SALT EXTRACTION FROM HYDROGEN-SULFIDE SCRUBBER SOLUTION USING ELECTRODIALYSIS

The buildup of undesirable sulfur compounds (sulfates and thiosulfates ) reduces the scrubbing effectiveness of the LO-CAT I autocirculation sulfur recovery process from acid-gas stream, Among various processes, withdrawing and disposing of a portion of the scrubber solution and r eplacing this ''blowdown'' with fresh solution have been the practice in the industry. The application of the electrodialysis system to recy cle the blowdown is presented, Experiments were carried out using elec trodialysis to separate salts (sulfates and thiosulfates) from the LO- CAT I autocirculation scrubber solution containing organic chelating a gents, il on, and various alkali-metal inorganic salts. The results in dicated that the electrodialysis was successful in removing 50% of the salts fi om the scrubber solution with less than. 8% loss of organic and 8% loss of carbonates. The fluxes of the undesired salt species we re high even at low current densities (200 to 400 A/m(2)).