regenerating {HEAD ~ nitrogen dioxide}, in a second zone of said voloxidation vessel, by reacting oxidizing gas comprising {TAIL ~ nitrogen monoxide} and oxygen at a temperature ranging from 0 80° C., wherein said first zone and said second zone are separate 
regenerating { HEAD ~ nitrogen dioxide } , in a second zone of said voloxidation vessel , by reacting oxidizing gas comprising { TAIL ~ nitrogen monoxide } and oxygen at a temperature ranging from 0 80 ° C. , wherein said first zone and said second zone are separate
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH