Mass transfer during solvent extraction from dispersed particles of a polym
er solution in an aqueous medium with simultaneous solvent sublimation from
the continuum phase was simulated, A mathematical model includes the gener
al description of macro- and microkinetics of a complex heat-and-mass-trans
fer process in a dynamic-interface heterogeneous system. A formula for the
shrinkage rate of polymer solution particles is obtained. A numerical techn
ique for process characterization takes into account the transition from a
varying region to a fixed one. It uses a special difference scheme to solve
the convective diffusion equation in which the convective and diffusion te
rms vanish with time. This model of mass transfer in dynamic-interface hete
rogeneous systems made it possible to simulate process stages in the produc
tion of ball-grain gun powder.