GB511250A - A process for recovering phenols from waste waters and apparatus for use in carrying same into effect - Google Patents

Abstract

511,250. Extracting phenols. ADLER, R Nov. 19, 1938, No. 33708. [Class 2 (iii)] To remove phenols from liquids, e.g., waste water from gas, coke, charcoal or power gas plants, the, liquids are passed through a layer of active carbon from which adsorbed phenols are therefrom recovered by extraction with a normally liquid organic solvent. used at a temperature far above its normal boiling point and at such an increased. pressure that its evaporation is prevented. The phenol is then recovered by evaporation of the solvent, either after reducing the solution to normal temperature and pressure or by reduction of the pressure on the,hot solution.;,;The increased temperature .and pressure, reduces the amount of phenols left in the active 'carbon which has therefor a longer life. Due to the increased pressure, a finely powdered, active carbon may be used and smaller apparatus with smaller quantities of solvent. Suitable solvents are, benzene, alcohols or chlorinated hydrocarbons. Phenol containing water is pumped by pump B into adsorber A<1> and thence into adsorber A<2> containing active carbon arid discharged at 3. When the carbon in adsorber A<1> is saturated with phenols it is extracted and the adsorbers are then changed round. The solvent is evaporated at C, condensed at D and pumped by pump E, via tube 7, leading through water separator G and heater F, to the. adsorber which is to be extracted. After extraction the phenol laden solvent passes through a pressure reducing valve H and cooler J to evaporator C wherein the solvent is again evaporated for further use while phenols are drained off by cock 10. Solvent is driven off from the extracted adsorbers by steam introduced. by pipe 11. A branch from this pipe may pass to evaporator C to provide the heat needed there. In a modification, in place of elements C, Hand J an expansion chamber K, Fig. 2, is provided. The hot phenol laden solvent under pressure enters this chamber by pipe 8 with regulating valve M. Solvent is vaporized and leaves by pipe 6 for condenser D while phenols or phenol-water mixture separates and is drained off by cock 13. A liquid trap L prevents phenol passing into tube 6. A safety valve N is provided. Specification 448,712 is referred to.