Analysis of transient ash pneumatic conveying over long distance and prediction of transport capacity

Abstract

Pneumatic conveying of the lignite ash from blow tanks to a nearly 600m distant silo at the 620 MWe thermal power plant is analyzed based on pressure measurements along the telescoping transport pipeline. Transient character of the ash transport is shown with an occurrence of blockages. The ash transport capacity of the pneumatic conveying is determined by predicting a pressure drop in the steady-state compressible air–ash mixture flow for a defined air flow rate, inlet and outlet pressure values and lengths, diameters and inclinations of pipeline sections. The predicted transport capacity is in agreement with the lignite ash production calculated on the basis of lignite ash content and a lignite mills load. In addition, the calculated pressure change along the pipeline shows good agreement with mean values of measured pressure amplitudes at a number of locations along the pipeline. The presented modelling approach can be applied to the prediction of conveying capacity of ash transport pipelines.