Problems of the measurement and evaluation of RTD of gas phase in chemical reactors are presented and discussed. The measurement of RTD in an industry is mostly used in trouble shooting or for process intensification or optimization. Special PC-programs have been prepared for selection of an RTD model and for its verification by parametrical analysis.
An example of the procedure used in trouble shooting is demonstrated on basis of data of radiotracer impulse response of gas flow in a heat exchanger. The results of methods for identification (deconvolution) with regularization, from so called nonparametrical analysis are presented.
A combined model described by a set of differential equations has been suggested for gas flow in the reactor with baffles. The model identification by nonlinear regression yields important process parameters, the relative dead volume and mass exchange coefficient e.g.
The prediction of RTD for other steady state conditions (e.g. for another flow rate) can be done on the basis of dimensionless impulse response. However the similarity assumption should be verified by other experiments, because the same flow pattern as well as the same relative active volume must be assured at different steady conditions.
Another possibility is the prediction of a change of RTD (change of the values of RTD model parameters) on the basis of numerical solution of transport equations for fluid dynamics using particle tracking method or transient analysis of temperature pulse spreading. The results of the RTD prediction for a broad range of Reynolds numbers using software Fluent are presented.