Can a US citizen receive 72 hr visa flying: Detroit>Beijing>Guanzhou and exiting Guangzhou>Thailand?

Next week, I am flying from Detroit in USA to Guangzhou. However, I have a 3 hour layover in Beijing. So, the flight route is Detroit > Beijing > Guangzhou. I stay in Guangzhou for 30 hours then fly out from Guangzhou > Krabi, Thailand. I do not plan to leave Guangzhou/Guangdong province during those 30 hours.

Can I receive the 72 hour free transit even though I will technically first enter China through Beijing (this is just a 3 layover at airport) and exit through Guangzhou 30 hours later?

Thank you!