PET聚酯工艺塔的模拟优化

针对生产企业关于PET聚酯工艺塔塔顶凝液EG含量更苛刻的需求,采用化工模拟软件Aspen plus V10,选取NRTL-RK热力学模型,对聚酯工艺塔进行了模拟计算,并和现场数据进行校验,在此基础上,完成了工艺塔的优化分析,结果表明:回流温度控制在55～60℃、回流比1.3、塔板数增加到21～22块,工艺塔顶凝液EG含...     

酯化工艺塔EG循环量对酯化工艺的影响

改变酯化工艺塔EG循环量，测试工艺塔回流水中的非水分（有机物）含量，酯化热井中EG水含量及切片中端羧基和DEG含量，探讨酯化EG循环量变化对酯化反应的影响，为更高负荷生产扩展空间。     

PET生产EG分离塔塔顶蒸汽潜热回收利用

介绍了PET生产中EG分离塔和蒸发器工艺流程,指出了工艺塔存在巨大能源浪费,通过对装置的改造,将EG分离塔顶蒸汽潜热回收利用到EG蒸发器补给EG的预热。结合生产实际,通过理论计算解决了流体在管程中为层流状态下换热器类型的选择。     

甲胺污水处理塔的工艺改进

甲胺是一甲胺、二甲胺、三甲胺的通称,它被广泛用于生产农药、药品、溶剂、染料和促进剂等,是重要的有机化工中间体。主要工艺是原料在合成中经连续气化胺化反应得到粗胺,然后冷却送精馏工离分离。精 馏工序由五塔精馏组成,粗胺先在脱氨塔精馏,塔顶采出氨－三甲胺共沸物,塔底粉排至萃取塔。萃取塔用软水做萃取剂,塔顶采出无水三甲胺,塔底料排入脱水塔。脱水塔顶是一甲胺、二甲胺混合物送至分离塔进一步分离,得到无水一甲胺、二甲胺。脱水塔底含甲胺和甲醇的污水排至甲醇回收塔,在其顶部回收甲醇和甲胺,塔底排出废水。甲醇回收塔分离效果的好坏直接影响甲醇消耗,严重是甚至会造成环境污染。现将近几年加强工艺控制、减少污水中甲醇排放的具体措施介绍如下。     

新型填料塔技术在环己烯-环己烷萃取精馏塔中的应用

采用新型填料塔技术和新的工艺流程,对原环己烯分离塔系统进行改造,改造后环己烯分离塔塔顶环己烯从6．5％下降到4．0％,环己烯回收塔塔顶环己烷从3．5％—4％下降到2．5％,环己烯纯度从95％提高到97％以上．本次改造提供了一种萃取精馏塔扩能改造的新思路——更改部分工艺,提高提馏段效率。     

吉玛聚酯装置工艺塔的模拟分析和扩容改造

对吉玛聚酯装置工艺分离塔的操作工艺进行了模拟计算分析 ,采用导向浮阀塔板对该塔的内构件进行了改造。经实际操作考核 ,改造后的工艺塔处理量较原工况提高 3 0 % ,塔顶乙二醇含量由 0 8%～ 1%降至 0 3 %左右。     

浅述蒸馏四塔的优化操作

影响蒸馏四塔正常生产的原因在于原工艺参数设计不合理，将该塔顶、中、釜温度分别定为４８℃、６６℃和７２℃，可将馏出液ＶＡｃ含量和釜出液、ＭｅＯＡｃ含量同时控制在５％以下。     

甲醇双塔精馏流程的模拟与分析

应用ASPEN PLUS化工模拟系统中的RADFRAC塔精馏模块对甲醇双塔精馏过程进行模拟。分别讨论了操作回流比、进料位置、塔顶馏出量等参数对甲醇精馏过程的影响,获得了对高纯度甲醇精馏具有指导意义的相关工艺数据。模拟结果表明,该双塔流程生产出的精甲醇产品纯度高、水含量和乙醇含量低,并且该双塔模型能耗低,操作稳定、灵活。     

立体传质塔板在聚乙烯醇生产中的应用研究

采用立体传质塔板对聚合二塔、聚合三塔进行技改设计，技改后大幅度地提高了塔的生产能力、分离效率．塔顶馏出甲醇纯度达99．5％以上．可多回收甲醇5．76吨／年，三塔回流比进一步下降，从而降低了能耗和原材料消耗．     

超精镏塔的控制探讨

精馏过程一般要求将物料分成两股(塔顶馏分和塔底馏分)。当被分离的甲、乙两组分相对挥发度较小,而产品的质量要求比较高,则属于超精馏范畴。超精馏的特点是塔板数较多,回流比较大,操作控制要求较高。由于塔顶馏分和塔底馏分必须符合一定的质量要求,因此按塔顶和塔底两端的质量指标(通常是温度)同时进行控制。本文探讨了超精馏体系的控制特点。并指出,当按塔顶和塔底两端的质量指标同时进行控制时,对超精馏体系来说,存在着某些不需要对塔顶和塔底这两个调节方案进行解耦处理的有利条件。减压操作精馏塔分离沸点为152℃的甲组分(异丙苯)和沸点为164℃的乙组分(α-甲基苯乙烯),进料中异丙苯浓度为55%左右,塔顶余压100毫米汞柱,回流比9左右,塔板数70块。该塔运转中,流体力学的滞后时间短,而组成变化     

DMT间歇装置的PTA半连续工艺改造

通过对 2种工艺路线的热负荷计算 ,确定改造后的设备变动情况。合理地增加酯化釜的加热面积、酯化塔的高度 ,保证了酯化反应的正常进行及EG和水的分离效果。在其他设备相应配套改动后 ,PTA路线的产品质量比DMT路线有较大的改善。     

聚酯工艺塔废水中乙二醇含量分析

用色谱法（内标法）对聚酯工艺塔酯化废水中乙二醇含量进行了测定。介绍了色谱法的仪器条件、测试过程。结果表明,数据的精密度和准确度均较好,色谱法相比于手工滴定法,测定简单、准确度高,测定结果平行性好,避免了滴定法中使用剧毒物质亚砷酸钠带来的安全隐患。     

Surface adsorption and the effect of column diameter in the continuous foam separation process

Foam separation has been investigated as a technique for removing ethylhexadecyldimethylammonium bromide, a cationic surfactant, from dilute solutions. An ideal foam model has been used to determine the surface excess accumulated at the solution-air interface and to predict the foam and drain concentration in a continuous foam separation process. It was found that the model was valid only under conditions of good drainage and perfect foam stability. An increase in column diameter for a feed of constant composition and supplied at a constant rate increased the concentration of the surfactant in the overhead stream. This highly desirable effect was accompanied by an increase in the drain rate. The results indicate that an increase in column diameter had an entirely beneficial effect on the efficiency of the separation.     

聚酯工艺副产蒸汽余热在制冷上的利用

介绍了副产蒸汽制冷系统的工艺流程、系统特点,并列举了工程应用实例。聚酯工程的纺丝车间的空调用冷量都比较大,通过溴化锂吸收式制冷机,利用从乙二醇分离塔产生的副产蒸汽余热制取冷冻水供空调使用,可以节约能源,降低产品能耗。     

Ethylene glycol purification by melt crystallization:Removal of 2-methoxyethanol impurity

The coal (syngas)-to-ethylene glycol (CTEG),is contaminated with the naughty impurity 2-Methoxyethanol (ME) generated during the hydrogenation stage,which affect the quality of EG for fiber-grade polyester production.Distillation,is the employed separation process in industrial,which makes production complicated because of the heat sensitivity of the impurities system.Melt crystalliza-tion has been regarded as an effective technology to obtain high-purity organic compounds based on the melting points difference,which could avoid the problems by heating.In this work,we have explored the feasibility of the static melt crystallization on the separation of EG/ME in a jacketed crystallization tube.The experimental parameters were investigated,which covers crystallization and sweating stage in each step.The results showed that the purity of EG could reach ≥99.8％ from the binary system studied via the quaternary separation process.     

HDPE/expanded graphite nanocomposites prepared via masterbatch process

High Density Polyethylene (HDPE) was melt extruded with different amounts of expanded graphite (EG) based masterbatches. Conductive composites were obtained by diluting PE and PS masterbatches with 60 wt% content of expanded graphite. These masterbatches were readily dispersed into the molten HDPE matrix yielding well‐dispersed HDPE/EG nanocomposites which couldn't be done by direct melt extrusion process under the same conditions. Electrical conductivity measurements showed a reduced percolation threshold by this masterbatch filling technique while the resulting composites were 2–3 orders of magnitude lower than that of direct melt extrusion because EG sheets were effectively encapsulated by PE or PS carriers in these masterbatches which leads to a better EG dispersion in composites. Both scanning electron microscopy (SEM) and X‐Ray diffraction (XRD) proved an excellent dispersion of EG in polymer matrix with the worm‐like structure tended to break into pieces under intensive rolling. The improvements in mechanical and thermal properties have been studied for the nanocomposites as prepared by masterbatch process. The results depended greatly on the dispersion of EG and the compatibility between masterbatch and HDPE matrix. POLYM. ENG. SCI., 47:882–888, 2007. © 2007 Society of Plastics Engineers     

PET生产中EG的流向分配及流失

探讨了PET生产中EG随工艺废水废气而流失的原因,通过优化EG的流量分配、合理调整EG分离塔的塔顶参数,控制终缩聚釜刮板冷凝器、冷凝效果及温度,可以更好地保证PET产品品质指标,进一步降低PET生产中EG单耗、减少废水中污染物的排放量。     

D296树脂分离锆、铪洗脱的效果

介绍了在离子交换固定床上用D296强碱性阴离子交换树脂分离锆、铪的洗脱实验研究。吸附与洗脱实验的温度均控制在2~5℃,洗脱实验在饱和吸附的离子交换柱、过漏的离子交换柱、未过漏的离子交换柱中进行。研究结果表明:离子交换柱吸附状态以及洗脱剂酸度对分离效果有显著的影响。当离子交换柱存在交换区时,用任何酸度的硫酸作为洗脱剂,铪均被先洗脱出来,但高酸度的洗脱剂对分离锆、铪更有利;当离子交换柱为饱和状态时,低酸度和高酸度的洗脱剂洗脱,锆、铪不能得到分离。实验证明了单一的固定床分离锆、铪的效率低,要成功实现锆、铪的分离,需采用连续分离的离子交换移动床。