Control of the quality of polymer products in continuous reactors: comparison of performance of state estimators with and without updating of parameters

In the paper the control of the product quality in polymerization reactors is analysed in the presence of persistent perturbations (unmodeled disturbances, modeling errors), as met in industrial reactors. The free radical polymerization of methyl-methacrylate in a continuous stirred tank reactor is studied. It is shown that state estimators (Extended Kalman Filters) with constant parameters cannot give offset free performance. Criteria for the selection of a set of parameters to be updated as additional states in the filter and to evaluate their effectiveness in opposing the action of realistic perturbations are given by an analysis of the linearized model of the system. Performance of different types of estimators, including one and two-time scale filters, with and without updating of parameters, is analysed by simulation on the full order process and the predictions made by previous analysis are confirmed. In the most common case of presence of perturbations affecting the energy balance and the concentration of initiator in the reactor, offset free control of the molecular weight of the product can be achieved by means of a filter which is based only on measurements of temperature and conversion and makes an update of two parameters. In the case that also the kinetic model of the polymerization reaction is affected by errors, a two-time scale filter, which makes use also of Molecular Weight values and updates three parameters, becomes necessary to obtain offset free performance.     

采用先进技术提高装置运行水平

介绍了中国石油化工股份有限公司高桥分公司 1.4Mt/a同轴式重油催化裂化装置的特点和生产情况。为了满足市场需求 ,提高经济效益 ,几年来在该装置上又采用了一些新技术 ,使装置的运转水平进一步提高。如应用降烯烃催化剂GOR Q ,与使用MLC 5 0 0催化剂相比 ,汽油烯烃体积含量约 30 % ,下降 8～ 10个百分点 ;汽油辛烷值基本不变 ;产品分布改善 ;液体收率增加 ;柴油性质变化不大。又如最大量烷烃异构化 (MIP)新型提升管反应系统的应用 ,与常规催化裂化相比 ,产品分布相当 ,汽油的烯烃体积含量下降至 30 %～ 35 % ,MON增加 0 .5～ 0 .8个单位 ,RON下降幅度不大于 0 .5个单位     

撞击流管式反应制备超细氧化锆粉体

我国氧化锆粉体产业目前基本上“精进粗出”，迫切需要开发氧化锆粉体备新工艺，特别是具有高附加值的纳米氧化锆粉体制备技术，液相反应沉淀法具有成本低，易于工业化等优点而成为研究的热点。本文采用撞击流管式反应新工艺，撞击流接触反应强化了过程的微观混合。实现了均匀成核，使得成核过程易于控制，而管式反应器的独特设计克服了返混，因而使得反应沉淀过程易于控制，粒子分布窄。用该工艺结合醇热处理表面改性制备的超细氧化锆粉体。平均粒径约为14nm，粒度分布窄并无硬团聚发生。该方法过程简单，易于工业化大生产。     

催化裂化装置中旋流快分系统（VQS）的结构设计

阐述了全渣油催化裂化装置反应器中旋流快分系统(VQS)的工作原理,对其受力情况进行了分析。较详细介绍了放流快分系统的支撑结构形式,并就支撑梁(焊接工字钢)的选材、几何尺寸进行了详细的分析与比较。     

五氯吡啶的合成研究

以吡啶为原料，氯气为氯化剂，通过固定床催化反应合成了五氯吡啶。为此，在分析反应机理的基础上，分别以第Ⅱ、Ⅷ和IB族的金属盐类或其混合物为活性成分制备了一系列催化剂，并在493-663K、空速200—1200hr^-1、吡啶/氯气摩尔比(R)1：6—1：12范围内，对上述各催化剂性能进行考察。结果表明，Ba、Ca、La、Rh等金属的盐类混合物对本反应有较高的活性，收率高达95％，纯度96％(GC)。同时还获得了针对该催化剂适宜的工艺参数：温度590-650K，空速600-800hr^-1，R为8．5。     

Velocity Profile in Fixed Beds: A Study on the Representativeness of the Experimental Measurement of Downstream Flow Characteristics

Although considerable progress has been made in the development of experimental techniques for investigating velocity distribution inside a fixed bed, these techniques were limited to special cases. Consequently, the velocity distribution is normally measured at downstream of the fixed bed and then this measurement is considered to be representative for the flow inside the bed. To evaluate the representativeness of this technique, this work presents a study of the change in the flow characteristics, starting from the boundary of the fixed bed within the pipe to a downstream position where the experimental measurement is taken, by using simulations based on computational fluid dynamics methods.     

Experimental investigations of the effect of new passive safety systems on the temperature state of fuel elements

Results of experiments conducted on a large-scale integral PSB-VVéR bench and directed toward investigation of the performance of new passive safety systems for nuclear plants with a water-cooled power reactor, an additional system for passive flooding of the active zone, and a system for the passive removal of heat from steam generators are presented. __________ Translated from élektricheskie Stantsii, No. 9, September 2007, pp. 7–10.     

Albemarle渣油加氢处理催化剂研究

渣油加氢处理技术在炼油生产中占有很重要的地位.Albemarle最近开发的固定床催化剂KFR22和 KFR72具有出色的脱沥青质活性和更高的脱氮性能,最近开发的沸腾床催化剂是KF1302T 和KF1311,与以前的沸腾床催化剂相比 ,这些催化剂的组合降低了沉积物的生成,可提供更高的加氢脱硫性能.     

Autothermal two-stage gasification of low-density waste-derived fuels

In order to increase the efficiency of waste utilization in thermal conversion processes, pre-treatment is advantageous. With the Herhof Stabilat^® process, residual domestic waste is upgraded to waste-derived fuel by means of biological drying and mechanical separation of inerts and metals. The dried and homogenized waste-derived Stabilat^® fuel has a relatively high calorific value and contains high volatile matter which makes it suitable for gasification. As a result of extensive mechanical treatment, the Stabilat^® produced is of a fluffy appearance with a low density. A two-stage gasifier, based on a parallel-arranged bubbling fluidized bed and a fixed bed reactor, has been developed to convert Stabilat^® into hydrogen-rich product gas. This paper focuses on the design and construction of the configured laboratory-scale gasifier and experience with its operation. The processing of low-density fluffy waste-derived fuel using small-scale equipment demands special technical solutions for the core components as well as for the peripheral equipment. These are discussed here. The operating results of Stabilat^® gasification are also presented.     

Design for a high power-density Astron reactor

A liquid lithium blanket surrounding the plasma volume is described. The liquid lithium flows along magnetic flux tubes at a high speed. There is no vacuum wall between the blanket and the plasma. The E-layer of relativistic particles within which the plasma is confined serves as a vacuum wall protecting the plasma from the lithium vapor, which is continuously produced at the surface of the blanket, by ionizing the lithium atoms and ejecting the same along open magnetic lines. The heat load at the surface of the blanket generated by 14 MeV neutrons can be several hundred MW per square meter.Work performed under the auspices of the U.S. Atomic Energy Commission.Deceased September 24, 1972.