Determining the Fouling Tendency of Different Feedstocks in the Fouling Assessment Setup

The use of heavier feedstocks, or even the possibility of direct conversion of crude oil into chemicals has created new challenges for the steam cracking process, as severe fouling in the different sections of steam crackers is observed then. In order to obtain a more fundamental understanding about the fouling phenomenon and its relation to feedstock composition and process conditions the “Fouling Assessment SeTup (FAST)” was developed. This experimental unit was used to determine the fouling tendency of a heavy hydrocarbon mixture (HHM) in the different sections of a steam cracker, i.e. convection, radiant, and transfer line heat exchanger (TLE) sections via a post cracking decoking procedure and the continuous weighting of a suspended coupon in TLE with a Magnetic Suspension Balance (MSB). Additionally, a fouling mitigation concept of wetting fluid injection in TLE via an in-house apparatus was tested. The injection of a paraffinic fluid substantially reduced fouling in this section.