Stable discharge of coal liquefaction residue (CLR) from a vacuum distillation tower is required to get high oil yield and stable operation of the NEDOL process. From this point of view, fluidity of CLR was investigated by measuring the viscosity of three kinds of CLR produced in the 1 t/d Process Supporting Unit (PSU).
The relationship between viscosity and temperature showed that apparent activation energy for flow of CLR differs in temperature ranges and its value below a certain temperature (Tr) is greater than that above Tr. This Tr had a good linear relationship to the softening temperature of CLR. Since CLR viscosity was considered to be remrkably influenced by ash content and organic entity viscosity, the effects of these factors were studied. Viscosity of CLR drastically increased as ash content of CLR went up to over 32 mass %, because the ash content reached to its critical value for viscous flow of CLR, i.e., 38 to 40 mass %. On the other hand, organic entity viscosity of CLR estimated by the Mori-Ototake's equation modified using present experimental results increased with the increase in carbon content of raw coal.
