Controller 5 with {TAIL ~ input} from flowmeter 6 and output to control valve 7 acts to control the flow of {HEAD ~ an oxygen} reducing agent such as an alkaline sulfite 11, with sodium sulfite being preferred, to maintain an operator selectable ratio of reducing agent flow 11 to flow of stream 1 
Controller 5 with { TAIL ~ input } from flowmeter 6 and output to control valve 7 acts to control the flow of { HEAD ~ an oxygen } reducing agent such as an alkaline sulfite 11 , with sodium sulfite being preferred , to maintain an operator selectable ratio of reducing agent flow 11 to flow of stream 1
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH