Perpustakaan Digital ITB

In the nickel laterite RKEF process, the reduction kiln is a central unit with substantial fuel usage and cost implications. Therefore, efficient and stable burner operation is crucial. The burner’s atomizer nozzle geometry strongly affects flame development. This study uses computational fluid dynamics (CFD) to analyze the flame profile in a representative reduction-kiln burner, focusing on how variations in outer nozzle hole count and slope angle modify the flame. The objectives are to quantify flame length, width, and peak temperature with various outer nozzle designs, and to identify the optimal nozzle configuration for PT X’s kiln. Three-dimensional models of the reduction kiln with integrated burner system were built in AutoCAD and ANSYS SpaceClaim, and simulations were run and post-processed in ANSYS FLUENT and CFD-Post. The simulations assumed a diesel-fueled diffusion flame (non-premixed combustion) in an axi-symmetrical fluid region model (45° sector). Parametric cases combined outer nozzle hole count of 4, 12, and 20 with slope angles of 35°, 45°, and 55°, resulting in 9 simulation cases. Key outputs were flame length, flame width, and peak flame temperature. Model validation included convergence checks (criteria below 10?3) and stable flame temperature after 4000 iterations, consistent with theoretical flame trends. The longest, widest, and hottest flames were recorded at 0.812 m, 4.184 cm, and 1773 K, respectively, and were produced by the 20-hole at 35°, 4-hole at 55°, and 4-hole at 35° outer nozzles, in that order. Results show that increasing the hole count produces a longer flame with lower peak temperature and slightly reduced width, whereas increasing the slope angle yields a shorter, wider flame with lower peak temperature. Among all cases, the 20-hole nozzle at 35° produced the longest, most stable flame with controlled width and the lowest peak temperature. This optimal configuration ensures stable, axially directed flames near the burner, which are crucial for delivering heat and CO to downstream reduction reactions in real-world operation.