Investigating the Performance of CO Boiler Burners in the RFCC Unit with CFD Simulation

Abstract

The combustion chamber's internal refractory in Imam Khomeini Oil Refinery Company (IKORC) was damaged in several parts, requiring operating conditions and re-inspecting the design of the combustion chamber using CFD. Simplify the combustion chamber 3D simulation, decrease in the number of calculations, the symmetry principle was applied in the simulation. The results, independent of the mesh network, were investigated via increasing the mesh nodes. The one-stage, two-stage, multi-stage and overall mechanisms, which were designated, were examined and compared to actual measured data and a calculation error of less than 8% was obtained. Ultimately, selecting overall mechanisms, the simulation results, streams mixing and length of the chamber were scrutinized, and as a result, the current design was approved. The temperature and velocity of the flows in the combustion chamber were investigated. In the combustion chamber, the farther we are from the burners, the more uniform the velocity and temperature profiles also become as the wall temperature increases. The rate of combustion reaction was evaluated with the temperature of different points in the combustion chamber. The results showed that the combustion chamber wall's temperature is in the appropriate range and has not suffered any thermal damage. Unlike the combustion chamber wall, the burner wall (at the mixing point) has an unauthorized temperature; there is the possibility of thermal damage that can be eliminated by changing the number of currents. Unsuitable thermal profiles also showed large amounts of oxygen in the exhaust gas indicated that the steam boiler performance is far from the optimal condition and specific changes would be required in the air streams. Streamline demonstrated that the primary air stream was more effective for decreasing CO and NOX amounts in the outlet stream. The secondary air stream was also significant to prevent thermal damage to the internal coating and reduce safety hazards.