Research on the performance of the new flow regulating valve in industrial scale bore size for pulverized coal is carried out on the dense phase pneumatic conveying experimental device.Through changing the parameters and operational conditions,the influence of the structures of valve trim on conveying characteristics is observed.On the basis of systematic tests and analysis for valves with different structure of valve trims,the optimal trim configuration is obtained.The results of research indicate that under the same flow rate of pulverized coal,the solid-gas ratios obtained under different valve trim configurations are basically equal;under optimal configuration,with throttle area changing from 12% to 100%,corresponding regulating range of flow for pulverized coal is 50% to 96%;the smaller the throttling area are,the poorer the stability of conveying is.

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.