DCS在30m^3聚合釜控制中的应用

介绍了电化厂聚合技改后的聚合釜温度控制方案，CS3000DCS在控制中的应用。实现了从进料、升温、恒温、直至反应结束的全过程自动控制，在操作站实现了动态工程沈程图、控制分组、历史趋势等显示功能，可变参数在权限范围内的下载及报表打印等功能。     

聚酰胺66直纺大容量聚合装置技术改造及工艺研究

通过对聚酰胺66直纺大容量聚合装置的技术改造及工艺研究,对聚合关键装置的物料平衡、热量平衡、反应机制、控制及输送系统等的研究设计,对盐预热器、浓缩槽、减压器、聚合器、输送泵等关键装备的增容改造,延长了缩聚时间,加快了水分蒸发或脱水速率,实现了高黏聚合物连续稳定控制。通过聚合装置及关键工艺控制等方面的研究,单线纺丝产能突破12 000 t/a并稳定生产,实现关键技术突破,经济和社会效益显著。     

CENTUM CS3000在国产70 m3聚合釜PVC生产工艺中的应用

介绍无锡格林艾普化工股份有限公司国产70m^3聚合釜实现PVC生产工艺全自动控制系统、控制方案和控制功能的过程,并分析了典型控制方案、控制功能及组态。该装置实现全自动控制运行以来,生产能力达到了4．5万t／a,优级品率在90％以上,产品相对表观密度达0．53～0．55,1t PVC树脂耗VCM为1．008～1．010t。     

137 m~3聚合釜悬浮法PVC生产工艺的国产化

介绍了137 m~3大型聚合釜悬浮法PVC生产工艺国产化过程中,设备、聚合生产工艺、DCS控制等方面的改进工作。从以下4个方面重点介绍了DCS控制软件的主要功能及控制过程:(1)聚合生产过程的批量控制,(2)安全生产联锁,(3)聚合反应过程中反应温度控制,(4)紧急情况下的ESD操作系统。     

连续微流体在光聚合制备聚合物颗粒中的应用进展

光聚合以其对环境友好、反应条件温和、适应性广、成本低等优点备受关注。连续微流体在光聚合中的应用有助于提高反应效率并实现聚合的高度控制。连续微流体在光聚合制备聚合物颗粒中的优点包括可重复性高、合成精度高、能控制聚合物的粒径、多分散性和内部结构。在这篇综述中，总结了连续微流体在光聚合合成纳米颗粒中的应用，其中包括单相微流体光聚合和多相微流体光聚合，具有各种形态的聚合物颗粒的形成机理以及典型实例。     

国产110m~3聚氯乙烯生产热水入料工艺优化控制

通过DCS系统实现了对聚合入料、热水升温、最短时间过渡过程控制、精确控制恒温阶段反应温度及聚合物后处理的辅助智能控制,从而使国产110m~3聚氯乙烯聚合生产实现了热水入料工艺,达到了提高和稳定产品产量、质量、安全和环保等方面的目的。     

浙江大学推广VCM多相(共)聚合反应工程研究项目

在建立控制用VCM聚合速率、聚合度、复合引发剂聚合动力学等多项(数学)模型基础上,浙江大学建成我国首套VCM聚合动力学计算机在线实时检测系统,实现了对该聚合过程的设计、预测、监控,且已应用于SG7、8型及卫生级PVC树脂的开发及缩短VCM聚合时间的工业化生产,使30m~3釜     

PA66切片生产中的DCS控制系统

以平顶山神马工程塑料有限责任公司年产2万tPA66切片连续聚合项目为例,介绍了日本横河公司CENTUM/CS3000集散型控制系统的配置及其功能,并从聚合工艺中浓缩槽液位的控制回路、联锁报警等方面介绍了DCS在化工生产中的应用.     

Smith-Fuzzy自整定PID聚合反应釜温度控制系统

设计了srnith-Fuzzy自整定PID控制器,实现反应釜聚合温度的精确控制,较好地解决了聚合温度的大滞后、非线性及模型确定困难造成的控制难题。     

50m~3糊树脂聚合釜温度控制

分析了糊树脂生产中影响聚合温度的各种因素,采用釜内压力补偿釜温、结合分程控制实现糊树脂聚合温度的自动控制。对控制方案、控制过程、仪表选型及控制参数整定进行阐述。     

合成氨催化剂还原温度对活性的影响

通过对合成氨催化剂的期温度波动对活性影响的研究，证明在催化剂还原过程中严格控制温度有利于得到良好的还原态催化剂，提高催化剂的低温活性，延长使用寿命。     

耐火材料高温弯曲应力-应变关系测试方法及影响因素

介绍了耐火材料弯曲应力-应变测试仪的基本构成以及对试验炉、加荷装置、变形量测量装置和计算机控制系统等各构件的要求;重点介绍了使用该仪器研究耐火材料应力-应变关系的方法以及影响测试结果的相关的因素。该方法可以用来研究耐火材料在高温下承受弯曲应力时的变形问题,确定耐火材料在各温度下的应力-应变关系,测试和判断耐火材料的弹性、塑性和粘滞流动的温度范围,并根据应力-应变关系计算耐火材料在不同温度下的弹性模量。     

Phase-space volume based control of semibatch reactors

We present and apply a control methodology using the divergence of the system as a goal function to control semibatch chemical reactors and show how the process operation may be optimized by only measuring the reactor and jacket temperatures. The implementation of the approach is also demonstrated using phase-space reconstruction techniques. This new control methodology offers a complementary approach to more traditional techniques and it can be easily extended to other industrial installations and processes.     

Alignment‐Improved and Diameter‐Reduced Electrospun Polymer Fibers via the Hot‐Stretching Process

Electrospinning is one of the most facile and versatile techniques to prepare polymer fibers ranging from micrometers to nanometers. Although several parameters can be tuned to control the sizes and morphologies of electrospun fibers, many obstacles are still encountered as the target sizes of the fibers are getting smaller; for example, the sizes of the fibers can be effectively reduced by lowering the polymer solution concentrations but beaded or beads‐on‐string structures are usually formed. To overcome such obstacles, here a simple technique to prepare alignment‐improved and diameter‐reduced fibers without bead formation by hot‐stretching electrospun fibers at temperatures higher than the glass transition temperatures of the polymers is developed. Polystyrene and poly(methyl methacrylate) are both used in this work as model materials. The relationship between the draw ratio and diameter of the fibers is quantitatively analyzed, demonstrating the control of the fiber diameters. Moreover, higher degrees of alignment improvement at the middle part of the fibers than those at the end part is observed, which results in lower water contact angles at the middle part of the fibers. This work provides a useful post‐treatment technique to control the sizes and orientations of electrospun polymer fibers.     

THE MEASUREMENT OF PARTICLE TEMPERATURE IN A FLUID1ZED BED DRYER

A probe for particle temperature measurements in fluidized bed dryers is described in this work. The probe, consisting of a thermistor placed inside a turning cup, was tested in a pilot scale dryer, where particle temperatures were monitored during batch drying tests. The measurements were validated by comparison with readings made in collapsed beds. Temperature readings were given a physical interpretation, as surface particle temperature, or average particle temperature, depending on the drying regime. The dynamic response of the probe was also analyzed. As an application, it is shown how panicle temperatures, along with local wet bulb and dry bulb air temperatures, can be used to monitor and control the drying process. The simplicity of construction, installation and associated method makes the probe attractive for both research and industrial purposes.     

THE MEASUREMENT OF PARTICLE TEMPERATURE IN A FLUID1ZED BED DRYER

ABSTRACT

A probe for particle temperature measurements in fluidized bed dryers is described in this work. The probe, consisting of a thermistor placed inside a turning cup, was tested in a pilot scale dryer, where particle temperatures were monitored during batch drying tests. The measurements were validated by comparison with readings made in collapsed beds. Temperature readings were given a physical interpretation, as surface particle temperature, or average particle temperature, depending on the drying regime. The dynamic response of the probe was also analyzed. As an application, it is shown how panicle temperatures, along with local wet bulb and dry bulb air temperatures, can be used to monitor and control the drying process. The simplicity of construction, installation and associated method makes the probe attractive for both research and industrial purposes.     

Combined microwave–hot-air drying of burdock slices with feedback temperature control at surface and core

During combined microwave–hot-air drying, the surface and the core temperatures of the sample have great influence on the process. To investigate the influence systematically, drying system with feedback control strategy of the two temperatures was proposed. Then various pairs of the two temperatures were applied in the drying mode 1. However, it was found difficulty to achieve both short drying time and high product quality with fixed temperature pair, because the interaction between microwave and the sample changes as the moisture content decreases in the drying process. Different temperature pairs were applied during the three drying stages in drying mode 2, so that better product can be obtained in shorter drying time. To further improve the product quality, the drying rate was controlled by a feedback loop within a desired range in drying mode 3. The change of drying rate was realized by adjusting the two temperatures continuously. To omit the weighing scale, a feedforward control strategy for the drying rate was put forward in drying mode 4, where the temperatures were controlled along with preset lines. The results showed that the product quality and the drying time were similar to those in drying mode 3.     

New Dry Process for Separating HCl from Flue Gases by Adsorption on MgO

Fossil fuels are still the most important source for supplying the world's energy and heating needs. The growing demands of more stringent pollution control regulations make it necessary to develop new flue gas cleaning processes. Up to now there is no known process that allows the dry separation of hydrogen chloride from flue gases with ready adsorbent regeneration. The well known BF-Uhde process cannot be applied to flue gases containing hydrogen chloride. Our aim was to develop a process for dry separation of hydrogen chloride from flue gases that can be used in combination with the BF-Uhde process. The new process is based on a gas-solid reaction between active magnesia and hydrogen chloride at temperatures of about 120 °C. The new process performed well in experiments conducted under industrial conditions. The adsorbent can be regenerated at temperatures of about 450 °C. Hydrogen fluoride is the only known flue gas component that interferes with the regeneration capability of the adsorbent.     

Tailoring the microstructure by a proper electric current control in flash sintering: The case of barium titanate

Flash sintering is arousing growing interest because high-density ceramics can be obtained at lower temperatures and shorter dwell times than conventional sintering. However, not only temperature and dwell times should be controlled during flash sintering but also parameters such as the electric field and electric current should be considered. Controlling all the parameters during the processing allows comprehensive control of the microstructure and, consequently, functional properties can be improved. In this work, it is evidenced that an exhaustive control of the flash electric current is a crucial factor for tailoring the microstructure of BaTiO₃ ceramics. The results reveal that the most suitable way to control the sintering process is by using non-linear current profiles because better densification and improved grain growth is achieved. Although the results focus on BaTiO₃, this work offers a new pathway to tailor the microstructure of flash sintered ceramics, which may be extended to other materials.     

烧结红柱石的X射线分析

对化学组成和粒度不同的红柱石精矿和粗精矿在不同温度下的莫来石化行为进行了X射线分析。测出了烧结样的起始、快速和终止分解温度，对含非晶棺的X射线定量分析在无标样和无对比相条件下的计算公式作了推导。