Process for producing maleic anhydride

Claim 1

A CONTINUOUS PROCESS FOR THE CONVERSION OF MALEIC ACID TO MALEIC ANHYDRIDE COMPRISING PASSING AN AQUEOUS SOLUTION OF MALEIC ACID RAPIDLY THROUGH AN EVAPORATOR, WHEREIN THE CHARGE IS HEATED TO A TEMPERATURE OF ABOUT 125-140* C. SO AS TO CAUSE A PARTIAL VAPORIZATION OF UP TO ABOUT 85% OF THE CHARGE, PASSING THE PARTIALLY VAPORIZED CHARGE INTO A COMBINATION CONDENSER AND SEPARTOR, WHEREIN THE CHARGE IS COOLED TO A TEMPERATURE GREATER THAN ABOUT 120* C. BUT NOT GREATER THAN ABOUT 130* C., WHEREIN THE VAPORIZED WATER IS SEPARATED FROM THE MIXTURE OF MALEIC ACID SOLUTION AND MALEIC ANHYDRIDE, PASSING SAID MIXTURE RAPIDLY THROUGH A SECOND EVAPORATOR; WHEREIN THE CHARGE IS HEATED TO A TEMPERATURE OF ABOUT 160*-175* C. SO AS TO CAUSE A PARTIAL VAPORIZATION OF UP TO ABOUT 50% OF THE CHARGE, PASSING THE PARTIALLY VAPORIZED CHARGE INTO A COMBINATION SECOND CONDENSER AND SEPARTOR, WHEREIN THE CHARGE IS COOLED TO A TEMPERATURE BETWEEN ABOUT 130*-160* C., WHEREIN THE VAPORIZED WATER IS SEPARATED FROM THE MIXTURE OF MALEIC ACID AND THE MALEIC ANHYDRIDE, PASSING THE MIXTURE RAPIDLY THROUGH A THIRD EVAPORATOR WHEREIN THE CHARGE IS HEATED TO A TEMPERATURE OF ABOUT 180*-195* C., SO AS TO CAUSE A PARTIAL VAPORIZATION OF UP TO ABOUT 50% OF THE CHARGE, PASSING THE PARTIALLY VAPORIZED CHARGE INTO A THIRD COMBINATION CONDENSER AND SEPARATOR, COOLED SUFFICIENTLY SO AS TO REDUCE THE TEMPERATURE OF THE CHARGE TO BETWEEN ABOUT 160-190* C., WHEREIN THE VAPORIZED WATER RELEASED FROM THE MALEIC ACID IN ITS CONVERSION TO MALEIC ANHYDRIDE IS SUBSTANTIALY COMPLETELY REMOVED AND RECOVERING A SUBSTANTIALLY PURE MALEIC ANHYDRIDE.