I was born in HK and only have a birth certificate. Would I able to apply for a HK passport in van

Only a person who is a Chinese citizen, a permanent resident of the HKSAR or a holder of a valid Hong Kong permanent identity card can apply for a Hk passport.
Thus, it seems that it's impossible for you to apply for a Hk passport.
Does either of your parents has Hong Kong permanent identity card? If so, you can apply for a HK permanent identity card first with your Hong Kong birth certificate and your parent's Hong Kong permanent identity card.