Imam Khomeini (RA) Shazand Refinery (Arak Refinery) is one of the subsidiaries of the National Iranian Oil Refining and Distribution Company. It was launched in 1993 as the largest single-unit refinery in Iran with a nominal capacity of 150,000 barrels per day. It is also the first refinery whose study and implementation operations started after the Islamic Revolution and in the first year after the imposed war. With the efforts of dedicated and specialized personnel, the refinery's production capacity reached 170,000 barrels per day. The change in the consumption pattern of petroleum products in the country from intermediate products to gasoline, as well as the improvement of the quality of the produced products in accordance with environmental requirements and international standards, prompted the authorities to approve and communicate the plan for increasing the capacity and improving the quality of Imam Khomeini (RA) Shazand Refinery's products. With the implementation of this plan, the refinery's production capacity has increased from 170,000 barrels per day to 250,000 barrels per day. Furthermore, gasoline production has increased to 12 million liters per day in exchange for reducing furnace oil production. The refinery's feedstock has changed from 100% sweet and light crude oil to a mixture of 55% light and 45% heavy crude oil. The refinery's products meet the standards of Europe in 2004 and 2005 in terms of specifications and quality.