Abstract:
Objective Establishing an on-site calibration method for natural gas online moisture meters and its uncertainty evaluation as a key technique for ensuring the accuracy and traceability of determination results of water content in pipeline natural gas is crucial for quality control and process optimization of natural gas.
Method This paper adopted water vapor standard substances, introduced the uncertainty of standard substances on the basis of the least squares method to establish a new calibration model, and evaluated the uncertainty of the calibration model based on principles of linear algebra and statistics.
Result After calibrating four online moisture meters with different measurement principles using this method, the average relative deviation of the measurement results of the online moisture meters decreased from 53.6% to 3.6%, and the relative expanded uncertainty of the calibration values was basically within 5%, with a maximum not exceeding 10%.
Conclusion This calibration method can meet the calibration work of natural gas online moisture meters within the water content (volume fraction) range of (30−200)×10−6, and can effectively reduce the measurement error of online analyzers.
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