Mixture of gas

Operations of most fuel cell power systems involve a mixture of gases. Therefore, we need to perform thermodynamic analysis and transport phenomena analysis with a mixture of gases. The gas mixture may be a mixture of ideal gases or a mixture of real gases. In this book, the presentation of fuel cell analysis is restricted to the mixture of ideal gases only. 

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Dalton s law of partial pressures The total pressure (P) exerted by a mixture of gases is equal to the sum of the partial pressures (p) of the components of the gas mixture. The partial pressure is defined as the pressure the gas would exert if it was contained in the same volume as that occupied by the mixture. 

The potential model has been applied to the adsorption of mixtures of gases. In the ideal adsorbed solution model, the adsorbed layer is treated as a simple solution, but with potential parameters assigned to each component (see Refs. 76-79). 

In the case of mixtures of gases of different molecular size, an adsorbent of D > 2 will effect some segregation by size. This segregation will also affect the probability of bimolecular reactions between molecules of different sizes [168]. 

When a mixture of gases replaces the pure gas, but there is no relative diffusion of the separate species, the total flux is given by equation (2.22), The flux of each species separately is then given by -X B p... 

One application of the grand canonical Monte Carlo simulation method is in the study ol adsorption and transport of fluids through porous solids. Mixtures of gases or liquids ca separated by the selective adsorption of one component in an appropriate porous mate The efficacy of the separation depends to a large extent upon the ability of the materit adsorb one component in the mixture much more strongly than the other component, separation may be performed over a range of temperatures and so it is useful to be to predict the adsorption isotherms of the mixtures. 

By passing a mixture of carbon monoxide and hydrogen chloride into the aromatic hydrocarbon in the presence of a mixture of cuprous chloride and aluminium chloride which acts as a catalyst (Gattermann - Koch reaction). The mixture of gases probably reacts as the equivalent of the unisolated acid chloride of formic acid (formyl chloride) ... 

The intensities reflect the number of carbon atoms in each position. Comparing the C Is signals from CO2 and from C=0 shows that the mixture of gases is almost equimolar. The C Is signal from the methyl groups of acetone should then have twice the intensity of the other two signals because the carbon atoms are symmetrically equivalent. 

The energy input into a CO2 laser is in the form of an electrical discharge through the mixture of gases. The cavity may be sealed, in which case a little water vapour must be added in order to convert back to CO2 any CO which is formed. More commonly, longitudinal or, preferably, transverse gas flow through the cavity is used. The CO2 laser can operate in a CW or pulsed mode, with power up to 1 kW possible in the CW mode. 

Dry-bulb Temperature (DB) (Abscissa). DBT is the temperature of a gas or mixture of gases iadicated by an accurate thermometer after... 

A third pumping method (Fig. Ic) uses an electrical discharge in a mixture of gases. It relies on electronic excitation of the first component of the gas mixture, so that those atoms are raised to an upper energy level. The two components are chosen so that there can be a resonant transfer of energy by collisions from the upper level of the first component to level 3 of the second component. Because there are no atoms in level 2, this produces a population inversion between level 3 and level 2. After laser emission, the atoms in the second component return to the ground state by collisions. 

In some cases, it is impractical to use a plenum chamber under the constriction plate. This condition arises when a flammable or explosive mixture of gases is being introduced to the reactor. One solution is to pipe the gases to a multitude of individual gas inlets in the floor of the reactor. In this way it may be possible to maintain the gas velocities in the pipes above the flame velocity or to reduce the volume of gas in each pipe to the point at which an explosion can be safely contained. Another solution is to provide separate inlets for the different gases and depend on mixing in the fluidized bed. The inlets should be fairly close to one another, as lateral gas mixing in fluidized beds is poor. 

This mixture of gases has been used to prepare silicon nitride particles photochemically, the overall reaction being represented by... 

For example, carbon dioxide from air or ethene nitrogen oxides from nitrogen methanol from diethyl ether. In general, carbon dioxide, carbon monoxide, ammonia, hydrogen sulfide, mercaptans, ethane, ethene, acetylene (ethyne), propane and propylene are readily removed at 25°. In mixtures of gases, the more polar ones are preferentially adsorbed). 

Although air is a mixture of gases, it is generally treated as an individual gas with accounting made only for other components such as moisture when present. 

Hydrochloric acid may conveniently be prepared by combustion of hydrogen with chlorine. In a typical process dry hydrogen chloride is passed into a vapour blender to be mixed with an equimolar proportion of dry acetylene. The presence of chlorine may cause an explosion and thus a device is used to detect any sudden rise in temperature. In such circumstances the hydrogen chloride is automatically diverted to the atmosphere. The mixture of gases is then led to a multi-tubular reactor, each tube of which is packed with a mercuric chloride catalyst on an activated carbon support. The reaction is initiated by heat but once it has started cooling has to be applied to control the highly exothermic reaction at about 90-100°C. In addition to the main reaction the side reactions shown in Figure 12.6 may occur. 

Liquefied petroleum gas, such as commercial propane and commercial butane, and any mixture thereof, when held under refrigeration at a pressure <1.4 bar absolute. Gas or any mixture of gases which is flammable in air, when held as a gas. 

The effects of this mixture of gases are insidious several hours may elapse before lung iiTitation develops. It is feebly irritant to the upper respiratory tract due to its relatively low solubility. 

An analogous series of hydrocarbons, and one of the simplest, are the compounds known as the alkanes. In this series, the names of all the compounds end in -ane. The first compound in this series is methane. Methane s molecular formula is CH. Methane is a gas and is the principal ingredient in the mixture of gases known as natural gas. The next compound is this series is ethane, whose molecular formula is CjHj. It is also a gas present in natural gas, although in a much lower percentage than methane. The difference in the molecular formulas of methane and ethane is one carbon and two hydrogen atoms. 

Explosivity limits for various pure components are given in Table 3. The limits of flammability ( concentration, C) for a mixture of gases can be computed from the following expression ... 

The heat capacity of gases is essential for some process engineering design involving gas-phase chemical reactions. Here, tlie heat capacities, Cp, for gases are required to determine the heat necessary to bring the chemical compound increase to the reaction temperature. The heat capacity of a mixture of gases may he found from the heat capacities of the individual components contained in the mixtures. 

Flue gas The mixture of gases produced during the combustion process. 

Volumetric analysis The determination of the amount of a particular gas in a mixture of gases, as the percentage of the total volume. See Gravimetric analysis. 

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