Patent ID: 8434241

Claim:
A method for drying a pasty wet material, which comprises a dry material (TS) admixed with a liquid to be distilled (Fd), using a gas-tight container system that is resistant to excess and/or negative pressure, said container system comprising a drying container with the wet material the temperature of which can be adjusted, where the liquid turns to vapor, a condenser for condensing the vapor to give a condensate as well as a vapor chamber connecting the drying container and the condenser, wherein the vapor chamber is provided with a pressure sensor for measuring a mixed pressure (pm) established therein, a temperature sensor for measuring the mixed temperature (Tm) established therein and a pressure regulator, the method including the following process steps: a) the drying container with the wet material is brought to a first temperature (T 1 ), and the condenser to a second lower temperature (T 2 ); b) the mixed pressure (pm) and the mixed temperature (Tm) are measured; c) the saturation vapor pressure (ps) of the liquid (Fd) at the measured mixed temperature (Tm) is determined; d) a set-pressure range is calculated, which is limited by a lower pressure limit (p 1 ), which is at least 0.1% above the saturation vapor pressure (ps) and an upper pressure limit (p 2 ), which is at the most 6% above the saturation vapor pressure (ps); e) the mixed pressure (pm) is compared with a set pressure range; f) the mixed pressure (pm) is reduced by the pressure regulator exactly until it has reached the lower pressure limit (p 1 ); g) the steps a) to e) are repeated, until the mixed pressure (pm) has reached the upper pressure limit (p 2 ); h) the steps f) and g) are repeated until the drying is to be stopped; wherein during pressure reduction in step f) gases at the end of a condensation pathway in the condenser are sucked off to remove foreign gas from the container system as much as possible and wherein the method runs in a continuous operation.