Density gas densities

In fan spray atomization, the effects of process parameters on the mean droplet size are similar to those in pressure-swirl atomization. In general, the mean droplet size increases with an increase in liquid viscosity, surface tension, and/or liquid sheet thickness and length. It decreases with increasing liquid velocity, liquid density, gas density, spray angle, and/or relative velocity between liquid and surrounding air. 

QlKQl + Qg) no-slip density no-slip viscosity liquid density gas density liquid viscosity gas viscosity... 

It can be observed that it is possible to calculate the height corresponding to the minimum fluidizing condition. From the knowledge of the values of solid density, gas density, and void fraction, one can easily determine the pressure drop. 

Gases have relatively low densities. Gas density is usually measured in units of grams per liter (g/L), whereas liquid and solid densities are in grams per milliliter (g/mL), about 1000 times as dense. For example, at 20°C and normal atmospheric pressure, the density of 02(g) is 1.3 g/L, whereas the density of H2O(0 is 1.0 g/mL and the density of NaCKs) is 2.2 g/mL. When a gas cools, its density increases because its volume decreases on cooling from 20°C to 0°C, the density of 02(g) inaeases from 1.3 to 1.4 g/L. 

Composition. Liquid density Gas density Boiling point Electrol3 tic conductivity Viscosity Dielectric constant Dew point Temperature Temperature, pressure Pressure Temperature Temperature Temperature Pressure... 

At pressures to a few bars, the vapor phase is at a relatively low density, i.e., on the average, the molecules interact with one another less strongly than do the molecules in the much denser liquid phase. It is therefore a common simplification to assume that all the nonideality in vapor-liquid systems exist in the liquid phase and that the vapor phase can be treated as an ideal gas. This leads to the simple result that the fugacity of component i is given by its partial pressure, i.e. the product of y, the mole fraction of i in the vapor, and P, the total pressure. A somewhat less restrictive simplification is the Lewis fugacity rule which sets the fugacity of i in the vapor mixture proportional to its mole fraction in the vapor phase the constant of proportionality is the fugacity of pure i vapor at the temperature and pressure of the mixture. These simplifications are attractive because they make the calculation of vapor-liquid equilibria much easier the K factors = i i ... 

Regnault s method Obsolete method for determining gas densities by direct weighing of a known volume of gas under known conditions of temperature and pressure. 

P = pressure M = molecular weight R = ideal gas constant T = temperature Pi = liquid density... 

Viscosity can be expressed as a function of reduced density to which the viscosity of the ideal gas must by added. We will use the formulation proposed by Dean and Stiel in 1965 ... 

Properties of Gases 4 4.1 Thermodynamic Properties of Gases 4.4.1.1 Gas Density... 

This relation is easily transformed to express the ideal gas density ... 

Calculation of thermophysical properties of gases relies on the principle of corresponding states. Viscosity and conductivity are expressed as the sum of the ideal gas property and a function of the reduced density ... 

Gas bubble separation time of petroleum oils NFT 60-149 ASTM D 3427 Time for air liberation after supersaturation (measurement of density)... 

Hydrocarbons are of a lower density than formation water. Thus, if no mechanism is in place to stop their upward migration they will eventually seep to the surface. On seabed surveys in some offshore areas we can detect crater like features ( pock marks ) which also bear witness to the escape of oil and gas to the surface. It is assumed that throughout the geologic past vast quantities of hydrocarbons have been lost in this manner from sedimentary basins. 

Considerable effort will be made to predict the onset of overpressures ahead of the drill bit. The most reliable indioations are gas readings, porosity - depth trends, rate of penetration and shale density measurements. 

Density is the most commonly measured property of a gas, and is obtained experimentally by measuring the specific gravity of the gas (density of the gas relative to air = 1). As pressure increases, so does gas density, but the relationship is non-linear since the dimensionless gas compressibility (z-factor) also varies with pressure. The gas density (pg) can be calculated at any pressure and temperature using the real gas law ... 

Gas density at reservoir conditions is useful for calculation the pressure gradient of the gas when constructing pressure-depth relationships (see Section 5.2.8). 

Measured in MJ/m or Btu/ft, the Wobbe Index has an advantage over the calorific value of a gas (the heating value per unit volume or weight), which varies with the density of the gas. The Wobbe Index Is commonly specified in gas contracts as a guarantee of product quality. A customer usually requires a product whose Wobbe Index lies within a narrow range, since a burner will need adjustment to a different fuel air ratio if the fuel quality varies significantly. A sudden increase in heating value of the feed can cause a flame-out. 

This section will firstly consider the properties of oils in the reservoir (compressibility, viscosity and density), and secondly the relationship of subsurface to surface volume of oil during the production process (formation volume factor and gas oil ratio). 

The same definition of viscosity applies to oil as gas (see Section 5.2.6), but sometimes the kinematic viscosity is quoted. This is the viscosity divided by the density (u = i7p), and has a straight line relationship with temperature. 

Typical analysis in the laboratory consists of sample validation, a compositional analysis of the individual and reoombined samples, measurement of oil and gas density and viscosity over a range of temperatures, and determination of the basic PVT parameters Bo, Roand B. ... 

Formation water density is a function of its salinity (which ranges from 0 to 300,000 ppm), amount of dissolved gas, and the reservoir temperature and pressure. As pressure increases, so does water density, though the compressibility is small... 

Flence it can be seen that from the density of a fluid, the pressure gradient may be caloulated. Furthermore, the densities of water, oil and gas are so significantly different, that they will show quite different gradients on a pressure-depth plot. 

Reservoir fluids (oil, water, gas) and the rock matrix are contained under high temperatures and pressures they are compressed relative to their densities at standard temperature and pressure. Any reduction in pressure on the fluids or rock will result in an increase in the volume, according to the definition of compressibility. As discussed in Section 5.2, isothermal conditions are assumed in the reservoir. Isothermal compressibility is defined as ... 

When a customer agrees to purchase gas, product quality is specified in terms of the calorific value of the gas, measured by the Wobbe index (calorific value divided by density), the hydrocarbon dew point and the water dew point, and the fraction of other gases such as Nj, COj, HjS. The Wobbe index specification ensures that the gas the customer receives has a predictable calorific value and hence predictable burning characteristics. If the gas becomes lean, less energy is released, and if the gas becomes too rich there is a risk that the gas burners flame out . Water and hydrocarbon dew points (the pressure and temperature at which liquids start to drop out of the gas) are specified to ensure that over the range of temperature and pressure at which the gas is handled by the customer, no liquids will drop out (these could cause possible corrosion and/or hydrate formation). 

For calculation of the volumetric flow rate only the cross section area of the pipe is to be known. In order to give flow under standard conditions the temperature and pressure must be measured, and for conversion to mass flow the composition or density of the gas must be determined. These process parameters are often monitored by calibrated instrumentation. 

Unfortunately, however, one cannot subject a liquid surface to an increased pressure without introducing a second component into the system, such as some inteit gas. One thus increases the density of matter in the gas phase and, moreover, there will be some gas adsorbed on the liquid surface with a corresponding volume change. 

Fig. Ill-13. (a) Plots of molecular density versus distance normal to the interface a is molecular diameter. Upper plot a dielectric liquid. Lower plot as calculated for liquid mercury. (From Ref. 122.) (b) Equilibrium density profiles for atoms A and B in a rare-gas-like mixmre for which o,bb/ o,aa = 0.4 and q,ab is given by Eq. III-56. Atoms A and B have the same a (of Eq. m-46) and the same molecular weight of SO g/mol the solution mole fraction is jcb = 0.047. Note the strong adsorption of B at the interface. [Reprinted with permission from D. J. Lee, M. M. Telo de Gama, and K. E. Gubbins, J. Phys. Chem., 89, 1514 (1985) (Ref. 88). Copyright 1985, American Chemical Society.]...

It was noted in connection with Eq. III-56 that molecular dynamics calculations can be made for a liquid mixture of rare gas-like atoms to obtain surface tension versus composition. The same calculation also gives the variation of density for each species across the interface [88], as illustrated in Fig. Ill-13b. The density profiles allow a calculation, of course, of the surface excess quantities. 

The three general states of monolayers are illustrated in the pressure-area isotherm in Fig. IV-16. A low-pressure gas phase, G, condenses to a liquid phase termed the /i uid-expanded (LE or L ) phase by Adam [183] and Harkins [9]. One or more of several more dense, liquid-condensed phase (LC) exist at higher pressures and lower temperatures. A solid phase (S) exists at high pressures and densities. We briefly describe these phases and their characteristic features and transitions several useful articles provide a more detailed description [184-187]. 

---