Q & A > Question Details
In our refinery CDU we injected corrosion inhibitor (filming) mixed with Heavy Naphtha in one tank then we injected air (for mixing).
My boss suggests injecting superheated steam instead of air because air contains oxygen that causes corrosion.
Is this right or no?
27/02/2020 A: Chris Claesen, Ecolab, cclaesen@ecolab.com
This does not seem right. When you use steam you will get condensation and introduce water in the system, this will make a thick emulsion with the Heavy Naphtha and filmer. There may also be a safety concern with the superheated steam causing flashing of the lighter fractions of the Heavy Naphtha.
A better practice that is often applied is to line up a slipstream from the reflux or OVHD product pump to the OVHD filmer injection location and inject the neat filmer into this slipstream.
22/02/2020 A: keith bowers, B and B Consulting, kebowers47@gmail.com
Yes and No. Never inject air into a tank of flammable hydrocarbon as this will cause a potential explosive mixture. Use inert gas/nitrogen. Superheated steam will condense immediately with little mixing effect.
22/02/2020 A: Apoorv Gupta, IOCL Haldia, apoorv.work19@gmail.com
Air should be avoided in any mixture feeding to the column. mixing with an agitator cane be a better and safer option.

Steam will condense and create a new phase, proper mixing may not be feasible .
22/02/2020 A: Feroz Ahmed, Petromax Refinery Ltd, feroz_erl94@yahoo.com
Please use an agitator
21/02/2020 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Technically that is correct. Corrosion in the tank itself should be minimal. Since the inhibitor injection rate is low the amount of oxygen to the process is negligible. If you use steam you have to be careful not to damage the tank. It’s easy to pull a vacuum when the tank cools down and the steam condenses.