Process for purifying sulfur oxides-containing gas

A process for purifying a gas containing sulfur dioxide and impurities comprising sulfur trioxide, ammonia and halogen compounds which comprises:

• feeding a feed gas containing sulfur dioxide and impurities comprising sulfur trioxide, ammonia and halogen compounds to a first water washing column;
• feeding first water to said first water washing column into effective contact with said feed gas under conditions sufficient to cool said feed gas and to wash halides and ammonia from said feed gas to form a first gaseous effluent comprising water and washed feed gas;
• causing said first gaseous effluent to be at a temperature sufficient to maximize the water content thereof, and avoiding supercooling of said first gaseous effluent;
• forming a first water effluent, comprising water and said washed out halides and ammonia, from said first water washing column;
• without substantially cooling said first water effluent, recycling water from said first water effluent as a portion of said first water;
• feeding said first gaseous effluent to a second water washing column;
• feeding second water, which is at a lower temperature than said first water, to said second water washing column into effective contact with said first gaseous effluent under conditions sufficient to cool said first gaseous effluent, to thereby condense water from said first gaseous effluent, to wash halides and ammonia from said first gaseous effluent, and to thereby form a second gaseous effluent comprising sulfur dioxide and less of said impurities, and a second water effluent comprising water and said washed out impurities;
• passing said second gaseous effluent out of said second water washing column;
• passing said second water effluent out of said second water washing column;
• cooling said second water effluent;
• recycling a portion of said cooled second water effluent to said first water such that said first water consists essentially of first water effluent and second water effluent;
• recycling the remainder of said cooled second water effluent to said second water washing column such that said second water consists essentially of second water effluent;
• and
• adding substantially no fresh water to the process.