A microwave energy emitter (108) is positioned in a chamber within a material holding cavity of a containment vessel (106) that is transparent to microwave energy absorption that is further surrounded by a microwave reflective component to reflect the waves back into the vessel. The vessel (106) encloses a material that absorbs microwave energy through molecular vibration of its molecules. An inlet path (116) and outlet path (112) is provided for the material to flow in and out of the vessel upon predetermined conditions. Heated material can be condensed via a condenser (124) into a collection vessel (120). A controller (126) is provided to send control signals to switching device for controlling the material flow and receiving sensing signals for decision generation.