.
Specific objectives are: 1) to provide upgraded instrumentation and control capabilities for ammonium bisulfate fouling and air preheater outlet temperature at Cayuga Unit 1; 2) to perform field testing that includes the combined boiler/SCR/back-end system; and 3) to develop upgraded process control strategies for minimum boiler NOx generation, optimal SCR operation, minimum injection of NH3 for maximum NOx reduction, and optimal air pre-heater cold-end operation.
Benefits of the project include reduced stack emissions of NOx, reduced ammonia usage, reduced catalyst replacement frequency, and savings in air pre-heater cleaning. The estimated annual cost savings for a 600 MW unit is between $1-2 million.
The Contractor was able to document significant energy and cost saving with measurement and the application of advanced control algorithms. The AES Cayuga facility has adopted some of the improvements. A final report was prepared and articles published in peer-reviewed journals.
117 Atlss Drive
Bethlehem, PA 18015
Waste Management and Pollution Prevention
NYSERDA Contact Information
R&D -Transport & Power Systems