It is a characteristic feature of the invention that {HEAD ~ the air} fed to {TAIL ~ at least one air level} is preheated by using vapor generated in the concentration of the black liquor as heat source 
fed to
It is a characteristic feature of the invention that { HEAD ~ the air } fed to { TAIL ~ at least one air level } is preheated by using vapor generated in the concentration of the black liquor as heat source
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH