合成技术及应用

[目的]针对聚对苯二甲酸丁二醇酯(PBT)酯化工艺塔在50%负荷工况下塔顶1,4-丁二醇(BD)含量异常升高的问题,[方法]本文基于非平衡级(速率级)传质理论,采用Aspen Plus中的RadFac模块建立了严格的酯化工艺塔模型,并利用50%与80%两种操作负荷下的工业运行数据对塔板温度分布及关键组分含量进行了验证。[结果]结果表明,模拟值与实测值吻合良好,所建模型能够准确反映酯化工艺塔的分离性能,具有较高的可靠性。在此基础上开展塔板水力学核算发现,50%负荷工况下塔板存在漏液风险,是引起塔顶BD含量升高的主要原因。工艺参数灵敏度分析表明,抑制塔顶BD含量升高的有效措施依次为:提高液相进料负荷、增大回流比、降低塔顶操作压力或降低塔釜温度。然而,上述调整均以增加装置能耗为代价,需在分离效率与能耗经济性之间进行权衡。[结论]研究结果可为PBT酯化塔的优化运行、故障诊断及扩能改造提供定量化的理论依据与决策支持。

[Objective] To address the abnormal increase in 1,4-butanediol(BD) content at the top of the poly butylene terephthalate(PBT) esterification process column under 50% load conditions,a rigorous column model was developed based on nonequilibrium-stage(rate-based) mass transfer theory using the RadFrac module in Aspen Plus.[Methods] The model was validated against industrial operating data at both 50% and 80% load conditions with respect to tray temperature profiles and key component concentrations.[Results] Good agreement between simulated and measured values confirmed that the model accurately reflected the separation performance of the esterification column with high reliability.Tray hydraulic calculations subsequently revealed a weeping risk under the50% load condition,which was identified as the primary cause of the elevated BD content at the column top.Process parameter sensitivity analysis indicated that the effective countermeasures,in order of priority,were increasing the liquid feed load,raising the reflux ratio,and reducing the top operating pressure or reboiler temperature.However,all these adjustments entail increased energy consumption,necessitating a trade-off between separation efficiency and energy economy.[Conclusion]The findings provide quantitative theoretical support and decision-making guidance for the optimized operation,fault diagnosis,and capacity expansion of PBT esterification columns.