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