{HEAD ~ The reaction chamber} preferably has {TAIL ~ a multiplicity} of ports, so that depending upon the particular stream, its BTU value, and other parameters, the appropriately spaced ports are selected as injection ports 
preferably has
{ HEAD ~ The reaction chamber } preferably has { TAIL ~ a multiplicity } of ports , so that depending upon the particular stream , its BTU value , and other parameters , the appropriately spaced ports are selected as injection ports
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH