consideritsolved:

In very general terminology, the feed stream enters most fractionator columns at about the mid-point of a column's height. The section above the feed entry point is called the "rectifying" section. The section below the feed entry is called the "stripping" section.

A stripper is so named because it has no rectifying section. The feed to a stripper usually enters at the top tray of the stripper or very close to the top tray. Examples of strippers in an oil refinery are:

-- Sour water strippers in which steam is used to remove H2S and NH3 for sour waters.
-- Side-cut strippers on crude oil atmospheric distillation towers in which steam is used to remove the lightest components from side-cut products such as kerosene, jet fuel, or diesel oil.

Municipal wastewater and other wastewater treatment plants sometimes include strippers that use air to strip NH3 from the wastewaters.

In essence, a stripper is a truncated version of a fractionator because it contains no rectifying section.

Milton Beychok
(Visit me at www.air-dispersion.com)
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I'd go a step farther in that strippers don't usually have a reboiler, a steam stripper may have one the generate steam, or you could just use a live steam input directly.  The inverse to a stripper is an absorber and one with a reboiler is a reboiled absorber.