Catalytic cracking TCC process

The first moving-bed process employed countercurrent flow of catalyst and reactants in both vessels and used mechanical bucket elevators to transfer the catalyst from one vessel to the other. This process, originally developed by the Socony-Vacuum Oil Company, was named the Thermo-for Catalytic Cracking (TCC) process (239,295,339). Two major improvements were subsequently developed change from countercurrent to concurrent flow in the reactor (297,298) and substitution of a gas-lift system for transfer of catalyst. In the gas-lift system, the catalyst pellets are conveyed upward through a pipe, or pipes, by a stream of flue gas or air. 

Al-Yassir. N, and le van Mao, R., Catalysts for the thermo-catalytic cracking (TCC) process Interaction between the yttria in yttria-doped alumina aerogel and the mono-oxide MoO,. CeOj, and bi-oxide MofT-CeOj species, Appl. Catal. A, 332, 273, 2007. 

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. 

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 Catalyst was withdrawn continuously from the bottom of the reactor and lifted in buckets or by an air stream to the top of a regenerator, or kiln, after the residual hydrocarbons had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... 

Airlift Thermofor Catalytic Cracking Also called Airlift TCC. A continuous catalytic process for converting heavy petroleum fractions to lighter ones. The catalyst granules are moved continuously by a stream of air. Developed by Mobil Oil Corp., United States, and first operated in 1950. See also Thermofor. 

The point here 1s that the cost advantage of FCC over TCC or HCC is an order of magnitude less than the cost advantage of any of the three processes over no catalytic cracking at all. Ap-... 

While natural or activated clay catalysts are no longer employed in the fixed-bed Houdry process, they are still widely used in the fluid process and to a considerable extent in the TCC process. A natural bauxite catalyst is employed in the fixed-bed cycloversion process, developed by the Phillips Petroleum Company. This process is of greater importance as a naphtha reforming process than as a catalytic cracking process. 

The TCC moving bed process went commercial in 1943. At the end of World War II the installed capacity for catalytic cracking was over 900,000 bbls/day. 

FIGURE 15.13 Hydrocarbon content of gasoline fraction produced by bitumen processing. TCC, thermo-catalytic cracking RTC, radiation-thermal cracking. 

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. 

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