I.FLUID CATALYTIC CRACKING/A.PROCESS(Contd.)
www.wissenschaftler-avh.in
Q-20:
A number of refiners are adding a chloride dispersant to address FCC main fractionator overhead system plugging issues.What is your experience with these products
and have you had issues with downstream product quality?
A-20:
The processing of increased amounts of imported FCC feed,both gas oils and reduced crude.has
resulted in increased chloride salts in the FCC Main Fractionator.Ammonium chloride salt dispersants, a chemical which is used to move(disperse)ammonium chloride salts to prevent
plugging of FCC Main Fractionator.It is injected into the Main Fractionator reflux and ultimately
removed through the heavy gasoline and LCO draws.
The use of a chloride salt dispersant may reduce corrosion by tying up ammonium chloride.Corrosion may still an issue where the salts accumulate,however.Water will make salts very corrosive.The dispersant is not very effective at moving salts where low velocities are present so they may accumulate in very low velocity zones further down the column.One unit experienced massive salt buildup and severe piping corrosion in a low velocity reflux line.
No product quality for either gasoline or light cycle oil products have been reported at facilities using the dispersant.However,most units treat the FCC products prior to sales,and the treatment generally remove the salts.There has been evidence of chloride salts downstream of the unit which resulted in increased corrosion,but it is unclear whether the dispersant was involved.
