An ejector curve requires four things in order for the curve to be valid:
The ejector’s motive steam conditions must be at or better than design. This includes a motive steam pressure that is -0%/+20% of the design pressure and no more than 50 deg F hotter than the design temperature. The motive steam must not be wet.
The ejector needs to be operating with a discharge pressure that is better than its design.
The ejector must be in good physical condition and free of debris, build up, or internal mechanical damage. Any internal damage to the ejector's motive nozzle, diffuser, or internal motive steam leaks will impact the ejector performance in a way that would not be accounted for in the performance curve. Any buildup of debris in the motive nozzle or process build up in the ejector will also impact an ejector’s performance.
The load must be in vapor phase only and not including any liquid droplets from the upstream process.