Do I qualify for the 72 hour free transit if my flight route is SriLank-Beijing-Srilanka-Dubai

I am travelling for a 12 day break at Easter. I have an Irish passport with a Dubai residency Visa. I am flying from Dubai to Sri Lanka, then on to Beijing for less than 72 hours. I am then flying back through Sri Lanka to get back to Dubai. Do I qualify for the 72 hour free transit or will I be I stopped from entering as I am arriving from the same airport I will be departing to 2 days later?????
I cannot get a Visa here as I am working full-time and the office only opens 9-12 Sun to Thurs. Any help is greatly appreciated!