(174d) CFD Modeling of Coke Calcination Rotary Kiln for Troubleshooting and Operation Optimization

In Petroleum industry, Coke Calcination is a process of producing Calcined Petroleum Coke from Green Coke (raw petroleum coke) and the process is carried out in a large energy intensive rotary kiln (> 3m diameter and >60 m length for instance). The Calcined product is sold to aluminum and steel industry where it is used to make carbon anode for their smelting processes. In Coke Calcination Unit of Project A, repeated failure of the Rotary Kiln inner refractory lining and castables were detected which frequently interrupted the initial operating years after commissioning. Determining root case of the failures and adjusting the unit to safe operating condition was a paramount concern. To this end, Computational Fluid Dynamics (CFD) model of the Coke Calcination Rotary Kiln was developed to simulate the kiln operation and get insights of the phenomena occurring inside the kiln. Analysis revealed that excess fine content (more than 20%) in feed made the process sensitive to other process operating variables and when subjected to overly excess combustion air supply and improper control of firing hood pressure, undesired combustion pattern and flame shapes were produced whose repeated occurrence caused the refractory failures. Optimal range of operating variables for stable operation was recommended based on operation optimization.