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Definition: This calculator determines the initial concentration of reactant needed in a Plug Flow Reactor (PFR) for a zero-order reaction based on the rate constant, space time, and desired conversion.
Purpose: It helps chemical engineers design PFR systems by calculating the required initial reactant concentration to achieve a specific conversion.
The calculator uses the formula:
Where:
Explanation: For zero-order reactions, the reaction rate is independent of reactant concentration. The initial concentration is directly proportional to the rate constant and space time, and inversely proportional to conversion.
Details: Accurate initial concentration calculation ensures proper reactor design, optimal reaction conditions, and desired product yields in chemical processes.
Tips: Enter the rate constant (k₀), space time (τ_PFR), and desired conversion (X_A,PFR as a decimal). All values must be positive, with conversion between 0 and 1.
Q1: What is a zero-order reaction?
A: A reaction where the rate is independent of the reactant concentration. The rate is constant and equal to k₀.
Q2: What is space time in a PFR?
A: The time required to process one reactor volume of feed at entrance conditions (τ = V/v₀).
Q3: How does conversion affect the calculation?
A: Higher conversion requires higher initial concentration for the same space time and rate constant.
Q4: What are typical units for k₀ in zero-order reactions?
A: Common units are mol/m³·s or mol/L·s, depending on concentration units used.
Q5: When is this formula not applicable?
A: For non-zero-order reactions or when other factors like backmixing or temperature gradients are significant.