M. Kostoglou et Aj. Karabelas, COMPREHENSIVE MODELING OF PRECIPITATION AND FOULING IN TURBULENT PIPE-FLOW, Industrial & engineering chemistry research, 37(4), 1998, pp. 1536-1550
Supersaturation with respect to an active compound triggers several pr
ecipitation-related processes that may proceed (essentially concurrent
ly) along the flow path. The interaction between fluid dynamics and ph
ysicochemical processes (i.e., nucleation, particle growth, and coagul
ation) leads to an axial variation of bulk properties (species concent
ration and particle size distribution) and of ionic and particulate de
position rates at the pipe wall. To simulate this complicated system,
very simple hydrodynamics (plug flow) is combined with rather comprehe
nsive modeling of physicochemical phenomena. Considerable effort is de
voted to the optimization of computational requirements, thus developi
ng a numerical algorithm efficient and flexible enough to cope with ev
en more demanding future tasks such as the inclusion of mixing. The pe
rformance of the model is examined using, as a test case, the precipit
ation of a sparingly soluble salt under conditions typical for geother
mal installations. An extensive study of the effects of the initial sa
turation ratio and of the tendency for particle coagulation on the dep
osition rate and on the particle size distribution along the pipe is c
arried out.