is a characteristic of
the mixing that occurs in the chemical reactor. There is no axial mixing in a
plug-flow reactor, and this omission is reflected in the RTD. The CSTR is thoroughly mixed and possesses a far different kind of RTD than the plug-flow
reactor. As will be illustrated later, not all RTDs are unique to a particular reactor type; markedly different reactors can display identical RTDs. Nevertheless,
the RTD exhibited by a given reactor yields distinctive clues to the type of
mixing occurring within it and is one of the most informative characterizations
of the reactor.