There may be an immigration line open from the domestic side to international. If so will speed up process. However can't promise it'll be open. If not, then you must exit all the way out to main terminal, walk to international side, and go through exit immigration and security. I don't remember if there's a quick connection lane or not. I wouldnt have booked this simply because intra-China flights are frequently delayed. I arrived at PEK for my 2230 flight to SHA. It was delayed till 0230. They put me on the 1630 flight that was leaving at 2145!