Process for recovering sulfur dioxide from gases

Abstract

Abstract THE DISCLOSURE IS OF AN IMPROVEMENT IN A SULFUR DIOXIDE REMOVAL PROCESS WHEREIN A SULFUR DIOXIDE-CONTAINING GAS IS CONTACTED WITH AN AQUEOUS ABSORBING SOLUTION OF A METAL SULFITE, E.G, SODIUM SULFITE, TO YIELD A SPENT ABSORBING SOLUTION OF METAL BISULFITE, AND THE LATTER IS DECOMPOSED TO PRODUCE THE SULFITE, SULFUR DIOXIDE AND WATER, WITH WATER AND SULFUR DIOXIDE BEING EVAPORATED AND SULFITE BEING PRECIPITATED FROM SOLUTION, THE DECOMPOSITION IS CONDUCTED WHILE ADDING HEAT TO THE METAL UNDERGOING DECOMPOSITION BY THE USE OF INDIRECT HEAT EXCHANGE BETWEEN THE MATERIAL WHICH IS PASED THROUGH THE TUBES OF THE HEAT EXCHANGER, AND A HEAT-SUPPLYING MEDIUM IN CONTACT WITH THE EXTERIOR SURFACES OF THE TUBES. THE OPERATION IS PARTICULARLY CHARACTERIZED BY THE PRESENCE OF AT LEAST ABOUT 25 WEIGHT PERCENT UNDISOLVED SOLIDS IN THE MATERIAL UNDERGOING DECOMPOSITION, PREFERABLY AMOUNT 30 TO 50 WEIGHT PERCENT. A PORTION OF THE MATERIAL UNDERGOING DECOMPOSITION AND CONTAINING SULFITE CAN BE RECYCLED TO THE ABSORPTION STEP TO SERVE AS A SOURCE OF AQUEOUS ABSORBING SOLUTION. PREFERABLY, THIS RECYCLSTREAM IS FORMED BY ADDING WATER TO A PORTION OF THE MATERIAL UNDERGOING DECOMPOSITION WITHOUT SEPARATION OF SIGNIFICANT AMOUNTS OF UNDISSOLVED SOLIDS.

Inventors

• 👤 C Earl
• 👤 F Hughes

Bibliographic Details