Molecular Characterization Of Sulfur-containing Compounds In Crude Oils From Kazakhstan

Using the individual sulfur species information for the heavy oils,it would be possible to estimate their sulfur removal process ability.The sulfur removal chemistry of heavy oils has been unraveled by systematically investigating several heavy oils with an extremely wide range of properties.A method we use in the study is methylation/demethylation technology.This method based on selective separation of thiophenes and sulfides compounds from petroleum.The method was utilized applied to Kazakhstan crude oil.In this work,we use eight crude oils of differing sulfur contents were employed to examine the feasibility of the process.Sulfur fractions were characterized by high resolution Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS).The result showed the all samples content the thiophenic compounds with high atomicity.Meanwhile,after chemical separation new components were discovered not previously visible with conventional analyses determination of sulfur compounds.That is,substances with relatively low molecular weight(15-25 carbon number)and high aromaticity(9-15 DBEs).For Kossagil crude oil this compounds distributed between 9-12 DBEs,and 15-20 carbon numbers,for Karazhanbas crude oil,between 9-16 DBEs 15-22,for Kumkol(south)crude oil,9-15 DBEs,15-20 carbon numbers,for Uzen crude oil,8-14 DBEs,13-20 carbon numbers.The S1 class species were the most abundant sulfur compounds in the eight crude oils from Kazakhstan.The S1 class species with DBE values of 6 and greater are likely thiophenes,the most abundant in Kossagil,Kumkol(north)and Kumkol(south),Village Balgimbaev,Uzen,Botakhan and Karazhanbas crude oils.While those with DBE values less than 3 are sulfides in Kumkol(north),village Balgimbaev,Botakhan,Uzen,Kossagil,Karazhanbas crude oils.The most plentiful content of class S2 is contained in oil from Botakhan.The village Balgimbaev,Karazhanbas,Zhanatalap and Kumkol(south)showed a good composition of the class S2,while the other crude oil showed a slight amount of this class.This work dedicated for the characterization of petroleum sulfur compounds,and provides broad application prospects in research studies on petroleum geochemistry and petroleum composition.