An Investigation of Solid-Liquid Flow Distribution Through Slurry Pipeline

Abstract

Pipeline transport is considered environment friendly and economical as compared to rail and road transport. To design the pipelines and its associated facilities designers need accurate information regarding pressure drop, critical velocity, flow regimes, hold up etc. Many large slurry pipelines were built and operating around the world. Such flows are complex and the correlations presently available in open literatures for the above mentioned parameters have a prediction error 25-35 %. This much of error in design and slurry operation has serious cost implication and is totally unacceptable. In the present study, an attempt has been made to simulate the mineral (zinc taling and lime water) slurry flow through straight pipeline to predict the pressure drop, velocity profile and behavior of solid particles. To simulate the slurry flow commercial CFD software FLUENT 14.5 has been used. An Eulerian model based on kinetic theory of granular flow is used to represent multiphase phenomenon. To describe the turbulence present in the flow Standard k-ɛ turbulent model coupled with standard wall treatment with dispersed properties has been used. All these models are part of CFD software package FLUENT 14.5. The Simulation is performed on pipeline having 42 mm diameter and 7 m length. The experimental data consist of zinc water slurry and lime water slurry with 33 μm particle diameter. The velocity of the flow is varied from 1.5 to 3.5 m/s and concentration is varied from 30 to 60 % by weight. The effect of increase in particle diameter at same concentration is also analyzed and comparison is made on pressure drop, power consumed, and volume fraction contour. Before performing simulation on the desired slurry, first the simulation results are validated with the experimental data taken from the open literature. The simulated results indicate that the particles are asymmetrically distributed in the vertical plane with the degree of asymmetry increases with increase in particle diameter. The predicted pressure drop at different velocities and concentration shows good agreement with experimental data obtained from open literature.