Vaporization processes

It is not particularly difficult to find macroscopic measures of interactions between small molecules of the same type, that is, quantities which are proportional to Wii and W22 in Eq. (8.40). Among the possibilities, we consider the change in internal energy AU for the vaporization process for component i. This can be related to Wjj in terms of the lattice model by the expression... 

The vaporization process describes the phase change liquid (1) gas (g), so from the definition of AH we can write... 

The vaporization process requires energy both to overcome intermolecular attractions and to push back the surroundings to make room for the vapor. The quantity AU measures the former, while AH takes both into account. In connection with the mixing process, it is the contribution of intermolecular forces which we seek to evaluate, so AU is a more suitable measure of this quantity. 

The Diikler theory is applicable for condensate films on horizontal tubes and also for falling films, in general, i.e., those not associated with condensation or vaporization processes. 

A multiple-factor method for predesign cost estimating has been put forward by D. H. Allen and R. C. Paffe [Chem. Eng., 82, 142-150 (Mar. 3, 1975)] for fluid-type plants (F) that include some vapor processing. The method requires the following input information ... 

The simplifying assumptions that make Tick s law useful for other processes are not vaHd for pei vaporation. The activity gradient across the membrane is far more important than the pressure gradient. Equation (22-110) is generally used to describe the pei vaporation process ... 

A cornerstone of the analysis of vaporization processes in a vacuum is the classical theory of gases. In this theory, a gas is assumed to consist of noninteracting molecules which undergo elastic collisions with one another and... 

Natural gas requires no fuel treatment however, low-Btu gas, espeeially if derived from various coal gasification processes, requires various types of cleaners for use in a gas turbine. These cycles can get very complex as indicated by a typical system, which utilizes a steam bottoming cycle to achieve high efficiency. Vaporized fuel oil gas is already cleansed of its impurities in the vaporization process. 

VFO works well in gas turbines. In a nine-month test program, the combustion properties of VFO were studied in a combustion test module. A gas turbine was also operated on VFO. The tests were conducted to study the combustion characteristics of VFO, the erosive and corrosive effects of VFO, and the operation of a gas turbine on VFO. The combustion tests were conducted on a combustion test module built from a GE Frame 5 combustion can and liner. The gas turbine tests were conducted on a Ford model 707 industrial gas turbine. Both the combustion module and gas turbine were used in the erosion and corrosion evaluation. The combustion tests showed the VFO to match natural gas in flame patterns, temperature profile, and flame color. The operation of the gas turbine revealed that the gas turbine not only operated well on VFO, but its performance was improved. The turbine inlet temperature was lower at a given output with VFO than with either natural gas or diesel fuel. This phenomenon is due to the increase in exhaust mass flow provided by the addition of steam in the diesel for the vaporization process. Following the tests, a thorough inspection was made of materials in the combustion module and on the gas turbine, which came into contact with the vaporized fuel or with the combustion gas. The inspection revealed no harmful effects on any of the components due to the use of VFO. 

NFPA 30 (2000), Section 5.10, applies to vapor recovery (vent manifold) and vapor processing systems where the vapor sonrce operates at pressnres from vacnnm np to and inclnding 1 psig. Snhsection 5.10.7.6 is concerned with flame propagation hazards, hnt is not specific ahont installing flame arresters. It states as follows ... 

Clausius-Clapeyron Equation. This equation was originally derived to describe the vaporization process of a pure liquid, but it can be also applied to other two-phase transitions of a pure substance. The Clausius-Clapeyron equation relates the variation of vapor pressure (P ) with absolute temperature (T) to the molar latent heat of vaporization, i.e., the thermal energy required to vajxirize one mole of the pure liquid ... 

The Clausius-Clapeyron equation The Clapeyron equation can be used to derive an approximate equation that relates the vapor pressure of a liquid or solid to temperature. For the vaporization process... 

If a gas or vapor process stream is available at a high pressure and downstream conditions do not require this high pressure, the stream can be expanded to provide useful cooling. The cooling might allow partial condensation for recovery of the less volatile components in a mixture, or to... 

Fritz, W., and W. Eude, 1936, The Vaporization Process According to Cinematographic Pictures of Vapor Bubbles, Phys. Z. 37 391 401. (2)... 

In the vaporization process, the formation of a continuous vapor phase causes a transition from bubble to annular flow. This flow-pattern transition is accompanied by a gradual change in the heat-transfer mechanism. Both... 

For the total vaporization process, it is generally assumed that four basic heat-transfer regions exist within the tube, each representing a distinct heat-transfer mechanism with the transition from one region to another being gradual ... 

In a vaporization process, the pressure at each axial position must be known so that the saturation temperature can be calculated and the rate of phase change predicted. In Section I, the present state of the art for calculating pressure drop and holdups in isothermal incompressible two-phase... 

Ans. (a) The change of a liquid into a gas. (b) The change of a solid into a liquid, U) The enthalpy change accompanying a vaporization process, (d) The enthalpy change accompanying a melting (fusion) process. 

Sample. This source places no restrictions on target material. Clusters of metals, produced. For example, polyethylene and alumina have been studied as well as refractory metals like tungsten and niobium. Molecular solids, liquids, and solutions could also be used. However the complexity of the vaporization process and plasma chemistry makes for even more complex mixtures in the gas phase. To date the transition metals(1-3) and early members of group 13 (IIIA) and 14 (IVA)( 11-16) have been the most actively studied. 

Plan (1) Treat the vaporization process as a chemical reaction, then establish the relationship between Keq... 

Figure 6-6 Flammability diagram for methane at an initial temperature and pressure of 25°C and 1 atm. Source C. V. Mashuga and D. A. Crowl, Application of the Flammability Diagram for Evaluation of Fire and Explosion Hazards of Flammable Vapors, Process Safety Progress (1998), 17(3) 176-183.

Cars and buses are fuelled by a volatile mixture of hydrocarbons. The mixture is called petrol in the UK, and gas (short for gasoline) in the USA. One of the main chemicals in petrol is octane, albeit in several isomeric forms. In the internal combustion engine, the carburettor first vaporizes the petrol to form an aerosol (see Section 10.2) comprising tiny droplets of petrol suspended in air (Figure 8.3). This vaporization process is similar to that which converts liquid perfume into a fine spray. 

Control of the vaporization process, i.e. the temperature of the capillary, is of crucial importance. Optimum performance is obtained with around 95% vaporization of the liquid stream. Too much heat results in vaporization occurring within the capillary with deposition of analyte and, if operation of the interface under these conditions is continued for any length of time, blockage of the capillary. On the other hand, if insufficient heat is applied to the capillary, vaporization does not occur and liquid flows from it and no spray is obtained. The optimum temperature is dependent on a number of parameters, among the most important being the composition of the mobile phase and its flow rate. Good temperature control is therefore required to obtain the best conditions when gradient elution is employed. 

Similarly, the single solvent molecules required for the stepwise clustering can be obtained from the liquid by a vaporization process molecule by molecule. 

Vaporization processes that produce the high 5 Fe values of deep sea spherules are, of course, more complicated, because a large portion of the heating and vaporization occurs in the atmosphere, and is accompanied hy conversion of Fe metal to Fe oxides. 

Explosive boiling is certainly not the normal event to occur when liquids are heated. Thus, the very rapid vaporization process must be explained by theories other than standard equilibrium models. For example, if two liquids are brought into contact, and one is relatively nonvolatile but at a temperature significantly above the boiling point of the second liquid, an explosive rapid-phase transition sometimes results. Various models have been proposed to describe such transitions. None has been... 

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