HVGO cut in Vacuum distillation unit color increased from brownish to dark green during processing of Urals crude. No exchangers found leaking in preheat train. Draw off temperature and VDU heater COT also reduced to improve the color but no much improvement seen. Why does this happen?Sep-2021
Robert White, Process Consulting Services Inc, WHITERB1@YAHOO.COM
Dark green can be a normal colour for HVGO and can depend on the crude type, but the oil should be somewhat translucent.
Ramon uzcategui, Refidomsa, email@example.com
The colour of HVGO depend of several factors: 1 - CUT temperature or ZVI (instant vaporization zone) in the atmospheric column. 2 - The ZVI in the vacuum distillation column and the quality and temperature of the washer oil used in the packing of the vacuum column.