In this work, by using pinch technology, the preheating section of refinery distillation unit has been studied to reduce energy consumption by creating minimal changes to the existing heat exchanger network. This includes simulation of the unit by Aspen software, extracting the required information, information processing and finally correcting heat exchanger network. It is observed that through making changes in the network of heat exchangers, by adding a cooler and a shell & tube heat exchanger with $ 921,800 investment, 1.611*10(6) $ energy saving will be achieved annually and the investment return period is equal to 7 months.