Just off the top of my head, one way to refine it might be to heat the mass to a certain temperature, say 115°, that is safely below the coldest point of your veg system (my tank, the coldest point, runs at 130ish), and strain off the chunks so you only have liquid oil. Also be sure to filter it to 10 micron, or whatever your veg filter is rated, at this temperature. That way you won't have any congestion problems.

--EDIT-- After seeing Rashakor's post, you could also cut it with some, like 10% I think, RUG, and do the process I described above.