A method 1 further comprising {HEAD ~ a step} of condensing the vapor generated during the concentration of the black liquor by using water as {TAIL ~ a condensing medium}, and said water generates steam that is taken to pre heat the combustion air 
A method 1 further comprising { HEAD ~ a step } of condensing the vapor generated during the concentration of the black liquor by using water as { TAIL ~ a condensing medium } , and said water generates steam that is taken to pre heat the combustion air
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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH