| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiple-effect evaporator in which the purity of the purified water to be obtained can be prevented from being lowered even in the case of an auto-vapor compression type multiple-effect evaporator using impurity-containing high-pressure steam.SOLUTION: The multiple-effect evaporator is constituted so that an evaporation canister 1 for heating raw water by boiler steam to obtain steam is disposed in multiple stages and the steam generated in the evaporation canister 1D of an intermediate stage is sucked in an ejector 13 to compress/supply the sucked steam to the evaporation canister 1A of the previous stage thereof. The evaporation canister 1D of the intermediate stage, to which an auto-vapor compression method is applied, comprises: a suction steam-exclusive evaporation canister 1Da, the steam of which to be generated therein is introduced into the ejector; and a normal evaporation canister 1Db, the steam of which to be generated therein is not introduced into the ejector. A steam passage 3 of the suction steam-exclusive evaporation canister is connected to a suction part 13a of the ejector by a steam suction pipe 20 and a heat transfer pipe 4a of the evaporation canister of the previous stage is connected to the suction steam-exclusive evaporation canister by a condensed water transfer pipe 16, so that the steam of the evaporation canister one-stage previous to the suction steam-exclusive evaporation canister is introduced into both of the suction steam-exclusive evaporation canister and the normal evaporation canister through a steam introduction pipe 14. |
