Gravity constant

The equations are presented in their primitive form to keep them more universal. Consistent units must be used, as appropriate, at the time of application. The example problems will include conversion values for the units presented. The symbol g will be used for the universal gravity constant to maintain open form to the units. 

Calculate the flame height, using the cloud depth d, gravity constant g, S w, and r as follows ... 

It is now common to use Viscosity Gravity Constant (VGC) as the criterion for choice of a processing oil. The VGC represents the overall average aromaticity of an oil independent of its molecular weight. 

The hydrostatic pressure pstat corresponds to the density p of the liquid multiplied by the gravity constant g multiplied by the immersion depth of the capillary hE but can be eliminated by using a parallel second capillary with much larger radius [49] or by relative measurements of p [50], Usually, capillaries with radii of 0.5-2.5 mm and gas flow rates of 5-20 ml/min are used while the pressure difference is below 1000 Pa (100,000 Pa = 1 bar). 

The relationship is described by a fundamental scientific law (a first principle), formulated as a relative simple mathematical equation with all parameters known. An example is for instance the time, y, a falling stone needs for a given height, x the gravity constant, g, is known and y can be easily calculated by (2x/g)0 5—if special effects like air friction are ignored. 

The viscosity-gravity constant and the Universal Oil Prodncts characterization factor have been used to some extent as a means of classifying crnde oils. Both parameters are generally employed to give an indication of the paraffinic character of the crude oil, and both have been nsed, if a snbtle differentiation can be made, as a means of petroleum characterization rather than for petrolenm classification. 

Nevertheless, the viscosity-gravity constant (VGC) was one of the early indexes proposed to characterize (or classify) oil types ... 

Functions of properties such as the viscosity index or the viscosity gravity constant may be useful. However, the values of a function for a series of fractions of the same oil may be of approximately equal magnitude or may not be serial, as illustrated by the viscosity index (Table I). 

Point F represents the composition of the given feed stock. If we assign as desired end conditions a raffinate and extract viscosity-gravity-constant oF0.870 and 0.955, respectively (such values would represent a yield of 58.5% by weight), we can locate points Rn and E. Any addition of solvent to the feed stock must effect a composition which would fall on the line FA. Likewise, any mixture of final extract and raffinate layers must lie on the line r ei. An over-all materials balance requires that the solvent-feed mixture... 

Considerable data have been published and additional unpublished confirmatory data have been collected which indicate that for a given degree of refinement, measured by increased viscosity index or decreased viscosity gravity constant, the quality of refined oils produced by all popular solvent refining processes is so nearly equivalent that there is no clear-cut generalization possible which would favor one process over another. From the point of view of economy, two other considerations are important—namely, selectivity and... 

Ci = concentration of solute in first of two immiscible phases C2 = concentration of solute in second of two immiscible phases F = composition of feed to solvent extraction operation VGC = viscosity gravity constant... 

Figure 14.5. Representation of solvent extraction behavior in terms of certain properties rather than direct compositions [Dunstan et aL, Sci. Pet., 1825-1855 (1938)]. (a) Behavior of a naphthenic distillate of VGC = 0.874 with nitrobenzene at 10°C. The viscosity-gravity constant is low for paraffins and high for naphthenes, (b) Behavior of a kerosene with 95% ethanol at 17°C. The aniline point is low for aromatics and naphthenes and high for paraffins, (c) Behavior of a dewaxed crude oil with liquid propane at 70°F, with composition expressed in terms of specific gravity.

Subscripts s and b stand for small and big reactor, d is typical diameter, n is revolutions of agitator per unit time, N is power input of agitator, 17 is viscosity, p is density, and g is gravity constant. Using this set of equations, it is impossible to calculate the power input (Nb) and the... 

Since gravity force F(i is equal to mass m times gravity constant g,... 

Type 104 oils are subclassified into types 104A and 104B for styrene-butadiene rubber viscosity-gravity constant (VGC) greater than 0.820 (ASTM D 2501). and are naphthenic Type 104B oils have a VGC of 0.820 max., and are paraffinic. See aromatic, naphthene, paraffin. 

To overcome limitations of end-channel detection systems (see Section 34.1.3), a design with sheath-flow channels (1cm long) that flank the separation channel and join it just before the channel exit has been reported [42]. At the end of these auxiliary channels, buffer reservoirs are created by inserting pipette tips into the drilled access holes for generating a gravity constant flow into the detection reservoir. 

VGC (viscosity-gravity constant) an index of the chemical composition of crude oil defined by the general relation between specific gravity, sg, at 60°F and Saybolt Universal viscosity, SUV, at 100°F ... 

FIGURE 12 Reynolds number-power number curve for several impeller types D, impeller diameter N, impeller rotational speed p, liquid density 11, liquid viscosity P, power and g, gravity constant. 

---