Report of the Effect of hydrogen admixture on the accuracy of a rotary flow meter.

This report is describing the investigation of the effect on the performance of a high-pressure gas flow meter (rotary meter) when mixing hydrogen with natural gas. The rotary gas flow meter was calibrated using both natural gas and hydrogen enriched natural gas (nominally 15% hydrogen), at two different pressures: 9 and 16 bar. Results indicate that the differences in the meter errors between hydrogen enriched natural gas calibration and natural gas calibration at high-pressure are smaller than the corresponding differences between atmospheric pressure air calibration and high-pressure natural gas calibration.