1. What is Space Time for First Order Reaction in Vessel i?

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).

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \tau_i' \) — Space time for vessel i (seconds)
• \( C_{i-1} \) — Reactant concentration in previous vessel (mol/m³)
• \( C_i \) — Reactant concentration in current vessel (mol/m³)
• \( k' \) — Rate constant for first-order reaction (1/s)

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.

3. Importance of Space Time Calculation

Details: Proper space time calculation ensures optimal reactor design, efficient reaction conversion, and cost-effective process operation.

4. Using the Calculator

Tips: Enter the reactant concentrations in mol/m³ and the rate constant in 1/s. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

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.