72 hours visa-free transit

I want ask about the 72-hour free Transit, I am flying from Kiev to Shanghai Pudong International Airport with Emirates Airline, then will fly from Shanghai to Taipei with Southern China Airline. I want to visit Shanghai when making transit in Shanghai. I am holding Canadian passport.

So, I was wondering if I could stay 72 hours while arriving in Shanghai before flying to Taipei, then when I finish my vacation in Taipei, can I stay another 72 hours free in Shanghai before catching my flight back to Kiev ? So, totally, I planned to visit Shanghai for 72 + 72 = 144 hours. Does the free transit applies here? Also, please advise how and where to apply for the transit permits. Thank you.