(211e) Primary Fractionator Fundamentals & Flexibility to Feedstocks

The Primary Fractionator is a typical component of the quench system in liquid crackers. Besides quenching pyrolysis gases from the furnaces, it provides fractionation of raw pyrolysis gasoline (RPG) and ensures heat integration between the furnace effluent and dilution steam generation. Over the years, many liquid crackers have developed feed flexibility by processing a mix of liquid and natural gas liquids (NGL) feedstocks. In the last 5 to 7 years, the availability and use of ethane feedstock has pushed the feed flexibility to challenging levels for reliable operation of the Primary Fractionator due to the changes in quench oil make and composition. Known to be a fouling service the Primary Fractionator could become a constraint to achieving desired plant run length. This paper discussed the governing factors that affect operation of Primary Fractionators. The impacts of feedstock, tower internals and metallurgy are also covered.