Fluid catalytic cracking, liquefied

Ethylene is synthesized by steam cracking however, propylene is merely a by-product. Propylene is synthesized by other methods, such as propane dehydrogenation. FCC LPG (fluid catalytic cracking, liquefied petroleum gas) is an important propylene and butylenes source, as in Fig. 2.3. 

Olefins are hydrocarbon compounds with at least two carbon atoms and having a double bond. Their unstable nature and tendency to polymerize makes them one of the very important building blocks for the chemical and petrochemical industry (Gary and Handwerk, 1994). Although olefins are produced by fluid catalytic cracking in refineries, the main production source is through steam cracking of liquefied petroleum gas (LPG), naphtha or gas oils. 

Fluid Catalytic Cracking (FCC) is one of the most important processes in an oil refinery. Its function is to convert heavy hydrocarbon petroleum streams into more valuable, lighter hydrocarbon fractions such as middle distillate, gasoline and liquefied petroleum gas etc. Optimal operation of the process is decisive for overall economic and environmental health. Often several objectives and constraints are involved in the process, and optimisation studies incorporating these conflicting objectives would be invaluable to the process engineer. 

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