National Measurement System
National Measurement System
Explore our Publications section to access the work carried out by our flow measurement experts as part of the NMS research programmes.
Read some of our recent academic journal articles to learn more about the research carried out at the UK’s Designated Institute for Flow and Density Measurement.
Russell Brown a, Gabriele Chinello a, Marcel Workamp b, Bodo Mickan c
Flow Measurement and Instrumentation Volume 99, October 2024, 102672
The need for accurate flow measurement within the Carbon Capture, Utilisation and Storage (CCUS) transport network is widely reported and understood as a requirement of Emission Trading Schemes and commercial contracts. In meeting this requirement, traceable calibration is needed in conditions which closely mimic the process conditions. However, currently accredited calibration facilities cannot meet the conditions for calibrating in gaseous CO2 and so a likely alternative solution for these custody transfer flow meters is to be calibrated with an alternative fluid and the calibration transferred. In this article, which was produced under the framework of the EMPIR project “Metrology for Decarbonising the Gas Grid”, the authors will investigate this approach with a number of flow meters tested in natural gas, nitrogen gas and finally in carbon dioxide gas at varying pressures. The results of which will suggest that orifice and Coriolis meters can be calibrated in another fluid however, an ultrasonic meter would require further work and potentially require calibration in CO2. This article will also investigate the effects of impurities in a CO2 gas stream for a rotary displacement flow meter and a thermal mass flow controller compared against a piston prover which provides a primary reference flow standard.
a
TÜV SÜD National Engineering Laboratory, East Kilbride, United Kingdom
b
VSL National Metrology Institute, Delft, the Netherlands
c
Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
Johnson Jimba a, Gabriele Chinello b, Russell Brown b, Sean Higgins a, M. Mercedes Maroto-Valer a
International Journal of Greenhouse Gas Control Volume 136, July 2024, 104191
Accurate flow measurement plays a pivotal role in monitoring CO2 flows across the CCS value chain. This not only bolsters the overall business model of the CCS industry, but also ensures adherence to environmental legislations and regulatory requirements. Unlike other industrial process fluids, such as water, oil & natural gas, it is unclear whether current commercially available metering technologies can meet the requisite accuracy levels, specifically the ±2.5 % recommended within the EU/UK European Trading Scheme for CO2 mass transfer. Accordingly, the aim of this work was to gain a comprehensive understanding of CO2 flow measurement within the context of CCS transport conditions. Firstly, GERG-2008 equation of state was implemented on REFPROP v10 to predict the optimal transport conditions for CO2-rich mixtures and to understand the influence of non-condensable gas impurities in CCS flow operations. Then, a dedicated laboratory-scale gravimetric flow facility was designed and used to evaluate the performance of a Coriolis flow meter under gas, liquid, and supercritical flow conditions. The results indicate that the impurities have a relatively minor impact on the measurement performance of the meter, with maximum mean absolute measurement errors of 0.25 %, 0.12 %, and 0.28 % observed in gas, liquid, and supercritical CO2 flow conditions, respectively. The findings support the use of Coriolis metering technology as a reliable option for CCS metering, underscoring its suitability for accurate measurements in single-phase CO2 transport applications.
a
Research Centre for Carbon Solutions (RCCS), School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom
b
TÜV SÜD National Engineering Laboratory, East Kilbride, Glasgow, G75 0QF, United Kingdom
Russell Brown, Gabriele Chinello, Flow Measurement and Instrumentation, Volume 98, September 2024, 102644
Carbon Capture Utilisation and Storage (CCUS) technology is pivotal for achieving global emissions reduction goals. The rise in CCUS facilities, with a near doubling of global capture capacity, indicates industry momentum. Robust flow measurement across the CCUS transport and storage networks are essential for commercial contracts, financial incentives, and regulatory compliance since these are underpinned by accurate quantification of the CO2 quantity transferred across the CCUS chain. However, a critical gap exists in verification and quality assurance of flow meters as currently there are no traceable calibration facilities that operates with liquid and/or dense phase CO2. However, globally there are many accredited traceable water and oil calibration facilities in operation, which can meet the required flow rates and meter sizes. An experimental study was then conducted at TÜV SÜD National Engineering Laboratory, UK, and at the Institute for Energy Technologies, NO, to explore the transferability of calibration between water, oil, and CO2 using five flow meter technologies with the aim of providing a preliminary assessment of whether meters calibrated in alternative fluids can accurately measure liquid and supercritical CO2. The results suggest that this approach could work for Coriolis meters. The results also suggest caution in relying solely on using Equations of State to calculate density values and a recommendation is presented to currently employing direct density measurements until a more comprehensive understanding is achieved on Equations of State performance for CO2-rich mixtures. To the best of the author's knowledge this is the first time that such experimental investigation is conducted, and the results shared publicly.
Marc MacDonald, Dale Anderson et al, Flow Measurement and Instrumentation, Volume 97, July 2024, 102594
A considerable reduction in greenhouse gas emissions may be achieved if hydrogen is injected to the European gas networks, but accuracy of billing must be ensured. This paper presents the results for accuracy testing on seven domestic and one commercial gas meter. The domestic meters were calibrated by two different laboratories, at atmospheric pressure using various gases including hydrogen, methane and mixtures of hydrogen with methane. A third laboratory performed calibrations on a rotary gas meter with hydrogen and hydrogen/natural gas mixtures at two test pressures: 9 and 16 bar.
For the domestic meter tests, consistent results were obtained from both facilities. Most meters tested met the accuracy requirements of the applicable standards. Whilst the error curves differed for each test gas, errors for hydrogen or hydrogen/methane blends were comparable with the other test gases. For the calibrations of the rotary gas meter, differences in the error curves between natural gas and the hydrogen/natural gas mixture were smaller than the measurement uncertainty of the test facility and therefore considered metrologically insignificant.
Dr Gabriele Chinello, Dr Edris Joonaki et al., 18 June 2024, Nexus, Volume 1, Issue 2, 100013
Anthropogenic greenhouse gas emissions, particularly carbon dioxide (CO2), are unequivocally linked to the observed global warming trend. Urgent mitigation measures are imperative to combat irreversible climate changes. Carbon capture and storage (CCS) stands as a pivotal technology for reducing CO2 emissions by serving as an artificial sink. However, global deployment of CCS faces multiple challenges encompassing technical, regulatory, policy, and financial realms. Despite governmental strategies and ongoing efforts, current CCS deployment remains minimal compared with emission rates. Accurate measurement and quantification of captured CO2 are crucial for financial transactions, regulatory compliance, and product certification. Addressing the need for standardized measurement practices, this review identifies measurement requirements across the CCS chain and outlines technical aspects of equipment. While previous studies have tackled specific technical challenges, this review offers a comprehensive examination of flow measurement, composition analysis, and fluid properties collectively, bridging research developments with industrial needs. By highlighting existing gaps and offering recommendations, this article aims to contribute to the establishment of an international standard for CO2 measurement across the CCS value chain.
Kehinde Owoeye, August 2023, Procedia Computer Science, Vol. 222
Current trends in language modelling leverage large language models pre-trained on a huge corpus of data to achieve state of the art results on several NLP tasks. On the other hand, humans acquire language from small amount of data using cognitive principles. Recently, a continual learning approach using compositionality to disentangle the syntax and semantics of an input sentence for downstream sequence to sequence tasks was proposed. In this work, we show how curriculum learning can be incorporated with this framework to improve performance. More specifically, first, we show that using the model of interest with reduced hidden size as the auxiliary model to generate curriculum is not necessarily optimal and second, we propose a novel variant of the one best score approach for curriculum learning where, a sequence to sequence model is used as the auxiliary model to generate the conditional probabilities of word predictions (proxy for difficulty) and consequently used this to generate a curriculum. Results on a variety of translation tasks, demonstrate the superiority of the proposed approach compared to several baselines, enabling the improvement of sentence accuracy with respect to knowledge transfer and catastrophic-forgetting both by at least a significant margin of 35% with respect to the best performing baseline on the English-French translation task.
Chen, Yuan; Chinello, Gabriele; Tait, Paul; Jia, Jiabin, December 2022, Flow Measurement and Instrumentation Vol. 88
Venturi tubes are widely used to measure the gas flow rate in a wet-gas stream. To calculate the gas flow rate, wet-gas Venturi tubes require the liquid loading (i.e. Lockhart-Martinelli parameter) to be known as an input to a so-called over-reading correction correlation. It is challenging to derive the Lockhart-Martinelli parameter without installing additional devices in series to the Venturi tube thus adding significant cost and complexity. A relatively low cost and easy to implement method is to derive the Lockhart-Martinelli parameter by measuring the pressure drop across the Venturi tube or along a pipe section. A correlation that predicts the Lockhart-Martinelli parameter by measuring the pressure drop along a vertical pipe section downstream of the Venturi tube is presented. The correlation was obtained by fitting experimental results from TUV-SUD National Engineering Laboratory's wet-gas test facility with nitrogen-water in a 4″ vertical pipe, Lockhart-Martinelli from 0.04 to 0.29, and gas Froude number from 1 to 2.7. Further experiments were conducted at Spirax Sarco Engineering plc to evaluate the performance of the proposed correlation under steam-water conditions. Tests were conducted with steam-water in a vertical 2″ pipe, Lockhart-Martinelli from 0.005 to 0.064, and gas Froude number from 0.55 to 1.35. The Lockhart-Martinelli parameter is predicted within ±0.035 absolute value with the proposed new correlation for both the National Engineering Laboratory and Spirax Sarco datasets. Gas flow rate values within approximately ±5% error are obtained with the proposed correlation together with ISO/TR 11583 over-reading correlation for the NEL dataset. Although further improvements to the proposed method are required, this work demonstrates the efficacy of an agile, simple, and low-cost differential pressure method to aid the Venturi meter to determine the gas mass flow rate in wet-gas flow.
Olbrich, Marc; Riazy, Leili; Kretz, Tobias; Leonard, Terri; van Putten, Dennis S.; Bär, Markus; Oberleithner, Kilian; Schmelter, Sonja, December 2022, International Journal of Multiphase Flow Vol. 157
The slug flow pattern is one of the most common gas–liquid flow patterns in multiphase transportation pipelines, particularly in the oil and gas industry. This flow pattern can cause severe problems for industrial processes. Hence, a detailed description of the spatial distribution of the different phases in the pipe is needed for automated process control and calibration of predictive models. In this paper, a deep-learning based image processing technique is presented that extracts the gas–liquid interface from video observations of multiphase flows in horizontal pipes. The supervised deep learning model consists of a convolutional neural network, which was trained and tested with video data from slug flow experiments. The consistency of the hand-labelled data and the predictions of the trained model have been evaluated in an inter-observer reliability test. The model was further tested with other data sets, which also included recordings of a different flow pattern. It is shown that the presented method provides accurate and reliable predictions of the gas–liquid interface for slug flow as well as for other separate flow patterns. Moreover, it is demonstrated how flow characteristics can be obtained from the results of the deep-learning based image processing technique.
Mills, Chris; Chinello, Gabriele; Henry, Manus, December 2022, Flow Measurement and Instrumentation, Vol.88
Carbon Capture, Utilisation and Storage (CCUS) is a key element in the United Kingdom Government strategy for reducing carbon dioxide (CO2) emissions. The UK aims to capture and store 10 million tonnes of CO2 each year by 2030. At each stage in the CCUS infrastructure, accurate measurement of the CO2 flow rate is required, over a range of temperatures, pressures, flow rates and fluid phases, where the flow measurement must be validated through a credible traceability chain. The traceability chain provides the underpinning confidence required to verify meter performance, financial and fiscal transactions, and environmental compliance. The UK equivalent of the EU Emissions Trading System (EU ETS) specifies a maximum uncertainty value for CO2 flow measurement. Accordingly, the provision of accurate and traceable flow measurement of CO2 is a prerequisite for an operational CCUS scheme. However, there are currently no CO2 flow measurement facilities, nationally or internationally, providing traceable flow calibrations of gas phase, liquid/dense phase and supercritical phase CO2 that replicate real-world CCUS conditions. This lack of traceable CO2 gas and liquid flow measurement facilities and associated flow measurement standards is a significant barrier to the successful implementation of CCUS projects worldwide. This paper presents an overview of the traceability chain required for CO2 flow measurement in the UK and globally. Current challenges are described along with potential solutions and opportunities for the flow measurement community.
Mills, Chris; Batista, Elsa; Bissig, Hugo; Ogheard, Florestan; Boudaoud, Abir Wissam; Büker, Oliver; Stolt, Krister; Morgan, John; Kartmann, Sabrina; Thiemann, Kerstin; Miotto, Guilherme; Niemann, Anders; Klein, Stephan; Ratering, Gijs; Lötters, Joost, August 2022, Biomedical Engineering / Biomedizinische Technik, Vol. 68
Improving the accuracy and enabling traceable measurements of volume, flow, and pressure in existing drug delivery devices and in-line sensors operating at very low flow rates is essential in several fields of activities and specially in medical applications. This can only be achieved through the development of new calibrationmethods and by expanding the existing metrological infrastructure to perform micro-flow and nano-flow measurements. In this paper, we will investigate new traceable techniques for measuring flow rate, from 5 nL/min to 1,500 nL/min and present the results of an inter-comparison between nine laboratories for the calibration of two different flow meters and a syringe pump.
Tait, Paul; Chen, Yuan; Senjyu, Wataru; Watanabe, Toru; Inamura, Yasuo; Presotto, Valentina; Mojsak, Radek; Chinello, Gabriele; Jia, Jiabin, Mar 2022, Flow Measurement and Instrumentation, Vol. 83
The measurement of void fraction in multiphase flow is important for a wide range of industrial processes. Existing methods for void fraction measurement require intrusive, expensive and potentially hazardous equipments which constrict the flow, adding both capital and operational costs. Two phase flow experiments were carried out at the National Engineering Laboratory (NEL) to measure void fraction via pressure drop in a vertical pipe. Additional experiments are carried out at Spirax Sarco Inc. to validate the efficacy of the method on steam/water flow mixtures at high temperature and pressure, in gas mass fraction range between 0.17 and 0.95 and void fraction range between 0.75 and 1.0. The void fraction calculated by the presented differential pressure (dP) method is confirmed via established correlations. The work demonstrates the efficacy of a low cost, non-intrusive method to determine void fraction in two phase flow over a wide range of flow conditions.
Edris Joonaki, June 2021, ACS Energy Letters 2021 6 (6), 2181-2186
Can the Oil and Gas Industry be a Credible Partner in Attaining the Net-Zero Target?
Not only oil & gas infrastructure, but also oil & gas knowledge can be repurposed to develop both existing and emerging Hydrogen and CCUS technologies.
Potentially as part of decommissioning plan and for reducing costs integrated into any new business model, the depleted hydrocarbon fields with a wealth of reservoir and operational data can be repurposed for the storage of blue/green hydrogen as a sustainable low-carbon energy source. Digitalised platforms will be asset to this strategy.
Finally, there will be limited competition with CO2 geological storage for place, as hydrogen will require one large storage site to provide proper capacity for seasonal energy storage for many countries worldwide. Both of these crucial decarbonisation technologies could work in parallel to limit global climate change.
Author: Aliakbar Hassanpouryouzband, Edris Joonaki, Katriona Edlmann, and R. Stuart Haszeldine
Journal: ACS Energy Letters 2021 6 (6), 2181-2186
Dr Chris Mills, March 2020, Flow Measurement and Instrumentation, Vol. 71.
The temperature, pressure and viscosity of produced oil from a reservoir can differ considerably from standard calibration laboratory conditions. The standard practice for calibrating flow meters for the oil & gas industry has been to match the fluid viscosity and, if possible, the fluid temperature and pressure. However, matching all parameters is seldom possible due to the limitations set by the calibration facilities. As such, the parameter that is most often matched is the fluid viscosity. A limitation of the above approach is that temperature and pressure variations are known to influence properties, other than fluid viscosity, that may also be critical to the overall measurement uncertainty.
To address this, NEL have built and commissioned a fully accredited elevated pressure and temperature (EPAT) liquid flow facility. This facility has been used to investigate the performance of flow meters at elevated pressures and temperatures. It also allows for liquid flow calibrations to be completed close to service conditions. This work will provide traceable data on the performance of Coriolis flow meters when operated at elevated pressures and temperatures. This data can then be used to update the Coriolis ISO standard 10790. At present, the latest revision in 2015 includes little practical guidance for the operation of Coriolis meters at elevated pressures, temperatures and viscosities.
Unfortunately, the methodology for calibrating and operating Coriolis meters at elevated conditions appears fragmented.
The purpose of this paper will be to highlight the influence of elevated temperatures, pressures and viscosities and to provide the end user with the correct methodology for calibrating Coriolis meters for these conditions. The paper will also highlight the requirement for the ISO standard 10790 to be updated given the current knowledge level.
Author: Chris Mills
Journal: Flow Measurement and Instrumentation
Volume 71, March 2020, 101649
Marc MacDonald, February 2021, Flow Measurement and Instrumentation, 101915
The performance of four Coriolis flow meters designed for use in hydrogen refuelling stations was evaluated with air and nitrogen by three members of the MetroHyVe JRP consortium: NEL, METAS and CESAME EXADEBIT.
A wide range of conditions were tested overall, with gas flow rates ranging from (0.05–2) kg/min and pressures ranging from (20–86) bar. The majority of tests were conducted at nominal pressures of either 20 bar or 40 bar, in order to match the density of hydrogen at 350 bar and 20 °C or 700 bar and −40 °C. For the conditions tested, pressure did not have a noticeable influence on meter performance.
When the flow meters were operated at ambient temperatures and within the manufacturer's recommended flow rate ranges, errors were generally within ±1%. Errors within ±0.5% were achievable for the medium to high flow rates.
The influence of temperature on meter performance was also studied, with testing under both stable and transient conditions and temperatures as low as −40 °C.
When the tested flow meters were allowed sufficient time to reach thermal equilibrium with the incoming gas, temperature effects were limited. The magnitude and spread of errors increased, but errors within ±2% were achievable at moderate to high flow rates. Conversely, errors as high as 15% were observed in tests where logging began before temperatures stabilised and there was a large difference in temperature between the flow meter and the incoming gas.
One of the flow meters tested with nitrogen was later installed in a hydrogen refuelling station and tested against the METAS Hydrogen Field Test Standard (HFTS). Under these conditions, errors ranged from 0.47% to 0.91%. Testing with nitrogen at the same flow rates yielded errors of −0.61% to −0.82%.
Author: Marc MacDonald, Marc de Huu, Rémy Maury, Oliver Büker
Journal: Journal of Flow Measurement and Instrumentation
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Dr Asaad Kenbar, January 2021, Cryogenics, Vol 113
The global custody transfer market for liquefied natural gas (LNG) has grown at a strong pace in the last decade and use of LNG as transport fuel has considerable environmental benefits. The quantity of LNG is traded on the basis of energy transferred, calculated from volume, density and gross calorific value. High-speed, accurate density measurement is therefore of significant commercial value.
The electrical capacitance tomography (ECT) device described in this paper has the potential to measure the LNG density rapidly, on-line at a moderate cost. Continuous monitoring of variation in LNG density during dynamic LNG flow measurement also gives a good indication of change in fluid quality and thus onset of boiling which is known to affect measurement accuracy. ECT is a leading candidate to be explored for online density measurements through measurement of electrical permittivity, as in addition to average value, it offers the image of permittivity across the whole flow conduit, allowing localised bubbles, boiling or other variations to be identified and measured.
We report here experiments to explore the use of ECT in cryogenic applications. An 8-electrode test ECT sensor was designed, built and tested in laboratory conditions and then in liquid nitrogen. The resolution and imaging capability in cryogenic conditions are shown to be comparable to that under laboratory conditions. The experiments reported here use liquid nitrogen as an analogue fluid, but the results presented are believed to be representative of many cryogenic fluids. Although the use of ECT has been widely reported in the literature for multiphase flows in general, its use has not previously been reported for cryogenic flows. This paper offers proof of principle for ECT cryogenic multi-phase density and flow measurement.
Dielectric constant is strongly linked to fluid density, and the ECT sensor design tested here shows an estimated measurement of the relative permittivity of liquid nitrogen of 1.45 with a standard measurement error of 0.034. Measurement stability at cryogenic conditions gave an rms variation of output under static conditions of better than 0.001 relative permittivity units even though it was unguarded and only a single electrode ring. The primary errors are associated with the unguarded nature of the test sensor, which was primarily designed as a proof of concept and material demonstrator.
In addition, such an ECT sensor would provide clear images of any gas in the liquid and give a good estimation of the concentration and velocity of the gas bubbles. The scope of this work is to provide a proof of concept of the cryogenic ECT sensor.
Dr Behzad Nobakht, December 2020, International Journal of Greenhouse Gas Control, Vol 103
Several researchers have studied the Sleipner model to understand the inherent flow physics better, to find a satisfactory match of the CO2 plume migration. Various sources of uncertainty in the geological model and the fluid have been investigated. Most of the work undertaken on the Sleipner model employed the one factor at a time (OFAT) method and analysed the impact of uncertain parameters on plume match individually.
In this study, we have investigated the impact of some of the most cited sources of uncertainties including porosity, permeability, caprock elevation, reservoir temperature, reservoir pressure and injection rate on CO2 plume migration and structural tapping in the Sleipner. We tried to fully span the uncertainty space on Sleipner 2019 Benchmark (Layer 9) using a vertical-equilibrium based simulator. To the best of our knowledge, this is the first time that a study has focused on the joint effect of six uncertain parameters using data-driven models. This work would raise our scientific understanding of the complexity of the impact of the reservoir uncertainty on CO2 plume migration in a real field model. The caprock elevation was shown to be the most important parameter in controlling the plume migration (overall importance of 26 %) followed by injection rate (24 %), temperature (22 %), heterogeneity in permeability (13 %), pressure (9 %) and porosity (6 %).
Marc MacDonald, June 2020, Journal of Flow Measurement and Instrumentation
The Federal Institute of Metrology METAS developed a Hydrogen Field Test Standard (HFTS) that can be used for field verification and calibration of hydrogen refuelling stations. The testing method is based on the gravimetric principle. The experimental design of the HFTS as well as the description of the method are presented here. The HFTS has been tested at METAS with nitrogen gas at −40 °C to mimic a refuelling process in the field. Laboratory tests have shown that icing on the pipes of the HFTS have a non-negligible impact on the results. Field-testing with the HFTS has also been performed at the Empa hydrogen refuelling station with hydrogen at up to 70 MPa. The major uncertainty components have been identified and assigned values. The required expanded uncertainty of 0.3% could be achieved. A detailed uncertainty budget has been presented and shows that the scale is the largest contributor; buoyancy corrections only play a minor role. For the lowest uncertainty measurements, appropriate waiting times or cleaning methods to get rid of icing are required.
Author: Marc MacDonald
Journal: Journal of Flow Measurement and Instrumentation
01 June 2020
Marc MacDonald, August 2020, Journal of Flow Measurement and Instrumentation
Of all the alternatives to hydrocarbon fuels, hydrogen offers the greatest long-term potential to radically reduce the many problems inherent in fuel used for transportation. Hydrogen vehicles have zero tailpipe emissions and are very efficient. If the hydrogen is made from renewable sources, such as nuclear power or fossil sources with carbon emissions captured and sequestered, hydrogen use on a global scale would produce almost zero greenhouse gas emissions and greatly reduce air pollutant emissions.The aim of this work is to realise a traceability chain for hydrogen flow metering in the range typical for fuelling applications in a wide pressure range, with pressures up to 875 bar (for Hydrogen Refuelling Station - HRS with Nominal Working Pressure of 700 bar) and temperature changes from −40 °C (pre-cooling) to 85 °C (maximum allowed vehicle tank temperature) in accordance with the worldwide accepted standard SAE J2601. Several HRS have been tested in Europe (France, Netherlands and Germany) and the results show a good repeatability for all tests. This demonstrates that the testing equipment works well in real conditions. Depending on the installation configuration, some systematic errors have been detected and explained. Errors observed for Configuration 1 stations can be explained by pressure differences at the beginning and end of fueling, in the piping between the Coriolis Flow Meter (CFM) and the dispenser: the longer the distance, the bigger the errors. For Configuration 2, where this distance is very short, the error is negligible.
Author: Marc MacDonald
Journal: Journal of Flow Measurement and Instrumentation
01 August 2020
Dr Edris Joonaki, June 2020, Chemical Society Reviews
Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination. Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates. This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies. This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade. Challenges, limitations, and future perspectives of each field are briefly discussed. The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field.
Author: Dr Edris Joonaki
Journal: Chemical Society Reviews
Advance Article
Dr Gordon Lindsay, June 2020, Flow Measurement and Instrumentation, Vol 73
Coriolis metering technology is widely applied throughout industry. In addition to the mass flow rate, a Coriolis meter can measure fluid density based on the resonant frequency of the flow tube vibration. There is currently increasing interest in utilising this density measurement capability as the primary process value in applications such as precision control for fluid property conditioning, and fluid contamination monitoring.
However, within these applications, ambient temperature variation can be significant.
This paper details research data obtained using TÜV SÜD National Engineering Laboratory's ‘Very Low Flow’ single-phase facility. The rig was modified to include a programmable temperature enclosure in which a Coriolis meter was installed. Two commercial meter models from the same manufacturer were tested. Both meters showed fluid density errors when subjected to fluctuations in the surrounding ambient air temperature. The fluid properties of the test medium were confirmed to be stable using the UKAS standard reference instrumentation.
Previous temperature effects research for Coriolis meters have focussed on the process fluid temperature and there is little published data on the effects of ambient temperature.
Dr Edris Joonaki,June 2020, Nature Scientific Data
The use of hydrogen (H2) as a substitute for fossil fuel, which accounts for the majority of the world’s energy, is environmentally the most benign option for the reduction of CO2 emissions. This will require gigawatt-scale storage systems and as such, H2 storage in porous rocks in the subsurface will be required. Accurate estimation of the thermodynamic and transport properties of H2 mixed with other gases found within the storage system is therefore essential for the efficient design for the processes involved in this system chain. In this study, we used the established and regarded GERG-2008 Equation of State (EoS) and SuperTRAPP model to predict the thermo-physical properties of H2 mixed with CH4, N2, CO2, and a typical natural gas from the North-Sea. The data covers a wide range of mole fraction of H2 (10–90 Mole%), pressures (0.01–100MPa), and temperatures (200–500K) with high accuracy and precision. Moreover, to increase ease of access to the data, a user-friendly software (H2Themobank) is developed and made publicly available.
Author: Dr Edris Joonaki (co-author)
Journal: Nature Scientific Data
09/07/2020
Emmelyn Graham, 01 June 2020, Journal of Flow Measurement and Instrumentation
Venturi tubes are commonly used for wet-gas flow measurement, and the majority of commercial wet-gas flow meters generally include a Venturi tube installed vertically with embedded secondary instrumentation. The presence of the liquid causes an increase in the measured differential pressure and results in the Venturi tube over-reading the actual amount of gas passing through the meter. Most of the research in the literature is focused on the investigation of the over-reading for horizontally oriented Venturi tubes, thus limiting the development of over-reading correlations for vertical installation. An experimental campaign was recently conducted at the TÜV SÜD National Engineering Laboratory (NEL) high-pressure wet-gas loop, where three Venturi tubes of the same nominal diameter (4”) but different throat to inlet diameter ratio (0.4, 0.6, 0.75) were tested, installed vertically after a blind tee. The results of this experimental campaign are presented in this paper and the effects of various parameters (line pressure, gas Froude number, diameter ratio) on the over-reading are briefly discussed. It is shown that the over-reading correlation included in the ISO/TR 11583:2012 and developed for horizontally oriented Venturis, is not applicable to vertically oriented Venturis. However, if modified, the correlation included in the ISO/TR 11583 is capable of meeting its stated uncertainty limits for the experimental data presented here for vertically installed Venturis.
Author: Emmelyn Graham
Journal: Journal of Flow Measurement and Instrumentation
01 June 2020
Dr Chris Mills, August 2020, Journal of Flow Measurement and Instrumentation
This paper presents a method for identifying, via pressure measurements at frequencies ranging from 10 Hz–142 Hz, laminar-turbulent transitional flow. The fluctuations in pressure can be successfully used as a diagnostic to infer whether the flow is fully laminar, turbulent or transitioning between the two defined regions. The critical Reynolds number of a flow can be determined from the diagnosis of the pressure loss data at high-frequency when monitored with respect to time. With sufficient resolution of the data, the swift movement between laminar and turbulent flow can be witnessed.
Author: Dr Chris Mills
Journal: Journal of Flow Measurement and Instrumentation
01 August 2020
Dr Asaad Kenbar and Dr Menne Schakel, June 2020
In the last decade significant progress has been achieved in the development of measurement traceability for LNG inline metering technologies such as Coriolis and ultrasonic flow meters. In 2019, the world’s first LNG research and calibration facility has been realised thus enabling calibration and performance testing of small and mid-scale LNG flow meters under realistic cryogenic conditions at a maximum flow rate of 200 m3/hr and provisional mass flow measurement uncertainty of 0.30% (k = 2) using liquid nitrogen as the calibration fluid. This facility enabled the work described in this paper to be carried out to achieve three main objectives; the first is to reduce the onsite flow measurement uncertainty for small and mid-scale LNG applications to meet a target measurement uncertainty of 0.50% (k = 2), the second is to systematically assess the impact of upstream flow disturbances and meter insulation on meter performance and the third is to assess transferability of meter calibrations with water at ambient conditions to cryogenic conditions. SI-traceable flow calibration results from testing six LNG flow meters (four Coriolis and two ultrasonic, see acknowledgement section) with water and liquid nitrogen (LIN) under various test conditions are fully described in this paper. It was observed that the influence of removing the meter insulation on mass flow rate measurement accuracy can be more significant (meter error > ±0.50%) than the influence of many typical upstream disturbances when the meter is preceded by a straight piping length equal to twenty pipe diameters (20D) with no additional flow conditioning devices, in particular for ultrasonic meters. The results indicate that the correction models used to transfer the water calibration to cryogenic conditions (using LIN) can potentially result in mass flow rate measurement errors below ±0.5%; however, the correction models are specific to the meter type and manufacturer. This work shows that the target measurement uncertainty of 0.50% can be achieved if the expanded standard error of the mean value measured by the meter is smaller than 0.40% (k = 2). This was the case for about 85% of the LIN test results.
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