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.
Check with the hotel you are staying at. ....and if you have ID and credit card, some hotels will allow you to stay. However, there seems to be some discretion given to some hotels to set their own policy for 21 to 25. Seems odd to me,.