Pressure and temperature effect on the mean chemical structure of coal hydrogenolysis product

Abstract

The hydrogenolysis reaction of coal using red-mud and sulphur as catalyst has been carried out at 400 and 450 °C, 10 MPa or 3 MPa of hydrogen, and 3 MPa of hydrogen plus 7 MPa of nitrogen. The mean chemical structures of the asphaltenes and oils produced show that at first the portion with relatively fewer aromatic rings and more aliphatic structures becomes soluble because of the saturation of the aromatic rings, and then gradually that having more aromatic rings and less of the aliphatic structures does likewise. The higher pressure contributes more to the saturation of aromatic rings and yields more extract. The higher temperature causes thermal decomposition of the aliphatic structures without changing the aromatic structures. When only the total reaction pressure is high, though the hydrogen density is unchanged, the chemical structure of the product is the same, but the reaction rate is accelerated because the reaction proceeds to a greater extent in the liquid state by the suppression of vaporization of low-molecular-weight matter under the higher pressure.