Gas pressure calculation

Finally, if a different value of e is considered, the results would have been quite different. For instance if Eo>s set equal to 0.001 so Co = Si = 0.001, then failure takes place along the sample for 3.6 g/h and the maximum gas pressure calculated is 2.88 MPa. This situation approximates better a fracture that forms in a completely undamaged medium. 

The preceding case studies have shown that gas explosion calculations inside realistic process plant layouts are possible, using the state-of-the-art 3D computer model, named EXSIM. The peak pressures found in the four chosen calculation cases are summarized in the following table ... 

Assuming an ideal gas mixture at amiospheric pressure, calculate llie mole fraction and ppm of a component if its partial pressure is 19 mniHg. 

From manufacturers rating tables for air or gas, at the required cfm at inlet operating conditions and the equivalent static pressure calculated in (2), read the rpm and bhp. Interpolate if necessary. 

In calculations that involve gas pressure and volume, absolute pressure or pounds per square inch absolute (psia) must be used. 

The absolute gas pressures must be used in this calculation (see Section 1.4). 

Given that 1.00 mol of neon and 1.00 mol of hydrogen chloride gas are in separate containers at the same temperature and pressure, calculate eadi of the following ratios. 

Remove 8, and let the rarefied gas begin to dissolve in the liquid, pressing down a reversibly. The pressure on a is, in any given position, less than before, because some gas is now in solution. It follows from assumption (1) at the beginning of this section, that the pistons (3 and 7 may be kept fixed, and no work is done by them. The value of the gas pressure for the position x has been calculated in 126, (5), to be ... 

We need an equation of state for a real gas to calculate ASm. i. The modified Berthelot equation is often used for pressures near ambient and was used in the original reference to calculate the correction to ideal behavior for N gas.h This equation is as follows... 

Fugacity, like other thermodynamics properties, is a defined quantity that does not need to have physical significance, but it is nice that it does relate to physical quantities. Under some conditions, it becomes (within experimental error) the equilibrium gas pressure (vapor pressure) above a condensed phase. It is this property that makes fugacity especially useful. We will now define fugacity, see how to calculate it, and see how it is related to vapor pressure. We will then define a related quantity known as the activity and describe the properties of fugacity and activity, especially in solution. 

Thus, p can be estimated from the observed pressure and the ideal pressure calculated from the molar volume and the ideal gas equation. Klotz and Rosenburg3 report that the error in using equation (6.23) to calculate p is less than 1% for O2 up to a pressure of 10 MPa. For CO2 (g) the error is 1% at 2.5 MPa and 4% at 5 MPa. 

A gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, is Mowing through a pipe 0.25 nt internal diameter and 5 km long at the rate of 0.4 nt3/s and is delivered at atmospheric pressure, Calculate the pressure required to maintain this rate of flow under isothermal conditions. 

Self-Test 6.6B Suppose that 1.00 kj of energy is transferred as heat to oxygen in a cylinder fitted with a piston the external pressure is 2.00 atm. The oxygen expands from 1.00 L to 3.00 L against this constant pressure. Calculate w and AU for the entire process by treating the 02 as an ideal gas. 

Solution The obvious way to solve this problem is to choose a pressure, calculate Oq using the ideal gas law, and then conduct a batch reaction at constant T and P. Equation (7.38) gives the reaction rate. Any reasonable values for n and kfCm. be used. Since there is a change in the number of moles upon reaction, a variable-volume reactor is needed. A straightforward but messy approach uses the methodology of Section 2.6 and solves component balances in terms of the number of moles, Na, Nb, and Nc-... 

The values of E° for electrode reactions (or of E°, when sufficiently reliable activity data are not available) are listed in special tables some values of this type are shown in Table 3.1. When using such tables we must bear in mind that the val-nes of ii° for reactions involving gases have been calculated for partial pressures of 1 atm, which in SI units corresponds to 101, 325 Pa (about 0.1 MPa). Hence, in the Nemst eqnation we must use gas pressures in the now-obsolete unit atmospheres. 

The pressure calculated with the ideal-gas equation (Equation (1.13)) is 3.63 bar, so the value we calculate with the van der Waals equation (Equation (2.2)) is 1 per cent smaller. The experimental value is 3.11 bar, so the result with the van der Waals equation is superior. 

Figure 5.2. Calculated gas flow fields in the near-nozzle region of free-fall atomizers. Primary gas pressure 0.140 MPa secondary gas pressure 0.189 MPa angle of secondary gas nozzle relative to the spray centerline 10° angle of primary gas nozzle relative to the spray centerline (a) 0°, (b) 22.5°, and (c) 30° designed for minimizing recirculation gas flow. (Reprinted from Ref. 612.)...

The volume occupied by a mole of a gas is calculated in this experiment. A sample of a solid substance is heated, decomposing it into several products, including a gas. The mass of the gas is determined by the weight difference of the solid before and after heating and is then converted to moles. The volume of the gas, the pressure, and temperature are measured. (See the chapter on Gases.)... 

The efficiency of a column can be assessed in a similar manner to that described for HPLC and values for the resolution index of two solutes, the number of theoretical plates and the height equivalent to a theoretical plate may also be calculated. Although it is easier to measure gas pressure, it is the actual gas flow, which is affected by the particle size and compression of the packing, that should be used in column assessment investigations. 

The estimation of the solubility at one atmosphere gas pressure was made by one of two procedures. If the solubility was measured at only one pressure at a given temperature, Henry s law was used, and the inverse of Henry s constant was calculated as X2(1 atm) = 1/H2 i = X2/P2. The procedure works well at moderate gas partial pressures, but at higher gas partial pressures of 25 atm or more the procedure often appears to give low solubility values. However, it is the only practical procedure when the solubility was measured at only one pressure. When solubility values were measured at several pressures at a given temperature, the data were fitted by a linear regression to an empirical function X2/P2 = a + bP2 to obtain the unit pressure solubility value. In some cases a quadratic rather than a linear function of pressure was used. 

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