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NIST Programs to Advance Accurate, Internationally-Recognized Stack Emissions Measurements



Aaron N. Johnson, Iosif I. Shinder, Rodney A. Bryant, JohnPaul R. Abbott, Keith A. Gillis, Joey T. Boyd, Bernard J. Filla, Michael R. Moldover


Accurate flow measurements are essential to quantify the amount of greenhouse gases (GHGs) and other pollutants emitted from power plant stacks. Although protocols have been developed, the uncertainty of stack flow measurements has not been documented.  Large differences between CEMS and EIA CO2 emissions data suggest better measurements are needed. NIST has focused on improving the accuracy of the flow measurements since concentration measurements are traceable to NIST via certified gas standards, but no path of flow traceability exist. Moreover, the adverse flow conditions (turbulent, swirling flow with skewed velocity profiles) that are prevalent in stacks make accurate flow measurements difficult.  To address this problem NIST is developing measurement programs to quantify, and potentially lower, the uncertainty of flow measurements.  Measurement programs encompass 1) NIST Airspeed Facility for S-Type and Multi-Hole Differential Pressure Probes, 2) assessing the performance of CEMS flow monitors and pitot traverse methods using the Scale-Model Smokestack Simulator, 3) Evaluating CO2 Emissions using the National Fire Research Laboratory, and 4) developing innovative ways of measuring flow using long wavelength sound. 
Proceedings Title
MEGA Symposium 2016
Conference Dates
August 16-18, 2016
Conference Location
Baltimore, MD
Conference Title
Power Plant Pollutant Control and Carbon Management


airspeed, s-probe, turbulence, flow calibration, stack velocity, smokestack, continuous emissions monitoring, carbon dioxide, greenhouse gas, calorimetry, fire research, ultrasonic flow monitor, CEMS, RATA, relative accuracy test audit, flow traceability, NFRL, SMSS, long wavelength acoustic flowmeter, doppler effect
Created September 15, 2016, Updated February 19, 2017