How petroleum coke is made
Refineries bake the last dregs of crude into rock, then cut it out of steel drums with high-pressure water.
- stations
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- things upstream
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- raw source
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- step from the ground
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The short version
After a refinery has taken what it can from crude, a heavy residue is left. A delayed coker heats that to about 480 to 505 °C and sends it into a tall drum, where it cracks into lighter oils and a solid carbon rock. Water jets cut the solid out. Clean grades become anodes for aluminum smelters, and the rest is fuel.
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Collect the heavy residue
Residual oil left at the bottom of vacuum distillation is pumped to the coker's main fractionator. Hot vapors preheat it there before it goes on to the furnace.
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Fire through the furnace
The oil and some injected steam run through furnace tubes and reach about 480 to 505 °C, its cracking temperature. The steam keeps the flow fast, so the solid does not form in the tubes. That delay gives the process its name.
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Crack it in a drum
Cracking finishes in a huge drum, up to 10 meters across and 43 meters tall. Lighter oils leave as vapor, and solid carbon builds up inside over 12 to 24 hours while a second drum waits its turn.
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Steam and quench
Steam sweeps out remaining hydrocarbons from the filled drum. Water then floods it for several hours to cool the mass, and is drained away.
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Cut it out with water
With the heads of the drum removed, a high-pressure water jet on a rotating drill stem bores through the mass and cuts it free. Green lumps fall into a pit below.
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Calcine the best grades
Low-sulfur, low-metal coke tumbles through a rotary kiln that drives off remaining volatile hydrocarbons. It goes on to make aluminum anodes and synthetic graphite. High-metal coke skips this and is burned as fuel.
Worth repeating
- Delayed coking turns about 18 to 30 percent of the residue into solid coke by weight.
- Some refineries produce as much as 2,000 to 3,000 tons of petroleum coke a day.
- Burned for energy, petcoke emits 5% to 10% more carbon dioxide than coal.
Back to the ground
Follow every input upstream and petroleum coke starts as these 1 raw source.
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Where it goes next
Petroleum coke feeds 2 lines directly and reaches 159 things in total.
Further down the line
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Sources
Cite this page: "How petroleum coke is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/petroleum-coke