Energy-use analysis and optimization for a continuous catalytic reforming unit

摘要

The continuous catalytic reforming unit consumes a large amount of energy in upgrading of naphtha to produce high-octane reformate,benzene-toluene-xylene and liquefied petroleum gas.To identify the potential of energy savings and then propose corresponding improvements to the process are crucial for better energy-use efficiency.In this paper,energy-use analysis and optimization to a domestic continuous catalytic reforming unit are performed by using three-link energy structural model as well as energy grade-heat load(ε-Q)diagram.The results show that poor design of the heat exchanger network(HEN)and inappropriate column operation are the bottlenecks of energy-use.Low-temperature cold streams are directly preheated by the high-temperature hot streams,and the large heat transfer temperature difference between them causes large exergy destruction.Moreover,repeated heating or cooling along the stream additionally introduces unreasonable exergy destruction.By using software PRO/II,the feeding temperature,fractionating columns pressure and the feed location are optimized for operation improvement.Overall,our optimized process decreases the energy requirement by about 7％as compared to that of the original unit,which suggests that the applied strategies are beneficial to the future design and operation of continuous catalytic reforming unites.