Vaporization heat

This chapter presents quantitative methods for calculation of enthalpies of vapor-phase and liquid-phase mixtures. These methods rely primarily on pure-component data, in particular ideal-vapor heat capacities and vapor-pressure data, both as functions of temperature. Vapor-phase corrections for nonideality are usually relatively small. Liquid-phase excess enthalpies are also usually not important. As indicated in Chapter 4, for mixtures containing noncondensable components, we restrict attention to liquid solutions which are dilute with respect to all noncondensable components. 

This high degree of association results in highly nonideal physical properties. For example, heat effects resulting from vapor association may be significantly larger than the latent heat of vaporization (Fig. 9). Vapor heats of association J for HF to (HF) per mole of (HF) are as follows. To... 

Equations for Hadacher vapor pressure, vapor heat capacity, saturated Hquid volume, and Hquid viscosity can be found in Refs. 34 and 41. 

Many of the common properties of isoprene have been presented graphically (9). These include vapor pressure, heat of vaporization, Hquid heat capacity, vapor heat capacity, Hquid density, vapor viscosity, Hquid viscosity, surface tension, and vapor thermal conductivity. 

Vinyl acetate is a colorless, flammable Hquid having an initially pleasant odor which quickly becomes sharp and irritating. Table 1 Hsts the physical properties of the monomer. Information on properties, safety, and handling of vinyl acetate has been pubUshed (5—9). The vapor pressure, heat of vaporization, vapor heat capacity, Hquid heat capacity, Hquid density, vapor viscosity, Hquid viscosity, surface tension, vapor thermal conductivity, and Hquid thermal conductivity profile over temperature ranges have also been pubHshed (10). Table 2 (11) Hsts the solubiHty information for vinyl acetate. Unlike monomers such as styrene, vinyl acetate has a significant level of solubiHty in water which contributes to unique polymerization behavior. Vinyl acetate forms azeotropic mixtures (Table 3) (12). 

K, have been tabulated (2). Also given are data for superheated carbon dioxide vapor from 228 to 923 K at pressures from 7 to 7,000 kPa (1—1,000 psi). A graphical presentation of heat of formation, free energy of formation, heat of vaporization, surface tension, vapor pressure, Hquid and vapor heat capacities, densities, viscosities, and thermal conductivities has been provided (3). CompressibiHty factors of carbon dioxide from 268 to 473 K and 1,400—69,000 kPa (203—10,000 psi) are available (4). 

Values for many properties can be determined using reference substances, including density, surface tension, viscosity, partition coefficient, solubihty, diffusion coefficient, vapor pressure, latent heat, critical properties, entropies of vaporization, heats of solution, coUigative properties, and activity coefficients. Table 1 Hsts the equations needed for determining these properties. 

Temperature rc) Humidity kg HjO/kg dry air) Water vapor partial pressure (kPa) Water v K>r partial density (kg/m ) Water vaporization heat M/kg) Mixture enthalpy (kj/kg dry air) Dry air partial density (lKinematic viscosity (I0< mJ/s) Specific heat (kJ/K kg) Heat conductivity (W/m K) Diffusion factor water air (1 O mJ/s) Temperature rc)... 

On the other hand, the vaporization heat of water at temperature ad... 

The vaporization heat of water, which depends on the humidity, is accurately determined by... 

The shell-and-tube exchanger is by far the most common type of heat exchanger used in production operations. It can be applied to liquid/liquid, liquid/vapor, or vapor/vapor heat transfer services. The TEMA standards dcTine the design requirements for virtually all ranges of temperature and pressure that would be encountered in an oil or gas production facility. 

Mercury vapor Heat exchanger DOWTHERM Forced circn. Steel 220-350 Product... 

Figure 10-48. Fiow inside tubes for gases and vapors. Heat transfer coefficient for vapors and gases in turbuient fiow. (Used by permission Ning Hsing Chen, Chemical Engineering, V. 66, No. 1, 1959. McGraw-Hiii, inc. Aii rights reserved.)...

Gilmour, C. H., Performance of Vaporizers, Heat Transfer Analysis of Plant Data presented at Second National Heat Transfer Conference, Aug. 1958, Chicago, IL. Preprint No. 33, AIChE, New York 36, N.Y, pub. Chem Eng. Prog, Sym. Series No. 29, V. 55 (1959). 

The heat absorbed when a solid melts (s —> Z) is referred to as the heat of fusion that absorbed when a liquid vaporizes (2 — g) is called the heat of vaporization. Heats of fusion (AHta) and vaporization (AHv p) are most often expressed in kilojoules per mole (kj/mol). Values for several different substances are given in Table 8.2. 

In a subsequent study (Ref 43), Al, Au, Ft and W wires were investigated to determine the effect of the wire material on the initiation of PETN by exploding wires. Hie wires were exploded by a l-uf capacitor charged to 2000v. The results indicate that favorable wire materials are those into which energy is deposited at a rapid rate. They also have low bp s and heats of vaporization. Heat of oxidation of the wire material plays only a minor role. Different wire materials have different optimum lengths for effecting detonation... 

Heat of Explosion. 1138.5 keal/kg (w as vapor) Heat of Formation. 78.1kcal/mole Power. 540ml or 92% NG by Trauzl Pb block test with w tamping... 

An increase of the Peclet number leads to a decrease of the length of liquid domain, as well as an increase of the liquid-vapor heat flux ratio at the evaporating front. 

Feiba VH Immuno Plasma Vapor heat lla, Vila, Villa, IXa, Xa... 

Chen, J. C., F. T. Ozkaynak, and R. K. Sundaram, 1979, Vapor Heat Transfer in Post CHF Region Including the Effect of Thermal Nonequilibrium, Nuclear Eng. Design 51.T43 155. (4)... 

A precooling of dewar with liquid nitrogen (LN2) from 300 to 77 K saves a large amount of LHe liquid N2 has a vaporization heat 60 times that of LHe and a cost 20 times less. Moreover, the enthalpy of materials (es. A1) between 77 and 300 K (162 J/g) is much higher than that between 4 and 77 K (9 J/g). 

HF anhydrous hydrogen fluoride heat generation, liberating toxic vapors heat generation, liberating toxic vapors strong acid corrosive toxic vapor and liquid ... 

GlLMOUR, C. H. Chem. Eng. Prog. Symp. Ser. No. 29, 55 (1959) 67-78. Performance of vaporizers Heat transfer analysis of plant data. 

Heat capacity Thermal conductivity Heat of vaporization Heat of fusion... 

As with the other reactor configurations, vaporizers, heat exchangers, and a heat source are also needed for microreactors.Unless the hydrogen is 99.999% pure, the PEM fuel cell typically will utilize 70—80% of the diluted hydrogen fed to it. The unreacted hydrogen from the fuel cell anode, augmented with additional fuel as needed, can be used as fuel for the combustor. The use of anode off-gas requires special controls for transient operating conditions for example, a mechanism is needed to... 

Carnot Refrigerator and Heat Pump Basic Vapor Refrigeration Cycle Actual Vapor Refrigeration Cycle Basic Vapor Heat Pump Cycle Actual Vapor Heat Pump Cycle Working Fluids for Vapor Refrigeration and Heat Pump Systems Cascade and Multistaged Vapor Refrigerators... 

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