Influence of O₂ enrichment in dry air on combustion temperature, contaminant production and sulfur recovery, in SRU reaction furnace

Process difficulties such as low temperature in Claus reaction furnaces result in the deactivation of catalysts and thus darken the color of produced sulfur. Combustion temperature of the reactor is a key factor that directly influences the sulfur recovery and emission of contaminants. To solve this problem, the influence of O₂ enrichment in dry air on the amount of the produced sulfur, contaminants and reaction furnace temperature was investigated in Abadan Oil Refinery with commercial Ansys Fluent software. The k‑ε, eddy dissipation and P1 models were used to model turbulent flow, combustion and radiation respectively. Besides, the numerical predictions of reactor temperature and mole fraction of products were validated with experimental data. The O₂ enrichment was done in three cases by assuming moisture-free inlet air. As the O₂ concentration is increased, the combustion temperature increases uniformly and the sulfur recovery reaches its maximum in high O₂ concentration. Moreover, with high O₂ concentration, the amount of contaminants such as COS and CS₂ decrease significantly. A six step chemical kinetics was used for the purpose of numerical simulation, which yielded more accurate predictions in comparison to previous works.