| 摘要 |
PURPOSE:To obtain purified tar acid, by dissolving tar acid recovered from a coke oven in water as Na salt, washing the tar acid Na salt with gas oil as solvent in a plurality of runs, and removing high-boiling tar bases at a high removal rate. CONSTITUTION:Crude tar acid recovered from a coke oven is dissolved in water as Na salt. The obtained aqueous solution of the tar acid sodium salt is introduced into the first washing tank and washed with part of a solvent comprising gas oil to extract and remove high-boiling tar bases contained in the solution. Next, the solution and the gas oil are separated from each other utilizing a difference in their specific gravities and the solution is introduced into the second washing tank and washed with gas oil, After that, a plurality of washing runs with gas oil are carried out in the same manner, and hence the high-boiling tar bases are removed at a high removal rate to obtain a purified aqueous solution of tar acid sodium salt.
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