A process and apparatus which reduces the fines in a liquid discharge stream and/or increases the dryness of a solids discharge stream while under a pressure equal to or greater than the vapor pressure of the liquid. There is provided a process for separating particles such as polyethylene terephthalate or polyethylene naphthalate from a liquid in a slurry comprising: a. feeding a slurry comprising solid particles and a liquid into a within a separation zone maintained at a pressure equal to or greater than the vapor pressure of the liquid; b. contacting the slurry in the separation zone with a porous filter, optionally a microfilter, nanofilter, reverse osmosis filter, or ultrafilter, and separating liquid from the particles, wherein the liquid flows through the filter into an outer annulus defined as a space between the wall of the separation device and the filter, and said porous filter optionally having a terminal point beyond which the separated liquid does not pass from the outer annulus back through the filter; c. accumulating no liquid in the outer annulus or accumulating liquid in the outer annulus at a level below or in front of the terminal point, and continuously discharging the separated liquid from the outer annulus through a liquid outlet; d. decoupling the particles from the separation zone through the solids outlet to a low pressure below the vapor pressure of the liquid at the liquid temperature within the separation zone while maintaining a pressure on the particles prior to decoupling at or above the vapor pressure of the liquid within the separation zone.