A plug flow reactor (PFR) is a type of chemical reactor where the reactants flow through a cylindrical tube in a "plug" manner. This means that the fluid moves in a uniform stream, with little to no mixing in the direction of flow. As a result, each "plug" of fluid experiences the same reaction conditions, allowing for efficient processing of chemical reactions. PFRs are commonly used in industrial applications due to their high efficiency and ability to handle large volumes of reactants. They are particularly effective for continuous processes, where reactants are fed in and products are removed without interruption, making them ideal for large-scale production in the chemical industry.