中文摘要：

运用流程模拟软件PRO/Ⅱ进行甲苯歧化（TDP）过程模拟,构造新鲜进料和补充进料预热过程的能级-热量（ε-Q）图,对进料预热过程进行热力学分析,发现存在不合理混合、重复冷却升温和大温差换热火用损。应用夹点分析估算2股进料的理论换热终温,确定换热流程优化调整目标,通过热联合及低温余热利用,对冷热物流进行合理匹配,极大减小了过程火用损。分析表明,改造后2股进料混合火用损分别减小54.1%、16.3%,冷热升温火用损减小40.1%,大温差火用损减小25.0%,2股进料换热终温分别提高了9.0℃、22.3℃,加热炉及加热器负荷相应降低,各环节均表现出较大的节能潜力。经济分析表明换热器的投资费用为94639.84$,节能效益约为126750.49$,投资回收期为0.75年,效果明显。

英文摘要：

The process of toluene disproportionation（TDF） was simulated by the process simulation system of PRO/H.The energy level and heat duty（ε-Q） diagrams of fresh feed and supplemental feed preheating processes were constructed.Based on the thermodynamic analysis,it was found that there were more exergy destructions from mixing,repeated cooling and heating processes and large temperature differences in the heat exchange process for feed preheating.The pinch analysis was introduced to estimate the theoretical final temperature of the two feeds,which determines the optimal goal of the heat exchange process by using the heat integration and low-temperature heat utilization.The cold and hot streams were reasonably matched,which greatly reduced the exergy destructions of the two feeds＇ preheating process.The analysis results showed that the mixing exergy destructions of the two feeds were reduced 54.1%andl6.3%,respectively.The exergy destructions resulted from the repeated cooling and heating were reduced 40.1%,and the exergy destructions of heat exchange processes with large temperature differences were reduced 25.0%after retrofit.The final preheating temperatures of the two feeds were increased by 9.0 ℃and12.3 ℃respectively.The heat duty of the furnace and heater were reduced.Economic analysis showed that the investment cost of heat exchangers was about 94639.84 $,and the cost of energy saving was about 126750.49 $.The payback period was 0.75 years,which demonstrates that the retrofit＇s profit is notable