Fluidized Catalytic Cracker

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Fluidized Catalytic Cracking is a technology in petroleum refining where heavier petroleum fractions are converted to more valuable lighter fractions like LPG, gasoline and diesel.
Introduction:
In petroleum refining, crude oil is distilled at atmospheric pressure to recover valuable petroleum products like LPG, Naphtha, Kero, ATF and Diesel. The residual heavier fraction, which has little commercial value, is further distilled under vacuum to separate Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO) and Vacuum Residue.
LVGO and HVGO are high boiling petroleum fractions with long carbon chains (number of carbon atoms in a molecule greater than fourteen). These long carbon chains can be cracked into small carbon chain products like LPG, gasoline and diesel at high temperatures and the process is called Cracking. The cracking of heavy hydrocarbons occurs through the formation of intermediate free radicals by the breaking of a carbon-carbon bond or carbon-hydrogen bond at high temperature.
Why Fluidized Catalytic Cracking?
During the process of thermal cracking, reactive products polymerize to form coke in the reactor when heated to high temperatures. Coking results in loss of yield, mechanical failure of equipments, fouling and poor operational performance.
Coking can be significantly reduced by: a) achieving cracking at lower temperatures and b) by reducing the residence time inside a reactor. Former can be achieved by use of a catalyst that promotes cracking reaction and later factor can be achieved by fluidization inside a rector. Use of catalyst and fluidization in a cracking process is termed as Fluidized Catalytic Cracking (FCC).
Advantages of Catalytic Cracking over thermal cracking:
1. Catalytic cracking gives mor...

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...as a fuel internally. Typical FCC yields are:
Fraction UOM Value
Dry gas Wt% 3.65
LPG Vol% 28.04
Naphtha Vol% 57.9
LCO Vol% 18.41
Bottoms- Fuel Oil Vol% 6.59
Coke Wt% 5.18
Data taken from (Wilson, 1997, p. 59)
Yields of fractions change with prolonged catalyst usage, variation in temperature, feed distribution etc.
Emissions:
The process involves significant emissions which include Carbon dioxide, Carbon monoxide from the regeneration section. Unrecovered catalyst particles travelling with flue gas can act as particulate matter.

Works Cited

Fluidized Catalytic Cracking. (n.d.). Retrieved January 15, 2014, from Wikipedia: http://en.wikipedia.org/wiki/Fluid_catalytic_cracking
Julius Scherzer, A. G. (1996). Hydrocracking Science and Technology. New York: MARCEL DEKKER, Inc.
Wilson, J. W. (1997). Fluid Catalytic Cracking Technology and Operations. PennWell Books.

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