1. What is Space Time for First Order Reaction?

Definition: Space time (τi) is the time required to process one reactor volume of feed at specified conditions.

Purpose: It helps chemical engineers determine the residence time needed for a first-order reaction 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)
• \( V_i \) — Volume of reactor vessel i (cubic meters)
• \( \upsilon \) — Volumetric flow rate of feed (cubic meters per second)

Explanation: The reactor volume is divided by the volumetric flow rate to determine how long it takes for one reactor volume of feed to pass through the system.

3. Importance of Space Time Calculation

Details: Proper space time calculation ensures sufficient residence time for the desired reaction conversion and helps in reactor design and optimization.

4. Using the Calculator

Tips: Enter the reactor volume in cubic meters and the volumetric flow rate in cubic meters per second. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between space time and residence time?
A: Space time is a design parameter based on empty reactor volume, while residence time is the actual time fluid elements spend in the reactor.

Q2: How does space time relate to conversion?
A: For a first-order reaction, conversion = 1 - exp(-kτ), where k is the rate constant and τ is space time.

Q3: What units should I use?
A: Consistent SI units are recommended (m³ for volume, m³/s for flow rate, s for space time).

Q4: Can this be used for batch reactors?
A: No, space time is specifically for continuous flow reactors like CSTRs.

Q5: How does space time affect reactor size?
A: Higher required space times generally mean larger reactor volumes for a given flow rate.