Nowadays, the accurate and fast simulation of the operational units such as distillation units to implement the changes, optimization and increase of their capacity have became possible with the specific simulation software of refinery processes such as Petro-SIM.In this article distillation unit of Bandar Abbas  refinery was simulated in software Petro-SIM 4 and by using the results  the required cases were evaluated in order to feasibility of the increase of Bandar Abbas Oil Refinery feedstocks and products by performing direct injection of sweet  gas condensate to atmospheric tower of the distillation units. Finally, the most efficient mode of direct injection of gas condensates to atmospheric tower proposed. Also, by help of simulate conditions inside the tower and other parts distillation unit injection of liquid phenomena such as flooding, temperature gradient along the tower, the tower of the return flow, specification of outlet products, capacity of air coolers and pumps and other equipment, were determined The test field located in Bandar Abbas refinery distillation units currently ongoing. The most important achievements can be the increase of crude oil and gas condensate refine and increase in the production of strategic products such as gasoline and diesel.