Claus Waste Heat Boiler Economics – Pay Me Now or Pay Me Later
Through a newly developed rate-based heat transfer and chemical reaction model of the Waste Heat Boiler, quantitative behaviour of the WHB and how it subtly impacts SRU plant performance can be predicted based on the recombination reactions that occur at the front of the WHB.
Radiative heat transfer, coupled with the exothermic recombination reactions, collectively increase the peak heat flux at the front of the boiler well above predictions from models that ignore or discount these factors. Tube wall temperatures, pressure drop, and heat flux predictions from the model are examined down the length of the tubes for oxygen-enriched vs. air-only operations. Elevated tube wall temperatures well downstream of the area protected by ceramic ferrules for the higher mass velocity cases is demonstrated, backing up documented failures in the industry. The implications of sulfidic corrosion and the resulting impact on boiler tube life and sulfur plant reliability economics are examined with this new information.