Abstract: An exemplary process air recirculation system, and an electric heater mixing apparatus is disclosed herein. Exemplary process air recirculation systems comprise the electric heating mixing apparatus. An exemplary electric heating mixing apparatus comprises: walls defining a first chamber having a first upstream opening and a first downstream opening, and a second chamber having a first upstream opening and a first downstream opening, wherein the second chamber is adjacently disposed to the first chamber, a first inlet damper disposed at the first upstream opening, a second inlet damper disposed at the second upstream opening, and a resistance-type electric air heater disposed in the first chamber.