Q & A > Question Details
Any experience about neutraliser, filmer dosage and wash water incection into the O/H line of mail fractionator on FCC Unit. Is it allowed to mix neutraliser anf filmer into the washwater line? What is common practice for injection of neutralizer, filmer and washwater and why?
09/05/2016 A: Eric Hennings, Technip Stone & Webster, EHennings@technip.com
We do not use neutralization or filming chemicals in RFCC. As stated by others, the residual NH4HS retains alkaline pH in the water phase. Recall that RFCC uses appreciable steam injection which serves as well-distributed water wash in the Main Fractionator overhead.
Salts can be an issue in top section of M/F at very low naphtha endpoint.
09/05/2016 A: James Chacko, GE Power and Water, james.chacko@ge.com
Generally for FCC systems, the causes of corrosion are mainly Cyanides, High pH(Ammonia), Sulphides, Carbonates, Organic acids. Here I am not able to find a technical justification of a neutraliser at all.
However in such situations there are Water based filmer solutions that we could offer and have multiples experiences
Of course we do not recommend APS
02/09/2015 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
There is normally a large excess of NH3 present in the FCC OH, so neutralizer is not typically required. If you are getting corrosion in your system it is most likely from salt formation (most likely ammonium chloride). A well designed water wash can be effective at eliminating this sort of problem. I am not used to seeing filmers applied in this service, but you could try it. Wash water rates, injection system design, etc. would be done similar to a crude unit overhead system.
02/09/2015 A: Berthold Otzisk, Kurita Europe GmbH, Berthold.Otzisk@kurita.eu
It is good practice to inject an oil-soluble filming amine (together with a hydrocarbon slipstream) and separately the neutralising amine. The wash water injection in front of the overhead heat exchangers is an additional very useful tool to remove corrosive salts (i.e. NH4Cl, NH4HS, etc.) from the metal surface. The filming amine will form a very thin protection layer on the metal surface, which stops or significantly reduces the corrosion potential. The neutralising amine also acts as a corrosion inhibitor as it reacts with the acidic components. It shifts the pH of the very acidic first condensing drops to a higher pH level.
It is possible to inject a water-soluble filming amine together with the neutralising amine into the wash water. In most cases higher amounts of the filming amine are required compared to oil-soluble filming amines. Imidazoline filming amines are well established products and can be offered as oil-soluble filming amines or its salts as water-soluble filming amines. The required higher amount of water-soluble filming amine could be an economic aspect in selecting an oil-soluble filming amine.
02/09/2015 A: Eugen F C Goudsmith, Nalco Europe BV, egoudsmith@nalco.com
Mixing is possible but definitely not best practice. Neutralizers are not applied that often. Suggest to contact a company like Nalco Champion that can help you