Catalytic cracking fluid, development

FCC (fluid catalytic cracking) to develop novel molecular sieves which are comparable with or better than ZSM-5 in shape-selectivity of light olefins (C3=-C5=). 

Degnan, T.F., Chitnis, G.K., Schipper, P.H., 2000. History of ZSM-5 fluid catalytic cracking additive development at Mobil. Microporous and Mesoporous Materials 35—36 (0), 245-252. 

Deep C t lytic Crocking. This process is a variation of fluid catalytic cracking. It uses heavy petroleum fractions, such as heavy vacuum gas oil, to produce propylene- and butylene-rich gaseous products and an aromatic-rich Hquid product. The Hquid product contains predorninantiy ben2ene, toluene, and xylene (see BTX processing). This process is being developed by SINOPEC in China (42,73). SINOPEC is currentiy converting one of its fluid catalytic units into a demonstration unit with a capacity of 60,000 t/yr of vacuum gas oil feedstock. 

Catalytic Pyrolysis. This should not be confused with fluid catalytic cracking, which is used in petroleum refining (see Catalysts, regeneration). Catalytic pyrolysis is aimed at producing primarily ethylene. There are many patents and research articles covering the last 20 years (84—89). Catalytic research until 1988 has been summarized (86). Almost all catalysts produce higher amounts of CO and CO2 than normally obtained with conventional pyrolysis. This indicates that the water gas reaction is also very active with these catalysts, and usually this leads to some deterioration of the olefin yield. Significant amounts of coke have been found in these catalysts, and thus there is a further reduction in olefin yield with on-stream time. Most of these catalysts are based on low surface area alumina catalysts (86). A notable exception is the catalyst developed in the former USSR (89). This catalyst primarily contains vanadium as the active material on pumice (89), and is claimed to produce low levels of carbon oxides. 

Various companies worked on the development of Fluid catalytic cracking units. During World War II, the government requested some of the leaders in this field to pool their knowledge so as to speed the production of aviation gasoline. The fact that so many Fluid units were constructed and put into operation in such a short time shows that this joint effort was successful. However, because of this effort, many of the basic Fluid patents were held for many years in combination with other companies, some of which also developed their own Fluid designs. 

Fluid bed reactors became important to the petroleum industry with the development of fluid catalytic cracking (FCC) early in the Second World War. Today FCC is still widely used. The following section surveys the various fluid bed processes and examines the benefits of fluidization. The basic theories of fluidization phenomena are also reviewed. 

Murphy, J. R., Air Products-HRI, The Development of Feed and Air Distribution Systems in Fluid Catalytic Cracking, presented at the 1984 Akzo Chemicals Symposium, Amsterdam, The Netherlands... 

MSCC [Millisecond catalytic cracking] A fluid catalytic cracking process which uses an ultra-short contact time reaction system. It is claimed that less capital investment and higher liquid yields can be achieved using this process, compared with conventional FCC units. Developed by Bar-Co and now offered by UOP it has been operating since 1994. 

The first cracking catalysts were acid-leached montmorillonite clays. The acid leach was to remove various metal impurities, principally iron, copper, and nickel, that could exert adverse effects on the cracking performance of a catalyst. The catalysts were first used in fixed- and moving-bed reactor systems in the form of shaped pellets. Later, with the development of the fluid catalytic cracking process, clay catalysts were made in the form of a ground, sized powder. Clay catalysts are relatively inexpensive and have been used extensively for many years. 

The desire to have catalysts that were uniform in composition and catalytic performance led to the development of synthetic catalysts. The first synthetic cracking catalyst, consisting of 87% silica (Si02) and 13% alumina (AI2O3), was used in pellet form and used in fixed-bed units in 1940. Catalysts of this composition were ground and sized for use in fluid catalytic cracking units. In 1944, catalysts in the form of beads about 2.5 to 5.0 mm in diameter were introduced and comprised about 90% silica and 10% alumina and were extremely durable. One version of these catalysts contained a minor amount of chromia (Cr203) to act as an oxidation promoter. 

Prior to 1938, gasoline was obtained from thermal-cracking plants then the Houdry fixed-bed catalytic cracking process led to the development of a fluidized-bed process by Standard Oil for the catalytic production of motor fuels (4-8). Acid-treated clays of the montmorilIonite type were the first fluid-cracking catalysts widely employed by the industry. However, the ever greater demand for aviation fuels during the 1939-1945 period prompted the search for more active and selective catalysts. Research on novel catalyst... 

They began reduced crude cracking experimentation in a small 12,000 barrel per day (B/D) Fluid Catalytic Cracking (FCC) operating unit at Louisville, Ky. The RCC process was born from these goals, concepts and a small operating unit. The development and attributes of this process have been described in a number of articles and patents (1-6). 

In response to recent federal and local environmental concerns (e.g., industrial emission controls and lead phase-out) and to the growing interest of refiners in cracking residual fuels, researchers have generated new families of cracking catalysts. There is now a need to review the merits of these newly developed materials. This volume contains contributions from researchers involved in the preparation and characterization of cracking catalysts. Other important aspects of fluid catalytic cracking, such as feedstocks and process hardware effects in refining, have been intentionally omitted because of time limitations and should be treated separately in future volumes. 

Al-Enezi, G., Fawzi, N., and Elkamel, A. (1999) Development of regression models to control product yields and properties of the fluid catalytic cracking process. Petroleum Science e[ Technology, 17, 535. 

Table 7 shows the yield distribution of the C4 isomers from different feedstocks with specific processing schemes. The largest yield of butylenes comes from the refineries processing middle distillates and from olefins plants cracking naphtha. The refinery product contains 35 to 65% butanes olefins plants, 3 to 5%. Catalyst type and operating severity determine the selectivity of the C4 isomer distribution (41) in the refinery process stream. Processes that parallel fluid catalytic cracking to produce butylenes and propylene from heavy cmde oil fractions are under development (42). 

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