Eger Murphree and the Four Horsemen: FCC, Fluid Catalytic Cracking

Donald Campbell, Homer Martin, Eger Murphree and Charles Tyson, who were known for their development of a process still used today to produce more than half of the world’s gasoline. These “Four Horsemen” were part of the Exxon Research Co. The world’s first commercial Fluid Catalytic Cracking facility began production for Exxon in 1942. The Fluid Catalytic Cracking process revolutionized the petroleum industry by more efficiently transforming higher boiling oils into lighter, usable products.

Their notable US Patent No. 2,451,804: A Method of and Apparatus for Contacting Solids and Gases describes their milestone invention. Over half the world’s gasoline is currently produced by a process developed in 1942 by the “Four Horsemen” of Exxon Research and Engineering Company. The world’s first commercial Fluid Catalytic Cracking facility began production for Exxon on May 25, 1942. The Fluid Cat Cracking process revolutionized the petroleum industry by more efficiently transforming higher boiling oils into lighter, usable products. When Exxon’s first commercial cat cracking facility went on-line in 1942, the U.S. had just entered World War II and was facing a shortage of high-octane aviation gasoline. This new process allowed the U.S. petroleum industry to increase output of aviation fuel by 6,000% over the next three years. Fluid Cat Cracking also aided the rapid buildup of butadiene production, which enhanced Exxon’s process for making synthetic butyl rubber–another new technology vital to the Allied war effort. By the 1930s, Exxon began looking for a way to increase the yield of high-octane gasoline from crude oil.

Researchers discovered that a finely powdered catalyst behaved like a fluid when mixed with oil in the form of vapor. During the cracking process, a catalyst will split hydrocarbon molecule chains into smaller pieces. These smaller, or cracked, molecules then go through a distillation process to retrieve the usable product. During the cracking process, the catalyst becomes covered with carbon; the carbon is then burned off and the catalyst can be re-used. Campbell, Martin, Murphree, and Tyson began thinking of a design that would allow for a moving catalyst to ensure a steady and continuous cracking operation. The four ultimately invented a fluidized solids reactor bed and a pipe transfer system between the reactor and the regenerator unit in which the catalyst is processed for re-use. In this way, the solids and gases are continuously brought in contact with each other to bring on the chemical change.

This work culminated in a 100 barrel-per-day demonstration pilot plant located at Exxon’s Baton Rouge facility. The first commercial production plant processed 13,000 barrels of heavy oil daily, making 275,000 gallons of gasoline.

Considered essential to refinery operation, Fluid Cat Cracking produces gasoline as well as heating oil, fuel oil, propane, butane, and chemical feedstocks that are instrumental in producing other products such as plastics, synthetic rubbers and fabrics, and cosmetics. During today’s Fluid Cat Cracking process, a boxcar load of catalyst is mixed with a stream of oil vapor every minute. It is this mixture, behaving like a fluid, that moves continuously through the system as cracking reactions take place. Fluid Cat Cracking currently takes place in over 370 Fluid Cat Cracking units in refineries around the world, producing almost 1/2 billion gallons of gasoline daily. It is considered one of the most important chemical engineering achievements of the 20th century. Fluid Cat Cracking technology continues to evolve as cleaner high-performance fuels are explored.
 
Contributed by National Inventors Hall of Fame website
1999