CRE-Class-5-Summary

MSubbu discussed the characterization of non-ideal reactors and heterogeneous reactions involving catalysts, including steps like adsorption and desorption. He explained how to model rate expressions using the LHHW (Langmuir-Hinshelwood-Hougen-Watson) model and mentioned that more aspects of heterogeneous catalysis would be covered in the next class on Tuesday. MSubbu also covered residence time distribution (RTD) and how to calculate the mean residence time from tracer studies using pulse inputs. He provided a step-by-step method to find the mean residence time using concentration-time data and simple integration, concluding that the mean residence time in this example was one time unit.

MSubbu explained the calculation of the centroid (\(\bar{t}\)) for triangles and its application in residence time analysis. He demonstrated how to find the \(x\)-coordinate of the centroid by averaging the \(x\)-values of the three triangle points, and showed that the E-curve (exit age distribution) is a scaled version of the C-curve (concentration versus time). MSubbu also described how to calculate the mean residence time (\(\bar{t}\)) from the E-curve using integration, and explained the relationship between F-curve and E-curve.

MSubbu discussed residence time distribution (RTD) and its applications in chemical reactors. He explained how to calculate mean residence times and conversions in both ideal and non-ideal reactors using RTD data and kinetic information. MSubbu emphasized that understanding the relationship between RTD, kinetics, and conversion is crucial for solving such problems. He also highlighted the importance of being able to derive equations for concentration profiles and residence time distributions from given data.

MSubbu discussed the configuration and behavior of reactors, focusing on the combination of plug flow reactors (PFR) and continuous stirred tank reactors (CSTR) within a real reactor system. He explained how tracer studies can be used to determine the volume ratios of PFR to MFR and to identify the conversion capabilities of the reactor system. MSubbu also described the characteristics of ideal PFR and CSTR systems, highlighting how tracer injection and output curves can help distinguish between the two reactor types and calculate residence times.

MSubbu discussed the characteristics of different reactor types, focusing on plug flow reactors (PFR) and mixed flow reactors (MFR). He explained how to identify reactor types using tracer studies and step input data, converting concentration curves to F curves for analysis. MSubbu demonstrated that the first curve corresponds to a CSTR with dead space, while the second curve represents a PFR followed by a CSTR in series, with no dead space. He emphasized that the order of PFR and CSTR cannot be determined from tracer studies alone.

MSubbu explained the Langmuir-Hinshelwood-Hougen Watson model for heterogeneous reactions involving a catalyst surface. He outlined the three key steps: adsorption, surface reaction, and desorption, emphasizing that adsorption and desorption are at equilibrium, while the surface reaction is the rate-limiting step. MSubbu derived the rate expression for the reaction, incorporating equilibrium constants for adsorption and surface reaction, and showed how to express the fraction of vacant catalyst sites in terms of measurable concentrations.

MSubbu discussed the derivation of rate expressions for catalytic reactions, focusing on different reaction mechanisms and rate-limiting steps. He explained how to determine the rate expression for surface reactions, adsorption, and desorption, and how to screen mechanisms based on adsorption states of reactants and products. MSubbu also mentioned upcoming changes to the fast-track classes, including more problem-solving and fewer repetitive lectures. He encouraged students to lead peer discussion sessions and record their study time.