Seoul - Beijing - Portugal

Jose, there are no direct flights from Beijing to Portugal. Never mind, if you are traveling from Beijing toward Portugal by a direct flight to any country with the exception of South Korea, you will be eligible for 144 hour visa free transit in wider Beijing area and you do not need any kind of visa. 72 hours were replaced by more generous 144 hours in Beijing many years ago. Upon your landing in Beijing, you will approach 144 hour visa free transit counter and there you will get a stamp to be allowed to exit the airport and to enjoy your time in wider Beijing area at your own will.