CATALYST DEACTIVATION BY PORE PLUGGING AND ACTIVE SITE POISONING MECHANISMS II. PARALLEL POISONING IN BIDISPERSE STRUCTURED CATALYST

A catalyst deactivation model is formulated which includes the combined effects of pore plugging and active site poisoning in bidisperse structured catalyst particles. Intraparticle mass transfer is described by an equation which accounts for the configurational nature of diffusion in the micropores, and poison deposition is assumed to be in accord with a parallel poisoning mechanism. The model is used to explore the effects of macroporosity and micropore size on initial activity and activity maintenance, and model predictions appear to be consistent with observations from a recent coal liquefaction catalyst development program.     

仪化涤纶三厂PTA输送装置的介绍和工艺设计分析

介绍了改造后的PTA输送装置，分析了装置改造的特点，并对其工艺设计进行了核算和讨论。     

精馏过程专家系统用数据库系统的设计与实现

化工物性数据内容庞杂，数据库的设计是化工软件的重点和难点，本文提出一种用ＴＵＲ－ＢＯＰＲＯＬＯＧ语言外部数据库技术实现基于磁盘的数据库管理系统的设计方法，解决了数据库庞大与微型机内存不够的矛盾，通过接口计算模块可方便地从本数据库中调用数据；实现了友好的用户界面，提高了数据库管理的效率和透明性。     

不饱和聚酯树脂固化过程及结构变化

本文概述了不饱和聚酯树脂固化过程发生的各种化学反应。重点介绍动力学－凝胶机理及应用此机理对反应动力学的各种结果的解释。     

化肥装置用材与工艺的分析

通过对九江化肥装置材料选择、使用条件、腐蚀机理的分析,结合类似装置曾发生的设备损坏事故,对装置运行中工艺参数条件控制的若干方面进行了讨论,以延长设备使用寿命,保证安全稳定生产。     

CATALYTIC CONVERTER DESIGN FOR MINIMISATION OF COLD-START EMISSIONS

The axial catalyst distribution in a monolithic converter that minimises cold-start pollutant emissions is investigated numerically, under the constraint of fixed total catalyst surface area. Various warm-up mechanisms can be present during the transient period. The catalyst distribution affects greatly which mechanisms prevail. For the optimal distribution, a large amount of catalyst is required in the upstream section of the monolith This ensures that the hot spot is kept at the monolith inlet throughout the warm-up period, and hence heat transfer by convection dominates. A result of practical significance is that the evolution and the steady-state value of the temperature of the exhaust gas stream at the monolith inlet do not affect significantly the form of The optimal distribution. Even though the local catalyst surface area of the optimal distribution in the downstream section of the converter is reduced as compared to the uniform distribution, steady-state performance is not adversely affected. A converter with two-zones, each having a different but uniform catalyst loading is also examined. It is shown that such a design can closely approximate the optimal distribution. Finally, performance degradation due to sintering is shown to be more severe for The case of the uniform catalyst distribution.     

催化剂孔结构参数的设计及对宏观活性的影响

催化剂孔结构对其宏观活性是至关重要的,而孔结构的设计与优化是反应工程与催化剂工程的交叉。本文着重就前人对某一特定催化反应内扩散对宏观反应速率(效率因子)影响的工作进行了评述,并指出以反应工程理论指导催化剂设计将对催化剂制造有很重要的作用和指导意义。     

A CASE STUDY FOR CONTROL STRUCTURE SELECTION: CHLORINATION STAGE IN THE BLEACHING PROCESS OF A PULP AND PAPER PLANT

The minimization of chlorinated organic compounds in the effluents of the chlorination unit of a pulp mill is proposed by the use of a control structure for the chlorination unit. Bleached pulp properties are related to the unbleached pulp properties: lignin content, brightness, and viscosity, as well as the amount of chlorinated organics in the bleachery effluent. The best feasible control pairings are studied by RGA and SVD methods. Kappa number of the bleached pulp (a measure of lignin content) and percent consistency of the pulp to be bleached; residual chlorine (which affects the amount of chlorinated organics discharged) and percent chlorine/pulp ratio adapted in the chlorination stage; and exit pulp viscosity (which directly affects strength and tear resistance of the paper) and residence time in the chlorinator are chosen to be the best pairings.     

ROLE OF SUPPORT STRUCTURE ON KINETIC PARAMETER ESTIMATIONS IN A SHELL CATALYST

The kinetic parameters for VOC oxidation by a shell catalyst are generally obtained from the experimental data of conversion-temperature in a laboratory scale isothermal fixed bed reactor. The kinetics of these reactions are often represented by a bi-molecular Langmuir-Hinshelwood expresion. With the help of experimental data for n-hexane, the present study showed that the values of the kinetic parameters estimated depend significantly upon the location and width of the active catalyst layer as well as value of the effective diffusivity of the reactant within the porous structure. The present analysis showed that accurate a priori assessment of these parameters is very important for the reliable estimations of the kinetic parameters.     

制药厂反渗透系统的工艺及系统运行

本文介绍了江苏某制药厂两级反渗透纯水系统在调试和其后的运行过程中出现的问题以及处理措施。     

一典型结构复合材料零件的VARTM注射方式优化及实验

利用RTM-Worx模拟软件对一典型结构复合材料零件使用6种常用真空辅助树脂传递模塑(VARTM)注射方式进行充填模拟,通过对模拟结果进行分析对比,选择了其中最合适的线注射方案,并对该线注射方案进行注射流道长度及双线注射流道位置优化设计,得到了该类零件的最优化VARTM注射方式并进行了实验验证,实验与充填模拟结果吻合较好,得出了如下结论:增长注射流道长度虽然可以增加树脂进入的瞬时体积流量,减少充填时间,但流道过长可能造成流到边缘的树脂往构件中心方向回流,容易形成气泡、干斑缺陷,影响制件质量;当构件宽度较大时,可以选用多线注射,且当采用n线注射时,注射流道可顺着构件长方向布于其宽方向i/2n(i=1,3,5,…,2n-1)位置处。     

生物发酵工厂灭菌工艺的设计

阐述了以现代生物技术为特征的生物发酵工厂灭菌工艺的设计方法。     

桐乡市城市污水处理厂A2/O工艺设计与运行

桐乡市城市污水处理厂设计规模为5×104 m3·d-1,采用A2/O工艺.本文介绍了其工艺流程、主要构筑物的特点和设计参数,反馈了实际运行中存在的问题及采取的技术性措施.并详细阐述了"喷洒天然植物提取液除臭方案"的设计情况.     

乙烯装置与干气回收联合的再生系统探讨

介绍了乙烯装置与干气回收装置联合的情况下再生系统工艺流程,探讨了某再生系统优化前后的工艺流程设计,认为优化后的再生流程在安全性、可操作性和能耗等方面均有较大改善,为同类装置的工程设计提供借鉴。     

炭素回转窑的工艺设计与计算

通过对各种参数的计算,导出回转窑的长度,内径,煤气量、空气量,并对回转窑的物料平衡和热平衡进行计算,最终计算出烟气量,烟气成分及温度。     

百万吨级乙烯装置裂解炉先进控制系统设计与应用

以恒力石化(大连)化工有限公司1500 kt/a乙烯装置裂解炉为例,详细描述裂解炉的工艺流程,分析常规控制方案存在的问题,进而重新设计控制系统,该系统包括平均COT控制、支路温度平衡控制、支路温度“高控”“低控”和总进料流量提/降量控制。并且还介绍控制系统的工程实施,其中包括先进控制系统硬软件平台、先进控制与常规控制的切换逻辑、先进控制系统操作界面等。本系统的投用提高了裂解炉控制的平稳度,延长了裂解炉的运行周期,带来了显著的经济效益。     

A STUDY OF CLOSED CYCLE DRYING FOR THE COATED FILM WITH ORGANIC SOLVENT ON THE CONTINUOUS SHEET MATERIALS

The conventional drying of the coated film with organic solvent on continuous sheet materials is usually performed in open or one pass drying system using air as the drying medium. The concentration of evaporated organic solvent in the drying system must be low enough to prevent explosion and large volume of off gas from dryer to solvent recovery system is required, resulting in poor heat economy for all the plant

To improve the heat economy of the plant it had been proposed to use a closed cycle drying system, where an inert gas, e.g. nitrogen, is used as the drying medium. High concentration of the organic solvent in the recycle gas mixture may then be used, which results in smaller volume of recycle gas and possibility of applying an inexpensive solvent recovery system of dehumidification. This investigation includes two important problems to realize the closed cycle drying

(1)Measurement of solvent (toluene) evaporation rate from coated film in the gas mixture of toluene andnitrogen over a wide range of toluene/nitrogen ratios (0-1.0) and drying temperature using bench scaleapparatus

(2)Development of a contactless sealing method, using an inert gas, for closed cycle drying of continuoussheet materials. The results of preliminary tests demonstrate its feasibility.     

THE DESIGN AND DEVELOPMENT OF A NOVEL TRANSDUCER FOR THE MONITORING OF PROCESS PARAMETERS UNDER AGGRESSIVE ENVIRONMENTS

This paper describes the design and development of a novel vibrating reed transducer capable of providing routine and on line measurements of various process parameters. The system is driven and detected remotely under ambient conditions by transmitting transverse vibrations through a stiff elastic rod which is securely clamped at an intermediate point along its length. This allows operation under aggressive environments as only one free span of the vibrating element enters the test medium. The unit, when employed in the form of a gas densitometer can provide density measurements with ±1 × 10^-3 g/cm³ resolution when tested with the gases N₂, C0₂ and He up to a maximum pressure of 150MPaand70°C.

A mathematical analysis is also developed which successfully predicts some of the design criteria required for developing systems which are stable and whose response is governed predominantly by the conditions prevailing at the sampling or the remote span of the reed.