Referring again to Figure 1-6, we can see that jet fuel can be downgraded to lower value products as follows: Heavy virgin naphtha. Poor stripping…
Several reasons have been observed for inefficient stripping. Operators note correctly that preheat is improved and steam is saved by minimizing stripping steam. However, far…
A side-stream product drawn from a crude tower is only half fractionated. Refluxing below the drawoff tray controls the product end point. Front-end fractionation takes…
Naphtha products may suddenly assume a yellowish cast and then return to a normal water-white condition. If this proves to be a recurring problem, the…
Operators may attempt to maximize heavy naphtha production at the expense of light naphtha by increasing the fractionator top reflux rate, which drops the tower…
Operators are usually more interested in making on-spec products than in saving energy. In the field one will often find pumparound rates cut back to…
Hot vapors, flowing up the fractionator from the flash zone, are partially condensed by contact with cooler pumparound liquid. The heat absorbed by the pumparound…
Although trays can corrode through, a more common cause of damage is unit upsets. A high liquid level, above the flash zone, will cause the…
Accounting for a loss in fractionation is a common troubleshooting assignment. For example, crude unit operators find that they can no longer meet furnace oil…
A large carry-over of coke or partially coked resid from the coke drum is called a foamover. Preventing such foamovers is vital to continued operation…