Method: Vary net vapor rate, no make-up gas.
Process: Vacuum systems. Must always have vapor product.
This is commonly referred to as a 'dry' or 'damp' system, depending
on the application, because there is no condenser before the vacuum
ejector.
Advantages: All ejector discharge available for recycle.
Often gives the most stable operation.
Disadvantages: Difficult to implement in systems with the
ejector directly attached to its condenser. Relatively large recycle
line and control valve often required. Overhead product must be
compatible with water.
Application: The best ejector pressure control system for
ejectors that are not stable to zero load. Often, the most economical
system for stable ejector control.
Variants: System often used without reflux return to the
tower (external liquid feed or pumparound reflux generation).
Configuration notes:
Operation: Recycle gas moves the vacuum jet ejector along
its operating curve. The higher the load to the ejector, the higher
the ejector suction pressure.
Warnings:
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