We get our feed gas (more than 90% CH4) from other petrochemical company. For measure the consumption we use orifice Flow Meter in battery limit of our plant, but our gas supplier use Ultrasonic Flow Meter and all time we have problem in final calculation.
According to this two type of flow meter approximately 2% difference is exist. Ultrasonic Flow Meter shows more flow than orifice Flow Meter.
is that normal?
We use temperature and pressure to compensate orifice Flow Meter. Do you suggest the other way to reduce the difference?