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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 ...
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 ...
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 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]
Membrane technology and membrane reactors have the potential to be applied in several processes among different sectors, such as energy, chemistry and food industries. However, the evaluation of their applicability requires a background in different disciplines, such as material science , physics , engineering , math , together with ...
"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 ...
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.
The surface of the catalyst quickly became coated with a layer of carbon or coke and became less effective. [6] There was already some work in this problem, e. g. in a 1917 patent alumina was suggested as a catalyst for oil cracking. [21] By 1927, having tested hundreds of catalysts, [13] Houdry had focused on naturally occurring Fuller's earth.