Catalytic cracking of residue and delayed coking
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This post was last edited by jacques0920 on 2016-12-21 08:22. Hello everyone; I am a beginner in the field of oil refining. What are the technical advantages of residue catalytic cracking compared to delayed coking? Why can’t delayed coking be used to replace residue catalytic cracking? Thank you.
Technical advantages don’t matter; since the target products are different, they cannot replace each other. High catalytic energy consumption and high liquid yield are mainly for gasoline and liquefied gas, while coking is for diesel. The success or failure depends on the market.
The delayed coking process is mainly a process in which vacuum residue is heated to produce diesel and petroleum coke. It has high energy consumption and low yield, and the added value of the by-product petroleum coke is very low. Catalytic cracking is more demanding in terms of reaction conditions and operational complexity compared to delayed coking, but it offers higher product yields and better quality of the target products.
This post was last edited by Ice-Cold Radio on 2016-12-16 at 13:50
One uses regular slag, while the other uses reduced slag. Catalytic cracking also produces coke, but in smaller amounts; it accumulates in the catalyst and is burned during catalyst regeneration. The coke yield in delayed coking is around 30%, resulting in a relatively high amount of coke produced. It’s all coal-to-oil processes these days. Delayed coking is the conversion of oil into coal, and it has no advantages from a fundamental perspective
As the core unit in domestic fuel-based refineries today, the catalytic cracking unit is the main facility for producing olefins and gasoline. As the main treatment unit for vacuum residue, the coking unit is also the primary facility for processing low-quality heavy oil; due to the nature of this unit, the yield of light oil is relatively low. Under the increasingly stringent environmental regulations today, with the development of residue hydrorefining units and the advancement of fluidized-bed residue hydrogenation, there is a trend for them to gradually replace coking units.
The fact that catalytic cracking of residue oil cannot handle all low-quality residues is probably the main reason why it cannot replace coking
Coking is regarded as a device for dealing with heavy oil, just as light hydrocarbon recovery serves as a means for handling light components; it is a system that converts waste into valuable resources. This aspect is quite important, while the underlying principles are less significant. After all, there is some heavy oil that cannot be processed through catalytic methods, and the yields and efficiency of other processes are not as good as those of coking. This is precisely why coking exists.