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.