| 摘要 |
PURPOSE:To enable stable recovery of heat from high temperature corrosive atmosphere exhaust gas, containing sodium sulfate and sodium carbonate, or potassium sulfate in a sodium recovery boiler for a long time, by a method wherein heat transfer tubes made of Ti or a heat transfer tubes made of a Ti based alloy, e.g., Ti-Pd, are used. CONSTITUTION:Exhaust gas, e.g., SOX, H2S and HCl, produced resulting from analysis of black liquid and partial combustion and containing sodium sulfate and sodium carbonate, or dust, e.g., potassium sulfate, is introduced to a heat exchanger 4. A heat transfer tube bundle 9, spanned between two headers 10 and 11 of a heat exchanger, is formed with heat transfer tubes, made of Ti or a Ti radical alloy, e.g., Ti-Pd, and this constitution results in remarkable prevention of the occurrence of usual corrosion by SOX and H2S through the presence of sodium sulfate and sodium carbonate or potassium sulfate, and in the possibility to use the heat transfer tube for a long time. Further, this constitution can reduce gap corrosion, occurring at a gap between the tubes and the two headers 10, 11 or a support plate 12 when steam is condensed on the surface of the heat transfer tube on the low temperature side, corrosion, occurring as a result of condensate producing an HCl solution, and corrosion on the high temperature side due to the use of a heat transfer tube made of Ti based alloy, e.g., Ti-Pd, and permits decrease of a rise in a price.
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