- A Delayed Coker is a thermal cracking process that uses heat to break large heavy molecules into smaller lighter ones. In the process, a solid product Petrocoke is produced as a by product.
- Cokers enable the production of high value products from heavy residue, and are particularly useful for refineries using heavy Crude Oil.
Delayed Cokers In Operation
- The first Delayed Coker came on-line in 1929 at the Standard Oil of Indiana refinery located in Whiting, IN.
- In 2010, the USA had 60 Delayed Cokers compared to 11 in Europe, 4 in the Middle East and 27 in the Far East.
- The United States has the greatest concentration of Delayed Cokers of any market in the World. Of the 130 refineries processing 17.8 million bpd of crude oil, 60 of these refineries use Delayed Coking to destroy the vacuum residue and increase the yield of distillates for further processing into transportation fuels
How It Works
- In delayed coking the heated charge is transferred to large coke drums which provide the long residence time needed to allow the cracking reactions to proceed to completion.
- Initially the heavy feedstock is fed to a furnace which heats the residuum to high temperatures (900°-950° F) at low pressures (25-30 psi) and is designed and controlled to prevent premature coking in the heater tubes.
- The mixture is passed from the heater to one or more coker drums where the hot material is held approximately 24 hours (delayed) at pressures of 25-75 psi, until it cracks into lighter products. Vapors from the drums are returned to a fractionator where gas, naphtha, and gas oils are separated out.
- The heavier hydrocarbons produced in the fractionator are recycled through the furnace.
- After the coke reaches a predetermined level in one drum, the flow is diverted to another drum to maintain continuous operation. The full drum is steamed to strip out uncracked hydrocarbons, cooled by water injection, and decoked by mechanical or hydraulic methods.
- The coke is mechanically removed by an auger rising from the bottom of the drum. Hydraulic decoking consists of fracturing the coke bed with high-pressure water ejected from a rotating cutter.
Feed & Products
- Feed: Vacuum Residue
- Products: Heavy & Light Gas Oils, Naphtha, Gases
- Debottlenecking a Delayed Coker to improve overall Liquid Yield and Selectivity towards Diesel Fuel
- Description Of Petroleum Refining Processes And Related Health And Safety Considerations