Density Specific Gravity

For porous solids, such as coal, there are three different density measurements true density, particle density, and apparent density. 

The true density is usually determined by displacement of a fluid, but because of the porous nature of coal and also because of physicochemical interactions the observed density data vary with the particular fluids employed (Agrawal, 1959 Mahajan and Walker, 1978). 

The apparent density of coal is determined by immersing a weighed sample of coal in a liquid followed by accurate measurement of the liquid that is displaced. For this procedure, the liquid should (1) wet the surface of the coal, (2) not absorb strongly to the coal surface, (3) not cause swelling, and (4) penetrate the pores of the coal. 

It is difQcult (if not impossible) to satisfy all of these conditions as evidenced by the differing experimental data obtained with solvents such as water, methanol, carbon tetrachloride, benzene, and other fluids. Thus, there is the need to always specify the liquid employed for the determination of density by means of this (pycnometer) method. Furthermore, a period of 24 h may be necessary for the determination because of the need for the liquid to penetrate the pore system of the coal to the maximum extent. 

The true density of coal is usually determined by helium displacement and, therefore, is often referred to as the helium density. Helium is used because it has the ability to penetrate all of the pores of a given sample of coal without (presumably) any chemical interaction. Thus, in the direct-pressure method, a known quantity of helium and a weighed sample of coal are introduced into an apparatus of known volume whereupon the pressure of the helium at a given temperature allows calculation of the volume of the coal. In the indirect method, mercury is used to compensate for the helium displaced by the introduction of the coal. 

Density (the mass of liquid per unit volume at 15°C) and the related terms specific gravity (the ratio of the mass of a given volume of liquid at 15°C to the mass of an equal volume of pure water at the same temperature) and relative density (same as specific gravity) are important properties of petroleum products as they are a part of product sales specifications, although playing only a minor role in studies of product composition. Usually, a hydrometer, pycnometer, or digital density meter is used for determination in all these standards. 

The determination of density (specific gravity) (ASTM D-287, ASTM D-891, ASTM D-941, ASTM D-1217, ASTM D-1298, ASTM D-1555, ASTM D-1657, ASTM D-2935, ASTM D-4052, ASTM D-5002, IP 160, IP 235, IP 365) (Fig. 4.4) provides a check on the uniformity of the naphtha and permits calculation of the weight per gallon. The temperature at which the 

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Relative density (specific gravity) of bituminous materials NF T 66-007 ASTM D 70 Pycnometer... 

Three frequently specified properties are density—specific gravity—API gravity, characterization factor, and sulfur content (2,6,7). The API (American Petroleum Institute) gravity is a measure of density or specific gravity (sp gr) ... 

Physical characteristics Molecular weight Vapour density Specific gravity Melting point Boiling point Solubility/miscibility with water Viscosity Particle size size distribution Eoaming/emulsification characteristics Critical temperature/pressure Expansion coefficient Surface tension Joule-Thompson effect Caking properties... 

Sometimes called relative density, specific gravity is the ratio of the fluid density with respect to a reference substance at a specified temperature. 

So far, we have explained the effects of atmospheric pressure on liquids and how external forces are distributed through liquids. Let us now focus our attention on forces generated by the weight of liquids themselves. To do this, we must first discuss density, specific gravity and Pascal s law. 

In this study the concentration of the water in the grid is adjusted to correspond to the density (specific gravity) of water at various temperatures. These adjusted concentrations are shown in Table 3.1. Run the example 3.2 for the adjusted concentrations of water in Example 3.2 in the program CASim for a temperature of 20°C. 

Physical characteristics Molecular weight Vapour density Specific gravity Melting point Boiling point... 

Physical/Chemical Properties Normal physical state Molecular weight Density/specific gravity Solubility Boiling point Melting point Vapor pressure/density... 

Assume a 1 liter solution of 39.77% H2S04 with density of 1.305 g/mL (density = specific gravity x 1.00 g/mL)... 

Hydrometers are calibrated in density, specific gravity, and several arbitrary units such as degrees Baume (°Be), degrees American Petroleum Institute (°API), or °Brix. These units are used for specialized purposes in various industries. The relationship between the specific gravity (sp. gr.) of a liquid with a density less than water and these specialized units is given by the following equations ... 

The data from the density (specific gravity) test method (ASTM D1298 IP 160) provides a means of identification of a grade of naphtha but is not a guarantee of composition and can only be used to indicate evaluate product composition or quality when used in conjunction with the data from other test methods. Density data are used primarily to convert naphtha volume to a weight basis, a requirement in many of the industries concerned. For the necessary temperature corrections and also for volume corrections, the appropriate sections of the petroleum measurement tables (ASTM D1250 IP 200) are used. 

Density or specific gravity (relative density) is used whenever conversions must be made between mass (weight) and volume measurements. This property is often used in combination with other test results to predict oil quality, and several methods are available for measurement of density (or specific gravity). However, the density (specific gravity) (ASTM D1298 IP 160) is probably of... 

The density specific gravity) of coke has a strong influence on future use and can affect the characteristics of the products such as carbon and graphite. The density (specific gravity) of coke can be measured conveniently by use of a pycnometer. In the test method (ASTM D5004), the mass of the sample is determined directly and the volume is derived by determining the mass of hquid displaced when the sample is introduced into a pycnometer. Oil or other material sprayed on calcined petroleum coke to control dust will interfere. Such oil can be removed by flushing with a solvent, which must be completely removed before the density determination. 

SERVICE 0 CONTINUOUS 0 NTERMITTENT(START/DAY) O PARALLEL OPERATION REQ D (2.1.11) O relative DENSITY (SPECIFIC GRAVITY) NORMAL MAX MIN O SPEOFIC HEAT. Co (kJ/ka ° C)... 

O RELATIVE DENSITY /SPECIFIC GRAVITY) 0 (" C) LANTERN RING... 

If particles with densities (specific gravity) larger than the surrounding liquid are distributed in a solution or suspension, and if a force acts which overcomes random thermal motion of these particles, the particles will move to form a stable pellet. The velocity of sedimentation depends on the size of the particle, on the density difference between particle and solution, on the viscosity of the solution, and on the force which causes the movement the gravitation or the centrifugal force. 

The maximum discharge pressure shaii be the maximum suction pressure pius the maximum differentiai pressure the pump is abie to deveiop when operating with the furnished impeiier at the rated speed and specified normal relative density (specific gravity). 

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