Carbon capture, utilization, and storage (CCUS) plays an important role in meeting the European Union’s target to reduce greenhouse gas emissions by 55% by 2030 and become carbon neutral by 2050. Accurate flow metering is required throughout the carbon capture and storage (CCS) chain to meet fiscal and regulatory requirements. To establish accurate CO₂ flow metering, flow meters must be calibrated with traceability to international standards of measurement at relevant flow conditions. To ensure confidence, reliability, and comparability of calibration results, calibration facilities perform interlaboratory comparisons. However, there is currently a lack of CO₂ gas flow meter calibration facilities. The flow metering calibration facilities of VSL, NEL, INRIM, DNV, and FORCE participated in an interlaboratory comparison with CO₂ up to 400 m³/h and 31 bar(a) to compare the calibration results with several flow metering principles. At the intermediate-scale facilities of NEL, VSL, and INRIM, the difference in results between the VSL and INRIM facilities were within the facilities’ CMC values, while NEL’s facility showed a significant difference primarily due to vibrational relaxational effects of CO₂ with small critical flow Venturi nozzles. At the large-scale facilities of NEL, DNV, and FORCE, 91% of the test points passed the equivalency criteria in the range of 20 m³/h to 400 m³/h with a Coriolis meter, confirming traceability for carbon dioxide across the facilities. Overall, the interlaboratory comparison has made it possible for the CCUS industry to calibrate gaseous CO₂ flow meters with traceability to international standards.

A review of single component condensation models is presented. The most exact model for condensation is the set of Becker-Döring equations. The first step toward reduced models is obtained by performing a Taylor series expansion on the discrete Becker-Döring equations, resulting in the Fokker–Planck equation. Further simplification of the Fokker–Planck equation leads to the stationary diffusion flux model, which is based on a steady state assumption in the region of small clusters. Discarding the small cluster size region results in the general dynamic equation, which is computationally the most attractive model. All condensation models are aimed at solving the cluster size distribution and differ in their ability to capture the physical process and their computational complexity. The assumptions needed to construct these reduced models are explained and the influences on the physical outcome are addressed. The models are applied to a nucleation pulse experiment and the computational times are compared.