London- Beijing- Seoul- Beijing- London

I’d like to have a 3 or 4 day stay in Beijing on my outward journey to Seoul. Spend maybe 4 days there and then either have another 2 days in Beijing on way back to London. My flight to Seoul would be a separate flight booking and may be from Beijings second international airport. Would this itinerary qualify for the 144 hours on both parts of the journey. Thank you