Fluid Catalytic Cracking FCC

Fluid catalytic cracking (FCC) has been used since the 1950s to turn heavy distillates (vacuum gas oil) into a series of light and dense fractions. The FCC catalysts can also be used as pyrolysis catalysts. 

It has been found for the catalytic cracking of a plastic mixture consisting of LDPF and ethylene-vinyl acetate (FVA) copolymer (86/14 w/w), that nanometer sized HZSM-5 was more active at cracking this plastic mixture at 420° C than the mesoporous catalyst 

Al-MCM-41. This was ascribed to the occurrence of cross-hnking reactions, leading to a fast deactivation of the mesoporous Al-MCM-41 catalysts by coke fouling [8], 

Feed to the FCC unit is mixed with hot catalyst and steam in a reactor line called a riser. The ratio of catalyst oil feed can typically range from 4 1 to 9 1 by weight. Overall, FCC is an endothermic process. Heat provided by the hot, circulating catalyst is the prime source of energy driving the FCC process. In the riser, vaporized oil is cracked catalytically in less than two seconds. The vapors and catalyst flow out of the riser and into the reactor. At this point, most cracking reactions have occurred. 

In the reactor, oil vapors and catalyst are separated by a deflector device or a cyclone. A cyclone facilitates separation by enabling catalyst to collect on its walls and drop from the cyclone to the stripping section at the bottom of the reactor. The vapors exit from the reactor and flow to the FCC fractionating tower. See FIGURE 2-3. 

In the fractionating tower, the cracked oil is distilled into the following components  

FCC Gasoline. The produced light FCC gasoline typically contains a mixture of paraffins, olefins, and aromatic compounds in a ratio of around 5 3 2. This ratio will often vary depending upon feedstock, catalyst quality, and reactor parameters. The research octane number of FCC gasoline will typically be much higher than the motor octane number. 

Cycle Oil. Heavier, distillate range compounds formed during FCC processing can accumulate within the FCC fractionator. The primary fraction is called light cycle oil (LCO) and contains high percentages of monoaromatic and diaromatic compounds plus olefins and heavier branched paraffins. Unhydrotreated LCO is often quite unstable and has a very low cetane number. For this reason, it is blended into diesel fuel in controlled amounts. Heavy cycle oil and heavy naphtha are additional side cuts that can be produced. These streams can be pumped around to remove heat from the fractionator, used to supply heat to other refinery units, or used as low-quality blendstock component. 

Catalyst Loading (wt.%) Surface Area (mVE) Ignition Temp. (K) total HjS released (amoles) 

Rapid and complete regeneration is possible over the range 773-973K, and only elemental sulfur is formed. 

Concerning de-sulfurization processes, ceria is succesfully applied in the direct catalytic reduction of SOj to sulfur using various reductants (CO, CH4, syngas) 

Using CO as reductant, the overall reactions involved in the process are  

Ceria-based catalyst containing small amount of transition metal oxides such as NiO, CuO, C02O3, are among the most active and selective catalysts for this reaction both in dry and/or wet gas stream [25], 

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The MTO process employs a turbulent fluid-bed reactor system and typical conversions exceed 99.9%. The coked catalyst is continuously withdrawn from the reactor and burned in a regenerator. Coke yield and catalyst circulation are an order of magnitude lower than in fluid catalytic cracking (FCC). The MTO process was first scaled up in a 0.64 m /d (4 bbl/d) pilot plant and a successfiil 15.9 m /d (100 bbl/d) demonstration plant was operated in Germany with U.S. and German government support. 

The ethylene feedstock used in most plants is of high purity and contains 200—2000 ppm of ethane as the only significant impurity. Ethane is inert in the reactor and is rejected from the plant in the vent gas for use as fuel. Dilute gas streams, such as treated fluid-catalytic cracking (FCC) off-gas from refineries with ethylene concentrations as low as 10%, have also been used as the ethylene feedstock. The refinery FCC off-gas, which is otherwise used as fuel, can be an attractive source of ethylene even with the added costs of the treatments needed to remove undesirable impurities such as acetylene and higher olefins. Its use for ethylbenzene production, however, is limited by the quantity available. Only large refineries are capable of deUvering sufficient FCC off-gas to support an ethylbenzene—styrene plant of an economical scale. 

The process of fluid catalytic cracking (FCC) is the central process in a modem, gasoline-oriented refinery. In U.S. refineries, the amount of feed processed by fluid catalytic cracking units (FCCU) is equivalent to 35% of the total cmde oil processed in the United States (1). As of January 1991, installed FCCU capacity in the United States was 8.6 x ICf m /d (5.4 x 10 barrels/d). 

A dephlegmator process can be used to recover ethylene—ethane and heavier hydrocarbons from fluid catalytic cracking (FCC) unit off-gas (Fig. 7). Pretreated feed gas is cooled to about 230 K and then further cooled and rectified in a dephlegmator to recover 90 to 98% of the ethylene, 99 % of the... 

Ethylene as a By-Product. The contribution to world ethylene production is small, but not zero. In petroleum refining fluid catalytic cracking (FCC) units, small amounts of ethylene are produced but generally not recovered, except in a few locations where large FCC units are adjacent to petrochemical faciUties. 

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. 

Another approach used to reduce the harmful effects of heavy metals in petroleum residues is metal passivation. In this process an oil-soluble treating agent containing antimony is used that deposits on the catalyst surface in competition with contaminant metals, thus reducing the catalytic activity of these metals in promoting coke and gas formation. Metal passivation is especially important in fluid catalytic cracking (FCC) processes. Additives that improve FCC processes were found to increase catalyst life and improve the yield and quality of products. ... 

Fluid catalytic cracking (FCC) continues to play a key role in an integrated refinery as the primary conversion process. For many refiners, the cat cracker is the key to profitability in that the successful operation of the unit determines whether or not the refiner can remain competitive in today s market. 

Carbon Monoxide Boilers Carbon monoxide boilers are used to recover waste heat generated from oil refining fluid catalytic cracking (FCC) processes. The FCC process produces copious volumes of by-product gas containing 5 to 8% carbon monoxide (CO), which has a heat content of about 150 Btu/lb. A 10,000 barrel (bbl) per day FCC unit produces 60,000 to 150,000 lb/hr of CO. 

The alkylation unit in a petroleum refinery is situated downstream of the fluid catalytic cracking (FCC) units. The C4 cut from the FCC unit contains linear butenes, isobutylene, n-butane, and isobutane. In some refineries, isobutylene is converted with methanol into MTBE. A typical modern refinery flow scheme showing the position of the alkylation together with an acid regeneration unit is displayed in Fig. 1. 

Favorski-Babayan conditions, 24 479 FCC catalyst coolers, 11 728-729 FCC catalysts. See also Fluid catalytic cracking (FCC)... 

See also Fluidized-bed entries Fluid-bed direct oxidation process, 10 656 Fluid-bed dryers, 9 122-123, 130-131 two-stage, 9 125 Fluid-bed roasters, 16 141 Fluid catalytic cracking (FCC), 11 678-699, 700-734 18 651, 653 20 777 24 257, 271. See also FCC entries Fluidized-bed catalytic cracking (FCC) clean fuels production and, 11 686-689 defined, 11 700... 

Catalytic cracking is a process that is currently performed exclusively over fluidized catalyst beds. The fluid catalytic cracking (FCC) process was introduced in 1942 and at that time replaced the conventional moving bed processes. These early processes were based on acid-treated clays as acidic catalysts. The replacement of the amorphous aluminosilicate catalysts by Faujasite-type zeolites in the early-1960s is regarded as a major improvement in FCC performance. The new acidic catalysts had a remarkable activity and produced substantially higher yields than the old ones. 

Most of the commercial zeolite catalyzed processes occur either through acid catalysis fluid catalytic cracking (FCC), aromatic alkylation, methanol to olefins (MTO),... 

Fires involving oxygen, e.g., systems for oxygen addition to a fluid catalytic cracking (FCC) unit... 

Fluidized catalytic processes, in which the finely powdered catalyst is handled as a fluid, have largely replaced the fixed-bed and moving-bed processes, which use a beaded or pelleted catalyst. A schematic flow diagram of fluid catalytic cracking (FCC) is shown in Fig. 4. 

Fluid catalytic cracking (FCC) and coker units generate most of the cyanides in refineries... 

A number of catalytic processes in current use make use of these strategies including reforming, isomerization, dimerization, alkylation and fluid catalytic cracking (FCC). The object of this paper is to discuss the catalytic strategies available to produce octane in the FCC unit. 

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). 

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