Catalysts fluid catalytic cracker unit

Some years later Statoil decided to start a project within catalytic cracking in order to learn more abont residue fluid catalytic cracking in general, and particnlarly abont catalysts suitable for this process. The project started as a prestudy for the residue fluid catalytic cracker unit (FCCU) that Statoil was planning to bnild at the Mongstad refinery in Norway. The intention was to crack North Sea atmospheric residue directly, without first using a vacuum gas distillation tower followed by cracking... 

Of the many factors which influence product yields in a fluid catalytic cracker, the feed stock quality and the catalyst composition are of particular interest as they can be controlled only to a limited extent by the refiner. In the past decade there has been a trend towards using heavier feedstocks in the FCC-unit. This trend is expected to continue in the foreseeable future. It is therefore important to study how molecular types, characteristic not only of heavy petroleum oil but also of e.g. coal liquid, shale oil and biomass oil, respond to cracking over catalysts of different compositions. 

In a typical fluid catalytic cracker, catalyst particles are continuously circulated from one portion of the operation to another. Figure 9 shows a schematic flow diagram of a typical unit W. Hot gas oil feed (500 -700°F) is mixed with 1250 F catalyst at the base of the riser in which the oil and catalyst residence times (from a few seconds to 1 min.) and the ratio of catalyst to the amount of oil is controlled to obtain the desired level of conversion for the product slate demand. The products are then removed from the separator while the catalyst drops back into the stripper. In the stripper adsorbed liquid hydrocarbons are steam stripped from the catalyst particles before the catalyst particles are transferred to the regenerator. 

Control of catalyst particle losses from both the cracker and regenerator of fluid catalytic cracking units is achieved by two cyclones operating in series right inside each unit. This is usually followed by an electrostatic precipitator for fine particle control, working on the exhaust side of the catalyst regenerator [62]. The metal content of spent catalysts may be recovered for reuse [63]. 

In refining alone, all over the world in 2007, about four hundred fluid catalytic crackers cracked about 10.6 million barrels of feedstock each day, with half of it occurring in the United States. In 2010, FGGs produced from 35 to 45 percent of the gasoline gained at different U.S. refineries. The exact designs of an FGG, and the catalysts used therein, have been closely held corporate proprietary information. 

Cracking of plastic wastes to gasoline and fuel oil in fluid catalytic cracker (FCC) should be more attractive than other pyrolysis processes except when the pyrolysis process is highly selective to high valued monomers, [3]. Most likely the presence of fillers in the waste can be compensated for by catalyst additions. Studies have shown that, in an FCC unit, the following significant product yields are obtained ... 

Fluid catalytic cracking is one of the key processes for the production of gasoline and diesel oil in present-day refineries. Worldwide, about 400 units are in operation with a total annual capacity of about 600 million tonnes. Commercial catalytic crackers operate at about 550 °C. Since after a contact time in the cracking section (upflow pipe, entrained bed) of only a few seconds the catalyst is largely deactivated by coke at a level of about 1 wt%, the catalyst is routed to a regenerator (fluidized bed), where the coke is burned off at temperatures of 700 °C with air to a level of less than 0.1%. The catalyst is returned pneumatically to the catalytic cracking section. 

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