Process for purifying sulfur oxides-containing gas

摘要

Impurities such as halides and ammonia are efficiently removed from a gas containing Sox at a high concentration without any substantial addition of fresh water in a process for purifying a sulfur oxides-containing gas. The process involves passing a gas containing sulfur oxides and impurities at a high concentration successively through a first washing column and thence through a second washing column, thereby water washing the gas through the two washing columns to remove the impurities from the gas. The first washing column is operated so that the outlet temperature of the gas from the first washing column is at a temperature at which the gas can have a maximum water content or a temperature near this temperature, and the second washing column is operated such that the outlet temperature of the gas from the second washing column at least 20 DEG C. lower than the outlet temperature of the gas from the first washing column.