High-effective and energy-saving concentrating device and high-effective and energy-saving concentrating method for N-ethylpiperazine by using same

A high-effective and energy-saving concentrating device and a high-effective and energy-saving concentrating method for N-ethylpiperazine by using same. A set of mechanical steam compression falling-film evaporator supplies both of a heat source in the bottom and a cold source in the top of a concentrating column in a conversion manner. A gas phase from the top of the concentrating column is compressed by a mechanical steam compressor, and is inputted as the heat source in the bottom of a concentrating column when calorific value grade is increased; the bottom liquid is heated in the tube pass of a falling-film heater and is fed into the column bottom, while the top gas phase is condensed into a liquid phase in the falling-film heater; one part of the liquid phase is fed back to the concentrating column as reflux, and the other part, as a top product, is heat-exchanged with feeding materials and then is withdrawn. Compared with conventional rectification, the calorific value grade of secondary steam in the co