Ezejector Blog - Steam ejectors, ejector efficiency explained, the many uses of ejectors, effect of steam pressure, how to control an ejector, isentropic and isenthalpic expansion compared and more, 

In the previous post the potential benefit of single critical ejectors was presented. Here we discuss this further. An ejector that is designed for single critical flow may be move sensitive to pressure and flow changes - please refer to the figure below. As can be see...

Will you get a higher discharge pressure for an ejector designed for single critical or double critical flow?

Single critical is where the motive gas flow is choked (sonic) in the nozzle but the entrained gas is not choked (subsonic). For double critical both are choked...

How do you control the flow and pressures at an ejector?  One method is shown above. For good control one needs to simulate the different scenarios.

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Some ejector applications are shown in the diagram.

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Use of ejectors provides a low cost option to boost production when well pressures decline late in field life. Pressure ratio boost of course depends on the spare compressor flow capacity - see graph below. Also see alternative flow schemes below.