Photochemical reactor balances

The experimental procedure adopted in the thermochemical study of reaction 10.17 was fairly simple. First, an electrical calibration was made. Then, after balancing the light input to the cells, 2.7 cm3 of a 7 x 10-3 mol dm-3 solution of hrms-azobenzene in heptane was added to the photochemical reactor. This solution was irradiated for a certain period (1.5-3.8 h) with 436 nm light, and the thermogram was recorded. The area of this thermogram multiplied by the calibration constant (e) gives A0b H. 

Photochemical reactors UV Mass and radiation energy balances Braun et al. (1993)... 

Photochemical reactor design involves simultaneous solution of the mass, energy, and momentum balance equations (as in normal reactors) along with equations for the radiation field and energy source (which are specific to photochemical reactors). Two approaches are possible (1) the intensity of the incident light, irrespective of the source, is used as the inlet boundary condition incidence models)-, (2) the emission from the source itself is part of the mathematical description emission models). The first approach has been extensively used but suffers from the weakness that the incident light is a function of scale, and hence a priori design from laboratory scale data tends to be uncertain. The second approach is formally correct, and involves no such uncertainty. 

Classical chemical reaction engineering provides mathematical concepts to describe the ideal (and real) mass balances and reaction kinetics of commonly used reactor types that include discontinuous batch, mixed flow, plug flow, batch recirculation systems and staged or cascade reactor configurations (Levenspiel, 1996). Mixed flow reactors are sometimes referred to as continuously stirred tank reactors (CSTRs). The different reactor types are shown schematically in Fig. 8-1. All these reactor types and configurations are amenable to photochemical reaction engineering. 

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