2results about "Cascade evaporators" patented technology

Provided is a method for concentrating a sodium hydroxide aqueous solution including: in a stepwise concentration process of sodium hydroxide aqueous solution, including a concentration part in which a plurality of evaporators from a first evaporator to a nth evaporator are connected in series, adding a sodium hydroxide aqueous solution to the first evaporator and then performing evaporation to obtain a first sodium hydroxide concentrate, and recovering steam evaporated from the sodium hydroxide aqueous solution; and adding the first sodium hydroxide concentrate to an evaporator at a subsequent stage, and adding the steam recovered from the first evaporator to a mechanical vapor recompression device to perform compression, wherein the nth evaporator uses the compressed steam as a heat source.

A method for concentrating an aqueous sodium hydroxide solution is provided, comprising: in a stepwise concentration process of an aqueous sodium hydroxide solution including a concentration section comprising a first evaporator to an nth evaporator connected in series, adding the aqueous sodium hydroxide solution to the first evaporator, then evaporating it to obtain a first sodium hydroxide concentrate, and recovering the vapor evaporated from the aqueous sodium hydroxide solution; and adding the first sodium hydroxide concentrate to a subsequent evaporator, and adding the vapor recovered from the first evaporator to a mechanical vapor recompression device for compression, wherein the nth evaporator uses the compressed vapor as a heat source.