Measurement and monitoring of CO2 flows across the CCS chain are essential to ensure accurate accounting of captured CO2 and help prevent leakage during transportation to storage sites. However, it is challenging to measure the CO2 mass flow rate under CCS conditions due to the high pressure and temperature involved and the complex flow states (gas, liquid, two-phase or supercritical) in CCS pipelines. The Kent team recently completed the UKCCSRC Call 2 project CO2 Flow Metering Through Multi-Modal Sensing and Statistical Data Fusion.
There were two main aspects of the project: the establishment of a dedicated CO2 flow test facility for flowmeter calibration and evaluation under CCS conditions and the development of a prototype multi-modal sensing system and data fusion algorithms for mass flow metering of CO2. We are delighted to report that all project objectives have been achieved successfully.
The CO2 flow test facility developed is probably one of the very few in the world. This facility is capable of providing single-phase (liquid or gas) or two-phase (liquid/gas) CO2 flows in one-inch bore, horizontal and vertical pipelines with pressures up to 72 bar. The precision weighing system as an integral part of the facility provides an uncertainty of 0.06% for CO2 liquid flows. The reference Coriolis flowmeters equipped on the facility offer uncertainties of 0.16% for CO2 liquid flows and 0.3% for CO2 gas flows. Different two-phase flow regimes such as stratified, bubbly, plug and slug flows can be created. Impurity gases can also be injected into the test section to assess their impact on the performance of CO2 flowmeters and pipeline materials. To design, build and commission the facility, a range of technical challenges have been overcome. The most challenging aspect of the work was related to the health and safety requirements of the key mechanical parts concerning the high pressure of CO2 flow. During the commissioning stage of the facility, several high-pressure valves leaked and had to be replaced. Several versions of the sight windows for observing CO2 flow regimes on the test sections failed before final working models were constructed and installed. Thanks to a concerted, collaborative effort between the Kent Instrumentation team, Krohne Ltd and researchers at Tianjin University and North China Electric Power University. Dr Lijun Sun as the RA working on the project played key role in this part of the project.