Hydrocracker Furnace

TWO-STAGE HYDROCRACKING. Hydrocracking Process.
In the first stage, preheated feedstock is mixed with recycled hydrogen and sent to the first-stage reactor, where catalysts convert sulfur and nitrogen compounds to hydrogen sulfide and ammonia. Limited hydrocracking also occurs.
After the hydrocarbon leaves the first stage, it is cooled and liquefied and run through a hydrocarbon separator. The hydrogen is recycled to the feedstock. The liquid is charged to a fractionator. Depending on the products desired (gasoline components, jet fuel, and gas oil), the fractionator is run to cut out some portion of the first stage reactor out-turn. Kerosene-range material can be taken as a separate side-draw product or included in the fractionator bottoms with the gas oil.
The fractionator bottoms are again mixed with a hydrogen stream and charged to the second stage. Since this material has already been subjected to some hydrogenation, cracking, and reforming in the first stage, the operations of the second stage are more severe (higher temperatures and pressures). Like the outturn of the first stage, the second stage product is separated from the hydrogen and charged to the fractionator.
HYDROCRACKING PROCESS.
Feedstock From Process Typical products . . . . To
High pour point Catalytic cracker, atmospheric
& vacuum tower
Decomposition, hydrogenation Kerosen, jet fuel . . . .Blending
Gas oil Vacuum tower, coker Gasoline, distillates . . Blending
Hydrogen Reformer   Recycle, reformer gas . . Gas plant