reasonable numbers of ejector for vacuum distillation tower

[engahmedbahgat]

Hello,

I was working on vacuum distillation tower design with following data

diameter : 6.8 m
Length : 20 m

I calculated the whole suction load needed as 25900 m3/hr @ 5 minutes needed to attain the vacuum.
and I select that I need 10 ejectors with size of every one is about 10 inches (suction size)

my question is: are these results & calculations are reasonable, in other words, has any one sow a vacuum tower with 10 ejectors, every one of them is 10 inches ?

thank you

 

[Duwe6]

No - doesn't pass the 'smell test'. Every system I have ever seen uses 3 ejectors in a row; X, Y, Z-stages, with Hx's to collapse the steam.

 

[zdas04]

I've never seen ejectors specified by the suction pipe size. Generally they are called out based on mass flow rate of power fluid (most often steam, but other condensible and non-condensible gases can be used) and number of stages. A 3 stage set up like Duwe6 mentions is common, and in general the suction pipe size on the 3 stages is different (each stage handles more mass, but at a higher pressure). If the power fluid is steam and you have an interstage cooler to condense the steam then the mass flow rate of the suction fluid does not increase much from stage to stage, for non-condensible power fluid the suction mass flow rate is very large by stage 3.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

 

[mbt22]

What's the load based on? Initial draw down, operational air ingress, lights from your feed?

Matt