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Osaka Gas believes that technologies serve as the foundation of corporate competitiveness, and considers R&D to be one of the most important elements in the strategy to make a difference.
For this reason, Osaka Gas works actively on R&D and commercialization of new technologies, as presented below.
Considering the increasing variety of LNG sources in the future, the difference of each calorific value may become larger and the control of calorific values will be more important than ever. However, the conventional calorimeters, that require vaporized and sampled gas for measuring LNG calorific value, are unsuitable for this purpose because the quick response is necessary for calorific value adjustment control.
To tackle the challenge, Osaka Gas has developed a Coriolis calorimeter for measuring LNG calorific values in the liquid-state without time delay.
LNG calorific value is derived from LNG density measured through the Coriolis mass flowmeter manufactured by Oval corporation. LNG density is obtained by measuring deviation of vibration cycles caused by mass inside the oscillation imposed tube. And an additional converter calculates LNG calorific value from LNG density.
This meter has excellent performances as below.
(1) Quick response (within 1 sec.)
(2) High accuracy (±0.5%RD)
(3) Direct measuring of LNG in the liquid state (sampling free)
(4) Simultaneous measurement of calorific value and flow rate
Conventionally, the Coriolis densimeter could measure only the fluid at the atmospheric temperature or higher. Therefore, Osaka Gas has developed a specific density correction method applicable to LNG as cryogenic fluid based on the field trials that has been operated in Osaka Gas Senboku LNG terminal II since 2009.
By installing the density correction and calorie conversion equations as software functions, we achieved very high accuracy of calorific value measurement with a Coriolis meter; that shows the maximum deviation 0.08MJ/m3N from that with a gas chromatography.
The calorimeter using a Coriolis meter can measure the calorific value of LNG in the liquid state in real-time and achieve the improvement of reaction capability and reliability of calorific value adjustment control. Osaka Gas has actually installed and operated the calorimeter in the liquid-liquid system at Senboku LNG terminal II since 2012.