1. What is Vapor Flowrate in Rectifying Section?

Definition: This calculator determines the molar flowrate of vapor in the rectifying section of a distillation column based on the stripping section vapor flowrate, feed flowrate, and feed quality.

Purpose: It helps chemical engineers and process designers analyze and design distillation columns by calculating the vapor flow in the upper section.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V_n \) — Vapor flowrate in rectifying section (mol/s)
• \( V_m \) — Vapor flowrate in stripping section (mol/s)
• \( F \) — Feed flowrate (mol/s)
• \( q \) — Feed quality (dimensionless)

Explanation: The formula accounts for the difference in vapor flow between the two sections of the distillation column based on the feed characteristics.

3. Importance of Vapor Flowrate Calculation

Details: Accurate vapor flowrate calculations are essential for proper column design, determining tray requirements, and ensuring efficient separation.

4. Using the Calculator

Tips: Enter the vapor flowrate in the stripping section (mol/s), feed flowrate (mol/s), and feed quality (dimensionless). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is feed quality (q) in distillation?
A: Feed quality represents the fraction of feed that is liquid, ranging from 0 (saturated vapor) to 1 (saturated liquid).

Q2: How do I determine the vapor flowrate in the stripping section?
A: This is typically calculated from the reboiler duty or can be measured experimentally.

Q3: What's a typical range for feed quality?
A: Most feed streams have q values between 0 (all vapor) and 1 (all liquid), with 0.2-0.8 being common.

Q4: Can this be used for non-ideal systems?
A: The basic formula works for ideal systems; for non-ideal systems, activity coefficients may need consideration.

Q5: How does feed quality affect vapor flowrate?
A: Higher q values (more liquid feed) result in greater difference between Vn and Vm.