The image below is a schematic flow diagram of a typical oil refinery that depicts the various unit processes and the flow of intermediate product streams that occurs between the inlet crude oil feedstock and the final end products.
In order to check-in into a hotel, the person must be 21 years old.  If the person is younger than 21, then a parent or guardian can  give permission for them to check-in. 1 person found this useful.
You must be at least 18 years of age to reserve and/or check into a room. All guests under 18 must be accompanied by a parent. Government issued identification may be required at check-in for all occupants.