Following the approval of my application for the UKCCSRC International Research Collaboration Fund, I visited Tianjin University, from 2 August 2015 to 19 September 2015. The following is a report on the activities that were undertaken during the visit.
The main activity of my visit was to undertake an extensive experimental programme on a 50 mm bore multiphase flow test rig at Tianjin University. The experimental programme lasted 24 days, including 11 days for the actual test work and 13 days for the preparatory work prior to the tests. The flow metering devices that were tested include a latest-generation Coriolis mass flowmeter (Optimass 6400 S50, supplied by Krohne Ltd), an Averaging Differential Pressure (ADP) flow sensor, two electrical impedance sensors with two semi-circle electrodes, and a Differential-Pressure (DP) transducer that was installed across the Coriolis flowmeter. Fig.1 shows the flow metering devices under test on a horizontal pipe section. Various two-phase, three-phase flow conditions were created in both horizontal and vertical pipe sections on the test rig to replicate the CO2 flow under CCS conditions.
The flow media tested include air/water, air/oil and air/oil/water mixtures. The oil tested was #5 white oil (a type of mineral, non-flammable oil with a density of 842 kg/m3 and a viscosity of 14.3 mPa). The mass flow rate of liquid achieved was from 1750 kg/h to 14500 kg/h while the range of air flow rate was 0-120 l/min. The gas volume fraction of up to 45% was achieved during the tests. Owing to the scale of the tests and manpower required for efficient changes in the flow conditions and associated data logging, one researcher from the Tianjin team and one from the Kent team supported Professor Yan throughout the test programme. Fig.2 shows Professor Yan installing the meters on the test rig. Substantial raw data were acquired from the test programme. At the time of writing, the joint research team is still processing the data and applying a range of data fusion techniques for the intended flow measurement. It is expected that the data will be jointly published by the Kent, Tianjin and Krohne Ltd in the near future. The data acquired from the visit is complementary to the current UKCCSRC‐C2‐218 project.
Several discussion meetings were held during my visit. Key staff from the Tianjin team, who attended the meetings, include Professor Tao Zhang, Professor Huaxiang Wang, Dr Ying Xu, Dr Lijun Sun and Dr Dandan Zheng. In addition, Dr Tao Wang from KROHNE Ltd also visited at Tianjin University, as originally planned. Fig.3 shows a group photo of the key staff at the first discussion meeting. The topics discussed at the meetings were focused on the challenges and their possible solutions in CO2 flow metering and establishment of CO2 flow calibration facilities both in China and in the UK as well as the execution of the planned experimental programme at Tianjin University.
Three research seminars were arranged during the visit. The first one was given by the collaborating researcher of this project at Tianjin, Professor Tao Zhang, who gave an overview of the multiphase flow metering expertise and facilities at Tianjin and current projects, including their recent work in supercritical CO2 flow measurement down the oil well. The second seminar, entitled “Coriolis flow measurement technology from a manufacturer’s perspective”, was given by Dr Tao Wang of Krohne Ltd. I gave a seminar entitled “CO2 flow metering and CO2 leakage detection in the CCS chain”. These seminars were attended by about 30 academic staff and research students at the School of Electrical Engineering and Automation at Tianjin University. There were questions from the audience and lively discussions following the seminars.
The significant changes in physical properties of CO2 depending on its state (gas, liquid, two-phase) mean that CO2 flows in CCS pipelines are complex by their nature. In this project we have combined Coriolis, ADP, electrical impedance and DP flow sensors to measure the CO2 flow rate under two-phase or multiphase conditions. The flow sensors tested were supplied collectively by the Tianjin and Kent teams and by Krohne Ltd whilst the Kent team provided the data fusion software. This visit created an excellent opportunity for the international team to undertake an intensive period of research on CO2 flow metering in CCS. The visit has benefited all parties in different ways, particularly the team members from the UK and China as well as the instrument manufacturer Krohne Ltd. The visit has enabled the Kent team to access the best expertise and facilities available in China in the area of CO2 flow metering. As a result of this visit, a stronger international partnership on CO2 flow measurement has been established. Follow-on activities are expected in the near future.