Simulation of sulfur furnace combustion using CFD approach

Abstract

In the sulfuric acid manufacturing process, Sulphur is burned to form Sulphur dioxide SO2 that then undergoes conversion to Sulphur trioxide SO3. The combustion happens in a large horizontal chamber which is a cylindrical vessel of carbon steel lined internally with refractory and insulation bricks. The chamber has two air inlets, one for primary air and another for the secondary one which is injected into the furnace after the initial combustion of Sulphur and is consumed in the conversion stage. The efficiency of this equipment is affected by scaling problems which may be caused by particle impurities inducted with liquid Sulphur in the inlet or caused by erosion of baffle walls. The present work contains CFD (Computational Fluid Dynamics) modeling and simulations of the hydrodynamic reacting flows in the furnace. The analysis and diagnosis of the CFD results have made it possible to determine the deep causes of those problems, which are mainly caused by the temperature gradients existing on both sides of the baffle walls. CFD results were validated against theoretical findings and recommendations have been proposed to improve the performance of the furnace.