Tranfer at Capitol International (PEK)

Good morning,
if I fly from Europe with Air China to Beijing (PEK T3) and I have a connection flight from Beijing (T3) to Guilin with Air China, are 2 hours enough to take the second flight ? Is the passport control at Beijing Capitol (PEK) or at Guilin airport ? If the passport control is at Beijing, is there a very long queue with the risk to lose the second flight ? Thank you