Is it possible to get a PhD based on research papers I have written?
I doubt that you will find such a thing anywhere. An earned doctorate almost always (I know of no exceptions) requires an official registration and most likely, your presence at the institution for some period of time. There are normally qualifying examinations and often (not always) some required coursework.

Your publication history, however, would be a very positive factor in obtaining admission to a program in most places. You don't say why you are having difficulties, so it is impossible to say if there is some impediment. 

But the only way to know about your chances are to apply to a program somewhere other than your institute, and possibly in another country. But a research background would help your chances.