Research article: Enhancement of the revised Klosek and McKinley method for density calculations of LNG

Enhancement of the revised Klosek and McKinley method for density calculations of liquefied natural gas (LNG) over the temperature range from (100 to 135) K at pressures up to 10 MPa

By Christopher Tietz, Markus Richter, Reiner Kleinrahm and Roland Span

Abstract:
The revised Klosek and McKinley (RKM) method is a well-established model for the calculation of saturated liquid densities within the field of liquefied natural gas (LNG) custody transfer. Due to pressures higher than the vapor pressure in pipes from tanks to transfer stations, the densities resulting from this easy-to-use approach often deviate from the true density of the compressed liquid phase. However, higher pressures are typical for pipe flows in receiving terminals. Therefore, the applicability of the RKM method was expanded with the most recent highly accurate (p, ρ, T, x) data sets for six compressed LNG mixtures measured with a special densimeter for cryogenic liquid mixtures. The newly developed enhanced RKM (ERKM) method now enables density calculations of LNG mixtures at pressures up to 10 MPa, and the temperature restriction of the RKMmethod (T b 115 K) was expanded to reach temperatures up to 135 K. The estimated expanded uncertainty (k = 2) of the newly developed equation is 0.10% for the temperature range from (100 to 115) K and 0.15% for temperatures between (115 and 135) K at pressures up to 10MPa. Further restrictions of the method are basically the same as for the RKM method and are specified in more detail within the present paper.

Read the paper here 

Metrological support for LNG custody transfer and transport

Abstract from paper

In the framework of the ongoing EMRP Joint Research Project (JRP) ENG 60 “Metrology for LNG” (2014-2017), co-funded by the European Union, a number of metrological challenges associated with custody transfer and transport of LNG will be faced. The project consists of four technical work packages (WP), whereby the main objective is to reduce the measurement uncertainty of LNG custody transfer by a factor two. The focus in WP1 is the design and development of a traceable mid-scale calibration standard for LNG mass and volume flow. The goal is to provide traceable mass and volume flow calibrations up to 400 m3/h (180000 kg/h). In WP2, the emphasis is on the development and validation of a LNG sampling and composition measurement reference standard, consisting of sampler, vaporizer, gas standards, and gas chromatography (GC), which will be used to test and calibrate commercially available LNG sampling and composition measurement systems. The priority in WP3 is given to the development and validation of a method for the determination of the methane number, including correlations based on the LNG composition and corrections for traces of nitrogen and higher hydrocarbons. Since physical properties and quantities play an important role in LNG custody transfer, WP4 comprises reference quality density measurements of LNG to validate and improve models for LNG density predictions, the uncertainty evaluation of enthalpy and calorific value calculations and the development of a novel cryogenic sensor for the simultaneous measurement of speed-of-sound and density. The present paper gives an overview of recently achieved objectives within the project and provides an outlook to future activities.

Read the paper here: FLOMEKO_Metrological support for LNG custody transfer and transport

World’s first LNG research and calibration facility

Abstract from paper by VSL, SP, NEL, Justervesenet, FORCE technology, OGM, and IMS: 
A Liquefied Natural Gas (LNG) flowmeter research and calibration facility is being built in Rotterdam by the Dutch metrology institute VSL. This cryogenic test loop will also be used to test and develop LNG analysers, new technologies and devices for measurement of LNG physical properties. The facility will consist of a Primary Standard Loop (PSL) that can measure the mass of LNG flows traceable to the International Kilogram standard in Paris. The primary standard is capable of flow measurements up to 25 m3/hr. A second Midscale Standard Loop (MSL) will measure volumetric flow rate of up to 200 m3/h, expandable to at least 400 m3/h in the future. The Midscale standard is traceable to the PSL and scales the flowrate up using bootstrapping techniques. This paper describes the combined PSL and MSL facility, its objectives, and accomplishments to date.

Read the paper here: FLOMEKO_World’s first LNG research and calibration facility

Programme for the 4th International Workshop of Metrology for LNG

Here you will find the programme for the workshop and the training course for the 4th International Workshop of Metrology for LNG, taking place at NPL on the 15-16 June:

LNG – Metrology for LNG Workshop Agenda 2016

LNG – Training Course Agenda 2016

If you want to participate but have not registered yet, please contact Garry Hensey:
Email: garry.hensey@npl.co.uk

For those attending – please find in the link below:

* Directions to get you to NPL,
* A visitors pack, and
* A list of local hotels within easy reach of NPL

http://www.npl.co.uk/contact-us/directions-to-npl/

Poster from the 19th Symposium on Thermophysical Properties

Lentner, R.; Richter, M.; Kleinrahm, R.; Span, R.: Accurate (p, ρ, T, x) Measurements on Different Liquefied Natural Gas (LNG) Mixtures in the Temperature Range from (105 to 135) K at Pressures up to 9 MPa. Poster, 19th Symp. on Thermophysical Properties, Boulder, USA, 2015.
Lentner et al_Poster Symposium 2015

Richter, M.; Kleinrahm, R.; Lentner, R.; Span, R.: Development of a special single-sinker densimeter for cryogenic liquid mixtures and first results for a liquefied natural gas (LNG). J. Chem. Thermodyn. 93 (2016), 205 – 221. doi:10.1016/j.jct.2015.09.034