Dust buildup removal in tank

[lukem]

I work in a blast furnace and we are currently having a lot of trouble removing dust buildup from the inside walls of our dustcatcher (a large pressure vessel where dust is removed from the dirty gas off the top of the furnace). The dust has a high iron content, and we only have limited windows (40hrs) to clean the buildup. We have been using very high pressure water blasting (15000psi), but this is not effective enough to remove the amount of material we need in the time available. I am looking into dry ice blasting. Has anyone had any experienc ewith this type of blasting? Any other suggestions on removing the material? It is worth noting that the access to the vessel is very limited, only 2 doors, approx 2m high by 1m wide.
Any suggestions appreciated.