A laboratory differential Simulation method is used for the design of carbonization columns at coal-tar processing in which phenols are regenerated from phenolate Solution by carbon dioxide absorption. The design method is based on integration of local absorption rates of carbon dioxide along the column. The local absorption rates into industrial phenolate Mixture are measured in a laboratory model contactor for various compositions of the gas and liquid phases under the conditions that ensure the absorption Fates in the laboratory absorber simulate the local rates in the industrial Column. This condition is the same value of physical liquid-side mass transfer coefficients in the laboratory model contactor and in the absorption column. As the model contactor a stirred cell is used in which the interfacial area is well defined. By using an auxiliary surface stirrer the Values of the physical mass transfer coefficient are extended Lip to the values encountered in packed absorbers. In experiments. carbon dioxide was absorbed into industrial phenolate mixture containing Na-phenolate of the phenol-mixture of the following approximate composition: phenol 44%, o-cresol 9%, p-cresol 10%, m-cresol 15%, 2,4-xylenol 2%, 2,5-xylenol 1%, 2,6-xylenol 0.5%. 2,3-xylenol 0.5%, 3,4-xylenol 1%. 3,5-xylenol 2%, o-ethyl-phenol 0.5%, m-ethyl-phenol 2%, p-ethyl-phenol 1.5%, others 11%. The experiments were performed in the following ranges of temperature 50-90 degrees C and pressure 100-700kPa. An explicit formula correlating the absorption rates with carbonization of phenolate solution, partial pressure of carbon dioxide and temperature was derived which facilitated an assessment of various technological variants. On the bases of the Calculations, two-step carbonization columns were designed for 30000 t/year of the phenolate solution treatment by carbon dioxide. The absorption proceeds at higher pressure of 500 kPa and temperatures from 50 to 65 C. pure carbon dioxide is Used and toluene is added. These conditions have the following favourable effects: (i) significant size reduction of the Columns, (ii) it is possible to process more concentrated solutions without danger of silting the columns by crystallization of NaHCO3 on the packing. (iii) small amount of inert gas is released; from environmental standpoint. this process arrangement represents an encapsulated technology without harmful influence on environment, (iv) lower alkalinity and better separability of the organic phase (phenols with toluene) from water phase (soda or bicarbonate solution) in separators. (C) 2008 Elsevier B.V. All rights reserved.