A plasma reactor comprises a torch body comprising a plasma torch for generating plasma, a reactor section in fluid communication with the torch body for receiving the plasma from the plasma torch, and a quench section in fluid communication with the reactor section. The quench section comprises an inner wall defining a quench chamber, the inner wall has a serrated configuration, and the quench chamber has an upstream end adjacent the reactor section and an opposite downstream end. The plasma reactor also comprises at least one heating element in thermal communication with the reactor section, wherein the at least one heating element provides for selectively modulating a temperature within the reactor section.