In a PFR, the reactants enter at one end and flow through the reactor in a linear fashion. The reaction takes place as the reactants move through the reactor, and the products are collected at the other end. The flow characteristics ensure that each infinitesimal element of volume in the reactor undergoes the same reaction time. This is different from other reactor types like Continuous Stirred Tank Reactors (CSTR), where complete mixing occurs and the reaction mixture has a uniform composition.
