Multi-scale modeling of Claus thermal furnace and waste heat boiler using detailed kinetics

• A detailed kinetic scheme is developed to characterize the Claus furnace.
• H2S/O2 flame is simulated with good accuracy.
• Simple reactor network is adopted to handle non-idealities of Claus furnace.
• The multi-scale (kinetic and reactor scales) model is validated on different industrial cases.

The modeling of thermal reaction furnaces of Sulfur Recovery Units (SRUs) is a rather complex problem since it involves different modeling scales such as the kinetic/molecular scale, the reactor scale, and the chemical process scale. This work introduces the multi-scale modeling approach to characterize the kinetic and reaction engineering scales for the thermal section of SRUs, involving the reactor furnace and the waste heat boiler. Specifically, also the waste heat boiler is modeled using detailed kinetics to characterize the recombination effects, which cannot be neglected any longer since they significantly influence the outlet compositions. The proposed models are validated on experimental and literature data for the kinetic scale. The reactor scale is validated on the industrial data coming from SRUs operating in Nanjing and Mumbai plants.