Coking unit reactors (called coke drums) are batch type, whereas the feed and product separation sections are continuous.Heavy vacuum residue liquid at about 500ºC is fed into a large drum where thermal cracking takes place.Heavy cracked material forms coke, and accumulates in the drum.Lighter cracked material evaporates into the fractionator.
One drum is in operation while the other drum goes through a sequence of
Coke stripping, drum cooling, opening, coke removal, closing, pressure test and heating up for next switch.
This sequence must end before the operating drum is filled with coke.
Drum switches create disturbances throughout the refinery
It isn’t possible to continuously measure coke level in the drum.There are two nuclear level switches, one at about 70% drum height, the other at 90%.
In terms of inferential models, it is useful to estimate the level of coke in the coke drum in order to prepare for the next switch.
The coker gas plant further eparates naphtha and lighter into fuel gas, LPG and stabilized naphtha.
Our distillation GDS model can help control the gas plant
The fractionator separates naphtha and lighter, LCGO (light coker gasoil) and HCGO (heavy coker gasoil).The fractionator bottom section serves as a feed surge drum, taking hot feed from the heater plus reflux of material heavier than HCGO.
Our fractionator GCC model can help control this separation through drum switch disturbances
The coker gas plant further eparates naphtha and lighter into fuel gas, LPG and stabilized naphtha.
Our distillation GDS model can help control the gas plant
