聚酯真空系统异常分析及处理

对聚酯真空系统的异常情况如预聚Ⅰ液环泵频繁切换,刮板冷凝器、真空大气腿堵塞、真空喷射泵EG喷淋流量降低,喷射泵本体工作性能偏低等进行了分析。采取优化工艺、技术改造等措施,保证了真空系统的稳定运行。     

聚酯装置真空系统堵塞的原因及在线处理

针对德国吉玛公司四釜反应流程聚酯装置真空系统的运行现状,分析了真空系统能力变差的原因并提出了真空系统堵塞的在线处理方法。真空系统能力变差的最主要原因是刮板冷凝器顶部真空管道结垢堵塞,主要堵塞部位是喷淋管线、大气腿和真空通道。通过实施热冲洗管道改造和刮板冷凝器顶部夹套改造,实现在线优化处理,解决了真空系统管道的缩颈和堵塞的问题,确保了真空系统长期稳定地运行。     

聚酯装置预聚气相管线堵塞现象及处理方法探讨

介绍了中纺院五釜装置预缩聚真空系统在运行过程中能力变差的异常现象，结合本装置的实际生产情况，提出对异常现象的判断方法和处理措施。预聚真空系统能力差的主要现象是真空调节阀持续下关，搅拌电流下降，原因是刮板顶部气相线堵塞，堵塞位置较高，通过在预缩聚刮板顶部氦检口，长期持续通入两路动力蒸汽在线醇解，使气相线内壁堵塞物质脱落，气线管路畅通，在线解决了预聚气相线堵塞的问题，保证了真空系统稳定运行，延长装置的使用周期。     

PET终聚釜喷淋冷凝器大气腿堵塞的原因及措施

结合生产实践,对PET装置终聚釜喷淋冷凝器大气腿堵塞的原因进行了剖析,包括落入大气腿的积聚物块过大,终聚釜液位过高,真空度过高和搅拌转速过快,反应温度过高等。找到了预防和处理终聚釜喷淋冷凝器大气腿堵塞的措施。     

聚酯真空系统中刮板冷凝器的机械设计与分析

在聚酯装置真空系统中采用刮板冷凝器，可以消除低聚物堵塞的弊端，提高生产率。文中主要对刮板冷凝器的整体结构、大开孔计算、弹性支座、轴封系统、轴承等的机械设计进行分析讨论，提出了一些看法     

PET装置真空系统优化

对20万t PET装置的真空系统经常出现的故障进行分析,通过增加缩聚真空管线电伴热,刮板冷凝器改造、大气腿反吹、真空喷淋管线改造等真空系统的技术改进,延长真空系统运行时间,为装置长周期平稳运行提供保障。     

聚酯预聚真空系统常见问题的处理

探讨了杜邦三釜聚酯装置预聚真空系统堵塞的处理方法。由于装置长年高负荷运行,预聚反应在高液位、高反应条件下,小颗粒分子被EG带出,在管线内壁逐渐堆积,利用增加新鲜EG冲洗喷嘴及高温EG进行热冲洗,可以减少或解决管线内小颗粒分子的堆积及堵塞现象。     

108m~3聚合釜PVC生产技术的改进

介绍了108m3聚合釜的PVC生产工艺特点及工艺流程,详细介绍了装置运行过程中出现的粘釜、釜顶冷凝器自聚、爆聚粗料、出料不彻底等问题及相应解决措施。     

50m^3聚合釜的外冷器防堵

叙述了釜外冷凝器的防堵方法、堵塞机理及使用效果。     

刮板冷凝器管线堵塞原因及措施

介绍了刮板冷凝器的工艺流程,对刮板冷凝器管线堵塞原因进行了分析,并针对产生原因,对缩聚反应釜的液位和真空控制进行了优化,刮板冷凝器新鲜BDO补加量和回用BDO温度控制做了相关调整,同时增加了外循环泵和备用管线等。     

分解炉扩径的技术改造

我厂3号回转窑(Φ4m×60m)生产线在1996年年底由SP窑(产量912t/d)改为NSP窑(产量1320t/d),预分解系统为四级旋风预热器带离线式分解炉     

乙烯酮(双乙烯酮)下游产品废水的治理技术

乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。     

水泥水化热测定方法综述

水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。     

A study of miscibility of blends of polybutadienes of varying microstructure

The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure.     

几种乙炔加压设备性能的比较

阐述并比较了几种加压设备在乙炔加压清净过程中的性能和特点。     

粉煤灰中烧失量检测的不确定度分析

以F类粉煤灰为例,详细介绍了测定粉煤灰中烧失量的步骤、计算数学模型、影响测量不确定度的因素以及各项测量不确定度分量评定,人员、设备、材料、方法、环境都是影响测量不确定的因素。     

生物油的成分分析及物性测定

以添加FeCl2的ZnCl2-KCl混合熔盐裂解纤维素和秸秆,制得生物油。采用傅立叶变换红外光谱法和气相色谱-质谱法分析生物油的成分。结果表明,生物油中成分复杂,含有氧元素、多种有机化合物,主要包括酮类、醛类、酚类及羧酸类等。测定了20～80℃生物油的密度和粘度,发现生物油的密度与温度呈较好线性关系,而生物油的粘度均大于水的粘度,且不同熔盐体系对秸秆生物油的粘度无较大影响。     

Effect of degree of deacetylation of chitosan on the kinetics of ultrasonic degradation of chitosan

The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003