Chicago Bridge & Iron Technical Services Company

James H Richardson

Gerald E Engdahl

Matloob Husain

William S Schoerner

A method of removing contaminants from an aqueous waste stream comprising feeding a contaminated aqueous liquid to the lower internal space of a feed tank and cooling the liquid in the tank to a temperature which results in precipitation of at least part of the contaminants; withdrawing the precipitated contaminants from the feed tank lower internal space; withdrawing aqueous liquid from the feed tank upper internal space and delivering it to a freezer; cooling the aqueous liquid in the freezer to convert at least part of the liquid to ice to produce an aqueous ice slurry; feeding aqueous ice slurry from the freezer to an aqueous ice slurry receiver; withdrawing aqueous ice slurry from the aqueous ice slurry receiver and recycling some of it to the freezer and some of it to the lower internal space of the feed tank; withdrawing aqueous ice slurry from the aqueous ice slurry receiver and delivering it to a central space of a separator-precipitate vessel; withdrawing aqueous ice slurry from the central space of the separator-precipitate vessel and delivering it to a lower internal space of an ice washer vessel; withdrawing precipitated contaminants from the lower internal space of the separator-precipitate vessel; washing the ice in the washer vessel and removing the washed ice therefrom; and withdrawing cold ice wash water from the washer vessel. The details of the apparatus used in the method are also disclosed.

Freeze concentration and precipitate removal system

A method and apparatus for cooling a warm feed stream of aqueous liquid to close to but above the freezing point of the aqueous liquid and delivering it to a mixing tank; withdrawing an aqueous ice slurry from an ice slurry receiver-crystallizer and delivering it to the mixing tank to further cool the contents and produce temperature control of the mixing tank contents; withdrawing an aqueous slurry from the mixing tank and delivering it to a slurry thickener tank for precipitate separation thereof; removing the precipitate from the slurry thickener tank and disposing of it; withdrawing aqueous liquid from the thickener tank and delivering it to the ice slurry receiver-crystallizer; and withdrawing an aqueous ice slurry from the ice slurry receiver-crystallizer, feeding it through a freeze exchanger to produce additional aqueous ice slurry and withdrawing the aqueous ice slurry from the freeze exchanger and feeding it to the ice slurry receiver-crystallizer. A single feed tank can be used in place of the mixing tank and the thickener tank.

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Aurora, IL, United States of America

James H Richardson