Petroleum pressure

Aerodynamic theory and Darcy flow modeling in porous media are similar in one respect only both derive from the Navier-Stokes equations governing viscous flows (Milne-Thomson, 1958 Schlichting, 1968 Slattery, 1981). We emphasize this because the great majority of our new solutions derive from the classical aerodynamics literature, but in a subtle manner. Very often, the superficial claim is made that, because petroleum pressure potentials satisfy p/9 + 9 p/9y = 0, the analogy to aerodynamic flowfields, which satisfy Laplace s equation + S cj/Sy = 0 for a similar velocity potential, can be... 

American Petroleum Institute, Bibliographies on Hydrocarbons, Vols. 1-4, "Vapor-Liquid Equilibrium Data for Hydrocarbon Systems" (1963), "Vapor Pressure Data for Hydrocarbons" (1964), "Volumetric and Thermodynamic Data for Pure Hydrocarbons and Their Mixtures" (1964), "Vapor-Liquid Equilibrium Data for Hydrocarbon-Nonhydrocarbon Gas Systems" (1964), API, Division of Refining, Washington. 

The base lubricant is usually a petroleum oil while the thickener usually consists of a soap or soap mixture. In addition they may contain small amounts of free alkali, free fatty acid, glycerine, anti-oxidant, extreme-pressure agent, graphite or molybdenum disulphide. 

As stated above for the TBP distillation, petroleum cannot be heated above 340°C without its molecules starting to crack. Because of this, analytical distillation of heavy fractions is done according to the ASTM D 1160 method for petroleum materials that can be partially or completely vaporized at a maximum temperature of 400°C at pressures from 50 to 1 mm of mercury (6.55 to 0.133 kPa). 

The isobaric specific heat for a petroleum fraction is estimated by a correlation attributed to Watson and Nelson in 1933, which was used again by. Johnson and Grayson in 1961 as well as by Lee and Kesler in 1975. This relation is valid at low pressures i... 

Liquid viscosity is one of the most difficult properties to calculate with accuracy, yet it has an important role in the calculation of heat transfer coefficients and pressure drop. No single method is satisfactory for all temperature and viscosity ranges. We will distinguish three cases for pure hydrocarbons and petroleum fractions ... 

P = saturation pressure for the petroleum fraction at T P = pseudocritical pressure for the petroleum fraction... 

For pure hydrocarbons and petroleum fractions the vapor pressure can be calculated by three methods which are ... 

The Reid vapor pressure characterizes the light petroleum products it is measured by a standard test (refer to Chapter 7) which can be easily simulated. 

When the critical constants for a pure substance or the pseudocritical constants for a petroleum fraction are known, the vapor pressure for hydrocarbons and petroleum fractions can be calculated using the Lee and Kesler equations ... 

Maxwell and Bonnel (1955) proposed a method to calculate the vapor pressure of pure hydrocarbons or petroleum fractions whose normal boiling point and specific gravity are known. It is iterative if the boiling point is greater than 366.5 K ... 

The Reid vapor pressure is generally barely different from the true vapor pressure at 37.8°C if the light gas content —methane, ethane, propane, and butane— of the sample is small, which is usually the case with petroleum products. The differences are greater for those products containing large quantities of dissolved gases such as the crude oils shown in Table 4.13. 

The flash curve of a petroleum cut is defined as the curve that represents the temperature as a function of the volume fraction of vaporised liquid, the residual liquid being in equilibrium with the total vapor, at constant pressure. 

Safety standards govern the manipulation and storage of crude oil and petroleum products with regard to their flash points which are directly linked to vapor pressure. 

Edmister, W.C. and K.K. Okamoto (1959), Applied hydrocarbon thermodynamics. Part 13 equilibrium flash vaporization for heavy oils under sub-atmospheric pressures . Petroleum Refiner, Vol. 38, No. 9, p. 271. 

Maxwell, J.B. and L.S. Bonnel (1955), Vapor pressure charts for petroleum engineers. Esso Research and Engineering Co., NJ. 

In Section 5.2.8 we shall look at pressure-depth relationships, and will see that the relationship is a linear function of the density of the fluid. Since water is the one fluid which is always associated with a petroleum reservoir, an understanding of what controls formation water density is required. Additionally, reservoir engineers need to know the fluid properties of the formation water to predict its expansion and movement, which can contribute significantly to the drive mechanism in a reservoir, especially if the volume of water surrounding the hydrocarbon accumulation is large. 

Selection of solvents. The choice of solvent will naturally depend in the first place upon the solubility relations of the substance. If this is already in solution, for example, as an extract, it is usually evaporated to dryness under reduced pressure and then dissolved in a suitable medium the solution must be dilute since crystallisation in the column must be avoided. The solvents generally employed possess boiling points between 40° and 85°. The most widely used medium is light petroleum (b.p. not above 80°) others are cycZohexane, carbon disulphide, benzene, chloroform, carbon tetrachloride, methylene chloride, ethyl acetate, ethyl alcohol, acetone, ether and acetic acid. 

The following is a modification of the process described and gives quite satisfactory results. Wash the crude mixture of benzonitrile and dibromopentane with sodium carbonate solution until the latter remains alkaline, and then with water. Distil it under reduced pressure and collect the fraction boiling up to 120°/18 mm. Dissolve this in twice its volume of light petroleum, b.p. 40-60°, which has previously been shaken with small volumes of concentrated sulphuric acid until the acid remains colourless. Shake the solution with 6 per cent, of its volume of concentrated sulphuric acid, allow to settle, and run ofi the sulphuric acid layer repeat the extraction until the acid is colourless or almost colourless. Wash successively with water, sodium carbonate solution and water, dry over anhydrous calcium chloride or calcium sulphate, and distil off the solvent. Distil the residue under diminished pressure and collect the 1 6-dibromopentane at 98- 100°/13 mm. 

Heat a suspension of 22 g. of the diacetate in a mixture of 120 ml. of concentrated hydrochloric acid, 190 ml. of water and 35 ml. of alcohol under reflux for 45 minutes. Cool the mixture to 0°, filter the solid with suction, and wash with water. Purify the crude aldehyde by rapid steam distillation (Fig. II, 41, 3) collect about 1500 ml. of distillate during 15 minutes, cool, filter, and dry in a vacuum desiccator over calcium chloride. The yield of pure o-nitrobenzaldehyde, m.p. 44—45°, is 10 g. The crude solid may also be purified after drying either by distillation under reduced pressure (the distillate of rather wide b.p., e.g., 120-144°/3-6 mm., is quite pure) or by dissolution in toluene (2-2-5 ml. per gram) and precipitation with light petroleum, b.p. 40°-60° (7 ml. per ml. of solution). 

To obtain crystalline perbenzoic acid, dry the moist chloroform solution with a little anhydrous sodium or magnesium sulphate for an hour, filter, and wash the desiccant with a little dry chloroform. Remove the chloroform under reduced pressure at the ordinary temperature whilst carbon dioxide is introduced through a capillary tube. Dry the white or pale yellow residue for several hours at 30-35° under 10 mm. pressure. The yield of crystalline perbenzoic acid, m.p. about 42°, which is contaminated with a little benzoic acid, is 22 g. It is moderately stable when kept in the dark in a cold place it is very soluble in chloroform, ethyl acetate and ether, but only shghtly soluble in cold water and in cold hght petroleum. 

Cool the flask in ice, acidify with 10 ml. of cold 1 1-hydro-chloric acid and distil under reduced pressure (water pump) until most of the alcohol is removed. Add water to the residue, extract several times with ether, wash the combined ethereal extracts with N ammonia solution until a test portion gives no precipitate upon acidification. Extract the combined alkahne solutions once with a fresh portion of ether, and add the aqueous solution to an excess of dilute hydrochloric acid the final mixture should still be acidic to Congo red. Collect the crystalhne half-ester by filtration at the pump, wash it with water and dry at 100°. The yield is 14-5 g., m.p. 122-125°. Recrystallise by dissolving in about 40 ml. of warm benzene and adding an equal volume of petroleum ether (b.p. 40- 60°) 13 -5 g. of the colourless half-ester, m.p. 125-126°, are obtained. 

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