Research on Dense Phase Pneumatic Conveying of the Mixture of Pulverized Coal and Extract Residue of Coal Liquefaction Residue at High Pressure

Abstract

In order to study on the high pressure dense phase conveying characteristics of extract residue of coal liquefaction residue (hereinafter referred to ER) blending to pulverized coal, the pulverized coal (M1) and the pulverized coal blending 20wt.% extraction residue (M2) were prepared as experimental samples. The conveying experiments were conduct at back pressures (receiver pressure) of 2 and 4Mpag in a pipeline with 25 mm inner diameter. The results showed that at the same superficial gas velocity, there is no significant difference in particles velocity when conveying M1 and M2 samples. The increasing of back pressure reduced the velocity difference between local superficial gas velocity and particles velocity. The conveying phenomena showed that both the mass flow rate and the particle concentration of these two samples increased with the increasing of flow rate of the fluidizing gas. When the fluidization number increased to 2.5, the fluidization effect were good enough to keep the mass flow rate of M1 and M2 stable; when back pressure decreased from 4 to 2Mpag, blending ER to pulverized coal will lead to a decrease in mass flow rate of the mixture powder. The effect of the blending ER to pulverized coal on particle concentration was mainly appeared in the low superficial gas velocity region, in the high gas velocity region, the particle concentration of M1 and M2 was similar during the conveying processes.