A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value.
The image below is a schematic flow diagram of a typical oil refinery depicting various unit processes and the flow of intermediate products between the inlet crude oil feedstock and the final products. The diagram depicts only one of the hundreds of different configurations. It does not include any of the usual facilities providing utilities such as steam, cooling water, and electric power as well as storage tanks for crude oil feedstock and for intermediate products and end products