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.
If you are a young adult trying to rent a hotel room, there are some things you should be aware of. How Old Do You Have To Be To Rent A Hotel Room? The answer depends upon the hotel policy. Some hotels will allow someone 18 years of age to rent a hotel room, while some require the person to be at least 21 years of age. Other people will allow someone over 21 to actually rent the room, but they can add a younger adult as someone that is valid to check in.