Disclosed is a device and method for alternately controlling the operation state of two treatment equipment, each of which alternately operates to treat process emissions from a semiconductor manufacturing process, with two pipelines conveying the emissions to each of the treatment equipment, and two electric heating units providing heat to each of the pipelines, wherein the control device has a human-machine interface controller, a programmable controller, and a signal transmission port, the programmable controller sequentially controlling each of the control valves and each of the electric heating units so as to cause the electric heating units to select ramping up or ramping down the power rate, respectively, to reduce the electric energy consumption of the electric heating units in a standby state, and to reduce the overall carbon emissions.