Chemical kinetics, iii

Berry, R.S. Rice, S. A. Ross. J. Physical and Chemical Kinetics , Part III of Physical Chemistry Wiley New York, 1980. 

Biological interfaces. 2. Chemical kinetics. 3. Biological transport. I. Leeuwen, H. P. van. II. Koster, Wolfgang. III. Series. 

Luther III, G. W. (1990), "The Frontier-Molecular-Orbital Theory Approach in Geochemical Processes", in W. Stumm, Ed., Aquatic Chemical Kinetics, John Wiley and Sons, New York, 173-198. 

Solvents. 2. Solvation. 3. Chemical reactions. 4. Chemical kinetics. I. Adams, Dave (Dave J.) II. Dyson, Paul J. III. Tavener, Stewart. 

Kee, R. J. Rupley, F. M. Meeks, E. and Miller, J. A. Chemkin-III A Fortran Chemical Kinetics Package for the Analysis of Gas-Phase Chemical and Plasma Kinetics , Sandia National Laboratories Report SAND96-8216, 1996. 

Dohmaru, T. In Chemical Kinetics of Small Organic Radicals, Volume III, Z.B. Alfassi (Ed.), CRC Press, Boca Raton, EL, 1988, pp. 165-195. 

S. W. Benson, The Foundations of Chemical Kinetics, McGraw-Hill, New York, 1960, ch. III. 

Section III discusses briefly (1) the relation between our logical equations and the differential equations as used in chemical kinetics (2) some aspects of logical versus numerical iteration methods (3) the possible application of our method (initially developed for genetic purposes) to other fields, and more particularly chemical kinetics and (4) the possibility of using this method al rovescio, that is, in a synthetic (inductive) way. In this perspective we assume that the essential elements of a system have been correctly identified and we ask to what extent one can proceed rationally from the observed behavior toward sets of interactions which account for this behavior. 

In the feed Is sufficiently high so that carbon cannot be present at equilibrium, the equilibrium composition can be calculated from consideration of only Chemical Reactions I and II. Accordingly, the activities of each of the species can be calculated If the equilibrium constants, Kj and KII and value of n are known provided the activity ratio Inequalities given In Equation 1 are met. If the Inequalities of Equation 1 are not met, coke deposition Is possible. Values of the n at which the equalities of Equation 1 are met represent the minimum steam/methane ratio, n., at which no carbon deposition will take place at equilibrium. Figure 1 displays n versus temperature, T. Extending the analysis to Include Chemical Reaction III permits the calculation of the equilibrium coke laydown as a function of n and T shown In Figure 2. These curves will be used later to compare with the corresponding kinetic curves obtained experimentally. 

Figure 3.3.7 Theoretical (dashed dotted) and real (solid) cell voltage (V) - current density (I) performance characteristics of a fuel cell. Overpotentials are responsible for the difference between theoretical and real performance and cause efficiency losses. They split into (i) activation polarization overpotentials at anode and cathode due to slow chemical kinetics, (ii) ohmic polarization overpotential due to ohmic voltage losses along the circuit, and (iii) concentration polarization overpotentials due to mass-transport limitations. The activation overpotentials of the cathode are typically the largest contribution to the total overvoltage.

Refs. [i] Christensen PA, Hamnett A (1994) Techniques and mechanisms in electrochemistry. Blackie Academic Professional, London [ii] Kory ta J, Dvorak J, Kavan L (1993) Principles of electrochemistry. Wiley, Chichester [iii] Calvo EJ (1986) Fundamentals. The basics of electrode reactions. In Bamford CH, Compton RG (eds) Comprehensive chemical kinetics, vol 26. Elsevier, Amsterdam, pp 1-78 [iv] Oldham KB, Zoski CG (1986) Mass transport to electrodes. In Bamford CH, Compton RG (eds) Comprehensive chemical kinetics, vol. 26. Elsevier, Amsterdam, pp 79-143... 

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