Abstract: Sulfur compounds in liquid products from residue contact cracking process were characterized by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS), results showing that there were sulfur species identified such as phenyl alkyl sulfides, thiophenols, thiophenes, benzothiophenes, dihydro-benzothiophenes, dibenzothiophenes, naphthothiophenes, tetrahydro-dibenzothiophenes, benzonaphthothiophenes, phenanthrothiophenes, benzodithiophenes and thiopyrans. Based on group separation and tile effect in GC×GC-TOFMS, carbon number distribution characteristics of thiophenes, benzothiophenes and dibenzothiophenes in liquid products were studied, in addition, 15 individual molecules of C2-DBTs which got extensive concern in oil processing were determined and recognized. Combined with residue contact cracking process, it was found that micro-reactor activities of contact agents had evident influence on molecular species and carbon number distribution of sulfur compounds in liquid products from residue cracking, and to be specific, sulfur molecule species were similar in products from one residue on different contact agents, while contents and distribution mode of them varied a lot. As for carbon number distribution of sulfur compounds in liquid products, taking benzothiophenes (BTs) for example, low carbon number alkyl (C1-C3) BTs dominated in their homologues distribution when using strong agent, while relatively high carbon number alkyl (C4+) BTs dominated on weak agent.

Key words: comprehensive two-dimensional gas chromatography, time-of-flight mass spectrometry, residue, sulfur compound, contact cracking, molecular characterization