Energy-saving process for recycling circulating propylene

The invention relates to an energy-saving process for recycling circulating propylene, and the process comprises the following steps: separating an impurity-containing crude propylene raw material from the top of a depropanizer to obtain a light component-containing propylene material flow at the top of the depropanizer and a recycled high-purity propylene material flow at the side line of the depropanizer, wherein a tower top material flow of the depropanization tower is divided into two flows after being pressurized and heated by a propylene heat pump compressor: the first flow enters the bottom of the deethanization tower, and the second flow enters the shell side of a reboiler of the depropanization tower as a heat source; enabling a second material flow obtained by heat release and condensation from the shell side to enter a depropanization tower reflux tank, and taking an oil phase in the tank as reflux liquid to flow to the top of the depropanization tower; enabling the first material flow to enter a d