Hydraulic Transport of Fine and Coarse Sediment Mixtures in Pipelines

Abstract

This paper presents results from a comprehensive laboratory study of the effects of a fine grained sediment (clay) carrier fluid on the hydraulic gradient of sand-sized sediments (600–2,000 microns) in a 103-mm diameter pipeline. Three sand sizes were evaluated in the pipeline: (1) medium sand (670 microns), coarse sand (1,260 microns), and very coarse sand (2,040 microns). Initial experiments were conducted with water as the carrier fluid. Sand concentrations of 0.05, 0.10, 0.20, and 0.30 by volume (Cv) were evaluated. For each sand concentration, the effect of phosphate clay concentrations on the hydraulic gradient was evaluated. The clay carrier fluids exhibited both Newtonian and non-Newtonian fluid properties. Study results indicate that the hydraulic gradient reduction effect resulting from phosphate clay added to sand and water slurries increases with sand concentration, decreases with particle size, and is maximum within the flow range representing maximum solids stratification with bed contact (2...