| Aromatic hydrocarbons are important organic chemical raw materials,with the increased demand of the aromatic,refineries often transform the catalytic reforming units to increase the output of aromatics.In this paper,which combined with 800,000tons/year aromatics distillation renovation project,I use two methods to simulate the new process.One is the conventional two-tower process,the other is the dividing wall column process.Then,I calculate the energy consumption and the annual operating cost of each process.At last,I compare the annual cost and operative difficulty of the process.The separation system of the bottom oil from decarburization six tower is a non-polar system,which is also a real material system.I choose the P-R equation to calculate the process.And I use the Aspen plus software to simulate this process.After the calculation of decarburization seven tower and xylene tower,we find the decarburization seven tower has 44 stages,the feed stage is the 18thstage,reflux ratio is1.5905;the xylene tower has 58 stages,the feed stage is the 26thstage,the reflux ratio is6.7623.The total reboiler duty of the two towers are 12089kw,the total condenser duty of the two towers are 14648kw.In order to save the energy,we use the bottom logistics of the decarburization seven tower which needs to be heated to change heat with the top logistics of the xylene tower which needs to be cooled.We find this process can decrease 40.996%total condenser duty and 34.1%total reboiler duty of the two towers.Then we calculate the process of the dividing wall column,and optimized the reflux ratio,number of stages and feed stage of the plate tower.We find that the dividing wall column process can save 2 stages,20.73%reboiler duty and 7.94%condenser duty compared with the non heat-exchange process.At last,we compared the TAC（annual operating cost）of the different process,.Then we find that the dividing wall column process has a 2.73%higher annual operating cost compared with the two-tower process. |
PDF Full Text Request