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