The resulting low temperature gases can be introduced into the hot reaction zone either through the carbon vehicle for {TAIL ~ the hot reaction bed} or directly mixed with {HEAD ~ fresh air} 
The resulting low temperature gases can be introduced into the hot reaction zone either through the carbon vehicle for { TAIL ~ the hot reaction bed } or directly mixed with { HEAD ~ fresh air }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD