2 Tickets, onward connection

I have two seperately purchased tickets:

Calgary - Beijing

Beijing - Melbourne

I want to use the 72hour free transit for beijing, but my onward ticket has a stopover in shanghai between PEK and MEL for 11 hours. Will that stopover affect the 72 transit? Is it still possible to go out of the airport in shanghai? Or do I have to stay in the airport? Or will I need to apply for a visa?