Dynamic Model Of Dividing Wall Column And Its Research And Application In Aromatics Separation Process

Most of the aromatic hydrocarbon mixtures originate from the catalytic reforming of heavy naphtha in refineries.Aromatic hydrocarbons such as benzene,toluene and xylene are important chemical raw materials.Rectification is currently the main means of separating large-scale aromatic hydrocarbon mixtures in China.However,traditional rectification technology is in low thermodynamic efficiency and high energy consumption.It is a hot topic in the chemical industry to explore effective technologies to saving energy in distillation.As a rectification energy-saving technology,the dividing wall column can not only improve the thermodynamic efficiency of the distillation process,reduce energy consumption,but also reduce the investment and the maintenance costs of the rectification unit.In this paper,a separation device of an aromatic hydrocarbon mixture with an annual output of 84,000 tons is taken as a research object,and the original process is modified by using a dividing wall column.In this paper,a strict model of the dividing wall column for steady-state simulation is established.The structural parameters of the dividing wall column are preliminarily established using the simplified model of the three-tower,and the steady-state simulation and optimization of the new separation process of the dividing wall distillation column is carried out.At the same time,the influence of the partition wall heat transfer of the dividing wall column on the separation process was analyzed.The results show that in the separation process,considering heat transfer of the partition wall is saving energy about 0.29%compared with ignoring heat transfer of the partition wall.Finally,by comparing the separation process of the dividing wall column with the original conventional two-column rectification sequence process,the use of the dividing wall column can save the total energy consumption about 24.35%,and can save the energy consumption of the reboiler about 25.48%.In order to study the dynamic characteristics of the separation process of the dividing wall column,a dynamic model suitable for the process is also established.The control scheme was analyzed and studied according to the actual process requirements.The disturbance analysis of the feed amount and the feed composition is carried out,through the response curve,the system can return to a stable state under different disturbances.The results show that the control scheme selected in this paper is reasonable,and the new process of dividing wall column with separation of aromatics mixture has controllability.