Characterization of an Ultrasonic Flowmeter for Liquid and Dense Phase Carbon Dioxide under Static Conditions

Carbon Capture and Storage (CCS), seen as a necessary technology to mitigate global greenhouse gas emissions, requires traceable fiscal metering technologies for large-scale deployment. The present work assesses ultrasonic measurement principles for CO₂. Static tests with pure CO₂ at pressure and temperature conditions relevant for CCS transport via ships and pipelines were undertaken; and the performance of the ultrasonic signals assessed. The effect that the CO₂ attenuation has on the signal quality is evaluated over various densities. The speed of sound measurements are presented and compared to theoretical figures. The results demonstrate that acoustic coupling efficiency of the ultrasonic wave from the transducer into the liquid is strong at high densities, but it deteriorates at transport conditions above 293 K. Consequently, measurement perspectives for shipping and pipeline conditions below 280 K show superior performance for the ultrasonic system under test. This paper also explores the limitations of ultrasonic technology for speed of sound and inter-channel variations.