Question

The enrichment of the vapour steam, as it passes through the column in contact with reflux is called -

• A. Steam distillation
• B. Rectification
• C. Gas absorption
• D. Stripping

Hint:

Refux ratio (\(R = L/D\)) is the ratio of liquid returned to the column as reflux to the distillate product removed.
Increasing the reflux ratio increases the purity of the vapor product (rectification efficiency) but increases energy consumption.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Fractional distillation of miscible liquids involves two primary mass transfer zones within a distillation column: the rectifying (enriching) section and the stripping section.

Step 2: Detailed Explanation:
- Rectification: The process occurring in the upper section of a distillation column (above the feed plate). Here, the rising vapor stream is continuously contacted with a portion of the condensed liquid flowing down (called reflux). This contact allows the more volatile components to vaporize into the vapor stream, while the less volatile components condense into the liquid, thereby enriching the vapor stream with the highly volatile component.
- Stripping: The process occurring in the lower section (below the feed plate) where volatile components are removed from the liquid.

Step 3: Final Answer:
The enrichment of vapor in contact with reflux is called rectification, which corresponds to option (B).