Taking pulverized coal and dry air or CO2 as the experimental materials

the blockage critical state of pulverized coal dense-phase pneumatic conveying with pipelines of 10 mm

15 mm and 20 mm (ID) were studied respectively.The blockage critical characteristics

such as solids gas ratio

transporting velocity

pressure signal were obtained through reducing gas flow rate.Characteristic parameters and characteristic frequency of different stages were obtained by analysis of pressure signal characteristics and power spectrum analysis.The results showed that the blockage critical velocity was related to pipeline diameter and carrying gas characteristics.A dimensionless equation describing the relationship between blockage critical velocity and aforementioned parameters was finally established. Fluctuation of pressure signal was significant and vibration frequency converted to low frequency near blockage critical state.The criterion for blockage was obtained by mathematical calculation of pressure signal.