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Chemical Engineering vocabulary · Reactions and Reactors

Residence time

Meaning in chemical engineering, with examples

nounCore term

In chemical engineering, residence time means: The average time that material spends inside a vessel or reactor, found for a simple case by dividing the volume by the volumetric flow rate.

In Turkish: kalma süresi, alıkonma süresi, kalış süresi

How it is used

Used in reactor design, settling tanks, dryers and scale-up. Engineers increase, reduce or calculate residence time and talk about the residence time distribution (RTD). 'Holdup time' is used in a similar way for separators.

Example sentences

  1. At the higher feed rate, the residence time drops to 20 minutes and conversion falls.

  2. The separator was sized for five minutes of liquid residence time.

Common collocations

  • average residence time
  • residence time distribution
  • increase the residence time
  • liquid residence time
  • reactorA vessel or piece of equipment where a chemical reaction is carried out under controlled temperature, pressure and mixing.
  • CSTRShort for continuous stirred-tank reactor: a tank with a mixer where feed flows in and product flows out all the time, and the contents are assumed to be perfectly mixed.
  • plug flow reactorAn ideal tube reactor in which the fluid moves forward like a series of thin slices with no mixing along the length, so the composition changes from inlet to outlet.
  • conversionThe fraction of a reactant that has reacted, usually given as a percentage of the amount fed to the reactor.
  • flow rateThe amount of fluid that passes a point in a given time, given either as mass (kg/h) or as volume (m³/h).

More terms: Reactions and Reactors

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