Abstract 1. A CONTINUOUS PROCESS FOR PURIFYING A GASEOUS STREAM DERIVED FROM FUEL COMBUSTION AND CONTAINING SULFUR DIOXIDE BY REMOVING THEREFROM SUBSTANTIALLY ALL OF THE SULFUR DIOXIDE BY A PROCESS WHICH COMPRISES: (1) FEEDING THE IMPURE GAS STREAM INTO A FIRST ZONE; (2) CONTACTING SAID IMPURE GAS STREAM AT A TEMPERATURE OF ABOUT 130 TO 180* C., IN SAID FIRST ZONE, WITH A CONCENTRATED AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE TO AT LEAST PARTIALLY DEHYDRATE SAID CONCENTRATED AQUEOUS SOLUTION, TO REMOVE A SUBSTANTIAL PORTION OF SOLID PARTICLES FROM SAID IMPURE GAS STREAM AND TO BRING THE TEMPERATURE OF SAID IMPURE GAS STREAM TO 45 TO 60* C.; (3) FEEDING THE RESULTING GASEOUS STREAM FROM STEP (2) INTO A SECOND ZONE; (4) COUNTERCURRENTLY CONTACTING SAID RESULTING GAS STREAM IN SAID SECOND ZONE WITH A FIRST AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE TO FORM A SECOND AQUEOUS SOLUTION CONTAINING SULFURIC ACID AND FERROUS SULFATE AND A PURIFIED GAS STREAM SUBSTANTIALLY FREE OF SULFUR DIOXIDE; (5) SEPARATING SAID SECOND AQUEOUS SOLUTION INTO A FIRST AND A SECOND PORTION; (6) ADDING IRON OR AN IRON COMPOUND TO ONLY SAID FIRST PORTION IN AN AMOUNT SUFFICIENT TO NEUTRALIZED THE SULFURIC ACID CONTAINED THEREIN TO FORM A THIRD AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERROUS SULFATE; (7) COMBINING SAID THIRD AQUEOUS SOLUTION AND SAID SECOND PORTION AND OXIDIZING THE COMBINED AQUEOUS SOLUTION BY CONTACTING SAID COMBINED AQUEOUS SOLUTION WITH A GAS CONSISTING OF AIR ONLY, SAID OXIDATION BEING CONDUCTED IN THE PRESENCE OF SULFURIC ACID DUE TO THE SULFURIC ACID REMAINING IN SAID SECOND PORTION; (8) WITHDRAWING A PORTION OF THE RESULTING OXIDIZED AQUEOUS SOLUTION AS A CONCENTRATED AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE AND FEEDING IT TO SAID FIRST ZONE AS SAID CONCENTRATED SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE; AND (9) FEEDING THE REMAINING PORTION OF THE RESULTING OXIDIZED AQUEOUS SOLUTION TO SAID SECOND ZONE AS SAID FIRST AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE; AND (10) REPEATING STEPS (1) THROUGH (9) TO OBTAIN A CONTINUOUS PROCESS.
A CONTINUOUS PROCESS FOR PURIFYING A GASEOUS STREAM DERIVED FROM FUEL COMBUSTION AND CONTAINING SULFUR DIOXIDE BY REMOVING THEREFROM SUBSTANTIALLY ALL OF THE SULFUR DIOXIDE BY A PROCESS WHICH COMPRISES: (1) FEEDING THE IMPURE GAS STREAM INTO A FIRST ZONE; (2) CONTACTING SAID IMPURE GAS STREAM AT A TEMPERATURE OF ABOUT 130 TO 180* C., IN SAID FIRST ZONE, WITH A CONCENTRATED AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE TO AT LEAST PARTIALLY DEHYDRATE SAID CONCENTRATED AQUEOUS SOLUTION, TO REMOVE A SUBSTANTIAL PORTION OF SOLID PARTICLES FROM SAID IMPURE GAS STREAM AND TO BRING THE TEMPERATURE OF SAID IMPURE GAS STREAM TO 45 TO 60* C.; (3) FEEDING THE RESULTING GASEOUS STREAM FROM STEP (2) INTO A SECOND ZONE; (4) COUNTERCURRENTLY CONTACTING SAID RESULTING GAS STREAM IN SAID SECOND ZONE WITH A FIRST AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE TO FORM A SECOND AQUEOUS SOLUTION CONTAINING SULFURIC ACID AND FERROUS SULFATE AND A PURIFIED GAS STREAM SUBSTANTIALLY FREE OF SULFUR DIOXIDE; (5) SEPARATING SAID SECOND AQUEOUS SOLUTION INTO A FIRST AND A SECOND PORTION; (6) ADDING IRON OR AN IRON COMPOUND TO ONLY SAID FIRST PORTION IN AN AMOUNT SUFFICIENT TO NEUTRALIZED THE SULFURIC ACID CONTAINED THEREIN TO FORM A THIRD AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERROUS SULFATE; (7) COMBINING SAID THIRD AQUEOUS SOLUTION AND SAID SECOND PORTION AND OXIDIZING THE COMBINED AQUEOUS SOLUTION BY CONTACTING SAID COMBINED AQUEOUS SOLUTION WITH A GAS CONSISTING OF AIR ONLY, SAID OXIDATION BEING CONDUCTED IN THE PRESENCE OF SULFURIC ACID DUE TO THE SULFURIC ACID REMAINING IN SAID SECOND PORTION; (8) WITHDRAWING A PORTION OF THE RESULTING OXIDIZED AQUEOUS SOLUTION AS A CONCENTRATED AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE AND FEEDING IT TO SAID FIRST ZONE AS SAID CONCENTRATED SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE; AND (9) FEEDING THE REMAINING PORTION OF THE RESULTING OXIDIZED AQUEOUS SOLUTION TO SAID SECOND ZONE AS SAID FIRST AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE; AND (10) REPEATING STEPS (1) THROUGH (9) TO OBTAIN A CONTINUOUS PROCESS.
Claim 2
Dependent Claim
332 words
A CONTINUOUS PROCESS FOR PURIFYING A GASEOUS STREAM DERIVED FROM FUEL COMBUSTION AND CONTAINING SULFUR DIOXIDE BY REMOVING THEREFROM SUBSTANTIALLY ALL OF THE SULFUR DIOXIDE BY A PROCESS WHICH COMPRISES: (1) FEEDING THE IMPURE GAS STREAM INTO A FIRST ZONE; (2) CONTACTING SAID IMPURE GAS STREAM AT A TEMPERATURE OF ABOUT 130 TO 180* C., IN SAID FIRST ZONE, WITH A CONCENTRATED AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE TO AT LEAST PARTIALLY DEHYDRATE SAID CONCENTRATED AQUEOUS SOLUTION, TO REMOVE A SUBSTANTIAL PORTION OF SOLID PARTICLES FROM SAID IMPURE GAS STREAM AND TO BRING THE TEMPERATURE OF SAID IMPURE GAS STREAM TO 45 TO 60* C.; (3) FEEDING THE RESULTING GASEOUS STREAM FROM STEP (2) INTO A SECOND ZONE; (4) COUNTERCURRENTLY CONTACTING SAID RESULTING GAS STREAM IN SAID SECOND ZONE WITH A FIRST AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE TO FORM A SECOND AQUEOUS SOLUTION CONTAINING SULFURIC ACID AND FERROUS SULFATE AND A PURIFIED GAS STREAM SUBSTANTIALLY FREE OF SULFUR DIOXIDE; (5) SEPARATING SAID SECOND AQUEOUS SOLUTION INTO A FIRST AND A SECOND PORTION; (6) ADDING IRON OR AN IRON COMPOUND TO ONLY SAID FIRST PORTION IN AN AMOUNT SUFFICIENT TO NEUTRALIZED THE SULFURIC ACID CONTAINED THEREIN TO FORM A THIRD AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERROUS SULFATE; (7) COMBINING SAID THIRD AQUEOUS SOLUTION AND SAID SECOND PORTION AND OXIDIZING THE COMBINED AQUEOUS SOLUTION BY CONTACTING SAID COMBINED AQUEOUS SOLUTION WITH A GAS CONSISTING OF AIR ONLY, SAID OXIDATION BEING CONDUCTED IN THE PRESENCE OF SULFURIC ACID DUE TO THE SULFURIC ACID REMAINING IN SAID SECOND PORTION; (8) WITHDRAWING A PORTION OF THE RESULTING OXIDIZED AQUEOUS SOLUTION AS A CONCENTRATED AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE AND FEEDING IT TO SAID FIRST ZONE AS SAID CONCENTRATED SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE; AND (9) FEEDING THE REMAINING PORTION OF THE RESULTING OXIDIZED AQUEOUS SOLUTION TO SAID SECOND ZONE AS SAID FIRST AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FERRIC SULFATE; AND (10) REPEATING STEPS (1) THROUGH (9) TO OBTAIN A CONTINUOUS PROCESS.