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The flow of spent catalyst to the regenerator is regulated by a slide valve in the spent catalyst line. Since the cracking reactions produce some carbonaceous material (referred to as catalyst coke) that deposits on the catalyst and very quickly reduces the catalyst activity, the catalyst is regenerated by burning off the deposited coke with ...
This petroleum coke can either be fuel grade (high in sulphur and metals) or anode grade (low in sulphur and metals). The raw coke from the coker is often referred to as green coke. [1] In this context, "green" means unprocessed. The further processing of green coke by calcining in a rotary kiln removes residual volatile hydrocarbons from the coke.
Needle coke, also called acicular coke, is a highly crystalline petroleum coke used in the production of electrodes for the steel and aluminium industries and is particularly valuable because the electrodes must be replaced regularly. Needle coke is produced exclusively from either fluid catalytic cracking (FCC) decant oil or coal tar pitch.
The "spent" catalyst then flows into a fluidized-bed regenerator where air (or in some cases air plus oxygen) is used to burn off the coke to restore catalyst activity and also provide the necessary heat for the next reaction cycle, cracking being an endothermic reaction. The "regenerated" catalyst then flows to the base of the riser, repeating ...
"Coking is a refinery unit operation that upgrades material called bottoms from the atmospheric or vacuum distillation column into higher-value products and produces petroleum coke—a coal-like material". [1] In heterogeneous catalysis, the process is undesirable because the clinker blocks the catalytic sites. Coking is characteristic of high ...
The main differences between each of them concerns the catalyst employed, design of the reactor and strategies to achieve higher conversion rates. [1] Olefins are useful precursors to myriad products. Steam cracking is the core technology that supports the largest scale chemical processes, i.e. ethylene and propylene. [2]
A 4-drum delayed coking unit in a petroleum refinery. A delayed coker is a type of coker whose process consists of heating a residual oil feed to its thermal cracking temperature in a furnace with multiple parallel passes.
These are used for high-temperature FT synthesis (nearly 340 °C) to produce low-molecular-weight unsaturated hydrocarbons on alkalized fused iron catalysts. The fluid-bed technology (as adapted from the catalytic cracking of heavy petroleum distillates) was introduced by Hydrocarbon Research in 1946–50 and named the 'Hydrocol' process.