Patent ID: 6848373

Claim:
A method of measuring heat flux and corrosion in a furnace of the type having a wall containing a plurality of tubes, adjacent pairs of tubes connected by a web, a front side of each tube and web being exposed to heat and products of combustion generated in the furnace and a back side of each tube and web not exposed to said heat and products of combustion, the method comprising: a) measuring a first heat flux temperature on the back side of a selected tube; b) measuring a second heat flux temperature on the back side of a web adjacent to the selected tube; c) determining a difference between the first heat flux temperature and the second heat flux temperature; d) periodically repeating steps a through c to determine subsequent differences between the first heat flux temperature and the second heat flux temperature; e) comparing subsequent differences to at least one previously determined difference; and f) correlating any increase in compared differences to slag melt and indicative of corrosive conditions in the furnace.