METHOD FOR REGENERATING STEAM

PURPOSE:To reduce the use of steam of a boiler for heating a new adsorption tank in case of exchanging a used tank to the new one by accompaning heat accumulated in the used adsorption tank and in activated carbon during desorption together with raw gas and leading it to an evaporator and recovering it as a heat for evaporating soft water incorporated in the evaporator. CONSTITUTION:When desorption of a first adsorption tank 11 is finished, raw gas 21 is slowly sent thereinto through a by-pass line 31 of a duct for raw gas and heat accumulated in the adsorption tank and in activated carbon during desorption is allowed to flow to an evaporator 16. In the evaporator 16, soft water is forcedly circulated with a circulation pump 17 of soft water and heated to evaporation temp. by recovered heat. After sufficiently recovering heat, a by-pass valve 13 of the by-pass line 31 of the duct for raw gas of the first adsorption tank is fully opened and an inlet valve 14 for raw gas is fully opened and desorption of a second adsorption tank 12 is started and the steam generated in the evaporator 16 is fed to the adsorption tank by a steam ejector 18 even during preheating time of the adsorption tank.