It looks like a Pilosocereus pachycladus which can get up to over 30 feet high after many, many years if grown in the ground.
If I could see the spines more clearly, I could be more sure of which species of Pilosocereus it is.
Notice the two spines that are pointing upwardly from the rest of spines? That's an identifying feature of this one. I looked at over 100 spine closeups and the only one I found that has those two spines pointing upward is Cereus fernambucensis. Also notice the the areolae have a small amount of wool which is also on C. fernambucensis. The only thing that dosen't look quite identical is the thickness of the branch(s) which could be either the enviromental conditions or you have a slightly different forma.
Cereus species tend to have many formas within the genus. So in my assessment, that's what it is.
Here are some other photos to compare and see the spines and wool, etc. http://davesgarden.com/guides/pf/showimage/56258/
I trawled through cactiguide.com & columnar cacti.com & couldn't find anything to match. I thought maybe Neocardenasia but the spines weren't a close match.
The three upward pointing spines on GAgirls picture are very difficult to match to anything