Refining, distillation

Most alkylphenols sold today require refinement. Distillation is by far the most common separation route. Multiple distillation tower separations are used to recover over 80% of the alkylphenol products in North America. Figure 4 shows a basic alkylphenol distillation train. Excess phenol is removed from the unrefined alkylphenol stream in the first tower. The by-products, which are less volatile than phenol but more volatile than the product, are removed in the second tower. The product comes off the third tower overhead while the heavy by-products come out the bottom. 

Refining/distillation of crude oil and crude-oil-derived products... 

Similar results were reported by BP France28 using a cobalt/molybdenum catalyst at 20 kg/cm2 pressure, temperatures in the range of 200°C to 350°C, and space velocities between 0.5 and 5.0. IFP also developed a hydrofinishing process applicable to naphthenic and solvent refined distillates.27 34 Bechtel30 has assumed licensing of Texaco s lube base oil technology. 

Polyolefin plastics are essentially polymers that are composed out of hydrocarbon molecules. These are typically obtained from fossil fuel that is, petroleum. After a relatively simple heat treatment in a refining (distillation) process, specific distillate fractions, being hydrocarbon... 

Distillates (petroleum), light hydrocracked. See Petroleum distillates, light hydrocracked Distillates (petroleum), solvent-refined heavy paraffinic. See Petroleum distillates, solvent-refined, heavy paraffinic Distillates (petroleum), solvent-refined light naphthenic. See Petroleum distillates, light naphthenic, solvent-refined Distillates (petroleum), solvent-refined (mild) heavy paraffinic. See Petroleum distillates, solvent-refined, heavy paraffinic Distillates (petroleum), solvent-refined (mild) light naphthenic. See Petroleum distillates, light naphthenic, solvent-refined Distillates (petroleum), sweetened middle. See Petroleum distillates, sweetened middle Distilled Lipolan. See Hydrogenated lanolin Distilled fatty acids, cottonseed oil. See Cottonseed acid... 

Synonyms Distillate, light naphthenic, solvent-refined Distillates, light naphthenic, solvent-refined Distillates (petroleum), solvent-refined light naphthenic Distillates (petroleum), solvent-refined (mild) light naphthenic Mineral oil, petroleum distillates, solvent-refined (mild) light naphthenic... 

In petroleum refining, distillation may take place in two stages ... 

Some very perceptive insights into the differences between petroleum refining distillation and that in the chemical industry are offered by Tolliver and Waggoner in an extensive literature review. 

Refining Distillation columns, overhead systems, heat exchangers, storage tanks... 

There are little or no olefins in crude oil or straight run (direct from crude distillation) products but they are found in refining products, particularly in the fractions coming from conversion of heavy fractions whether or not these processes are thermal or catalytic. The first few compounds of this family are very important raw materials for the petrochemical Industry e.g., ethylene, propylene, and butenes. 

In this manner, the KuQp of a petroieum cut can be calcuiated quickly from readily avkilable data, i. e., the specific gravity and the distillation curve. The A //np value is between 10 and 13 and defines the chemical nature of the cut as it will for the pure components. The characterization factor is extremely Va luable and widely used in refining although the discriminatory character of the Kuqp is less than that obtained by more modern physical methods described in 3.2 and 3.3. 

Tests employing the less-efficient distillations, D 86, D 1160, and D 1078 are generally conducted on refined products while those giving a detailed analysis, D 2887 and D 2892, are concerned mostly with crude oils and feeds to and effluents from conversion units. 

Generally speaking, these correlations for refined products lead to too-low results for the points at small distilled fractions and to too-high results for those of large distilled fractions. 

The properties of straight run diesel fuels depend on both nature of the crude oil and selected distillation range. Thus the paraffinic crudes give cuts of satisfactory cetane number but poorer cold characteristics the opposite will be observed with naphthenic or aromatic crudes. The increasing demand for diesel fuel could lead the refiner to increase the distillation end point, but that will result in a deterioration of the cloud point. It is generally accepted that a weight gain in yield of 0.5% could increase the cloud point by 1°C. The compromise between quantity and quality is particularly difficult to reconcile. 

The stocks used for jet fuel production come almost essentially from direct distillation of crude oil. They correspond to the fraction distilled between 145 and 240°C, more or less expanded or contracted according to the circumstances. The yield of such a cut depends largely on the nature of the crude but is always larger than the demand for jet fuel which reaches about 6% of the petroleum market in Europe. For the refiner, the tightest specifications are ... 

H2S is found with the reservoir gas and dissolved in the crude (< 50 ppm by weight), but it is formed during refining operations such as catalytic cracking, hydrodesulfurization, and thermal cracking or by thermal decomposition of sulfur[Pg.322]

These compounds can be malodorous as in the case of quinoline, or they can have a plecisant odor as does indole. They decompose on heating to give organic bases or ammonia that reduce the acidity of refining catalysts in conversion units such as reformers or crackers, and initiate gum formation in distillates (kerosene, gas oil). 

Hydrogen chloride released dissolves in water during condensation in the crude oil distillation column overhead or in the condenser, which cause corrosion of materials at these locations. The action of hydrochloric acid is favored and accelerated by the presence of hydrogen sulfide which results in the decomposition of sulfur-containing hydrocarbons this forces the refiner to inject a basic material like ammonia at the point where water condenses in the atmospheric distillation column. 

The graph gives the yields that the refiner would obtain at the outlet of the atmospheric distillation unit allowing him to set the unit s operating conditions in accordance with the desired production objectives. 

Figure 10.1 presents the part of the refining diagram that includes the atmospheric and reduced pressure distillations. 

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). 

Simple conventional refining is based essentially on atmospheric distillation. The residue from the distillation constitutes heavy fuel, the quantity and qualities of which are mainly determined by the crude feedstock available without many ways to improve it. Manufacture of products like asphalt and lubricant bases requires supplementary operations, in particular separation operations and is possible only with a relatively narrow selection of crudes (crudes for lube oils, crudes for asphalts). The distillates are not normally directly usable processing must be done to improve them, either mild treatment such as hydrodesulfurization of middle distillates at low pressure, or deep treatment usually with partial conversion such as catalytic reforming. The conventional refinery thereby has rather limited flexibility and makes products the quality of which is closely linked to the nature of the crude oil used. 

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