For isothermal, first-order chemical reactions, the mole balances form a system of linear equations. A non-ideal reactor can then be modeled as a collection of Lagrangian fluid elements moving independe n tly through the system. When parameterized by the amount of time it has spent in the system (i.e., its residence time), each fluid element behaves as abatch reactor. The species concentrations for such a system can be completely characterized by the inlet concentrations, the chemical rate constants, and the residence time distribution (RTD) of the reactor. The latter can be found from simple tracer experiments carried out under identical flow conditions. A brief overview of RTD theory is given below. [Pg.22]

From Table 20.6 we conclude that independent of which model we use, typical transfer times are between a few tenths of a second and a minute. Proton exchange reactions of the form (see Section 8.2) [Pg.932]

If finite chemical reaction times are put into the columnar diffusion flame theory (76), burning rates are predicted to be linearly proportional to pressure at low pressure and independent of pressure (plateau burning) at high pressure. Based on this model, von Elbe et al. (97) proposed the simple equation [Pg.267]

On this basis, models were constructed for computer simulation in which the species whole molecules, D, half molecules, H, and ligand, L, were allowed to diffuse independently for short increments of time, At, and then were coupled via chemical interaction. For example, if the overall reaction is [Pg.156]

The position approach strives to get the positions of the reactive particles explicitly at the reaction time t obtained in the IRT model. While the nonreac-tive particles are allowed to diffuse freely, the diffusion of the reactive particles is conditioned on having a distance between them equal to the reaction radius at the reaction time. Thus, following a fairly complex procedure, the position of the reactive product can be simulated, and its distance from other radicals or products evaluated, to generate a new sequence of independent reaction times (Clifford et al, 1986). [Pg.223]

Now, appropriate plots of the data are made, which, if linear, would indicate that the assumed model of Eq. (3) is adequate. For example, if ln(CjCA0) were linear with t, a first-order model would be adequate. Alternatively, one could assume a model (including the value of the parameter a), calculate the rate constant k at each data point, and tabulate the constants. If these constants remain constant, or if there is a reasonable trend of the constants with any independent variable, then the data do not reject the assumed model. For example, the value of In k would be expected to be independent of the value of the reaction time and to change linearly with the reciprocal of the absolute temperature. [Pg.103]

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