ex9: Example 9-Kinetic Oxidation of Dissolved Ferrous Iron With...

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Kinetic rate expressions can be defined in a completely general way in PHREEQC by using Basic statements in the RATES data block. The rate expressions can be used in batch-reaction and transport calculations with the KINETICS data block. For transport calculations (ADVECTION or TRANSPORT), kinetic reactions can be defined cell by cell by the number range following the KINETICS keyword (KINETICS m-n). The rate expressions are integrated with an embedded (up to) 5th-order Runge-Kutta-Fehlberg algorithm, or with a stiff, variable-order, variable-step multistep solver (Cohen and Hindmarsh, 1996). Equilibrium is calculated before a kinetic calculation is initiated and again when a kinetic reaction increment is added. Equilibrium includes solution species equilibrium; exchange-, equilibrium-phase-, solid-solution-, and surface-assemblage equilibrium; and gas-phase equilibrium. A check is performed to ensure that the difference between estimates of the integrated rate over a time interval is smaller than a user-defined tolerance. If the tolerance is not satisfied, then the integration over the time interval is automatically restarted with a smaller time interval. The example can be run using the phrRunString routine.





See Also

Other Examples: ex10, ex11, ex12, ex13a, ex14, ex15, ex16, ex17, ex18, ex19, ex1, ex20a, ex21, ex22, ex2, ex3, ex4, ex5, ex6, ex7, ex8



phreeqc documentation built on July 1, 2020, 11:46 p.m.