Liquid pressure measurements in a thermally assisted mechanical dewatering process

The thermally assisted mechanical dewatering process, investigated in this paper, couples in one stage mechanical dewatering at low pressure (Papplied < 1125 kPa) with a moderated heating (T < 80 °C). Previous studies emphasized that the separation enhancement depends on the product. To identify the mechanisms involved, a 1 Da 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, re-appears 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 less than half of this for cellulose suspension.