Fares Ben Rayana
The Biogas, also known as digester gas, is the gaseous product of anaerobic digestion (decomposition without oxygen) of organic matter. It is considered as a renewable energy source. GDF SUEZ is working actively on the development and recovery of this energy, drawing on synergies with the natural gas industry. In this context the CRIGEN had realized, for the first time in Europe, a complete study on a metering system for crud biogas (without any treatment). This study is carried out for ADEME and for three of the principal actors of treatment of waste in France (SITA, VEOLIA and COVED), and...
Fares Ben Rayana
The CRIGEN had realized a wide experimental study on gas flowrate limiter used on compact meter station for measuring gas flow at variable pressure. This device is used to control and limit, for a specified pressure, the flowrate of the meter station. It is a perforated plate with a constant holes size. Each hole is functioning as a sonic nozzle. The number and size of the hole are defined by the meter station maximal flowrate. This paper shows that the flowrate limiter geometry (the hole size, the ratio plate thickness/hole size and the number of holes) can be changed without affecting the...
F. Arpino, L. Celenza, R. D’Alessio, M. Dell’Isola, G. Ficco, P. Vigo, A. Viola
One of the main issues in the natural gas (NG) transport networks management is represented by the Unaccounted for Gas (UAG). UAG is the quantity to be considered in the balance equation to take into account the unavoidable errors due to measurements and estimations. The resulting problem is twofold: on one hand fiscal and contractual, on the other hand the unavoidable pressure from the national authorities to reduce UAG. In this paper the authors analyse the UAG trends in natural gas (NG) transport networks and present: i) an investigation about UAG in international networks; ii) a...
J. Sluše, J. Geršl
In this paper a possible cavitation of LNG in ultrasonic flowmeters is investigated. The cavitation is an unwanted effect which can occur especially near the ultrasound transducer mountings where sharp edges at the wall can appear. By means of numerical modelling we predict pressure drops which can occur near the pockets in front of the ultrasound transducers. We then calculate a minimal sub-cooling of LNG below the bubble point temperature for which the cavitation can be avoided for various velocities and pressures in the fluid.
Alain Strzelecki, A. Ouerdani, Y. Lehot, C. Windenberger, J. P. Vallet
A very promising alternative to the state-of-the-art static volume measurements for Liquid Natural Gas (LNG) custody transfer processes is the dynamic principle of flow metering. In the frame of the Joint Project Research “METROLOGY for LNG”, CESAME EXADEBIT explored a novel cryogenic flow metering technology using Laser Doppler Velocimetry (LDV), as alternative to ultrasonic and Coriolis flow metering. The study focused on the technological challenges and solutions for extending the LDV method to cryogenic temperatures, and on the estimation of the uncertainty thatcan be realistically...
Emmelyn Graham, Asaad Kenbar
Determining and reducing the measurement uncertainty of LNG energy transfer in custody transfer operations is considered extremely important and challenging for industry. The European Metrology Research Programme (EMRP) for Liquefied Natural Gas (LNG) project has been focusing on reducing the uncertainty in the evaluation of LNG energy transfers by improving existing measurement methods, validating new measurement methods and development of new traceable calibration systems. Part of this project was to produce realistic measurement uncertainty budgets and to determine the sensitivity of the...
T. Cousins, C. Hodges, R. Steven, Damon Myer
From a recent investigation by CEESI, it is clear that the independent data available on the performance of custody transfer metering systems to operate with high water content, 5-90%, is both scattered and sparse. As a result of the investigation, CEESI were commissioned to produce a water in oil test facility, aimed at carrying out experimental work on both the direct metering and sampling of high water cuts. It is designed to be able to change the oil viscosity, to look at the effect of viscosity variation on the performance of the measuring instruments. The paper describes the design of...
C. C. Li, J. Y. Chen, C. M. Su, J. W. Chen.
In this study, the effects of circulating fan setting conditions, such as number of fans and installation position and angle, on the distributions of air speed and temperature in the agricultural greenhouse, were investigated experimentally and numerically. The environment data of air speed, temperature, humidity and thermal radiation of a demonstrative greenhouse acquired via continuous automated measurement were integrated with micro-climate CFD simulation to reveal the optimal control rule of the air-conditioning instruments. The results show that the unformities of air speed and...
Furio Cascetta, Aline Piccato, Franscesco Rampazzo, Guiseppe Rotondo, Pier Giorgio Spazzini
Nowadays, smart static gas measurement technologies are available on the market and are used for metering natural gas consumption of final consumers. Both ultrasonic and thermal-mass flow metering technologies are considered today as "new electronic gas meters". Such digital meters require an adequate knowledge of the measurement principle in order to carry out correct calibration procedures. In other words, we are in the digital age of the gas measurement: digital meters require digital calibrations. The calibration procedures in use to calibrate a traditional (mechanical) "analogue" gas...
Lei Sui, Randy S. Pfenninger, Toan H. Nguyen, Nicholas A. Hobbs, Isaac Sadovnik, Liguo Su, James E. Matson
The use of ultrasound to measure flow is now well established with many installations worldwide in chemical and petrochemical plants, and refineries. In general, it is more challenging to apply ultrasonic techniques to gas flow measurement than liquid due to a variety of reasons, including the much lower acoustic impedance, higher Mach numbers, higher turn-down ratios, and larger pressure variations, associated with gas flow measurement. In this paper, ultrasonic flowmetering of Coal Seam Gas (CSG) or Coal Bed Methane Gas (CBMG) is investigated and reported. A theoretical model has been...