【作者】 秦伟；

【导师】 成有为；

【作者基本信息】 浙江大学 ， 化学工程与技术， 2020， 硕士

【摘要】 精对苯二甲酸(PTA)是生产聚对苯二甲酸乙二酯(PET)的重要原料。PTA生产工艺的物耗、能耗和排放情况是PTA工厂的核心竞争力。因此,发展节能、低耗、减排PTA新型生产工艺具有重要的意义。本文根据现有的PTA生产工艺,提出了 PX氧化+多级精馏耦合的新工艺,即在反应器顶部增设多级脱水塔,获取不同醋酸浓度的水溶剂用于洗涤液和排放废水,并利用反应热直接脱水,减少了物耗、能耗和废水排放。本文对PX氧化+多级精馏耦合工艺的全过程进行了设计和模拟,包括以下内容:(1)采用Aspen Plus软件构建了三种PTA工艺流程。结果表明,氧化+多级精馏耦合工艺通过物料的合理配置,溶剂的梯次化利用,在减少物耗和废水排放方面具有显著优势。进一步优化了脱水塔工艺条件,并对塔设备进行选型和设计。(2)考察了氧化和精制单元的系统集成方案。比较了 RPF+酸洗+干燥和RPF+水洗的技术方案,优化了压滤机的操作参数;对PTA精制母液回流方案进行了可行性分析,提出水循环流程,模拟并分析了该流程的水耗、PX物耗和醋酸单耗等指标。(3)对PTA生产工艺提出了进一步的节能降耗方案:分析了 4-CBA和MA含量对燃烧副反应的影响,建立了 4-CBA和MA含量与PX物耗和醋酸单耗的模型。分析了醋酸甲酯的生成机理,模拟和计算了 PTA新工艺的MA回收单元,对关键汽提塔进行计算和选型。更多还原

【Abstract】 Purified terephthalic acid(PTA)is an important raw material for the production of polyethylene terephthalate(PET).The consumptions and emissions of the PTA process are the core competitiveness of PTA plant.Therefore,it is of great significance to develop a new energy-saving,low-consumption and emission-reducing PTA process.According to the existing PTA process,this work proposed a new PX oxidation process coupled with multistage distillation,i.e.multi-stage dehydration towers was added at the top of the oxidation reactor.The obtained water solvents could be used as the washing water,and the oxidation heat could be used as dehydrate energy.Therefore energy consumption and the wastewater discharge of the process was reduced greatly.A full process modeling and flowsheeting for PTA production process was completed,and the specific contents included the following:(1)Comparing three different integrated PX oxidation and dehydration processes,it was shown that the oxidation+dehydration coupling process could greatly reduce the consumption of energy,deionized water and raw material,i.e.directly using the oxidation heat as the rectification heat source,and the refined mother liquor as the dehydration tower reflux.The process parameters of the dehydration towers were optimized and the tower equipment was designed.(2)The oxidation and refining unit was integrated.Schemes of RPF+acid washing+drying and RPF＋water washing were compared,and the operating parameters of the filter was optimized.The feasibility analysis of the refined mother liquor reflux was investigated and the water circulation was proposed.Then the indexs of water consumption,PX material consumption and acetic acid consumption of the PTA process was simulated and analyzed.(3)Energy-saving and consumption-reducing plans were proposed.The effect of 4-CBA and methyl acetate(MA)concentration on combustion reactions was analyzed,and the function of PX and acetic acid consumption on the 4-CBA and MA concentration were obtained.The formation mechanism of the MA were analyzed,and the MA recovery unit(the key stripping towers)were calculated and designed.更多还原