Deposition of inorganic salts in FCC main fractionator columns is a common cause of operating problems and lost profits. Salt deposits are composed primarily of ammonium chloride and tend to form and deposit in the mid-to-upper sections of the tower and side-stream pump-around exchangers. If not removed, these salts will accumulate and prevent optimal tower operation. These deposits can affect the operation of the entire FCC unit, introducing problems that include:

• Plugged trays and product draws
• Increased corrosion of fractionator trays and pump-around exchangers
• Loss of fractionation between heavy naphtha and LCO
• Loss of compressor capacity
• Air blower constraints
• Loss of duty in pump-around exchangers

Nalco Water has developed an effective method of solving tower salt fouling problems. We use proprietary chemistries to clean process surfaces of salts that have deposited and apply the technology to prevent further deposition, in-situ with the process remaining online. In dozens of FCC main fractionators, our salt fouling control method has been used to remove ammonium chloride deposits and prevent the buildup of salts on tower trays and pump-around exchangers.