Calibration of an Averaging Pitot Tube for Gaseous CO2 Flowmetering

In this paper, an averaging pitot tube (APT) with flow conditioning wing (FCW) geometry is used as a practical sensing device to measure and characterize the flow of single-phase gaseous carbon dioxide (CO₂). This technique demonstrates a simple, cost-effective, and potentially accurate option toward the measurement, accurate accounting, and characterization of CO₂ in carbon capture and storage pipelines. The metrological performance of the flow sensor is verified using air medium before being applied for gaseous CO₂. With a Coriolis mass flowmeter acting as a secondary calibration reference to further validate the performance of the APT-FCW flow sensor, both metering instruments were evaluated against a weighing scale apparatus. From the experimental and calibration data with air, the APT-FCWs average K-factor and linearity error are found to be 0.5091 and 0.725%, respectively. With operating conditions remaining unaltered in this particular flow measurement application and a target metering error within ±1%, the errors achieved for the Coriolis meter and the APT-FCW are better than ±0.6% and ±1.2%, respectively. Total uncertainty estimations under the stipulated environmental and working conditions are within ±1% and ±1.5% for the Coriolis meter and APT-FCW, respectively. The test results and other performance evaluation of the instruments are also discussed.