(211d) EPC Sasol Quench Tutorial Fundamentals Presentation

Abstract

An Ethylene Pyrolysis Cracking Quench System is designed to cool the hot furnace effluent gases by direct counter-current contact with the circulating quench water prior to entering the charge gas compression system. As a result of the direct contact water cooling, most of the dilution steam and some heavier hydrocarbons are condensed and exit at the bottom of the quench tower along with the heated quench water to the Quench Settler for an oil/water phase separation. The hot quench water is circulated through a series of exchangers before being recirculated back to the Quench Tower to be used as the cooling medium for the hot cracked gas. The cooled charge gas vapors exit the overhead of the Quench Tower and flow to the charge gas compressor system.

The presentation will cover the fundamental basics of a Quench System by providing a general flow scheme of Sasol’s Lake Charles Chemical Plant Quench System, a timeline / evolution of changes from Sasol’s plant inception from the mid 1960’s to present day configuration, good troubleshooting methods, and general problems that can occur. These problems include emulsion issues, typical turnaround drivers and solids / tar handling removal options which come with inherit risks and anticipative rewards.