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.
Dec 20, 2006, 2:35 AM. The Hilton Chicago allows guests of 18 years of age or older to check in. I called the Hotel directly and they affirmed me, I will be able to check in! This news came with relief as I was worried my News Years Eve celebrations would be voided.