In this research, the crude distillation unit (CDU) of a refinery has been chosen. Using a new method of ISO 14051 for determining the positive product and optimizing. Optimization can be a change in the operating conditions of the feed, the top and bottom pressure and temperature of the column, Also, with the environmental approach. Two crude oils named Dezful and Mansouri were studied as alternatives for Ahwaz crude oil. The products derived from Dezful crude oil show a difference of approximately 8 degrees API. The results of Mansouri illustrate that difference of about 30°C at boiling point, and with increasing temperature and feed pressure, there is no significant change in the quality of the main products in crude distillation unit.
