Examples catalytic cracking

Refinery Production. Refinery propylene is formed as a by-product of fluid catalytic cracking of gas oils and, to a far lesser extent, of thermal processes, eg, coking. The total amount of propylene produced depends on the mix of these processes and the specific refinery product slate. For example, in the United States, refiners have maximized gasoline production. This results in a higher level of propylene production than in Europe, where proportionally more heating oil is produced. 

While this unit is considerably cheaper, it also has certain disadvantages. For example, changes or upsets in any one unit may be felt throughout the refinery because of the changes in fractionator operation. However, the considerable cost saving possible with the combination type unit has permitted many small refineries to finance a catalytic cracking unit when they could not afford a conventional model. 

Residues containing high levels of heavy metals are not suitable for catalytic cracking units. These feedstocks may be subjected to a demetallization process to reduce their metal contents. For example, the metal content of vacuum residues could be substantially reduced by using a selective organic solvent such as pentane or hexane, which separates the residue into an oil (with a low metal and asphaltene content) and asphalt (with high metal content). Demetallized oils could be processed by direct hydrocatalysis. 

Products from catalytic cracking units are also more stable due to a lower olefin content in the liquid products. This reflects a higher hydrogen transfer activity, which leads to more saturated hydrocarbons than in thermally cracked products from delayed coking units, for example. 

Some invaluable isolated actions were taken from time to time in the last twenty to twenty five years that prevented air quality from declining at an even faster rate. For example, energy demand was met (electricity and refined oil products) by expanding capacity of plants located outside of the MCMA a metro was built the vehicular traffic system was reordered and new hydrotreating, reforming and catalytic cracking units reduced lead and sulfur in refined products. 

Consider the example in Fig. 26 of determining if there is a problem with the feed injection system of a fluidized catalytic cracking unit (Ramesh et al., 1992). In this example, there is a set of rules that relate combinations of process observations to establish or reject this possibility. 

Fig. 26. A fluidized catalytic cracking unit example of combining numeric-symbolic and symbolic-symbolic interpretation (Ramesh et at., 1992).

Figure 26, shown earlier, is a simple form of input mapping called table lookup. A more complicated inference mechanism is illustrated in Fig. 30. Here we see a simple example from a fluidized catalytic cracking unit in which multiple product quality attributes can be explained by multiple operating parameters (Ramesh et al., 1992).

Cerium oxides are outstanding oxide materials for catalytic purposes, and they are used in many catalytic applications, for example, for the oxidation of CO, the removal of SOx from fluid catalytic cracking flue gases, the water gas shift reaction, or in the oxidative coupling reaction of methane [155, 156]. Ceria is also widely used as an active component in the three-way catalyst for automotive exhaust pollution control,... 

For the purposes of this illustrative example, we wish to calculate the combined and effective diffusivities of cumene in a mixture of benzene and cumene at 1 atm total pressure and 510 °C within the pores of a typical TCC (Thermofor Catalytic Cracking) catalyst bead. For our present purposes, the approximation to the combined diffusivity given by equation 12.2.8 will be sufficient because we will see that the Knudsen diffusion term is the dominant factor in determining the combined diffusivity. 

Examples Continuous or batch chemical reactions Catalytic cracking Electrochemistry Examples Paint formulating Powder mixing Diluting with solvent Warehousing... 

The modem gasolines are produced by blending products from cmde oil distillation, that is, fluid catalytic cracking, hydrocraking, reforming, coking, polymerization, isomerization, and alkylation.Two clear examples of the possible use of solid-acid catalysts in refining processes are the isomerization of lineal alkanes and the alkylation of isobutene with butanes. In both these cases, and due to the octane... 

If deactivation is rapid and caused by a deposition and a physical blocking of the surface this process is often termed fouling. Removal of this solid is termed regeneration. Carbon deposition during catalytic cracking is a common example of fouling... 

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