PURPOSE: To make most of the heat energy to be consumed recoverable by drying a solid material in a turbulent drier which swirls evaporable substances in the form of steam to separate into a dried substance and steam and condensing the steam.

CONSTITUTION: A fixed material such as brown coal, peat and filter cake obtained by mechanical separation or a solid material such as sludge containing not more than 98 vol.% of an evaporable substance and especially water is fed from a feed zone 1 to a turbulent bed drier 2 where the solid material is indirectly heated and a turbulent bed 6 containing the solid material to be turbulently treated with a swirling medium of the evaporable substance in the form of steam is formed, and a dried substance is led from a solid material-leading apparatus 4 and the steam containing a gaseous substance of the evaporable substance, gaseous impurities and a component volatilizable at a temperature of not higher than the boiling point of the evaporable substance within the solid material is led from a leading conduit 8, cooled and condensed to separate an incondensable component and an insoluble component within the condensate of the evaporable substance and then discharged into the air or introduced into a deodorizing treatment zone and/or another gas purifying treatment zone.