The pipeline flow of coal‐in‐oil suspensions

TLDR: In this paper, the flow behavior of coal-in-oil suspensions at velocities up to ca. 20 ft/sec. has been investigated in a one-inch d. experimental pipeline.

Abstract: The flow behavior of coal-in-oil suspensions at velocities up to ca. 20 ft./sec. has been investigated in a one-inch d. experimental pipeline. Detailed data are presented for a bituminous and a subbituminous coal (effective size 70% w/w. At flow velocities greater than 2 ft./sec. and coal concentrations below 50% w/w, the suspensions were found to move as relatively homogeneous (or quasi-homogeneous) fluids, and pressure gradients followed the usual friction factor/Reynolds number relationship. But no satisfactory correlations could be established for flow at 50% w/w coal. In the latter case, laminar flow obtained at all velocities and the suspended particles tended to concentrate near the pipe axis (and to move along it as a definite ‘core'’. One effect of this phenomenon is a substantial reduction in the apparent viscosity of the suspension. Le comportement hydraulique de suspensions charbon-huile a ete etudie dans un oleoduc experimental (diametre 1′) pour des vitesses jusqu'a environ 20 pi./sec. Des donnees sont presentees pour un charbon bitumineux et un charbon sous-bitumineux (dimension effective inferieure a 700 microns) dans deux huiles de viscosite egale a 5.6 et 46.7 cp a 25°C. respectivement et ce pour des concentrations de charbon dans les suspensions allant jusqu'a plus de 70%. Les suspensions se deplacent comme des fluides relativement homogenes (ou quasi-homogenes) et les pertes de charge suivent la relation usuelle f/Re, pour des vitesses superieures a 2 pi/sec et des concentrations inferieures a 50%. Cependant aucune relation satisfaisante n'a pu ětre etablie pour des debits inferieurs a 2 pi/sec (influence appreciable due a la decantation) ou pour le comportement de suspensions superieures a 50% de charbon. Dans ce dernir cas, l'ecoulement laminaire a ete obtenu pour toute vitesse et les particules en suspension tendent a s'agglomerer pres de l'axe du tuyau et de s'ecouler comme un noyau bien defini. Une reduction substantielle de la viscosite apparente de la suspension decoule alors de ce phenomene.