Oil refinery. Crude oil is processed at an oil refinery to produce a variety of products. The oil is catalytically broken down and the products are separated in a fractionating column. Products can include natural gas, petroleum, kerosene, diesel oil and bitumen (used in asphalt to build roads). The fuel components are used to power vehicles and heat homes. Other petrochemical products are used as raw materials for products like plastics. This is the Marathon Ashland Petroleum Company's oil refinery at Catlettsburg, Kentucky, USA. It was developed from a smaller (1000 barrels of oil) site in 1924. It now (as of 2005) has a capacity of 222,000 barrels of oil a day.