Crude oil fractionation

Liquid products must undergo hydrogen processing before joining equivalent crude oil fractions and continuing the normal process property improvement steps. 

Secondary raw materials, or intermediates, are obtained from natural gas and crude oils through different processing schemes. The intermediates may be light hydrocarbon compounds such as methane and ethane, or heavier hydrocarbon mixtures such as naphtha or gas oil. Both naphtha and gas oil are crude oil fractions with different boiling ranges. The properties of these intermediates are discussed in Chapter 2. 

Paraffinic hydrocarbons used for producing petrochemicals range from the simplest hydrocarbon, methane, to heavier hydrocarbon gases and liquid mixtures present in crude oil fractions and residues. 

Approximate ASTM boiling point ranges for crude oil fractions... 

Naphthenic acids and cresylic acid, which are extracted from certain crude oil fractions, are briefly reviewed at the end of the chapter. 

Synthesis gas, the third important intermediate for petrochemicals, is generated hy steam reforming of either natural gas or crude oil fractions. Synthesis gas is the precursor of two hig-volume chemicals, ammonia and methanol. 

Molex) ensure the possibility of isolating the quantities of /z-paraffins from suitable crude oil fractions required for the synthesis of LAB. 

W. Ritter, C. Meyer, W. Zollner, C. P. Herold, and S. von Tapavicza. Use of selected acrylic and/or methacrylic acid ester copolymers as flow enhancers in paraffin-rich crude oil and crude oil fraction (II) (Verwendung ausgewahlter Copolymeren der Acryl- und/oder Methacrylsaureester als FlieBverbesserer in paraffinreichen Erdolen und Erdolfraktionen [II]). Patent EP 332002,1989. 

Homogeneous gas phase reactors will always be operated continuously whereas liquid phase reactors may be batch or continuous. Tubular (pipe-line) reactors are normally used for homogeneous gas-phase reactions for example, in the thermal cracking of petroleum crude oil fractions to ethylene, and the thermal decomposition of dichloroethane to vinyl chloride. Both tubular and stirred tank reactors are used for homogeneous liquid-phase reactions. 

The results of experiments with crude oil fractions in this study also suggest that several species were present in reaction interface. There are mainly long chain carboxylic acids. The difference in size and structure is expected to give them different pka values. As a result, different surface activity (i.e., IFT value) is obtained with different levels of alkali concentration. Crude oil fractions with lower surface activity only yield surface inactive salts that may appear as precipitates at the interface. 

In the resid, the largest molecular weight belongs to the asphaltenes, whose molecular structure is not known, until now. Asphaltenes are not defined in chemical or physical terms, but rather in an operational manner as a crude oil fraction that is insoluble in light... 

Boylan and Tripp [76] determined hydrocarbons in seawater extracts of crude oil and crude oil fractions. Samples of polluted seawater and the aqueous phases of simulated samples (prepared by agitation of oil-kerosene mixtures and unpolluted seawater to various degrees) were extracted with pentane. Each extract was subjected to gas chromatography on a column (8 ft x 0.06 in) packed with 0.2% of Apiezon L on glass beads (80-100 mesh) and temperatures programmed from 60 °C to 220 °C at 4°C per minute. The components were identified by means of ultraviolet and mass spectra. Polar aromatic compounds in the samples were extracted with methanol-dichlorome-thane (1 3). 

Wastewater from crude oil fractionation generally comes from three sources. The first source is the water drawn off from overhead accumulators prior to recirculation or transfer of hydrocarbons to other fractionators. This waste is a major source of sulfides and ammonia, especially when sour crudes are being processed. It also contains significant amounts of oil, chlorides, mercaptans, and phenols. 

Boylan DB, Tripp BW. 1971. Determination of hydrocarbons in seawater extracts of crade oil and crude oil fractions. Nature 230(5288) 44-47. 

The oxygen content of crude oil is typically low and is usually in the form of naphthenic acid compounds. Asphaltic crudes can contain significantly more of these acids than paraffinic crude oils. Also, the concentration of oxygen increases with the boiling point of the crude oil fraction. 

Crude oil typically contains little to no olefinic compounds. Through refining and processing, however, olefins are produced and become a part of various crude oil fractions. Olefins can be found in thermally cracked and catalytically cracked gasoline fractions as well as in FCC cycle oils and coker gas oils. For this reason, it is not unusual for finished gasoline and distillate blends to contain a high-olefin-content stream. 

A gaseous product rich in ethylene and propylene is made by pyrolysis of crude oil fractions according to the following description. Construct a flowsheet for the process. Use standard symbols for equipment and operating conditions. Space the symbols and proportion them in such a way that the sketch will have a pleasing appearance. 

Crude oil fractionators are an example of a more elaborate system. They make several products as side streams and usually have some pumparound reflux in addition to top reflux which serve to optimize the diameter of the tower. Figure 3.13 is of such a tower operating under vacuum in order to keep the temperature below cracking conditions. The side streams, particularly those drawn off atmospheric towers, often are steam stripped in external towers hooked up to the main tower in order to remove lighter components. These strippers each have four or five trays, operate... 

Fuels. Catalytic Cracking Catalysts are used lo refined a moderately heavy crude oil fraction known as gas oil to gasoline. The net result of the process is a lighter product with a high content of branched-chain and aromatic hydrocarbons, the species responsible for raising gasoline octane levels. The transformations are complex, hut can be considered lo involve ihe following major acid-catalyzed reactions ... 

TYPE ANALYSIS OF A BORNEO CRUDE OIL FRACTION (MOL. WT. 267) BY CHROMATOGRAPHIC SEPARATION... 

In the case of statistical methods of analysis of sulphur-containing crude oil fractions one generally confines oneself to small corrections on the applied graphs or equations. These corrections, which have been estimated empirically, are valid only for small percentages of sulphur and do not take into account the nature of the sulphur compounds present in the fractions. 

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