Based on electrical capacitance tomography technique

the flow regime of dense-phase pneumatic transportation of pulverized coal was investigated.Typical flow regimes in the horizontal pipe and riser were obtained.The study indicated that the flow regime in the horizontal pipe varied significantly with time and there existed several flow regimes

such as full pipe flow

settled layer flow

suspension flow

etc.Statistical analysis results revealed that there were obvious prevailing flow regimes

which changed with superficial gas velocity.An analysis on solids velocity and pressure signals showed that the flow regime correlated reasonably well with pressure signals

which proved the inherent instability of dense phase pneumatic conveying.On the other hand

the dynamic test result of the riser showed that the flow regime was mainly core-annulus structure.