{HEAD ~ The sulfur contents} reach {TAIL ~ up to 15,000 ppm}, preferably between 4,000 and 9,000 ppm 
{ HEAD ~ The sulfur contents } reach { TAIL ~ up to 15,000 ppm } , preferably between 4,000 and 9,000 ppm
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH