Catalytic cracking, petroleum industry

The Phenox process (254) removes phenol (qv) from the efduent from catalytic cracking in the petroleum industry. Extraction of phenols from ammoniacal coke-oven Hquor may show a small profit. Acetic acid can be recovered by extraction from dilute waste streams (255). Oils are recovered by extraction from oily wastewater from petroleum and petrochemical operations. Solvent extraction is employed commercially for the removal of valuable... 

Hydrocarbon resin is a broad term that is usually used to describe a low molecular weight thermoplastic polymer synthesized via the thermal or catalytic polymerization of coal-tar fractions, cracked petroleum distillates, terpenes, or pure olefinic monomers. These resins are used extensively as modifiers in the hot melt and pressure sensitive adhesive industries. They are also used in numerous other appHcations such as sealants, printing inks, paints, plastics, road marking, carpet backing, flooring, and oil field appHcations. They are rarely used alone. 

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. 

Solvent extraction may also be used to reduce asphaltenes and metals from heavy fractions and residues before using them in catalytic cracking. The organic solvent separates the resids into demetallized oil with lower metal and asphaltene content than the feed, and asphalt with high metal content. Figure 3-2 shows the IFP deasphalting process and Table 3-2 shows the analysis of feed before and after solvent treatment. Solvent extraction is used extensively in the petroleum refining industry. Each process uses its selective solvent, but, the basic principle is the same as above. 

The CFB catalytic cracking reactor plays an important role in the petroleum industry because of its better gas-solids contact and narrow residence time distribution, but its non-uniform radial flow structure and the extensive backmixing of gas and solids lead to a lower conversion rate and poorer selectivity to desired intermediate products [14]. 

Catalysts were expensive, however, so the petroleum industry did not solve the problem of cheap, lead-free, knock-free gasoline until the 1970s, after General Motors adopted the catalytic converter. Lead compounds inactivate the catalysts, and sophisticated catalytic cracking techniques had to be developed to replace the fuel additive. Ironically, an even more difficult job was finding a substitute for the protective coating that tetraethyl lead formed on exhaust valve seats not even newly developed, extremely hard materials prevent wear and tear on them as well as tetraethyl lead did. 

Write the equations describing a simple version of the petroleum industry s important catalytic cracking operation. There are two vessels as shown in Fig. P3.13. Component A is fed to the reactor where it reacts to form product B while depos-... 

In the United States, approximately one-third of all processed crude oil, amounting to about 5 x 10° bbl/day, is catalytically converted over fluidized catalysts. Over 500 tons of catalyst are required daily, yielding sales that in 1987 were estimated at -250 million dollars (1). Thus, in terms of catalyst usage and product value, catalytic cracking is still the most important unit operation of the petroleumrefining industry. This year, the worldwide sales of catalysts to the petroleum, petrochemical, and chemical industry are expected to exceed 2.4 billion dollars, and catalyst producers are preparing themselves for the turn of the century when catalysts are projected to become a 5 billion dollars per year global business (2). 

Olefins are hydrocarbon compounds with at least two carbon atoms and having a double bond. Their unstable nature and tendency to polymerize makes them one of the very important building blocks for the chemical and petrochemical industry (Gary and Handwerk, 1994). Although olefins are produced by fluid catalytic cracking in refineries, the main production source is through steam cracking of liquefied petroleum gas (LPG), naphtha or gas oils. 

In little more than half of the 25 years covered by this symposium, catalytic cracking has been developed from its first acceptance to a major industrial process. It has served to increase the amount and octane rating of gasoline and the amounts of valuable C3 and C gas components obtainable from petroleum feed stocks over those from thermal cracking alone. It is therefore of interest to seek an explanation of the nature of the products obtained in catalytic cracking in terms of the hydrocarbon and catalyst chemistry which has been developed within the past 25 years. 

In the chemical and petroleum industries, the term cracking is used to describe a chemically complex process in which the decomposition of larger hydrocarbon molecules into smaller fragments plays a dominant role but is accompanied by a number of other reactions (isomerisation, cyclisation, polymerisation, disproportionation etc.). In this section, under catalytic cracking, only the primary fission of a C—C bond, which yields an alkene and a fragment with a C—H bond in the place of the former C—C bond... 

In the petroleum industry, catalytic cracking units provide the major source of olefinic fuels for alkylation. A feedstock from a catalytic cracking units is typified by a Ci/C 4 charge with an approximate composition of propane, 12.7% propylene, 23.6% isobmaiie, 25.0% n-bulane, 6.9% isobutylene, 8.8% 1-butylene, 6.9% and 2-butylene, 16.1%. The butylenes will produce alkylates with octane numbers approximately three units higher than those from propylene. 

---