In 2021

China launched its national carbon market. To enhance the accuracy of carbon trading

it is essential that carbon emission data are measurable

reportable

and verifiable. Against this backdrop

online monitoring systems for flue gas have gained significant attentions as a method of quantifying carbon emissions. The basis for the effective work of continuous emission monitoring systems is the accurate measurement of flue gas flow. However

the challenge in accurately measuring flue gas flow rates is significantly heightened by the large size of power plant chimneys and the complexity of the gas flow characteristics within them. This paper focuses on analyzing the current research status of Pitot tube flowmeters and ultrasonic flowmeters in large-scale duct flow measurement

and provides a detailed introduction to gas flow measurement technologies for large-scale ducts. Additionally

it introduces an independent flow measurement method

namely the tracer gas dilution method

and discusses its current development and potential as a flow calibration method.