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Definition: This calculator determines the initial concentration of reactant in catalytic reactions where strong pore diffusion resistance is present, accounting for catalyst deactivation over time.
Purpose: It helps chemical engineers design and analyze catalytic reactors by estimating initial reactant concentrations under conditions of pore diffusion limitations.
The calculator uses the formula:
Where:
Explanation: The formula accounts for both pore diffusion resistance and catalyst deactivation over time through nested exponential terms.
Details: Accurate calculation is crucial for reactor design, predicting reaction rates, and understanding catalyst performance under diffusion-limited conditions.
Tips: Enter all required parameters with appropriate units. Default values are provided for typical conditions, but should be adjusted for specific catalysts and reactions.
Q1: What is strong pore diffusion resistance?
A: It occurs when reactant diffusion into catalyst pores is slow compared to reaction rate, creating concentration gradients within the catalyst particle.
Q2: How is the Thiele modulus determined?
A: MT is calculated from catalyst properties and reaction kinetics, typically ranging from 0.1 to 10 for significant pore diffusion effects.
Q3: What affects the rate of deactivation?
A: Catalyst poisoning, sintering, coking, and thermal degradation can all contribute to deactivation rates.
Q4: When is this calculation most important?
A: For reactions with fast kinetics using porous catalysts, where diffusion limitations significantly impact overall reaction rates.
Q5: How does space time differ from residence time?
A: Space time is based on reactor volume and inlet flow rate, while residence time accounts for actual fluid dynamics within the reactor.