Gas seperator/scrubber

[elvey]

We have a prototype high temp incinerator, the exhaust gas which is urged along,at low pressure, by a vac pump which is way down stream in the cool gas area. When the gas leaves the incinerator it is at approx 600 deg C. but as it cools down there is a tar like substance that settles out and completely gums up the pipework etc. We are trying a simple home made wet cascade scrubber, but I'm sure this is not the best technique, would have thought the best place to deal with the prob is where the gas is quite hot. I think we are trying to re-invent the wheel, is there a "off the shelf" solution. Any ideas PLEASE>