Continuous process and apparatus for drying and gel formation of gelable and solvent containing polymers

Solvent containing polymers, especially polysaccharide derivatives, e.g. hot aqueous cellulose ether suspensions, are dried by flash cooling at 0.1-800 hPa. Independent claims are included for: (1) a process in which polymer containing 1-65 %, preferably 10-40 %, solids at a pressure of 6000 hPa and a temperature of 20-100[deg]C, preferably 30-95[deg]C is introduced into an evaporation zone (1) where the pressure is 0.1-800 hPa, preferably 40-200 hPa. The polymer is cooled to 29-60[deg]C and the solvent released by stirrers (8). The solid is removed by a screw feeder to a drier (2) where the solvent content is reduced to 5 %wt; and (2) equipment comprises an evaporator vessel (3) with a stirrer (8), vapor removal (5) and vacuum plant (13). The bottom flights (10) of the stirrer are 5 mm above the exit leading to a screw conveyor.