| Ethylene is one of the most main organic chemical raw materials; ethylene industry holds a crucial status in national economy. At present, tubular furnace is used to produce ethylene almost all over the world, and cracking raw materials tends to become more diversified and heavier. In this paper, by establishing thermodynamics models and equipment models, process simulation technology is used to study the ethylene production process from light diesel oil cracking, providing a theoretical guidance for the operation and optimization of industrial facility. Specific research work is included as follows:First, a real-components cutting technology is used to analyze the composition of light diesel oil fraction. To establish the dynamic model of hight diesel oil cracking furnace, a set of real components are determined to fit the distillation data of light diesel oil fraction as well as its by-product fraction effectively.Second, by fully understanding the law of hydrocarbon cracking, based on the molecular reaction model proposed by Zong-xiang Wang, a light diesel oil cracking reaction network is established, including first reactions and secondary reactions, which then is used for further the study on cracking reaction mechanism. Steady state simulation is conducted for the whole process of cracking.Third, based on the result of steady state process simulation, a real-time dynamic simulation is performed for the key equipment, cracking furnace, to determine the optimal operating condition for cracking furnace.Fourth, the paper analyzes some factors that have an impact on the yield of ethylene, such as cracking furnace outlet temperature, residence time and ratio of dilution steam, the process condition for ethylene yield maximization is obtained. Finally, the best location of feed plate is determined, together with the reflux ratio for main products towers, such as ethylene distillation column and propylene distillation column. |
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