Frankfurt to Bangkok - Stopover in Shanghai

We are flying from Frankfurt to Bangkok, with a stopover in Shanghai and want to use the free visa procedure (to visit Shanghai in one day; in the evening, we are already flying through to Bangkok).
Because we are staying less than 30 days in Thailand, we don't need a Visum for Thailand. So, we can't show a visum for Thailand when we enter Shanghai. Is this gonna be ok for the Chinese authorities? Will we be able to enter China for one day?
Thank you!
Maarten