低碳烷烃脱氢丙烯精馏系统优化设计

Optimization of propylene distillation system in light alkane dehydrogenation plant

通过对某60万t/a烷烃脱氢装置丙烯精馏系统进行分析发现,设计中采用的塔板效率过低是造成塔的操作能耗偏高的主要原因。选取塔板效率95%,通过PROII软件对此精馏塔进行模拟,在实际塔板数不变的情况下,回流比可降低至18.76,塔顶和塔釜热负荷可分别降低至-428.0 MkJ/h、437.2 MkJ/h。在此基础上对温水系统进行改进,可取得节省2 772.4万元投资和节省操作费用768万元/a的效果,同时简化了操作流程。

Based on the analysis to the propylene distillation system of a 600 000 t/a PDH plant, it is found that the low efficiency of the trays employed in the design results in excessive energy-consumption in the operation of the distillation tower.By selecting 95% as tray efficiency, the propylene distillation tower is simulated through PROII software.Result shows that the reflux ratio can drop to 18.76,the duty of tower condenser and reboiler can decrease to-428.0 MkJ·h-1and 437.2 MkJ·h-1respectively while the actual number of trays remains unchanged.On this basis, the warm-water system is modified, which can save RMB 27 724 000 of cost and RMB 7.68 million per year of operating cost.