Mass transfer coupling

The equipartition principle is mainly used to investigate binary distillation columns, and should be extended to multicomponent and nonideal mixtures. One should also account for the coupling between driving forces since heat and mass transfer coupling may be considerable and should not be neglected especially in diabatic columns. 

The general expression (10.3) guides development of impedance models from proposed reaction sequences. The reaction mechanisms considered here include reactions dependent only on potential, reactions dependent on both potential and mass transfer, coupled reactions dependent on both potential and surface coverage, and coupled reactions dependent on potential, surface coverage, and mass transfer. The proposed reaction sequence has a major influence on the frequency dependence of the interfacial Faradaic impedance described in Qiapter 9. 

SECM techniques have made many valuable contributions to the investigation of phase transfer processes at solid/liquid interfaces by facilitating quantitative measurements under conditions of well-defined and high mass transfer coupled with high spatial resolution. At present there are effectively... 

The mass transfer rates of catalysts between two phases are difficultly realized due to the difficult identification of the active catalyst during the reaction [57,112-115], Mass transfer coupled rapid reactions subjected to LLPTC have been studied extensively [58,63,69,115,116], Mass transfer rates of catalysts in the reaction of 2,4,6-tribromophenol and tetra- -butylammonium bromide in a solution of KOH were determined [57,114],... 

The objective of this chapter is to give a comprehensive overview of both basics and peculiarities of RD modeling. A detailed description covers balance equations, mass and heat transfer, reaction kinetics including reaction-mass-transfer coupling, as well as steady-state and dynamic modeling issues. The achievements in the theoretical description are illustrated with several case studies supported by laboratory- and pilot-scale experimental investigations. 

For problems with reaction and mass-transfer coupling, e.g., like in Eqs. (10.16), it is always essential whether the reaction rate is comparable with the rate of diffusion [56, 57] or not. In most RD processes developed up to now, reaction rates are rather slow, and thus they determine the whole RD process rates, at least in the reaction zone. For such cases, the influence of the film reactions is usually negligible. This may, however, change for faster reactions. 

For measurement of kfi, typically pure gas is used so that gas-side resistance to mass transfer is eliminated. Limiting situations can be employed in experimentation by performing the mass transfer coupled with limiting types of reactions in the homogeneous phase, such as mass transfer with no reaction (in which case the estimate is actually affected by RTD of liquid), mass transfer with slow reaction (for low Hatta numbers, the estimated kia is independent of liquid RTD), mass transfer with instantaneous reaction (in which case also the kia estimate works out to be independent of liquid-phase mixing and can... 

Three different phenomena are considered to analyze the heat and mass transfers coupling (1) the different steps of the coupling of heat and mass transfers, (2) the impact of the heat flux density on drying time, and (3) the comparison between different THFs. 

Figure 19.18 Different steps of the heat and mass transfers coupling for the textile heat fluxmeter PES/CO3 with the heat flux density 464 W/m. ...

Theoretical Treatment of the Mass Transfer Coupled with the Heat Transfer... 

Dutour, S., Mazet, N., Joly, J.L. and Platel, V. (2005). Modeling of heat and mass transfer coupling with gas-solid reaction in a sorption heat pump cooled hy a two-phase closed thermosyphon. Chemical Engineering Science, Vol. 60, pp. 4093-4104. 

Chemical equilibrium and mass transfer mechanisms (chemical reactions, diffusion, fluid flow (advection), adsorption, etc.) (Chaps. 1,2, and 3) are examined in order to illustrate the compositional variation that exists within water (ground water, hydrothermal solution, seawater) and weathered and hydrothermally altered rocks and soils. To better understand the subsystems of the earth, equilibrium and mass transfer coupling models are apphed to the seawater system, as an example of a low-temperature exogenic system, and hydrothermal systems, as an example of high-temperature endogenic systems (Chap. 4). 

The two-film theory certainly lacks physical reality in postulating the existence of stagnant films at the interface, but nevertheless contains the essential features of dissolution and diffusion prior to the transfer in the turbulent bulk of the fluid. It also describes quantitatively quite well the phenomena of mass transfer coupled with a chemical reaction, as discussed in the subsequent chapters. Thereby, the following cases, as depicted in Figure 4.4.2, will be inspected ... 

Charpentier, J.-C., Mass transfer coupled with chemical reaction, Chapter 2, in A. Gianetto and P.L. Silveston (Eds), Multiphase Chemical Reactors, Hemisphere Publishing Corporation, Washington, DC, 1986. 

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