How do side strippers work?

• A. They Use Steam Injection to Reduce Partial Pressure, Allowing More Vaporization of Lighter Components
• B. They Add Cooling to Condense Heavy Components
• C. They Mix Feed Streams
• D. They Remove Vapor from the Top

Answer: (A)

Steam injection lowers the partial pressure in the stripping section, which shifts the vapor–liquid balance to favor vaporizing the lighter, more volatile components from the side-stream feed. The steam provides both energy and a low-pressure environment, so these light ends vaporize more readily and rise with the vapor to the overhead (or a condenser), while the heavier, less volatile components stay in the liquid and exit with the side-stream liquid. This setup lets you strip and recover light ends efficiently without heating the entire column to higher temperatures. Other actions like cooling to condense heavies, mixing feeds, or simply taking vapor from the top describe different parts of the process and aren’t how a side stripper achieves its primary separation.