Solid-liquid separation process for combining multiple-effect evaporation and agitated evaporation

Abstract

A solid-liquid separation process, comprising the following steps: A. concentrating an aqueous solution or a mixed solution in water-organic solvents containing soluble solids at a low concentration to give a medium-concentrated mixed solution; B. discharging the medium-concentrated mixed solution into a stirring evaporation kettle (9), and further concentrating same by evaporation to give a high-concentrated mixed solution; and C. controlling the solid content of the high-concentrated mixed solution to ensure that same is discharged out of the stirring evaporation kettle (9) in the liquid form; returning the vapour generated in step B to the multi-effect evaporation system and heating the liquid while the vapour phase is condensing, such that the heat is recovered and the recovery of the solution is ensured. The high-concentrated mixed solution discharged in the liquid form in step C is cooled and solidified.

Description

technical field [0001] The invention relates to a process method for solid-liquid separation using multi-effect evaporation combined with stirring evaporation, which belongs to the technical field of chemical engineering and process solid-liquid separation, and specifically relates to a solid-liquid solution of a water-organic solvent mixed solution containing low-concentration soluble solids. liquid separation process. Background technique [0002] Separation of soluble substances from solutions is a common chemical problem. According to the solubility of the soluble matter in the solvent, generally adjusting the temperature, pH, solution concentration and other parameters can achieve the purpose of soluble matter precipitation. Direct evaporation of solution is a simple and direct method to achieve solid-liquid separation by changing the concentration of solute in the solution, but the problem of direct evaporation is high energy consumption, and the solid content increas...

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Problems solved by technology

Direct evaporation of solution is a simple and direct method to achieve solid-liquid separation by changing the concentration of solute in the solution, but the problem of direct evaporation is high energy consumption, and the solid content increases with the precipitation of solute in the solution during the evaporation process It is easy to cause fouling and blockage of equipment

[0003] In addition, as the solid content concentration increases, the equilibrium partial pressure of the liquid decreases, which will also lead to a decrease in the efficiency of multi-effect evaporation.

[0004] In addition, for the solid-liquid separation operation, the Chinese patent CN101152969, by adding additives, adds acid to the concentrated solution to precipitate to obtain a solid-liquid mixture, and then separates the mixture from the solid-liquid, and the treatment process is relatively complicated; Use a centrifugal separator, but for materials with too small crystal particles, centrifugal separation may not be applicable

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