Abstract
AAs one of the basic reseaches on saline water conversion by freezing, a study on the drainage of the packed bed of ice crystal particles by centrifugal filter was made using two kinds of ice crystal particles of 0.14 and 0.47 mm in mean surface diameter, sand of 48/65 mesh, and crushed quartz sand of 24/28 mesh.
The saturations of the residual liquid in the packed bed of these particles were measured at a few minutes intervals during the drainage. From the results, it was found that the drainage of ice crystal particles by centrifugal force were as follows:
(1) With higher centrifugal effect (Z>300), the saturation of the residual brine in ice crystals bed differed from that of the residual liquid in sand beds, and the former was lower than the latter. This phenomenon seemed to be due to the partial melting of ice crystals caused by presssure owing to the centrifugal force and due to the self-washing.
(2) with lower centrifugal effect (Z<160), the melting of ice crystals was hardly observed and the saturation of the residual brine in the ice crystals bed could be treated in the similar manner to that in sand beds. And, assuming that the drainage was dominated mainly by film flow, the relation between the saturation (S) and drainage time (t) or centrifugal effect (Z) was as follows:
(S-S∞)=m (ρmKZt/μεL)n
m=2.0 (±1.0), n=-0.5
where S∞is residual equilibrium saturation, ρm is density of liquid, μ is viscosity, K, ε and L is permeability, porosity and thickness of the packed bed of particles respectively.
