Keywords
Fluid catalytic cracking • Catalytic cracking • Development of catalytic cracking •
Catalytic cracking equipment and operation • Cracking catalysts and additives
Introduction
Crude oil comprises hundreds of molecules that boil over a wide temperature range.
The lighter products can be separated directly by distillation into LPG, gasoline,
naphtha, kerosene, and diesel fuels. Heavier products (BP >650
F/344
C) include
vacuum gas oils and resids. Thermal and catalytic cracking processes in petroleum
refining reduce the molecular weight of these heavier constituents and produce
more valuable lighter products such as LPG, gasoline, and diesel fuels.
Catalytic cracking was first commercialized in 1936 by Eugene Houdry. This
fixed bed process was a major improvement over the thermal cracking processes it
replaced due to the improved yield distribution and superior product properties.
Multiple vessels were utilized that alternated between cracking, stripping, regeneration, and purge cycles. This configuration was quickly replaced by a moving bed
reactor and a separate regenerator or kiln that first used a bucket lift to move the
pelleted catalyst followed later by a pneumatic air lift system. The last of these units
was built around 1960.
Standard Oil of New Jersey developed their own cracking process rather than
pay the large royalty being asked at the time. They commercialized the fluid
catalytic cracking (FCC) process in 3 years, starting in 1939 and culminating in
1942 with the start-up of PCLA#1 at their Baton Rouge, Louisiana refinery. The
inherent superiority of the fluid process to transfer both heat and catalyst ultimately
made it the catalytic cracking process of choice.
Many different designs of fluid catalytic crackers have been introduced over the
years. Table 1 is a list of the various FCCU configurations and the approximate year
of their commercial introduction.
Fluid catalytic cracking has evolved considerably over the more than 70 years
since its inception. As seen in Fig. 1, these changes have encompassed all aspects of
the process as it has adapted to meet ever-changing environmental and performance
demands and to accommodate new technologies.
The initial units (1940s) were tall, had dense bed reactors, and were made of
carbon steel. Dilute phase catalyst coolers and regenerator steam coils were
employed to limit the regenerator temperatures. Recycle rates of 100–150 % were
needed to achieve acceptable conversions. Later designs (late 1940s to early 1950s)
were undertaken to reduce the height of the crackers, make them more compact, and
cater to the many small refiners around the United States.
In the late 1950s, side-by-side designs with straight feed risers were introduced
to improve gasoline selectivity. Residue cracking in fluid cracking units was first
practiced in the early 1960s. This unit was designed for 100 % atmospheric bottoms
and had large amounts of heat removal.
262
W. Letzsch
Fluid catalytic cracking • Catalytic cracking • Development of catalytic cracking •
Catalytic cracking equipment and operation • Cracking catalysts and additives
Introduction
Crude oil comprises hundreds of molecules that boil over a wide temperature range.
The lighter products can be separated directly by distillation into LPG, gasoline,
naphtha, kerosene, and diesel fuels. Heavier products (BP >650
F/344
C) include
vacuum gas oils and resids. Thermal and catalytic cracking processes in petroleum
refining reduce the molecular weight of these heavier constituents and produce
more valuable lighter products such as LPG, gasoline, and diesel fuels.
Catalytic cracking was first commercialized in 1936 by Eugene Houdry. This
fixed bed process was a major improvement over the thermal cracking processes it
replaced due to the improved yield distribution and superior product properties.
Multiple vessels were utilized that alternated between cracking, stripping, regeneration, and purge cycles. This configuration was quickly replaced by a moving bed
reactor and a separate regenerator or kiln that first used a bucket lift to move the
pelleted catalyst followed later by a pneumatic air lift system. The last of these units
was built around 1960.
Standard Oil of New Jersey developed their own cracking process rather than
pay the large royalty being asked at the time. They commercialized the fluid
catalytic cracking (FCC) process in 3 years, starting in 1939 and culminating in
1942 with the start-up of PCLA#1 at their Baton Rouge, Louisiana refinery. The
inherent superiority of the fluid process to transfer both heat and catalyst ultimately
made it the catalytic cracking process of choice.
Many different designs of fluid catalytic crackers have been introduced over the
years. Table 1 is a list of the various FCCU configurations and the approximate year
of their commercial introduction.
Fluid catalytic cracking has evolved considerably over the more than 70 years
since its inception. As seen in Fig. 1, these changes have encompassed all aspects of
the process as it has adapted to meet ever-changing environmental and performance
demands and to accommodate new technologies.
The initial units (1940s) were tall, had dense bed reactors, and were made of
carbon steel. Dilute phase catalyst coolers and regenerator steam coils were
employed to limit the regenerator temperatures. Recycle rates of 100–150 % were
needed to achieve acceptable conversions. Later designs (late 1940s to early 1950s)
were undertaken to reduce the height of the crackers, make them more compact, and
cater to the many small refiners around the United States.
In the late 1950s, side-by-side designs with straight feed risers were introduced
to improve gasoline selectivity. Residue cracking in fluid cracking units was first
practiced in the early 1960s. This unit was designed for 100 % atmospheric bottoms
and had large amounts of heat removal.
262
W. Letzsch