Vapour volume

A comparison of calculated and experimental values of vapour pressure and saturated liquid and vapour volumes at various temperatures is shown in Table 2. The water composition in the liquid phase and the corresponding degree of association,... 

Mousa, A.H.N. (1981) Vapour pressure and saturated-vapour volume of acetonitrile. J. Chem. Thermodyn. 13, 201-202. 

A formula for the latent heat of evaporation based on the Stefan relation with internal pressure ( 6.VIII G) was deduced from the van der Waals equation by Bakker. The internal pressure is K=alv and the work spent in expanding continuously ( 9.VTI C) from the liquid volume vi to the vapour volume Vg is equal to the internal latent heat ... 

It is well known that the volume of a vapour, V(g), is much larger than that of the equivalent amount of a liquid. As a result, it is reasonable that the V(g) of vapour volume represents the volume change of AVm. Further, the vapour can be considered a perfect gas. Based on the state equation of perfect gases for a mole gas, the Clausius-Clapeyron equation can be rewritten as... 

For a given amount of poison i in an oil feed, if the adsorption equilibrium constants, vapour volume, mass of catalyst, surface of catalyst and total fractional coverage are known then, the surface coverages of the individual components can be determined from the solution of equations 6-8. 

At the critical point the difference between liquid and vapour volumes approaches zero, suggesting that the energy needed for phase transition, in other words the enthalpy of vaporisation, should diminish to zero. The above observation illustrates in a simple manner the link between the PVT behaviour of a fluid and the energy implied in its physical changes. 

Table 7.1 Typical mobile phase flow rates and gas/vapour volumes...

HPLC-MS interfaces were developed after GC interfaces and considerably more work was required to produce efficient interfaces capable of dealing with the large vapour volumes from a liquid eluant [8,9]. Possible solutions to the problem include... 

In the technique of distillation it is usual to calculate with mole fractions and mole percentages, as this greatly facilitates the computation of vapour volumes, vapour velocities, limiting velocities and so on. Since as a rule it is further the practice to consider the separability of components in sequence, the calculation may be baaed on that of binary mixtures, in which case of course, the second component may represent a mixture of several constituents. The average molecular weight is then determined by the formida ... 

In gaseous form chlorine is extremely hazardous. Liquid chlorine is shipped in pressurised steel cylinders. One volume of liquid chlorine yields about 450 times vapour volume. Because of safety concerns liquid chlorine compounds such as sodium hypochlorite are used instead. Sodium hypochlorite (NaOCl) is handled in liquid form at concentrations between 5 and 15% available chlorine. Calcium hypochlorite [Ca(OCl)2] contains about 70% available chlorine. 

The modern cubic equations of state provide reliable predictions for pure-component thermodynamic properties at conditions where the substance is a gas, liquid or supercritical. Walas and Valderrama provided a thorough evaluation and recommendations on the use of cubic equation of state for primary and derivative properties. Vapour pressures for non-polar and slightly polar fluids can be calculated precisely from any of the modem cubic equations of state presented above (Soave-Redlich-Kwong, Peng-Robinson or Patel-Teja). The use of a complex funetion for a (such as those proposed by Twu and co-workers ) results in a significant improvement in uncertainty of the predicted values. For associating fluids (such as water and alcohols), a higher-order equation of state with explicit account for association, such as either the Elliott-Suresh-Donohue or CPA equations of state, are preferred. For saturated liquid volumes, a three-parameter cubic equation of state (such as Patel-Teja) should be used, whereas for saturated vapour volumes any modern cubic equation of state can be used. 

The large amounts of water vapour (1 g ice at the usual process pressure of approximately 0.1 mbar has a vapour volume of approximately 10 m ) which are produced during primary drying (sublimation) can only be pumped off economically by a cold condensation surface. 

Understanding the relationships between inlet liner geometry, carrier gas flow, injection volume and solvent vapour volume is essential for optimizing splitless injections. Especially the expansion volume of the solvent used must be taken into account. The maximum liquid injection volume needs to be adjusted in the hot... 

Stratified LNG as the pressure builds, as well as contractioii of flie vapour space above the liquid. Under no circumstances should the vapour space reduce to zero as flie liquid expands with increasing saturation pressure. Adequate vapour volume must exist so that, if the vent/safety valve lifts, there is no venting of liquid from the tank. 

When any liquid evaporates, whether cryogenic or otherwise, a very large volume of vapour is generated at the same pressure. In the case of liquid methane or LNG, the volume of vapour at ambient temperature and pressure is some 600 times the volume of the liquid before it evaporates. This means that, say, if only 1 % of the mass of the liquid in a transfer line evaporates, the volume occupied by the vapour is six times the total volume of unevaporated liquid. Although the vapour mass is 99 times less than the liquid mass, the vapour volume occupies six sevenths of the volume of the line, and the mass flow almost stops. 

Fig. 6.1 Size distributions of H (H20)n cluster ions (upper abscissa and left ordinate) for an altitude of 17 km, an H20-vapour volume mixing ratio of 3 X 10 and temperatures of 180, 190,...

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