Q & A > Question Details
In a vacuum distillation unit working with a multi-stage steam - ejectors system, and it's around 10000 BPD capacity.
The flowing of the suction fluid (hydrocarbon mixture) is 24975 M3/hr and 79 C˚.
Can we switch to vacuum pumps instead of the steam - ejector, from an economical point of view?
07/11/2018 A: keith bowers, B and B Consulting, kebowers47@gmail.com
The Vacuum Distillation Column must have a good, stable system pumping the non-condensables up to a pressure high enough to discharge to a 'recovery system.' Liquid ring vacuum pump technology and operating experience has grown as more systems have been designed and operated.
Usually steam jet ejectors are most economical for the first and second stages of the vacuum system because they easily deal with the large actual volume, compressing the vapor so the actual volume can be handled with liquid ring vacuum pumps.
The economics depend on total cost of steam vs pump driver energy source, INCLUDING boiler feed water treating and steam ejector condensate treating costs.
Some crudes make high quantities of phenolic contaminated water, which is difficult and costly to treat, arguing in favor of minimizing use of steam jet ejectors..
06/04/2017 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
A number of units in the last 20 years have vacuum pumps as the 3rd stages, rather than another eductor. I have not seen an economic comparison.
05/04/2017 A: Ganesh Maturu, Self, maturu.ganesh@gmail.com
I have seen some case studies by converting ejector to vac pump. however it was for vac dryer and small applications. it was not highly reliable to meet high vacuum and critical services like vacuum distillation column