Total pressure versus partial pressur

Fig. 1.32 Partial pressure of S2, Ps, versus total pressure of sulfur gas, P, at different temperatures.

Figure 9.9 Left BET adsorption isotherms plotted as total number of moles adsorbed, n, divided by the number of moles in a complete monolayer, ri7non, versus the partial pressure, P, divided by the equilibrium vapor pressure, Po. Isotherms were calculated for different values of the parameter C. Right Adsorption isotherms of water on a sample of alumina (Baikowski CR 1) and silica (Aerosil 200) at 20°C (P0 = 2.7 kPa, redrawn from Ref. [379]). The BET curves were plotted using Eq. (9.37) with C = 28 (alumina) and C = 11 (silica). To convert from n/nmo to thickness, the factors 0.194 nm and 0.104 nm were used, which correspond to n-mon = 6.5 and 3.6 water molecules per nm2, respectively.

The dew point must be warmer than -56.6°C to permit use of liquid carbon dioxide absorbent because pure liquid carbon dioxide cannot exist below the triple point. The carbon dioxide partial pressure, i.e., gas phase CO2 mol fraction times total pressure, of synthesis gas mixtures with -56.6°C dew points is plotted versus synthesis gas pressure in Figure 4. Increasing the H2 CO ratio at fixed total pressure decreases the carbon dioxide partial pressure required for a -56.6°C dew point. Liquid carbon dioxide can be used to absorb sulfur molecules for any combination of gas pressure and carbon dioxide partial pressure which lies above the curves of Figure 4. 

Kinetic measurements were made by monitoring the laser-induced fluorescence of CH following the excitation in the (0-0) band of the X — A transition as a function of the time delay after the ArF laser dissociation. In the absence of any added reactants, CH had a decay time of 100 to 300 /isec at a total pressure of 30 to 100 torr (CHBr3 pressures of 1 to 10 mtorr) which can be attributed mainly to the CH + CH reaction. The addition of the reactants listed in Table I shortened the CH radical decay times considerably, indicative of some removal process involving a bimolecular mechanism since the total pressure was always maintained constant. Least squares plots of the inverse lifetimes of CH radicals versus the partial pressure of the added reactant yielded... 

Experiments of physical absorption of C02 diluted with N2 into pure water allow to measure gas side mass transfer coefficients. In this case, we measure the total mass transfer resistance (liquid+gas), using the method for the kLa determination ( 3.1). Knowing the liquid resistance, we can then calculate the gas side one. The pressure of interest in this case is the partial pressure of C02, which is obtained by simultaneous measurements of total pressure and molar fraction of C02 versus time. 

The methane conversion at the exit of the 5 m reformer tube is obtained for each feed and plotted versus the corresponding steam partial pressure in feed as shown in Figure 3.9. In this figure it is clear that an optimum methane overall conversion can be obtained at a steam feed partial pressure of 0.9 MPa (which corresponds to S/M = 3 and P (total) - 1.205 MPa), although this feed composition does not give maximum reaction rate at the entrance. 

Figure 2-34. Calculated ternary CVD phase diagram for the Y-Ba-Cu-C-O-H system at a temperature of 877 °C, a total pressure of 760Torr, and an oxygen partial pressure of 750Torr. The contours represent iso-yields of the tetragonal 123 phase with the numerical legends given as molar percentages 123 versus other phases. (From Vahlas and Besmann [213].)...

In humidification and dehumidification operations the liquid phase is always a single pure component. Then, the equilibrium partial pressure of the solute in the gas phase is equal to the vapor pressure of the liquid at its temperature. By Dalton s law, the equilibrium partial pressure of the solute may be converted to the equilibrium mole fraction yA. in the gas phase once the total pressure is specified. Since the vapor pressure of any liquid depends only upon the temperature, for a given temperature and total pressure the equilibrium composition of the gas phase is fixed. Because the liquid is a single pure component, xA. is always unity. Equilibrium data are often presented as plots of yA. versus temperature at a given total pressure, as shown for the system air-water at 1 bar in Figure 8.1. 

Logarithmic plots of the equilibrium total conductivity versus the partial pressure of oxygen for LaSr2Fe3.yOg+5 at 950°C are shown in Fig.l as an example. The low-pressure segments of the isotherms near the minima, where deviations of the oxygen content from the nominal stoichiometric composition are very small, i.e. 6 1, are important for the analysis of the oxide ion contribution. Such minima are typical in oxides when oxygen pressure variations at constant temperature result in nearly equal concentrations of electron- and hole-like carriers. There may be another, pressure independent contribution in the conductivity and its presence is signaled by a smooth shape of the minima. Therefore the experimental results near the conductivity minima were approximated with the known relation... 

Hemy s law constant is the slope of a plot of pB versus tb in the limit of zero xb (Rg- 5.4). The partial pressures of CO2 are almost but not quite equal to the total pressures reported. 

The concept of reactant distribution was intensely investigated with mesoporous membranes (see, e.g., the reviews [221,222]), mainly for applications in selective oxidations in instances where low partial pressures of oxygen would favor the selective oxidation versus total oxidation. Under these conditions, distributing oxygen was beneficial and the... 

Using the code, we obtain the partial pressure profiles of all species as a function of time. Figure 8.9-1 shows the mean total pressure in the capillary versus time. Here we see that the mean total pressure in the capillary increases with time during the early stage of the diffusion. This is due to the faster diffusion of hydrogen into the capillary, more than to compensate for the slower outflux of methane. After this initial stage, the total pressure finally decays to the equilibrium total pressure of 1 atm. 

You know that the total pressure is 755 torr. Your first task is to reference a table of vapor pressures of water versus temperature. (You can find such a table in a variety of places, such as the Chemical Rubber Company (CRC) Handbook.) After looking at the table, you determine that the partial pressure of water at 20 degrees Celsius is 17.5 torr. Now you re ready to calculate the pressure of the oxygen ... 

A plot of the first term on the left versus time should be linear with a slope of - A. It should be noted that the pressures in these equations refer to Ae partial pressures of the gas being absorbed and will be less than the total pressure if the solvent has a significant vsq>or pressure. 

For simple HT/HP exposure tests involving either aqueous or nonaqueous phases with a gas cap over the solution, the total pressure is usually determined by the sum of the partial pressures of the constituents of the test environment, which will vary with temperature. Where liquid constituents are being used for the test environment, the partial pressure is usually taken to be the vapor pressure of the liquid at the intended test temperature (see Table 2 for steam pressure versus temperature). Vapor pressures for several other volatile compounds used in HT/HP corrosion testing can usually... 

Even though perovskite proton conductors are selected for their protonic conductivity, possessing a minority electronic conductivity component is not necessarily a disadvantage. Figure 7a shows a plot of the total conductivity versus the oxygen partial pressure P02) a logarithmic scale. The curve follows an equation of the type ... 

Perovskite Proton Conductor, Fig. 7 Two transport properties for a typical HTPC, plotted versus the logarithm of oxygen partial pressure (Poi) ( ) Total conductivity (b) Ionic transport number... 

Further experiments must be conducted for constant temperature and varying partial pressure of the reactive component This should be done at constant total pressure using inert gases such as nitrogen. Consequently, the same kind of evaluation can be done plotting the determined slopes versus Inp. ... 

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