Azadeh Mirvakili

One of the effective methods for reducing fuel consumption in furnaces is the utilization of surplus gases in petrochemical complexes. In the steam methane reforming furnace of Zagros Petrochemical Plant, 1252 kmol/h of fuel is consumed for syngas production of which 115 kmol/h is methane and the remainder consists of surplus process gases. This study investigates the effect of changing the fuel composition in the reformer furnace of Zagros Petrochemical Complex on its performance and syngas production. The furnace and catalytic tubes were simulated using computational fluid dynamics (CFD) and validated against industrial data. Five scenarios for the fuel composition using surplus process gases were defined and analyzed. Results showed that while the furnace outlet gas temperature remained stable (within ±5 K) due to similar fuel lower heating values, changing the fuel composition significantly impacted the combustion pattern, flame length, and radiative heat transfer proportion. Scenarios with a higher hydrogen fraction produced a shorter flame where convective heat transfer was dominant. In contrast, increasing the methane content resulted in a longer flame and a higher share of radiative heat transfer. Consequently, Case 5, with a 16% reduction in natural gas consumption and an approximately 2% increase in hydrogen production, was identified as the optimal fuel composition. This study concludes that using surplus process gases as furnace fuel requires careful consideration.