February 27, 2018 – Smokestacks at coal-fired power plants have sensors that continuously monitor their emissions by measuring the flow of gases such as carbon dioxide, mercury, sulfur dioxide, and nitrogen oxides. By federal law, these sensors need to be calibrated every year. They are calibrated with small, portable flow-measurement devices called pitot tubes.
But scientists suspect there are fairly high uncertainties on the calibration measurements conducted with the pitot tubes. And uncertainties will be a problem for companies if power plants are charged for their emissions under cap-and-trade policies.
In anticipation of the eventual need to increase the accuracy of these measurements, and working in consultation with the Electric Power Research Institute (EPRI) (link is external), researchers at the National Institute of Standards and Technology (NIST) have now measured the uncertainties of the different kinds of pitot tubes now being used to calibrate smokestack-emission sensors.
“The purpose of this study is to give industry options,” said NIST’s Aaron Johnson. “Can we make the measurements better? How much better? And can we do it cheaply?”
Source: Making Smokestack Emissions Tests Better, Faster, Cheaper | NIST
