Paraffin separation

Liquid propane is a selective hydrocarbon solvent used to separate paraffinic constituents in lube oil base stocks from harmful asphaltic materials. It is also a refrigerant for liquefying natural gas and used for the recovery of condensable hydrocarbons from natural gas. 

Promising applications of SFC include group separations (paraffins, olefins and aromatics) in petrochemical samples, monitoring of supercritical extraction processes (caffeine from coffee, nicotine from tabacco) and oligomer separations. However, it is in the field of applications that SFC has yet to prove its value. Unique separations that can be accomplished with SFC, but not with either GC or LC, have yet to be demonstrated. 

The costs of separating paraffin-olefin mixtures by extractive distillation are greatly affected by the solvent selectivity, the paraffin activity coefficient, and the solvent volatility they depend mostly upon solvent characteristics. For a solvent to be effective to separate key components A and B, the solvent must have a high value of y A/y B while it must also have a low y°V Further, the solvent vapor pressure should be lower, but not several orders of magnitude lower, than that of the less volatile hydrocarbon. 

A great many industrial products besides those mentioned in Sections 11.2 and 11.3 depend in some way on H bonds. For finished goods that require certain catalysts (hydrous metal oxides), color removal (by clay filtration), or flotation separation, adsorption influenced by H bonds is sometimes critical. Finally, some materials require H bonds to achieve or maintain their desired form or to cairry out their functions an example is the urea complexes used in separating paraffin hydrocarbons (110). 

The chemical classification of petroleum that distinguishes between oils of a paraffin base from those of an asphaltene base was introduced into petroleum chemistry to distinguish the oils that separate paraffin on cooling from those that separate asphaltenes. The presence of paraffins is usually reflected in the paraffinic nature of the constituent fractions whereas a high asphaltic content corresponds with the naphthenic properties of the fractions. This could lead to the misconception that paraffin-base petroleum consists mainly of paraffins and that asphalt-base petroleum consists mainly of cyclic (or naphthenic) hydrocarbons. In order to avoid confusion, a mixed base has been introduced for those oils that leave a mixture of asphaltic petroleum and paraffins as residue from nondestruc-... 

This process, applied to the treatment of C4 cuts and more specifically to the manufacture of 1-butene, is one the many variants of adsorption technology on molecular sieves called Sorbex and developed by VOP, to separate paraffins (Molex). olefins (Olexl... 

Use of propane and cresylic acid as solvents to separate paraffins from aromatics and naphthenes (Vol. 15, pp. 57-58)... 

J. R. Bernard, J. P. Gourlia, and M. J. Guttierrez, Separating Paraffin Isomers Using Chroma-... 

Paraffins are isolated from the sample matrix (edible oils or food extracts often containing much fat or oil) and separated from aromatics and olefins (e.g., sterenes from the raffination of edible oils) by NPLC. As it is difficult to maintain a high activity of silica gel to separate paraffins from olefins when large amounts of matrix material are injected, two columns are used up to 30 mg edible oil or fat is injected onto a first column of 25 cm x 2 mm i.d. The hydrocarbons are transferred to a second column of the same dimension. The first column is backflushed with dichloromethane to remove the oil and other materials of the food extract. The second column only comes in contact with pentane as the mobile phase and nonpolar sample components, i.e. it maintains its high retention power for unsaturated components. Transfer of the fraction of about 400 pi volume to GC mostly involves the retention gap... 

Using molecular sieve 13X it is possible to separate paraffinic and naphthenic hydrocarbons according to carbon number (22]. However, the retention of high boiling hydrocarbons was very high. For example, the time required for the elution of hydrocarbons up to Cii in a typical naphtha sample on a packed column is 1.5 h (see Fig. 2-3a [21]). With 10 m X 0.5 mm stainless steel ALOT column with 0.3 p.m porous layer, Cii hydrocarbons elute at 400 °C (see Fig. 2-3b [21]). ALOT column permits to decrease the maximal separation temperature (400 °C instead of 500 °C). 

Fixed embryos 1-3 are embedded in three separate paraffin blocks. The size of the paraffin blocks should be close to the size of the Si substrates (1.2 cm). 

MetallO Organic-CompIcxes Metallo-Organic-Molecular Sieves (MOMS) Storage of natural gas Gas separation (paraffins, olefins)... 

Molecular structure affects Lube quality. Solvent extraction and dewaxing processes preferentially separate the molecules as shown in Figure 10. Extraction separates -paraffins, /-paraffins, naphthenes and some aromatics fi om the distillate into the raffinate phase. Dewaxing rejects the n-paraffins and some /-paraffins from the raffinate to produce a dewaxed oil or base stock. The dewaxed oil will contain the slice of molecular types as shown in Figure 10. 

Chem. Eng., Separating paraffin isomers using chromatography," Chem. Eng., May 18 (1981), p. 92. 

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