穿流板式汽提塔在PVC生产中的应用

介绍了穿流板式汽提塔的结构、特点、在汽提装置中的应用以及与有溢流堰汽提塔主要工艺参数的比较。     

PVC生产用无堰穿流筛板汽提塔运行总结

在PVC生产中选用了自行设计开发的塔式汽提装置,使VCM在汽提塔出料中的残留量由原来的1.6×10-2降为5×10-6以下,在PVC树脂中的含量由原来的1×10-4降为1×10-6以下,经济效益和社会效益都很显著.     

小孔径穿流汽提塔探讨

指出了PVC生产过程中小孔径穿流汽提塔产能的局限性。通过物料流量的计算,得出了汽提塔开孔率与蒸汽流量大致成正比关系。在此基础上,通过扩大塔板筛孔的直径,提高了小孔径穿流汽提塔的生产能力。     

穿流式和折流式汽提塔的运行对比

对比了在悬浮法生产聚氯乙烯过程中,穿流式汽提塔和折流式汽提塔脱除VC的运行特点以及对PVC粉料质量的影响。     

盐酸生产工艺改造及穿流板式塔设计

本文着重说明氯化氢三级吸收制酸工艺,一、二两级为膜式冷却吸收,三级采用大筛孔穿流板式塔吸收;提出了微量气体吸收装置穿流板式塔的设计计算方法.     

PVC汽提塔的改进

介绍了用于PVC生产的筛板式汽提塔及溢流式筛板汽提塔的结构特点、技术特性以及改进制造过程。     

大型穿流式汽提塔的理论探讨

文章介绍了国内聚氯乙烯汽提的常用技术,结合实际生产特点,通过对汽提过程的深入分析,为大型穿流式汽提塔的设计提供了理论依据与实践经验,阐述了大型穿流式汽提塔的技术可行性。     

釜式固定管板式换热器折流板位置的改进

在设计釜式固定管板式换热器时,应将最后装配的那块折流板放在变径段的小端筒体上,这对换热管较长的该类设备尤为必要。     

穿流回转干燥器的开发与应用

介绍了穿流回转干燥器的基本结构、工作原理、操作参数的确定以及其用于干燥聚丙烯酰胺的主要参数和特点。     

汽提装置的应用及改造

简述了汽提装置在聚合后处理工序上的应用及改进方案,比较了采用汽提工艺的优缺点。     

废水汽提装置在PVC行业中的应用

介绍了废水汽提工艺在PVC行业中的应用现状,阐述了氯乙烯单位聚合过程中废水的来源及穿流塔、溢流堰筛板塔两种废水汽提装置的工艺流程,并对两种装置的运行情况进行了总结,分析了两种工艺的指标控制、能耗情况、汽提后效果和异常问题。     

高效环形流氯乙烯转化器的研究与应用

研究了一种新型氯乙烯转化器,并在PVC生产中应用。理论研究和实际应用表明:在转化器尺寸和列管数量都不变的情况下,新型转化器单台产能可提高50%以上,节省触媒用量50%以上。采用新型转化器将带来巨大的经济效益和社会效益。     

PVC树脂产品杂质的影响因素及改进措施

针对20Wt／a聚氯乙烯生产中产品杂质含量波动的情况，从工艺、设备等方面进行了分析，提出了采取的措施。     

Preparation and characterization of colloidal dispersions of vinyl alcohol–vinyl acetate copolymers: application as stabilizers for vinyl chloride suspension polymerization

Well‐defined colloidal dispersions of vinyl alcohol–vinyl acetate copolymers (PVAs) with different degrees of hydrolysis (DH) were prepared by a coacervation technique. Colloidal particles in the size range 150–250 nm, with an acetate‐rich core and a hydrophilic PVA corona, were obtained using a combination of a hydrophobic PVA (PVA II) having an average DH ( ) value of 43 mol% with a ‘blocky’ hydrophilic PVA (PVA I) with a value of 72 mol%. The core–shell structure of these particles was demonstrated using ¹H NMR and using fluorescence‐labelled PVA I. The stabilization efficiency of PVA I and PVA II and their combination was examined for 1‐chlorobutane–water emulsions, as a ‘model solvent’ for vinyl chloride–water emulsions. Preliminary tests of vinyl chloride suspension polymerization confirmed the beneficial effect of PVA I and PVA II combinations as stabilizers on the granulometry and the porosity specifications of the poly(vinyl chloride) grains. Copyright © 2006 Society of Chemical Industry     

Preparation of intercalated Mg‐Al layered double hydroxides and its application in PVC thermal stability

The Mg‐Al oxide precursor prepared by the calcination of Mg‐Al‐carbonated layered double hydroxide (LDH) at 500 K for 4 h is used as the host material, 2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid (BP) is used as the guest material, BP‐intercalated LDH (LDH‐BP) is prepared by ion‐exchange method. The structure of LDH‐BP is characterized by X‐ray diffraction (XRD), Fourier transform infrared (FTIR), and thermogravimetry and differential thermal analysis (TG‐DTA). The thermal stability of PVC/BP, PVC/LDH, PVC/LDH‐BP composites, as well as pure PVC is investigated by conventional Congo Red test and dynamic thermal stability analysis in both the open and closed processing environments. According to XRD and FTIR, BP anions have been intercalated into interlayer galleries of LDH. TG‐DTA results show that the layer‐anionic interaction results in the improvement of the thermal stability of BP. Congo Red tests indicate that the addition of BP catalyzes the thermal degradation of PVC. A little amount of LDH (such as 1 phr) makes PVC more stable, but excessive addition accelerates the thermal degradation of PVC. The addition of LDH‐BP markedly improves the static thermal stability of PVC. The results of dynamic thermal stability tests in both the open and closed processing environments are consistent with that of Congo Red tests. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

2005年世界PVC/VCM市场回顾

介绍了2005年世界PVC友VCM市场情况，重点介绍了国外对我国PVC市场的认识。     

Particle features of poly(vinyl chloride) resins prepared by a new heterogeneous polymerization process

The heterogeneous polymerization of vinyl chloride monomer (VCM), with n‐butane as the reaction medium, was used to prepare poly(vinyl chloride) (PVC) resins. The particle features of the resulting resins and the particle formation mechanism of the polymerization process were investigated. The PVC resins prepared by the new polymerization process had a volume‐average particle size comparable to that of suspension PVC resins and a lower number‐average particle size. From scanning electron micrographs, it could be seen that the new PVC resins had a regular particle shape and a smooth surface with no obvious skin. They also had a high porosity. The new PVC resins were composed of individual and loosely aggregated primary particles. The diameter of the primary particles in the top layer of the grains was smaller than that of the primary particles in the center part of the grains. On the basis of the particle features of these PVC resins, a particle formation mechanism for the new polymerization process was proposed. PVC chains precipitate from a VCM/n‐butane mixed medium to form primary aggregates at a very low conversion, and the primary aggregates of the PVC chains aggregate to form primary particles, which further aggregate to form grains. The primary particles and grains grow by the capture of newly formed PVC chains and their primary aggregates and by polymerization occurring inside the aggregates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 954–958, 2003