Modeling of heat transfer and pyrolysis reactions in ethylene cracking furnace based on 3-D combustion monitoring

• A distributed parameter model of an ethylene cracking furnace was established.
• The tube temperature reaches the maximum of 1088 °C.
• The tube temperature distribution was validated by a spectrometer system.

In this paper, a distributed parameter model for tubular reactor in the ethylene cracking furnace based on 3-D temperature reconstruction is developed. The mathematical model was formulated to predict the distributions of the heat flux and the tube temperature while considering a non-uniform distribution of the surface heat transfer and the ethylene pyrolysis process. The results show that the heat flux distribution on the tubular reactor has four high heat flux zones, and the tube temperature reaches a maximum of 1088 °C. The value of the maximum tube temperature decreases compared with the value of the maximum heat flux due to the heat exchange coefficient of pyrolysis gas increasing slowly in the bend region. The tube temperature distribution was validated by using a spectrometer system and the errors between three major product yields at the tube outlet obtained by the proposed model and in-situ measured values were within 5%. This distributed parameter model can be used as a guide for ethylene cracking furnace operators and as a tool for design.