GB/T 28766-2018 in English

This standard is equivalent to ISO 10723:2012, which specifies the performance evaluation method of the natural gas analysis system, focusing on solving two core problems:

• Determine the applicable composition range of the analysis system within the allowable error range
• Evaluate the measurement error and uncertainty under specific calibration gas

1. Determine the evaluation scope: clarify the component and content range (e.g. N₂ 0.10-12.00%)
2. Establish response function: through class=instrument>Gas chromatograph and other equipment to obtain calibration curves
3. WMS calibration: Use working measurement standard gas for 6-10 repeated measurements
4. Error analysis: Use Monte-Carlo method to simulate 10,000 sets of data
5. Performance verification: Compare MPE (maximum permissible error) and MPB (maximum permissible deviation)

Expanded uncertainty calculation formula:

U_c(δP) = k × √[u²(δP(t)) + u²(δP)]

When k=2, the confidence level reaches 95%

Instrument selection requirements

• At least detect N₂, CO₂, C₁-C₆ hydrocarbon components
• chromatograph must have backflush function to handle C₆₊ components

Calibration gas preparation

• Balance gas should be methane
• Heavy hydrocarbon components need to be dispersed in different gas cylinders (to prevent condensation)
• Uncertainty needs to be

Periodic verification

• Initial evaluation must be carried out for newly installed equipment
• Re-evaluation is required after replacement of key components
• Drift compensation calibration procedure is recommended