Space Time Formula:
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Definition: Space time (τmixed) is the time required to process one reactor volume of feed based on entrance conditions for a second-order reaction in a mixed flow reactor.
Purpose: It helps chemical engineers determine the residence time needed for a given conversion in a continuously stirred tank reactor (CSTR).
The calculator uses the formula:
Where:
Explanation: The formula calculates the time needed to achieve a specific concentration change in a CSTR for a second-order reaction.
Details: Accurate space time calculation ensures proper reactor sizing, optimal reaction conditions, and efficient process design in chemical engineering.
Tips: Enter the initial concentration (must be greater than final concentration), final concentration, and rate constant. All values must be positive numbers.
Q1: What is a mixed flow reactor?
A: A mixed flow reactor (or CSTR) is a reactor where contents are perfectly mixed and have uniform composition throughout.
Q2: Why is space time important?
A: Space time helps determine reactor volume needed for a given conversion and flow rate.
Q3: What are typical units for rate constant?
A: For second-order reactions, the rate constant has units of m³/(mol·s).
Q4: Can initial concentration be less than final?
A: No, for this calculation C₀ must be greater than C as concentration decreases over time in normal reactions.
Q5: How does this differ from plug flow reactors?
A: The space time calculation differs because mixing patterns affect reaction rates differently in CSTRs vs PFRs.