Oils refining

The non-TAG portion of soybean oils includes phospholipids, free fatty acid, chlorophyll pigment, oxidation products, and other unsaponifiable components such as tocopherols, sterols and hydrocarbons. Some of these minor components negatively affect oil quality, while some may play a positive role in nutrition and function. The goal of refining is therefore to remove the undesirable components and, at the same time, to maximize retention of the beneficial components. 

Recently, polymeric ultrafiltration membranes have been used for degumming crude soybean oil. Pagliero and co-workers (2001) showed that membranes were suitable for removing phospholipids from the miscella of crude oil and hexane. When surfactant-aided membrane degumming was applied to crude soybean oil, the degummed oil contained 20-58 ppm of phosphorus (Subramanian el al. 1999). Supercritical CO2 extraction (List el al. 1993) and ultrasonic degumming (Moulton and Mounts 1990) were also successfully used to reduce the gum content of soybean oil. 

There are three types of deodorization operations. The batch process is the least common, due to its low efficiency and inconsistent product quality. Semi-continuous and continuous deodorizers have improved processing efficiency. There are several configurations of the continuous deodorizer, including singleshell cylindrical vessel type, vertically stacked tray type, and the thin-film packed column type. This last provides excellent fatty acid stripping with minimum use of steam, but it achieves neither desired heat bleaching nor effective deodorization due to the relatively short retention time. A retention vessel has to be used after the column distillation (De Greyt and Kellens 2000). 

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At the end of the 1960 s, oil refining underwent significant transformation linked to the continuous increase in the need for light products (gasoline-diesel oil) at the expense of heavy products (fuel-oils) as shown in Table 10.1. 

A very good description of processes, mainly in the oil refining and fuel upgrading sector, highlighting the impact zeolites have made on this industry. 

Reforming (Section 2 16) Step in oil refining in which the pro portion of aromatic and branched chain hydrocarbons in petroleum is increased so as to improve the octane rating of gasoline... 

A new countercurrent continuous centrifugal extractor developed in the former USSR (214) has the feature that mechanical seals are replaced by Hquid seals with the result that operation and maintenance are simplified the mechanical seals are an operating weak point in most centrifugal extractors. The operating units range between 400 and 1200 mm in diameter, and a capacity of 70 m /h has been reported in service. The extractors have been appHed in coke-oven refining (see Coal conversion processes), erythromycin production, lube oil refining, etc. 

Table 1. Generalized Distillation Ranges for Products Obtained During Crude Oil Refining...

The main areas of commercial apphcation are automotive emission control catalysts (autocatalysts), oil refining, ammonia oxidation, hquid-phase ... 

Siace the mid 1950s, tall oil fatty acids (TOFA) have become available ia good quaUties and large quantities (see Carboxylic acids, fatty acids from TALL oil). Refined grades of TOFA have degrees of unsaturation rivaling that of soya acids. Siace it is a year-rouad by-product from the paper iadustry, its... 

The source of nitrogen is always air. However, hydrogen can be derived from a variety of raw materials including water, light and heavy hydrocarbons (qv) resulting from cmde oil refining, coal (qv), natural gas, and sometimes a combination of these raw materials. In all cases, part of the hydrogen produced is derived from water. 

Asphalt Roofing Components. Asphalt (qv) is a unique building material which occurs both naturally and as a by-product of cmde-oil refining. Because the chemical composition of cmde oils differs from source to source, the physical properties of asphalts derived from various cmdes also differ. However, these properties can be tailored by further ptocessiag to fit the appHcation for which the asphalt will be used. Softening poiat, ductility, flash poiat, and viscosity—temperature relationship are only a few of the asphalt properties that ate important ia the fabricatioa of roofing products. 

NaHS, marketed as 71.5—74.5 wt % flakes and 43—60 wt % Hquor ia the high purity grades, is also available as 10—40 wt % Hquor from the oil refining desulfurization process. NaHS is sold commercially ia 22.7-kg bags, 181.4-kg dmms, ia tank tmcks, and ia rail cars. 

Economic Aspects and Uses. Production and sales values for high purity sodium hydrosulfide are Hsted ia Table 1. These figures exclude the low purity material produced by oil refiners, beHeved to be sold primarily to pulp mills. Estimates of uses of NaHS ia the United States for 1994 are as shown (3,4) ... 

Over the years, larger quantities of sulfur have been recovered for a number of reasons. These iaclude iacreased petroleum refining and natural-gas processiag, more stringent limitations on sulfur dioxide emissions, and higher sulfur contents of the cmde oil refined. Another contributiag factor is the lower sulfur content limits set on petroleum-based fuels. 

Another sulfur dioxide appHcation in oil refining is as a selective extraction solvent in the Edeleanu process (323), wherein aromatic components are extracted from a kerosene stream by sulfur dioxide, leaving a purified stream of saturated aHphatic hydrocarbons which are relatively insoluble in sulfur dioxide. Sulfur dioxide acts as a cocatalyst or catalyst modifier in certain processes for oxidation of o-xylene or naphthalene to phthaHc anhydride (324,325). 

Straight Run Asphalt. In cmde-oil refining, the crude oil at 340—400°C is injected into a fractionating column (5,6,19,20). The lighter fractions are separated as overhead products and the residuum is straight-reduced asphalt. 

Fats and Oils. The oxidation of fats and oils in food products can be prevented by the addition of citric acid to chelate the trace metals that catalyze the oxidation. Citric acid is also used in the bleaching clays and the degumming process during oil refining to remove chlorophyll and phosphohpids (59—63). 

During World War II German scientists developed a method of hydrogenating soHd fuels to remove the sulfur by using a cobalt catalyst (see Coal CONVERSION processes). Subsequently, various American oil refining companies used the process in the hydrocracking of cmde fuels (see CATALYSIS SuLFUR REMOVAL AND RECOVERY). Cobalt catalysts are also used in the Fisher-Tropsch method of synthesizing Hquid fuels (21—23) (see Fuels, synthetic). 

There are many types, and only the most important can be mentioned here. [See also Hunter, in Dunstan (ed.). Science of Petroleum, vol. 3, Oxford, New York, 1938, pp. 1779-1797.] They are used fairly extensively in treating petroleum distillates, in vegetable-oil, refining, in extraction of phenol-bearing coke-oven liquors, in some met extractions, and the like. Kalichevsky and Kobe (Petroleum Refining... 

Gasoline accumulator Solvents Storage vessels Lube oil refining Polyethylene gas vents Styrene Copper naphthenates Insecticides Phthalic anhydride Resin reactors Ammonia Chlorine solutions Dry cleaning Degreasers Tar dipping Kraft paper... 

CONCAWE is the oil companies European organization for environment, health and safety. The emphasis of its work lies on technical and economic studies relevant to oil refining, distribution and marketing in Europe. 

Engine manufacturers and oil refiners are researching and developing a synthetic blended diesel fuel. The many advantages of diesel power can be greatly improved by reducing the exhaust emission levels to comply with ever stricter EPA-mandated levels. 

View of cracking stills at a Sinclair oil refiner/. (Corbis Corporation)... 

Liquid hydrocarbons removed from the production stream but not from oil refining... 

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