UKCCSRC Call 2 Project – Performance of Flow Meters with Dense Phase CO₂ and CCS Recovery Streams

My name is Mahmoud Nazeri and I am working as a research associate on the UKCCSRC project to investigate the performance of flow meters with dense phase CO₂ and CCS recovery streams at the Centre for Innovation in Carbon Capture and Storage (CICCS) at Heriot-Watt University. Prof Mercedes Maroto-Valer is the project PI and the Director of the Centre for Innovation in Carbon Capture and Storage (CICCS) at Heriot-Watt Univeristy.  The project also has Krohne as industrial partner.

During my PhD in petroleum engineering in the Institute of Petroleum Engineering (IPE) at Heriot-Watt University, I was working on the effect of impurities on thermophysical properties of CO₂-rich mixtures in CCS, including measurement and modelling of density, viscosity and frost point of high CO₂ content fluids at elevated pressures and high temperatures conditions. For me, this current UKCCSRC project is an extension of my achievements from my PhD to flow metering, as the performance of flow meters depends on the physical properties of the transported fluid.

In any carbon capture and storage project, different technologies can be employed to capture the CO₂ from the flue gases in power plant and industrial sources. The CO₂ captured is not pure and may contain impurities, with the type and concentrations depending on the capture technology employed. The captured CO₂ is then transported to the storage sites mostly by pipelines. One of the important issues in this stage is measuring the quantity of the pipelined CO₂ with impurities using flow meters. In this project, a Coriolis mass flow meter was selected, as they measure the mass directly and can have more accuracy compared to other flow meters, such as volumetric or differential pressure flow meters.

In this project we use a flow loop shown below that has been designed and constructed to calibrate and evaluate the selected flow meter. The calibration results of this system have been recently published in the journal Applied Energy. One of the most challenging issues at the beginning of the research was designing the flow loop to perform the evaluation of flowmeters which requires the combination knowledge of fluid mechanics, thermodynamics, automation and equipment design. Another challenge in this research was working at elevated pressures which need a high level of safety considerations, particularly with unusual physical properties of CO₂ in comparison to other fluids like natural gas and oil.

After optimising the design and preparing the flow loop, the system was calibrated using pure CO₂ both in the gas and dense liquid phases. Then, according to the literature review, different gas mixtures representing the outlet fluids from different capture technologies (post-combustion, pre-combustion and oxyfuel) were ordered from BOC, a gas company specialist in preparing scientific gas mixtures. The gas mixtures were then connected to the flow loop and the performance of Coriolis flow meter is being evaluated by comparing the amount of the mass shown by flowmeter to the amount of the mass measured using a robust weighing scale. This is a common technique used commercially to evaluate the performance of flowmeters. We are planning to conduct these comparative studies several times for each mixture at different pressure, temperature and flow rates to obtain the average uncertainty of the flowmeter. The results conducted thus far have shown that the uncertainty level of the selected flowmeter is in good agreement with the specifications and regulations mentioned by European Union Emission Trading Scheme (EU ETS) which stated the uncertainty must be below 1.5 mass percent.

The project will finish this summer so you will hear more from me then!