144 visa free transit

Yes, Passport from Belgium is eligible for 144 hour free transit in Shanghai as long as you don't stop anywhere else in mainland china. Taiwan counts as if it was a separate country from China.

Thanks very much, we will only be visiting Shanghai, so this is the perfect solution.

Now I'm having another problem. When informing Thai Airways (our carrier to Shanghai) of our intention to make use of this 144 free transit exemption, they responded that their system does not know any such exemption, hence we will not be allowed boarding in Bangkok.
Any suggestions, how I can deal with this problem? Thanks in advance for your answer;

Call the check-in officer at the airport.
if you call a hotline they don't know much about visa and such things.

It’s always pointless calling the airline. It’s a complete waste of time. Wait until you get to the airport, inform the agent you are in “transit without visa” (and use those words). When they check Timatic they must put Taiwan as the destination and Shanghai as the transit.

Thanks for your answer. I rephrased my question to Thai Airways, clearly stating Taipei = Final Destination and Shanghai = Transit. They looked into the matter again and confirmed that we were right. So it's just a matter of using the correct wording.