Gas compressibility correction factor

Equation (I.IS) Is valid for open tubular columns under all normal conditions and for packed columns at low mobile phase velocities. The average carrier gas velocity is calculated from the outlet velocity by correcting the latter for the pressure drop across the column, and is simply given by u - ju, where j is the gas compressibility correction factor, defined In equation (1.2). 

Gas compressibility correction factor (GC) 4 Gas purifier 233, 764 Gas-solid chromatography 199 carbosieves 204 glassy carbon 204 graphitlzed carbon blacks 202 modifiers 204 inorganic oxide adsorbents 200... 

Mobile phase compressibility correction factor, a factor, applying to a homogeneously filled column of uniform diameter, that corrects for the compressibility of the mobile phase in the column, also called Compressibility Correction Factor. In liquid chromatography the compressibility of the mobile phase is negligible. In gas chromatography, the correction factor can be calculated as ... 

The above equation is valid at low pressures where the assumptions hold. However, at typical reservoir temperatures and pressures, the assumptions are no longer valid, and the behaviour of hydrocarbon reservoir gases deviate from the ideal gas law. In practice, it is convenient to represent the behaviour of these real gases by introducing a correction factor known as the gas deviation factor, (also called the dimensionless compressibility factor, or z-factor) into the ideal gas law ... 

Each compressor unit and condition has its own specific horsepower point or requirement for operation. However, the general characteristic shape will he about the same, and for a reasonable range of conditions, the general shape and effect of varying a particular condition can be relatively established even for gases of other k values. Of course, the curves can be recalculated and drawn for the particular gas under consideration. The peaks will be in about the same ratio. Note that Figures 12-26 and 12-27 were established using a bhp/MMCFD correction factor at a mean pressure of 200 psia for the lower compression ratios where this correction is required. ... 

Retention is usually measured in units of time for convenience. Voliime units are more exact. Table 1.1, after suitable corrections have been applied (26). Under average chromatographic conditions liquids can be considered incompressible, but not so for gases, and in gas chromatography elution volumes are corrected to a mean column pressure by multiplying them by the gas compressibility factor, j, equation (1.2)... 

Figure 16-13 gives a correction factor to be used to adjust the compressibility for the effect of dissolved solids. Surprisingly, the amount of dissolved gas has no effect on the compressibility of water.7... 

Eq. 3.43 is valid for one mole of a gas only. If there are n moles of a gas occupying volume V, then, as illustrated above, the excluded volume will be given by nb and the compressible volume, therefore, will be V-nb. The pressure correction factor p for n moles, in the light of Eq. 3.41 will be proportional to n2p2, i.e., p °e n2p2 °c n2 1/V2... 

The values of at pressures above the saturation pressure are determined by the coefficient of compressibility of the gas-saturated coimate water. Value of these coefficients are given in Figure 85. The upper plot gives the coefficient ot compression of piue water or a gas-free brine as a fimction of temperatiue and pressure. The lower plot gives the multiplicative correction factor which must be applied to account for the increase in compressibility due to solution gas. 

The net retention volume V, corrected for the pressure drop across the column by the gas compressibility factor of James and Martin (20) Is given by... 

This correction factor (the compressibility factor) varies with both temperature and pressure for each gas. If there were no relation between the factors for different gases, it would be necessary to have charts or tables showing z as a function of temperature and pressure for each individual... 

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