Advanced process control of an ethylene cracking furnace

Abstract

The ethylene production plant is one of the most important units in petrochemical industry, and the ethylene cracking furnace is the heart of the plant. The ethylene cracking furnace is a multivariable, strong coupling, and nonlinear process, and therefore, it is difficult to be manipulated by traditional proportional-integral-derivative controls. This paper reports a real application of advanced process control in five 470-kton/year SC-I tubular reactors. The advanced process control deployed includes cracking outlet temperature control and feed volume control. This control system has been operating since 2012. The variation of cracking outlet temperature has been reduced from ±5 to ±1 C with a setting time less than a few minutes even under a large-scale disturbance. The variation of feed volume has been controlled within ±1%. As a result, the advanced process control system has achieved a total production increase by 0.3%.