Crude oil, cracking

Development of Scaling Methods for a Crude Oil Cracking Reactor by Using Short Duration Test Techniques... 

The chief sources of olefins are cracking operations, especially catalytic cracking. However, olefins can be produced by the dehydrogenation of paraffins butanes are dehydrogenated commercially to provide feeds to alkylation. Isobutane is obtained from crude oils, cracking operations, catalytic reformers, and natural gas. To supplement these sources, n-butane is sometimes isomer-ized. Only small concentrations of diolefins are permissible in feeds to alkylation, particularly for sulfuric add catalyst. Diolefins increase the consumption of acid. 

Table 1.2 Examples of a chemical ladder starting from alkenes (obtained from crude oil cracking) and ending in a variety of pharmaceuticals... 

Figure 3.45 Flow diagram for crude oil cracking according to the BASF process...

Figure 3.46 Kureha/ Union Carbide process for crude oil cracking...

Because of its high aromaticity, coal tar offers the most suitable source of naphthalene. Next to coal tar in terms of aromaticity comes pyrolysis tar (see Chapter 3.6, Figure 3.60), with an aromaticity of around 0.8. It is possible to recover naphthalene from both of these raw materials, and from naphthalene oil from crude-oil cracking (see Chapter 3.3.2.5.2), by distillation and crystallization. 

Naphthalene is present, in varying amounts, in all petroleum-derived pyrolysis products which have been exposed to a temperature of over 500 °C or to catalytic processes under relatively severe conditions. It can thus be found in the appropriate distillation fractions of the liquid products of steam cracking for the production of ethylene, in by-products of crude oil cracking and in residues of catalytic gasoline reforming as well as catalytic cracking of gas oils. The extraction of kerosene fractions provides a further source of naphthalene, after the separation of ali-phatics. 

This industry is engaged in producing gasoline, kerosine, fuel oils, residual fuel oils, lubricants, and other products through distillation of crude oil, cracking, or other processes. Petroleum refining is a combination of several interdependent processes, many of which are highly complex. There are more than two dozen separate processes... 

Wilkinson, L., and Gomi, S., Crude Oil Cracking for Olefins , Presented at National Petroleum Refiners Association 72nd Annual Meeting, Miami, Florida, March 31-April 2, 1974. 

The most common industrial synthesis path for alkenes is the cracking of crude oil. Cracking is the... 

Properly speaking, steam cracking is not a refining process. A key petrochemical process, it has the purpose of producing ethylene, propylene, butadiene, butenes and aromatics (BTX) mainly from light fractions of crude oil (LPG, naphthas), but also from heavy fractions hydrotreated or not (paraffinic vacuum distillates, residue from hydrocracking HOC). 

Mercaptans are naturally present in crude oil (Chapters 1 and 8), or they result from the decomposition of other sulfur compounds during thermai or catalytic cracking operations. 

Other compounds which may be found in crude oil are metals such as vanadium, nickel, copper, zinc and iron, but these are usually of little consequence. Vanadium, if present, is often distilled from the feed stock of catalytic cracking processes, since it may spoil catalysis. The treatment of emulsion sludges by bio-treatment may lead to the concentration of metals and radioactive material, causing subsequent disposal problems. 

In addition to the distillation of crude oil coming into the refinery, stills of various designs are used in other types of service throughout the refinery. Cracked products are separated in distillation equipment which is very similar to an atmospheric crude pipe still. The principal difference is that these products are hot from the cracking operation, so that a fired heater is not required. 

Normally, all of the heat is removed from the fractionator by three or more circulating reflux streams. The proportion of gas and naphtha in the cracked products is much higher than in crude oil, so it is seldom possible to reduce the diameter of the tower top as in atmospheric pipe still design. Due to the low operating pressure, it is necessary to provide expensive compression capacity to permit recovery of these light hydrocarbons in subsequent equipment. 

The primary process for separating the hydrocarbon components of crude oil is fractional distillation i.e. separation according to the boiling points of the components. These separated fractions are processed further by catalytic reformers, cracking units, alkylation units, or cokers which have there own fractional distillation towers for its products. 

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