Optimization of specific energy consumption in the high concentration slurry disposal pipelines for coal ash in thermal power plants

Abstract

ABSTRACT In thermal power plants, the disposal of coal fly ash is one of the major challenges requiring energy input for its safe disposal, so optimization is needed to minimize the required energy input at maximum fly ash transportation. Present work is focussed on high concentration optimized transportation of ash slurry in thermal power plants using Computational Fluid Dynamics (CFD) which behaves as a Bingham plastic fluid, modeled using Herschel-Bulkley model. Specific Energy Consumption (SEC) is the measure of the energy required for the slurry transportation. Therefore, a parametric investigation to establish the effect of concentration of slurry (Cw), pipe diameter (D), no. of pipes (N), particle size (d) over SEC is conducted. Therefore, these operational parameters need to be carefully selected, as even a minor variation from the desired optimum values may result in huge SEC consumption thereby causing financial consequences. It is found in the current study that the SEC substantially depends on all of the above-mentioned parameters. Mathematical models for prediction of SEC based on the study are also developed for the future designers of such systems.