Chemical structure of asphaltenes and preasphaltenes obtained by coal hydrogenation under high-speed heating conditions

Abstract

The results of experimental studies on the determination of the chemical structure of asphaltenes and preasphaltenes in the liquid hydrogenates of coal from the Zashulanskoe field in Transbaikalia are reported. These results were obtained under the conditions of high-speed heating (∼200 K/min; reaction time, 10 min). It was found that the structural characteristics of asphaltenes and preasphaltenes obtained by high-speed hydrogenation at 425°C and 10 MPa exhibited a number of special features. At similar fractions of aromatic carbon, these products differed from the coal hydrogenates obtained at a slow rate of heating (5 K/min; reaction time, 120 min) in terms of the distribution of hydrogen and oxygen over structural groups. In them, the hydrogen content of CH₂ and CH_ar groups was smaller and that of CH₃ groups was greater. The highest concentration of total oxygen-containing groups was detected in the high-speed process preasphaltenes, whereas it was lower in the asphaltenes.