Space Time Formula:
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Definition: Space time (τ) is the time required to process one reactor volume of fluid based on entrance conditions for a first-order reaction.
Purpose: It helps chemical engineers determine the residence time needed for a reaction to reach desired conversion in a continuous stirred-tank reactor (CSTR).
The calculator uses the formula:
Where:
Explanation: The formula calculates the residence time needed to achieve the concentration change from vessel i-1 to vessel i for a first-order reaction.
Details: Proper space time calculation ensures optimal reactor design, efficient reaction conversion, and cost-effective process operation.
Tips: Enter the reactant concentrations in mol/m³ and the rate constant in 1/s. All values must be positive numbers.
Q1: What is the difference between space time and residence time?
A: Space time is based on inlet conditions while residence time is the actual time fluid spends in the reactor.
Q2: How does this relate to reactor design?
A: Space time helps determine the required reactor volume for a given flow rate to achieve desired conversion.
Q3: What are typical units for the rate constant?
A: For first-order reactions, the rate constant has units of 1/s (inverse seconds).
Q4: Can this be used for batch reactors?
A: No, this formula is specifically for continuous flow reactors (CSTRs).
Q5: What if my concentrations are in different units?
A: Convert all concentrations to consistent units (mol/m³ recommended) before calculation.