Extending Furnace Runlength and Performance with Modeling

The requirement for achieving the highest efficiency and maximum output from existing ethylene facilities is increasing with world-scale crackers coming online. Balancing yield, efficiency, and availability of ethylene furnaces is now much easier with the technology tools that are available. A combination of commercially available simulation software for steady state and kinetic modeling and software for empirical-based modeling can be effectively applied in combination to provide ongoing insights for improved operation. These tools are not a substitute for Advanced Process Control and Real Time Optimization but a helpful addition that can increase furnace throughput substantially while improving both yield and efficiency.

Several case studies show that achieving between 5 to 20% increase in throughput can often be achieved by utilizing readily available technology tools. Radiant section heat flux models and yield models are useful for adjusting burners to maximize run length and achieve production targets. A recent software tool in Furnace simulation Coilsim1D has been found to be extremely robust and effective. Applying Coilsim1D along with HTRI for the convection section has allowed yield maximization with run length extension. Then utilizing multivariate statistical techniques, effects on feed-stock variation can be quickly analyzed so that profitability can be maximized. The case studies to be covered discuss the technology utilized and the results found in several ethylene facilities.