Process and apparatus for recovering clean water and solids from aqueous solids

A process for the recovery of clean water and substantially dry, fluidizing oil-free solids from aqueous solids dehydrated in a light fluidizing oil medium comprising the steps of (1) admixing aqueous solids with a low viscosity, relatively volatile, water-immiscible light fluidizing oil boiling within the range of from about 150.degree. F. to about 550.degree. F. to obtain a mixture which will remain fluid and pumpable after the removal of the water content therefrom;

• (2) subjecting the resultant oil-containing mixture of dehydration by heat evaporation whereby substantially all the water and part of the light fluidizing oil are vaporized yielding a mixed water and light oil vapor and a substantially anhydrous solids in oil slurry;
• (3) condensing said mixed water and light oil vapor;
• (4) separating the resultant condensate into a clean water fraction and a light oil fraction;
• (5) separating at least some of the relatively volatile, water-immiscible light fluidizing oil from said substantially anhydrous solids in oil slurry, and (6) bringing the resultant solids carrying residual light fluidizing oil into direct contact with blowing steam to thereby remove said light oil from said substantially anhydrous solids by heat evaporation;
• said aqueous solids being originally associated with a heavy, relatively non-volatile oil, said heavy oil being extracted from said solids by said light fluidizing oil in separation step (5) with said separated light oil and extracted heavy oil being divided into a light oil fraction and a heavy oil fraction, and said light oil fraction and the separated light oil fraction of step (4) being combined and admixed with fresh aqueous solids and recycled through the process as fluidizing oil whereby the substantially anhydrous solids of step (6) have a reduced heavy oil content.

An apparatus for recovering clean water and substantially dry, fluidizing oil-free solids from aqueous solids dehydrated in a light fluidizing oil medium, said apparatus comprising (1) a tank adapted to receive a stream of said aqueous solids and provided with a stirring or mixing mechanism, (2) a light fluidizing oil reservoir, (3) means for transmitting light fluidizing oil from said light oil reservoir to said tank wherein said light fluidizing oil and aqueous solids may be mixed, (4) an evaporator, (5) a conduit extending from said tank to said evaporator wherethrough may flow a stream of aqueous solids admixed with light fluidizing oil from said tank into the evaporating region of said evaporator, (6) a condenser, (7) a conduit extending from said evaporator to said condenser through which may flow a mixture of water vapor and light oil vapor formed as a result of heating of said aqueous solids and light fluidizing oil mixture, (8) an oil-water separating means, (9) a conduit extending from said condenser to said oil-water separating means wherethrough may flow a mixed condensate of water and light oil, (10) means for separately withdrawing light oil and clean water from said oil-water separating means, (11) a conduit extending from said withdrawing means to said light fluidizing oil reservoir wherethrough may flow a stream of light oil, (12) a liquid-solid separating means, (13) a conduit extending from said evaporator to said liquid-solid separating means wherethrough may flow a stream of a slurry of substantially anhydrous solids in light fluidizing oil, (14) a deoiler means, (15) a conduit extending from said liquid-solid separating means to said deoiler means wherethrough may flow a stream of solids carrying residual light fluidizing oil, and (16) a conduit extending from said liquid-solid separating means to said light fluidizing oil reservoir wherethrough may flow a stream of light oil.