Correction factor pressure, gases

ALTITUDE vs. ATMOSPHERIC PRESSURE AND ALTITUDE VS. CORRECTION FACTOR FOR GAS TURBINE OUTPUT AND FUEL CONSUMPTION... 

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 However, at typical reservoir temperatures and pressures, the assumptions are no longer valid, and the behaviour of hydrocarbon reservoir gases deviate from the ideal gas law.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 ... 

Water Vapor The contribution to the emissivity of a gas containing H9O depends on Tc andp L and on total pressure P and partial pressure p . Table 5-8 gives constants for use in evaluating . Allowance for departure from the special pressure conditions is made by multiplying by a correction factor C read from Fig. 5-21 as a function of (p + P) and p ,L. The absorptivity 0t of water vapor for blackbody radiation is evaluated from Table 5-8 but at T instead of Tc and at p LT /Tc instead of p, h. Multiply by (Tc/Ti)° . ... 

Compressibility of Natural Gas All gases deviate from the perfect gas law at some combinations of temperature and pressure, the extent depending on the gas. This behavior is described by a dimensionless compressibility factor Z that corrects the perfect gas law for real-gas behavior, FV = ZRT. Any consistent units may be used. Z is unity for an ideal gas, but for a real gas, Z has values ranging from less than 1 to greater than 1, depending on temperature and pressure. The compressibihty faclor is described further in Secs. 2 and 4 of this handbook. 

Note The curves above represent a compromise of the values recommended by a number of relief valve manufacturers and may be used when the make of the valve or the actual critical f ow pressure point for the vapor or gas is unknown. When the make is known, the manufacturer should be consulted tor the correction factor. These curves are for set pressures of 50 pounds per square inch gauge and above. They are limited to back-pressure below critical flow pressure for a given set pressure. For subcntical flow back-pressures below 50 pounds per square inch gauge, the rnanufacturer must be consulted tor values of Kk. 

Kj = valve coefficient of discharge = 0.92 Pi = flowing pressure, psia MW = molecular weight of gas = 17,4 Z = compres-sibility factor = 0.9561 C = gas constant based on ratio of specific heats Cp/C T = flowing temperature, R Kb = back-pressure correction factor... 

Kt, = vapor or gas flow correction factor for constant back pressures above critical pressure (see Figure 7-26). 

Capacity factor based on tower area, ft/sec Capacity fector at flood, ft/sec Liquid gradient vapor load correction factor or Discharge coefficient (see accompanying table) or Gas phase loading factor, ft/sec. Equation 8-281 Eddy loss coefficient, dimensionless. Table 8-22 Wet cap pressure drop correction factor. Figure 8-115... 

Leva [40] has correlated the data of Lubin into correction factors to apply to a non-irrigated bed pressure drop to end up vith pressure drop for a liquid-gas system in the loading to flooding range. In general this does not appear any more convenient to use than Figure 9-2 ID. 

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. ... 

Output One of the major factors affecting gas turbine output is the ambient air temperature. Increasing the air temperature results in a rapid fall in the gas turbine output. Figure 15.6 shows a typical correction to power output curve for changes in ambient temperature. Additionally, although to a lesser degree, output can be affected by inlet and outlet gas system pressure... 

Meters are accurate within close limits as legislation demands. However, gas is metered on a volume basis rather than a mass basis and is thus subject to variation with temperature and pressure. The Imperial Standard Conditions are 60°F, 30inHg, saturated (15.56°C, 1913.7405 mbar, saturated). Gas Tariff sales are not normally corrected, but sales on a contract basis are. Correction may be for pressure only on a fixed factor basis based on Boyle s Law or, for larger loads, over 190,000 therms per annum for both temperature and pressure using electronic (formerly mechanical) correctors. For high pressures, the compressibility factor Z may also be relevant. The current generation of correctors corrects for pressure on an absolute basis taking into account barometric pressure. 

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). 

The volumetric flow rate of propane at the reactor inlet is given by the product of the molal flow rate, the molal volume of the gas at standard conditions, and the pressure and temperature correction factors implied by the ideal gas law. 

One approach is to calculate the pressure drop for gas flow only and then multiply this pressure drop by a factor which accounts for the effect of the liquid flow. Equation 4.19 may be used for predicting the pressure drop for the gas only, and then the pressure drop with gas and liquid flowing is obtained by using the correction factors for the liquid flow rate given by Sherwood and Pigford(56). ... 

For single-component gas permeation through a microporous membrane, the flux (J) can be described by Eq. (10.1), where p is the density of the membrane, ris the thermodynamic correction factor which describes the equilibrium relationship between the concentration in the membrane and partial pressure of the permeating gas (adsorption isotherm), q is the concentration of the permeating species in zeolite and x is the position in the permeating direction in the membrane. Dc is the diffusivity corrected for the interaction between the transporting species and the membrane and is described by Eq. (10.2), where Ed is the diffusion activation energy, R is the ideal gas constant and T is the absolute temperature. 

The effect of hills is interesting, in that no credit can be taken for the downhill side of the pipeline. The sum of all the uphill elevations appears as a pressure loss in actual operating practice. Baker includes an elevation correction factor which attempts to allow for the fact that the fluid-mixture density in the inclined uphill portion of the line is not accurately known. The gas mass-velocity seems to be the major variable affecting this correction factor, although liquid mass-velocity, phase properties. 

The ideal gas equation assumes that the force of attraction between gas molecules is zero. The assumption that there is no force of attraction between gas particles is not true. If it was, gases would never condense to form liquids. In reality, there is a small force of attraction between gas molecules that tends to hold the molecules together. This force of attraction has two consequences (1) gases condense to form liquids at low temperatures, and (2) the pressure of a real gas is sometimes smaller than expected for an ideal gas. The correctional factor "a" corrects for the fact that the pressure of a real gas is smaller than expected from the ideal gas equation. 1 point for explaining "a" correctly and 1 point for supporting evidence. 

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