聚酯终聚釜搅拌器机封的改进

洛阳石化总厂聚酯装置采用杜邦技术，由2条生产线组成。工艺过程主要有浆料配制、酯化和缩聚组成，用于生产聚酯熔体。终聚釜搅拌器密封是聚酯生产过程的关键部位之一。如果密封失效，终聚釜真空度被破坏，终聚反应受到严重影响，造成装置停工。     

终缩聚真空系统异常的处理方法探讨

在聚酯生产过程中,PIC117024为终缩聚真空显示控制仪表,用于调整终缩聚真空度。若真空度不稳定,将会直接影响终缩聚的反应,最终导致产品品质波动,对终缩聚真空的异常情况进行原因分析,针对不同的原因找到解决处理的办法。     

PET聚酯的终缩聚化学及其反应器模型

聚酯生产技术国产化的基础研究应着眼于聚酯的冷、热模研究。在回顾、分析ＰＥＴ聚酯历史的基础上,对ＰＥＴ聚酯终缩聚化学及其反应器模型的研究方法和内容作了详细的综述。     

PET聚酯终缩聚过程的工程分析──卧式双轴脱挥反应器

聚酯生产技术国产化的基础研究应着眼于聚酯的冷、热模研究。在回顾总结PET聚酯冷模研究状况之基础上,对PET聚酯终缩聚过程的工程分析,尤其是对卧式双轴脱挥反应器冷模研究的内容和方法作了详细的综述。     

CTMC新三釜聚酯装置

CTMC新三釜聚酯装置含新型双区酯化釜、新型多层预缩聚釜、原创性栅缝降膜终缩聚塔各一台,三者均不设机械搅拌。新酯化釜和预缩聚釜已成功用于470 t/d聚酯装置,新终缩聚釜已完成生产中试,聚合速度显著高于传统圆盘或鼠笼釜,可直接生产高黏聚酯,无需SSP。     

PET终缩聚过程建模和质量控制方案的研究

首先从过程机理出发，建立了ＰＥＴ终缩聚反应过程的模型，对过程中的操作变量和产品质量指标的关系进行了讨论，通过与实际生产过程数据的校验，所建模型是可靠的；然后在过程模型的基础上，结合神经网络软测量技术，提出了ＰＥＴ终缩聚过程产品质量指标的内模控制方案，仿真结果证明了此方案的有效性．     

聚酯终缩聚釜液位波动的原因及对策

从生产实践出发,深入分析和探讨了聚酯终缩聚釜液位波动的原因:包括终缩聚釜液位控制阀故障或动作滞后,液位测量系统故障或控制器故障,搅拌故障或转速波动,相关工艺参数发生波动等。找到了控制和预防终缩聚釜液位波动的关键措施。     

聚酯反应均匀性初探

论述聚酯生产中影响反应均匀性的因素 ,指出工艺优化是改善均匀性和提高产品质量的方向。原料品质和工艺过程稳定 ,设备结构适宜是均匀性的基础。对于Karl Fisher装置 ,要恰当分配各釜反应负荷 ,进入终缩聚釜的熔体粘度要适当 ,注意过料平稳 ,减少涌流 ,对缩聚 2进行改造 ,合理安排产量 ,控制缩聚搅拌速度及终缩聚的液位。     

论直缩法聚酯生产的共性

为生产出高分子量的合格的聚酯产品,直缩法分成酯化、预缩聚、终缩聚三个工艺段是必要的,工艺段的划分原则是由工艺加工的任务和各阶段的反应和过程控制的特点所决定的。文中详细论述了各工艺段的任务、过程中发生的反应、过程特点、操作参数的定性影响、反应特点对设备的要求,并在对聚酯过程的理解基础上综合比较分析了直缩法生产聚酯各引进技术的工艺和设备型式。     

预缩聚Ⅱ搅拌器出现故障时的工艺处理方法

0　前言我公司使用的是德国吉玛公司配套的聚酯生产设备 ,该套设备由 5个反应釜组成 ,包括 2个酯化釜和 3个缩聚釜。在预缩聚Ⅱ反应釜中 ,聚酯熔体的特性粘度已经达到 0 2 5～ 0 30ｄＬ/ｇ。预缩聚Ⅱ反应釜的正常运行是终缩聚反应釜稳定运行的先决条件 ,是实现聚酯熔体最终粘度的必要保证。而在我公司的生产过程中 ,出现过预缩聚Ⅱ搅拌器齿轮箱一只轴承损坏 ,需停止该搅拌器进行更换。在更换该轴承的 4ｈ过程中 ,工艺技术人员采用了适当的处理方法 ,保证了在预缩聚Ⅱ搅拌器停车 4ｈ的情况下 ,最终的熔体粘度没有较大的波动 ,聚酯切片的各…     

PC/PET共混物流变性及可纺性

用熔融共混法制得一系列PC/PET共混物,通过Instron流变仪,小型纺丝机,差示扫描量热,广角X光衍射和热收缩等实验对PC/PET共混体系的流变性及可纺性进行研究。讨论了PC含量对流变参数及可纺性的影响。结果表明,PC/PET共混熔体属切力变稀流体,在PC含量小于15%(mol比)时有较好的可纺性及纤维力学性能,PC/PET共混拉伸丝是一种高收缩纤维。     

Modeling of polyethylene terephthalate reactors: 7. MWD considerations

A mathematical model has been developed to compute the molecular weight distribution (MWD) in the polyethylene terephthalate (PET) manufacturing process. Unlike the previous efforts, this model takes into account the influence of side reactions and various interchange reactions on MWD. The process of blending of molten polyester chips has also been simulated with a view to calculate the equilibrium MWD as well as the time required to reach the equilibrium MWD. The1 significance of the results has been discussed in terms of industrial operations involving PET polymerization and PET blending.     

Optimization of the transesterification stage of polyethylene terephthalate reactors

The tranesterification step of the polyethylene terephthalate (PET) formation consists of several side reactions in addition to the main ester interchange, transesterification, and polycondensation reactions. The side reactions considered in this work are acid end group, acetaldehyde, diethylene glycol, water, and vinyl end group formations. The objective function of the batch esterinterchange reactor is assumed to consist of maximizing the conversion and simultaneously minimizing the formation of side products. The control vector iteration procedure has been used to optimize the esterinterchange reactor and the temperature-time profile that gives the best performance has been found. It is found that the reactor should be operated at a high temperature initially to obtain high conversion of dimethyl terephthalate (DMT) first, but then it should be lowered to reduce the formation of side products.     

Finishing stages of PET synthesis: A comprehensive model

A comprehensive mathematical model for the finishing stages of polyethylene terephthalate (PET) synthesis is developed. The model takes into account the variables which have significant influences on polymerization but have not been hitherto taken into account, e.g., changing interfacial concentration and the presence of side reactions. The model is applicable to industrial polymerizations, and the predictions agree well with the literature and with certain pilot-plant and commercial data.     

Study of the reactions occurring during melt mixing of poly(ethylene terephthalate) and polycarbonate

In this work the reactions taking place during melt mixing of bisphenol-A polycarbonate (PC) with poly(ethylene terephthalate) (PET) were studied by selective degradation of PC sequences, solubility tests, and IR spectroscopy. It was found that exchange reactions between PC and PET took place, contrary to what has been previously suggested by other authors. Kinetic constants were evaluated from intrinsic viscosity measurements of PET blocks. The reaction rate was slow when only the Sb catalyst (residues of the PET polymerization) were present, but it was significantly accelerated by the addition of Ti(OBu)₄. In the presence of the latter catalyst, other side reactions, leading to discoloration and gas evolution, took place.     

草酸亚锡体系中对PET稳定剂的研究

本文研究了草酸亚锡体系中几种单一稳定剂和复合稳定剂对PET副反应的抑制。采用磷酸、磷酸酯类或亚磷酸、亚磷酸酯类作为稳定剂,均能提高PET的热稳定性,改善树脂的质量指标;与酚类抗氧剂一起作为复合稳定剂,效果更佳。较好的草酸亚锡体系与实用的三氧化二锑体系的比较,表明在实际生产中草酸亚锡作为缩聚催化剂是很有前途的。     

Solution of final stages of polyethylene terephthalate reactors using orthogonal collocation technique

The formation of polyethylene terephthalate (PET) has been modeled to have reactions with monofunctional compounds, redistribution, and cyclization reactions in addition to the usual polycondensation step. In the final stages, the overall polymerization is mass-transfer controlled and solution of the reactor performance equations have been determined through the orthogonal collocation technique. This technique is found to be considerably more efficient for PET reactors compared to the finite difference method; the use of ten collocation points gives results which are close to the exact solution.     

Poly(ethylene terephthalate), modified with bisphenol S units,with increased glass transition temperature

Novel copolyesters have been prepared by melt mixing poly(ethylene terephthalate) (PET) with an ethoxylated bisphenol S, with the aim to prepare new polyesters with increased T_g, to be used in a wider range of temperatures with respect to neat PET. No side reactions occur during the synthesis of the samples, as proved by NMR analysis. The insertion of the bisphenol S (sulfonyldiphenol) groups does not significantly alter the thermal stability of PET. The thermal analysis showed that T_m and crystallization rate of the copolymers decreased with incasing co‐unit content. The T_g of the copolyesters can be increased by bisphenol S insertion, up to 40°C higher with respect to neat PET, that allows the use of amorphous PET in a wider range of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

对国产涤纶短纤维纺丝设备LHV901的技术改造及其评价

论述了对国产涤纶短纤维纺丝设备LHV901的技术改造及效果。丝片宽度由160mm×6mm改为320mm×3mm,取消了A.B两侧之分,加强了电气和机械的同步性能:采用高温卷曲工艺,提高了生产效率:卷曲机由22kW直流电机单独驱动改为长边轴传动,使丝片在拉伸,卷曲等工序的张力保持平衡或同步。减少丝片张力波动;在浸油槽和水浴槽添加纺丝油剂,增强丝片的条理均匀性:把浸没法再上油形式改为油轮法,油剂单耗由20kg/t降为7kg/t,取消了四道拉伸机和松驰定型机。改造后使操作工序由25道减至20道,减少设备11台。     

Ester exchange reactions in polyarylate/poly(ethylene terephthalate) blends

Blends coagulated by a solution/precipitation procedure of a polyarylate (PAr) based on bisphenol A and tere/isophthalates with poly(ethylene terephthalate) (PET) have been studied by a variety of experimental methods. Differential scanning calorimetry experiments have shown that in blends containing more than 30% PET, conditioning of the blends at high temperatures required for calorimetric measurements resulted in progressive ester exchange reactions. The 10% and 20% PET mixtures, in which this extreme conditioning was not required, showed a single glass transition, contrary to the behaviour of the other PET compositions. These differences may be attributed to the shape of the spinodal curve, which has been simulated according to the McMaster model for polymer mixtures. The progression of the interchange reactions has been followed by solvent extraction of the resulting products and subsequent Fourier transform infra-red spectroscopy analysis. A parallel decrease in the PET heat and temperature of fusion in the insoluble fractions was observed. In our opinion this was due to the incorporation of PAr units in the PET chains, which caused a decrease in their crystallizable segment length.