Liquid pressure measurements in a thermally assisted mechanical dewatering process

Abstract

The thermally assisted mechanical dewatering process, investigated in this paper, couples in one stage mechanical dewatering at low pressure (P applied < 1125 kPa) with a moderated heating (T < 80°C). Former studies emphasized that the separation enhancement depends on the product. To identify the mechanisms involved, a 1D filtration/compression cell is instrumented with pore liquid sensors distributed on the wall. Talc and cellulose in suspensions in salt water are used as test materials. Cake growth and consolidation can be followed through these measurements. With heat supply, the liquid pressure gradient, which has vanished during the consolidation, reappears in the cake. An additional flow of liquid occurs when the thermal equilibrium is reached in the porous media. This additional flow represents 18% of the filtrate mass recovered at ambient temperature for talc suspensions and half less for cellulose suspensions.

Steam Dewatering of Filter Cakes in a Vertical Filter Press

“…In the field of coal dewatering, steam pressure filtration has been studied by, among others, Gerl and Stahl [5], Bongers et al [6] and Chen et al [7]. Thermally assisted mechanical dewatering (TAMD) with heating elements installed in the filter chamber has been studied by Couturier et al [8], Mahmoud et al [9], and Chantoiseau and Arlabosse [10]. Additionally, Bott and Langeloh [11] have detailed commercial steam-assisted hyperbaric disc and drum filters.…”