Effect of solvent on the viscosity changes of coal-oil slurry under high temperature-high pressure during heating

摘要

Heating coal-oil slurry is an important step in direct coal liquefaction. Some physical and chemical properties and the viscosity of coal-oil slurry will be the changes in the heating process. A self-manufactured rotary viscometer that can measure the viscosity of coal slurry at high-pressure temperature was designed. Two kinds of solvents including anthracene oil, Shenhua recycled oil (the catalytic hydrogenation products of Shenhua direct coal liquefaction) and Yanzhou coal were used. The results show that the viscosity of Yanzhou coal-anthracene oil and Shenhua recycled oil slurry decrease firstly with the decreasing of solvent viscosity, then increase with measuring temperature for the absorption and volatilization of the solvent in atmosphere. Both of them have a viscosity peak with increasing measuring temperature in atmosphere. However, the Yanzhou coal-anthracene oil slurry has a viscosity peak at about 583 K under high pressure during heating, while the Yanzhou coal-Shenhua recycled oil slurry does not have a viscosity peak, but coke deposits appear at 623 K and above, under high pressure. In addition, the viscosity-temperature characteristics of thermally treated coal-oil slurry at different temperatures are the same; both have a viscosity peak with increasing heating temperature at the same measuring temperature.