Needle coke is formed from condensed aromatic compounds. High boiling aromatic compounds (typically 950°F and higher) react in the coke drum by cross-linking the aromatic…
Category: Process Troubleshooting
Shot coke is composed of precipitated asphaltenes. Asphaltenes are large hydrocarbon molecules that are dispersed in the lighter aromatic and paraffinic oils in vacuum residuum.…
Petroleum coke sold for fuel may have a high VCM; coke sold for calcining must have a low (10%—13%) VCM. Making coke too soft (high…
A refinery designed to run a 30° American Petroleum Institute (API) crude must unexpectedly switch to a 40°API crude. Sometimes, large amounts of natural gas…
Heat transfer in crude exchangers often declines because of tube-side fouling. The difference in crude preheat may be 50°F for a dirty vs a clean…
Crude oil contains various chloride salts. Some of these salts decompose in the furnace to produce hydrochloric acid. The HCI boils overhead in the fractionator…
One of the important functions of a crude unit is to meet the flashpoint specification for the jet fuel product. This is best done by…
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…