Process and apparatus for sulfuric acid production

Claim 1

A PROCESS FOR THE INTENSIVE MANUFACTURE OF SULPHURIC ACID FROM SULPHUROUS GASES, AIR AND WATER, EMPOLOYING NITROGEN OXIDE AS REACTION ACCELERATORS, WHICH COMPRISES, CIRCULATING THROUGH A SERIES OF AT LEAST THREE REACTORS AN ACID CONTAINING FROM 75 TO 80% OF H2SO4 AND AT LEAST 3.5% OF NITROGEN OXIDES, CALCULATED AS N2O3, WHILE MAINTAINING THE COMPOSITION OF SAID ACID SUBSTANTIALLY THE SAME IN ALL OF SAID REACTORS, INTRODUCING A PORTION OF SAID ACID OF THE SAME COMPOSITION INTO A DENITRATOR, INTRODUCING SULPHUROUS GASES AND AIR INTO SAID DENITRATOR, IN CONTACT WITH SAID ACID, CAUSING THE GASES LEAVING SAID DENITRATOR TO PASS THROUGH THE SAID REACTORS IN SERIES WHEREBY TO FROM SULPHURIC ACID IN LIQUID PHASE, LEADING A CONTROLLED AMOUNT OF GAS DIRECTLY FROM THE NITRATOR TO AT LEAST ONE OF SAID REACTORS OTHER THAN THE FIRST AND LAST IN THE SERIES, PASSING THE GASES NOT ABSORBED BY SAID ACID INTO A RECOVERY TOWER, WITHDRAWING DENITRATED ACID FROM SAID DENITRATOR AND CAUSING IT TO PASS THROUGH THE RECOVERY TOWER IN CONTACT WITH SAID GASES, WITHDRAWING ACID FROM SAID RECOVERY TOWER AND INTRODUCING IT INTO SAID DENITRATOR IN CONTACT WITH THE INCOMING SULPHUROUS GASES, AIR AND WATER, THE QUANTITIES OF ACID CIRCULATING THROUGH THE DENITRATOR AND THE REACTORS BEING SUCH THAT THE MOLECULAR RATIO BETWEEN THE NITROGEN OXIDES IN THE ACID, CALCULATED AS N2O3, AND SO2 IS GREATER THAN 2,5 TO 1.