Faster, More Accurate, Stack-Flow Measurements

Published

February 25, 2020

Author(s)

Aaron N. Johnson, Iosif I. Shinder, Bernard J. Filla, Joey T. Boyd, Rodney A. Bryant, Michael R. Moldover, Thomaa D. Martz, Matthew Gentry

Abstract

Exhaust flows from coal-fired electricity-generating-plants are determined by measuring the flue gas velocity at prescribed points in the stack cross section. These velocity measurements are made using EPA-approved differential pressure probes such as the 2-hole S-probe or the 5-hole spherical probe. Measurements using the more accurate 5-hole spherical probes require a time-consuming rotation (or nulling) of the probe to find the yaw angle. We developed a time-saving non nulling technique using a spherical probe that measures all 3 components of velocity and therefore provides better accuracy than an S-probe. We compared the non-nulling and nulling techniques at both high (16 m/s) and low (7 m/s) loads. Their excellent mutual agreement (within 0.3 % of the flow) demonstrates that the non nulling technique accurately measures flue gas flows in a coal-fired stack.

Citation

Journal of Air and Waste Management Association

Volume

70

Issue

3

Pub Type

Journals

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DOI Link

Keywords

stack, CO2 emissions, flow RATA, relative accuracy test audit, Non-nulling, Spherical Probe, Coal-Fired Stack

Citation

Johnson, A. , Shinder, I. , Filla, B. , Boyd, J. , Bryant, R. , Moldover, M. , Martz, T. and Gentry, M. (2020), Faster, More Accurate, Stack-Flow Measurements, Journal of Air and Waste Management Association, [online], https://doi.org/10.1080/10962247.2020.1713249 (Accessed October 14, 2025)