A plug flow reactor (PFR) is a type of chemical reactor where the reactants flow through a cylindrical tube in a "plug-like" manner. In this setup, the fluid moves in one direction, and each "plug" of fluid has a uniform composition as it travels through the reactor. This design allows for efficient mixing and reaction of the chemicals, making it ideal for continuous processes. PFRs are commonly used in various industries, including the production of chemicals, pharmaceuticals, and biofuels. They can handle large volumes of reactants and are often preferred for reactions that require precise control over reaction time and temperature, enhancing overall efficiency and product yield.