氯乙烯生产技术

从氯乙烯(VCM)传统工艺和新工艺的研究热点着手,介绍了氯乙烯生产工艺。发现传统工艺包括电石乙炔法、乙烯法、乙烷法研究集中于关键催化剂的研究,电石乙炔法中无汞催化剂开发尚不成熟,其研究进展将制约电石乙炔法前景,乙烯法关键催化剂尚未实现国产化,乙烷法催化剂研究尚不成熟且难度较大。乙炔二氯乙烷重整催化法是正处于开发阶段的新工艺,尚需进一步论证且经工业化示范后方可实现工业应用,该技术过程清洁、成本较低,是一条符合我国国情的有发展前景的工艺。     

氯乙烯精馏尾气回收工艺

通过变压吸附装置处理氯乙烯精馏尾气,可以达到回收尾气中氯乙烯及净化提纯尾气净化气中氢气的目的,从而使净化后的气体达标排放,降低消耗,减少环境污染。     

Vinyl chloride technology: Present and future

The main lines of development in the technology of vinyl chloride in the midterm are considered. It is shown that the balanced process based on ethylene remains the main method of vinyl chloride production despite an increase in the fraction of vinyl chloride production from acetylene in China. Technological solutions that would favor the intensification of current technologies, especially at the stages of dichloroethane pyrolysis and the oxidative chlorination of ethylene, will play important role in the development of these processes. A possible method for the increase in the productivity of dichloroethane pyrolysis is the use of initiators that make it possible to increase the conversion of dichloroethane, decrease the temperature of the process, decrease power consumption, and increase the period of furnace operation without recovery. For the processes of oxidative chlorination of ethylene with the use of fluidized-bed catalysts, a low-active catalyst is recommended together with an increase in the process temperature to 250–260°C. This makes it possible to increase the real productivity of the catalyst and the overall stage by a factor of 1.8–2 because of intensified heat removal in the reactor without a decrease in the selectivity of the process.     

液氯液化尾气合成氯化氢生产氯乙烯

对液化尾氯的应用进行了可行性探索,通过对液化尾氯的生产数据分析,并从理论计算上求证,证明氯气液化尾氯合成氯化氢直供电石法PVC生产是安全可行的。     

氯乙烯合成转化器影响因素的分析与改进

介绍了氯乙烯合成过程中转化器的使用情况,从转化器的循环用水、催化剂触媒的装载、活化、转化器测温点的设置、转化器通气量以及转化器出现泄漏后的处理等方面进行了分析,从而使转化器的使用效果达到最优化。     

Vinyl chloride formation from the thermal degradation of poly(vinyl chloride)

The volatile products from the thermal degradation of poly(vinyl chloride) (PVC) resins and compounds are shown to contain trace amounts of vinyl chloride. Data presented show the effect of temperature and resin type on the amount of vinyl chloride formed. At the maximum temperatures involved in PVC processing which may reach 210°C, vinyl chloride monomer (VCM) evolution amounts to less than 1 ppm (resin basis). A technique employing a thermogravimetric balance and charcoal adsorption of volatiles is described for studying thermal degradation of PVC. The volatiles are analyzed for vinyl chloride by gas chromatography. Peak identity was confirmed by mass spectrometry.     

Vinyl chloride formation from the thermal degradation of poly(vinyl chloride)

The volatile products from the thermal degradation of poly(vinyl chloride) (PVC) resins and compounds are shown to contain trace amounts of vinyl chloride. Data presented show the effect of temperature and resin type on the amount of vinyl chloride formed. At the maximum temperatures involved in PVC processing which may reach 210°C., vinyl chloride monomer (VCM) evolution amounts to less than 1 ppm (resin basis). A technique employing a thermogravimetric balance and charcoal adsorption of volatiles is described for studying thermal degradation of PVC. The volatiles are analyzed for vinyl chloride by gas chromatography. Peak identity was confirmed by mass spectrometry.     

Vinyl chloride,identification and solution of a problem

More than 8 years have passed after the identification of vinyl chloride (VC) as having a carcinogenic potential. It appears to be useful to recapitulate the development of the VC disease and of the measures in the PVC producing plants, taken until now, in the Federal Republic of Germany. It can be shown how this problem has been solved by cooperation of all persons involved, the chemical companies, the organizations responsible for occupational safety, the trade-unions representatives, the physicians and other experts. As a result of the manifold technical, medical, and other precautions, the operating conditions could be improved essentially. Currently, concentration levels of VCM in the workplace amount to 1 ppm or below in nearly all plants.     

Vinyl chloride in rural water from pre‐1977 applications of PVC pipe

In the early 1990s, vinyl chloride monomer (VCM) was found in a rural water system that included poly(vinyl chloride) (PVC) pipe manufactured prior to 1977. Because VCM, considered a human carcinogen, was not regulated in pipe until 1977, some pre‐1977 pipes could contain it at significant levels. Manufacturing processes adopted in 1975 and in place by 1977 reduced VCM levels by as much as a factor of 1000. Pipe manufactured by using the newer resin technology does not show detectable VCM migration under any reasonable installation circumstances. Migration of VCM is a function of pipe size, VCM concentration at time of installation, water temperature, and flow rate. History, scientific investigations, and conclusions drawn from field investigations are summarized. Tools for the determination of possible candidate systems, potential noncompliance, and remediation, both short‐term and long‐term, are provided. A spreadsheet‐based computer model of diffusion is described.     

溶剂型废PVDC改性沥青防水涂料的研制

在阐述废ＰＶＤＣ树脂改性沥清防水涂料的配方设计，制备工艺及其性能测试的基础上，讨论了该防水涂料的制备工艺及废ＰＶＤＣ树脂的改性作用。     

Vinyl chloride suspension polymerization with constant rate. A numerical study of batch reactors

Based on the analysis of a simple mathematical model, different temperature profiles are generated in order to provide vinyl chloride (VCM) suspension polymerization with constant reaction rates in batch reactors. In order to reproduce these temperature profiles in industrial-scale reactors, some process variables, such as coolant temperature, initiator concentration, and rate of water and monomer condensation, have to be manipulated. It is shown that those temperature practices can almost never be applied to large-scale reactors if the jacket temperature is the only variable that can be manipulated. It is also shown that developing an initiator feed procedure or using a reflux condenser may be advantageous.     

Poly(Vinyl chloride)/plasticizer-mixture interactions—mixtures of various plasticizers of industrial importance

The Flory-Huggins interaction parameter, x, has been determined as a function of plasticizer composition, ?₂, for several ternary mixtures of poly(vinyl chloride) (PVC) and different pairs of plasticizers, selected mainly from the family of aliphatic esters. The method employed was the micro-determination of the apparent melting temperature of a PVC particle in excess plasticizer. In some systems X changed fairly gradually as a function of ?₂, while other systems exhibited a pronounced minimum in the X – ?₂ plots. Attention has been drawn to the similarity of this latter behavior to the well known co-solvency effect. The existence of such minima is of partical interest in plasticized PVC formulations.     

氯乙烯自聚对聚合系统生产及PVC质量的危害和预防措施

阐述了氯乙烯自聚的原因及对聚合系统和产品质量的危害,采取有效的阻聚方法后,不仅延缓了氯乙烯自聚,而且延长了设备的运行周期和使用寿命,节约了设备清理费用和安装费用。     

异山梨醇基增塑剂的制备及其增塑PVC的性能

通过异山梨醇和壬酸合成一种新型生物基增塑剂—异山梨醇二正壬酸酯(SDN)来改性聚氯乙烯(PVC)树脂.研究了绿色增塑剂的增塑作用及对共混物性能的影响.SDN特有的分子结构增大了分子链间的距离,增加了聚合物的自由体积,使共混物塑性得到明显的改善.研究表明,随着SDN增塑剂添加量的增加,材料韧性增强,增塑剂的引入降低了共混...     

Copolymerisation of Vinyl Stearate with Other Fatty Vinyl Monomers

Homopolymerisation of vinyl stearate and its copolymerisation with five other fatty vinyl monomers have been carried out in benzene using benzoyl peroxide as the initiator. The comonomers included stearyl acrylate, stearyl methacrylate, allyl stearate, stearyl vinyl ether and divinyl sebacate. Stearyl acrylate and stearyl methacrylate furnished copolymers with inherent viscosities much higher than that of the vinyl stearate homopolymer while allyl stearate and stearyl vinyl ether gave copolymers with inherent viscosities much lower than that of the vinyl stearate homopolymer.