Indexed on: 02 Feb '19Published on: 23 Jan '19Published in: Energy & Fuels
Various analytical techniques were used to study the molecular composition and structure of heteroatom compounds in Huadian (HD) shale oil. On the basis of the results obtained from gas chromatography–nitrogen chemiluminescence detection and gas chromatography–sulfur chemiluminescence detection, the composition of nitrogen- and sulfur-containing compounds was estimated. Molecular composition and structural information of heteroatom compounds were characterized on the basis of their type (double-bond equivalence (DBE)), class (number of oxygen, nitrogen, and sulfur heteroatoms), and carbon number distribution using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). In the positive-ion ESI FT-ICR MS mode, a total of 14 different basic species were detected for basic nitrogen compounds. N1 class compounds dominated followed by N1O1 and N2 class compounds. The DBE value of N1OX compounds having high relative abundance values increased with the increase in the number of oxygen atoms. In the negative-ion ESI FT-ICR MS mode, a total of 12 classes of compounds were detected for neutral nitrogen compounds and acidic compounds of HD shale oil. O2 class species were dominant, followed by N1 and O1 class compounds. N1 class species with DBE values of 9, 12, and 15 were carbazoles, benzocarbazoles, and dibenzocarbazoles, respectively.