Rockwood, Unfortunately I can't really prevent the soot from accumulating on the patio, as the chimney is almost directly above it. From watching the soot in the snow, it appears that I am blowing soot balls to soot chunks out when the volitiles burn off and they land directly on the patio. If it was being blown on to the patio from the ground or swept off the roof, I think your idea might work.
Thanks guys for the tips on the TSP. I figured I might have to clean with TSP before sealing anyhow, since I had to wait the winter to seal. Hopefully it will do the trick. I am kicking around the idea of acid staining the concrete prior to sealing now. I am guessing I won't be able to get the stains off, so maybe I can get the stains to blend in or add character.
I would have thought with the really nice secondary burn that I wouldn't have much soot, but it must becoming from later in the burn and then blow out each time I reload. I am using Thompson's Kentucky at the moment. It seems to be great to burn (no clinkers, little ash, and the fine ash falls easily through my grate with just a poke), but if I remember correctly Berlin has noted that Kentucky can be rather sooty. I may try a ton of Thompson's Ohio coal and see if it has less soot and how it burns in my rigged up bit burner. If it makes less of a mess, I could always burn it when the weather is damp and dreary and the soot is prone to accumulating and making a mess. Does anyone know if Thompson's Ohio Bit is less prone to soot?