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The RTD and MRT are parameters that are extremely pertinent to the operation of chemicalreactors, influencing both the throughput and the quality of the product.The concept of the RTD is fundamental to any engineering reactor design. The real timeexperimental RTD tracing is simple and reliable; it provides various important hydrodynamicparameters. From a well-conducted tracer experiment, it is expected to obtain the RTD of the tracedmaterial in a system. Accurate experimental RTD curve is crucial for system analysis or modeling.2.2. RESIDENCE TIME DISTRIBUTION DATA TREATMENTThe analysis of the residence time distribution (RTD) data depends upon the specific aim forwhich the radiotracer experiment has been carried out. The simples RTD data treatment is thecalculation of moments. Moments are used to characterize the RTD functions in terms of statisticalparameters such as MRT and variation (σ 2 ). The moments are defined as:where, i = 0, 1, 2, 3, ....MRT is equal to the first moment:Mi=∞∫0tiE() tdt∞∫0() tM1= t = tE dtThe spread of the RTD curve is characterized by the variance (σ2):2σ = M2− M21=∞2∫ ( t − t ) E( t)0dt∞∫02where M2= t E()t dt is the second moment.If N reactors are connected in series then MRT and variance of the cascade can be obtainedfrom the following relations:t = t + t + t + ... +cascade 1 2 3t N22σcascade= σ + σ + σ + ... + σN21For a fluid flowing in a system of volume V with constant flow rate Q, the theoretical MRT (τ)of the fluid is defined as:22τ = V/Q232.3. RESIDENCE TIME DISTRIBUTION MODELINGModeling a flow from RTD experimental data means to represent the experimental curve by aknown theoretical function. Flow model is the quantitative description of hydrodynamic characteristicsof the transported material. The model helps to understanding of a process and its prediction(simulation) for different conditions. Modeling of experimental RTD curve with theoretical functionsof different flow patterns is performed using different software. The arrangements of basic flowelements are used to provide a proper model that gives a response identical or close to the signal from15