Abstract:
Objective GB/T 17283-2014 is an important test method for measuring the dew point in natural gas and similar gases. At present, the standard does not stipulate the precision of the measurement results. This study determines the precision index of the dew point results, which provides the consistency evaluation basis for the users of the standard, and also can provide technical reference for revising the standard.
Methods Using eight dew point instruments with different instrument manufacturers and models, the precision test is carried out through testing water-gas standard substance dew points under different pressure. Referring to the repeatability standard deviation of the determination results provided by the Russian standard GOST 20060-2021 Determination of water dew point temperature of natural gas, the precision index of the results of water dew point measured by cooling mirror condensate hygrometer was studied and determined.
Results The limits of repeatability and reproducibility of measurement results are specified according to the measurement range of water dew point. The water dew point is -40.0 ℃≤tB≤-30.0 ℃, the limit of repeatability is ≤2.0 ℃, and the limit of reproducibility is ≤3.0 ℃. The dew point of water is -30.0 ℃ < tB≤0 ℃, the limit of repeatability is ≤1.5 ℃, and the limit of reproducibility is ≤2.5 ℃. The water dew point is 0 ℃ < tB≤10.0 ℃, the repeatability limit is ≤1.0 ℃, and the reproducibility limit is ≤2.0 ℃.
Conclusions In order to increase the practicability and operability of GB/T 17283, it is suggested that the standard should increase the precision requirement of water dew point measurement results, and the precision index proposed in this paper can be used as a technical reference for revising the standard.
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