PROJECT TITLE :

The Characterization of Pulverized-Coal Pneumatic Transport Using an Array of Intrusive Electrostatic Sensors

ABSTRACT:

Fan/impact mills are commonly applied in the grinding and dilute–pneumatic transportation of lignite or brown coals with high moisture contents to the furnaces in massive steam boilers. Each of the two to eight mills feeds pulverized coal into 2 or additional burner nozzles. An online detection of the pulverized-coal mass flow distribution among the burners is very important for the management of the combustion method. Knowing the distribution, measures for the redistribution of the coal or, alternatively, for the adjustment of the combustion air flow in step with the particular distribution will be employed. Determining the characteristics of a gas–solid two-phase flow using an electrostatic principle could be a promising on-line methodology of measurement because it's sturdy and inexpensive. Furthermore, because of their better spatial sensitivity, rod sensors are additional suitable for massive rectangular ducts connected to fan/impact mills than ring-, pin-, or arc-shaped sensors. Sets of 1-D and 2-D electrostatic sensor arrays with a corresponding information acquisition system were used to determine the mass flow distribution in the cross section of the duct that feeds the pulverized lignite to the four burner nozzles. Numerous operating regimes for the fan/impact mill were tested. The time series of the signals from the electrostatic sensors were analyzed statistically. It was shown that the skewness, kurtosis, and autocorrelation time delay at the characteristic worth will indicate completely different grinding qualities of the coal.