Oil Stability

The visbreaking process thermally cracks atmospheric or vacuum residues. Conversion is limited by specifications for marine or Industrial fuel-oil stability and by the formation of coke deposits in equipment such as heaters and exchangers. 

Most of the phosphate esters are used in the production of hydrauHc fluids (qv), plastic and elastomer additives, flame retardants (qv), oil stabilizers, pesticides (qv), and medicinal intermediates (see Surfactants). Some trialkyl phosphates, OP(OR)2, are outstanding solvents for nitrates, especially (UO2) (N02)2, and therefore are important in uranium processing (see Extraction). 

Absorber oil then flows to a still where it is heated to a high enough temperature to drive the propanes, butanes, pentanes and other natural gas liquid components to the overhead. The still is similar to a crude oil stabilizer with reflux. The closer the bottom temperature approaches the boiling temperature of the lean oil the purer the lean oil which will be recirculated to the absorber. Temperature control on the condenser keeps lean oil from being lost with the overhead. 

Many investigators of steric stabilization have measured colloidal stability without taking the effort to find out whether the stability actually resulted from electrostatic stabilization. In many published articles it has been concluded that steric stabilization had been attained and further study showed this was not the case. One such example is a recent paper on "steric" stabilization by an additive of the same type used in this work. (12) The published photograph shows the silica particles in oil stabilized at interparticle separations several times the distances provided by the adsorbed films no electrical measurements had been made, but it they had, this particular dispersant would have provided about -200 mV of zeta-potential and given excellent electrostatic repulsion. The reader should be wary of any claims of steric stabilization unless the electrostatic contribution has been measured. 

A widespread method for determining the induction period for autoxidation of oils and fats consists of passing a continuous stream of air through the heated sample and collecting the volatile acids evolved in a water trap, where they are determined on a real time basis. The time plot usually presents a flat appearance for a certain period and then takes off in an accelerated manner. This test is the basis of several national and international standards (e.g. AOCS Cd 12b-92—oil stability index" ISO 6886—accelerated oxidation test for oxidative stability of fats and oils ) and the design of the Rancimat equipment, where the end determination is based on conductivity measurements . In addition to oxidation stability as determined by the Rancimat method and POV, which negatively affects virgin olive oil stability, other nonstandard properties were proposed for better assessment of the quality of this oil, namely LC determination of Vitamin E (21), colorimetric determination of total polar phenols and UVD of total chlorophyll. ... 

However, organic peroxides will still form in stored fuel, and their gradual accumulation can contribute to elastomer degradation throughout the fuel storage and distribution system. Hydroperoxide formation and accumulation can be readily controlled by the addition of low levels of traditional fuel oil stabilizers. 

A fuel oil stabilizer additive listed in QPL-24682 may be blended into naval distillate fuel at rates up to 35 lb/1,000 barrels to protect against degradation and improve storage stability as measured by ASTM D-5304. Method ASTM D-2274 may also be used if the test duration is extended from 16 to 40 hours. 

Williams Brothers Pipeline Company. 1982. Williams Brothers fuel oil stability test. 

Emulsions of lemon oil stabilized with gum arabic, a conventional starch dextrin and a low viscosity starch octenylsuccinate were spray-dried and evaluated for encapsulating efficiencies. Oil retentions and surface oil determinations were made according to the Materials and Methods section. TABLE 3 demonstrates the superiority of the starch octenylsuccinate in flavor retention and surface oil to gum arabic and a starch dextrin (5) ... 

Because of the presence of hydrogen sulfide in Jay field crude oil, complex facilities, including oil stabilization, gas sweetening, and sulfur-recovery units, were required to produce salable oil and gas. To initiate field production and to provide extended well tests, a small 2.000-B/D facility was installed initially. As development drilling proceeded, 6.S00- and 12,000-B/D modules were built when and where needed. By using the modular-facility design concept, the field producing capacity was more than 00,000 B/D within 2V4 years of discovery. 

Process design for all plants is similar (Fig. 5). The typical Jay treating plant consists of three major parts (1) primary separation and crude-oil stabilization, (2) gas treating, and (3) sulfur recovery. ... 

A sample is heated, usually at or above 100°C, while air is bubbled through it, and the volatiles created are transferred to a water trap where conductivity is measured (Fig. D2.3.1). The induction period endpoint is determined by the time it takes for the sample to begin a rapid increase in conductivity. The time required for the sample to reach its induction period endpoint is termed the Oil Stability Index (OSI). The Oil Stability Index is Official Method Cd 12b-92 of the American Oil Chemists Society (AOCS, 1996). 

Figure D2.3.1 Schematic diagram of oil stability index (OSI) instrumentation.

Figure D2.3.2 Data from conductivity probe and determination of oil stability index (OSI) by Lipid Oxidation/ drawing tangents. Stability...

The oil stability index (OSI) method provides results in a matter of hours instead of months (required for studies done at ambient temperatures). These OSI results are useful as comparative measures of oxidative stability, i.e., to determine the effect of a treatment or antioxidant compared to a control sample. Meaningful predictions of the actual shelf lives of specific commodities require that such shelf life studies be performed at ambient conditions. If only accelerated tests are to be performed, two or more tests based on different principles of lipid oxidation measurement should be conducted the effect of accelerated storage temperature should also be investigated. 

Food deterioration desiccation/water activity, 61 -66 oil stability index, 541-545 primary lipid oxidation products,... 

Rancidity in food, measurement of oil stability index, 541 -545 secondary lipid oxidation, 531-539 Rapeseed oil, properties and composition of, 474 (table)... 

For oil paints, to keep the pigment in suspension throughout the oil, stabilizers, such as aluminate stearate or beeswax, can be added. 

The main objective in processing crude oil from the production well is to separate it into three phases—gas, oil, and water. Keeping this in mind, all processing is indeed simple. All successful operations are based on making the crude oil vapor pressure acceptable for pipeline transmission and removing sufficient water for the pipeline transmission. Conditioning the vapor pressure or degassing with crude water removal (dehydration) is commonly called crude oil stabilization. 

Crude oil stabilization is thus the major process quest of all surface facility processing. Crude oil flows into a first-stage separator from the wellhead gathering pipeline. A typical crude oil stabilization process train is shown in Fig. 4.1. Please note that this is a three-stage... 

Turbine oxidation oil stability test, or TOST. This a measure of an oil resistance to test oxidation in hours. 

FIG. 9 Sunflower oil stability (induction time (IT) sample/IT control) under Rancimat (110°C) conditions and in the presence of ground Echinacea (0.05-1%) E. purpurea herb (EPH) and root (EPR), and E. angustifolia herb (EAH) and root (EAR). 

In addition to oil-stability evaluations, AA retention was evaluated in orange juice treated with E. purpurea and E. angustifolia extracts and stored at room temperature. Our initial studies at North Dakota State University showed that the addition of ground Echinacea plant tissue was ineffective at preventing AA loss. For example, only 8% of the AA remained after 48 h in the orange juice treated with dried aerial parts. A 30% loss of AA after 48 h was found in the control juice. In contrast, 91 and 94% of AA was retained in the orange juice treated with ethanol extracts of the aerial parts and roots, respectively. In a subsequent study,... 

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