Thermofor kiln

Socony-Vacuum utilized Thermofor kilns to bum off coke deposited on Fuller s earth during the filtration of lube oils (57). They adapted one of these kilns to introduce the first moving bed catalytic cracking process. The first semi-commercial 500 BPD (barrel per day) Thermofor Catalytic Cracking (TCC) unit went on stream in the Paulsboro refinery in 1941. It utilized bucket elevators to transport catalyst from the reactor to the regenerator. In 1943, Socony-Vacuum installed a 10,000 BPD TCC unit (52) at a subsidiary refinery. 

The first step in the direction of a continuous process utilized buckets and conveyers to transfer spent catalyst from the reactor to a Thermofor kiln. The Thermofor kiln was in use at that time for burning coke off the Fullers earth used in the filtration of lube oils. The idea of transferring catalyst between a reaction and regeneration zone led to the eventual development of the early bucket elevator TCC, the Houdriflow, the airlift TCC, and eventually the Fluid Catalytic Cracking unit. 

The gas lift unit represents a further improvement over the Thermofor in the elimination of complex internals in the kiln and the mechanical catalyst elevators. These mechanical simplifications in combination with the greatly improved unit heat balance effected an appreciable reduction in investment cost and in unit operating cost. The elimination of so many mechanical components of the unit further resulted in a saving in maintenance, which at the very least would correspond to the reduction in investment. 

Thermofor catalytic cracking (TCC) introduced by Mobil in 1943, fluid catalytic cracking (FCC) introduced by Exxon, and several other similar processes used moving or fluidized beds of strong catalyst particles. Catalyst was withdrawn continuously from the bottom of the reactor and lifted in buckets or by an air stream to the top of a regenerator, or kiln, after the residual hydrocarbons had been stripped out with steam. Catalyst vyas then returned to the reactor after regeneration. There was a limit to the capacity of moving bed processes... 

Fia. 10-6. Diagram of Thermofor continuous clay-burning kiln. (Socony Mobil Oil Co.)... 

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