大试样热重分析仪及其在耐火材料研究中的应用

介绍了大试样高温热重分析仪的结构和特点以及在抗氧化性和氮化反应研究中的实际应用。该仪器由电加热、气氛控制、质量测量和自动控制四大系统组成。该仪器允许的最大试样尺寸为100mm×100mm×180mm,最大试样质量为5000g,最高试验温度达1600℃。该仪器既可以记录试样在匀速升温过程中的“质量-温度”曲线(升温法),又可以记录试样在恒定温度下的“质量-时间”曲线(恒温法)。采用升温法和恒温法分别研究了铝碳滑板试样和β-SiAlON结合刚玉试样的抗氧化性,并采用升温法研究了高铝矾土试样的氮化反应,结果均令人满意。     

间歇液相本体法聚丙烯聚合反应全过程的自动控制

介绍荆门炼油厂开发设计的间歇液相本体聚合反应全过程自动控制专用系统,它具有多调节规律并能自动切换的自动控制系统。1989年11月先后在本厂聚丙烯(PP)装置上投用4套该系统,对聚合反应升温、恒温直至反应终止的全过程控制平稳,减少了人为控制不当导致的不良后果,减轻了劳动强度,提高了经济效益。     

耐高温聚酰胺PA10T的聚合反应相态

研究了不同反应温度与压力条件下,耐高温聚酰胺聚对苯二甲酰癸二胺(PA10T)聚合反应相态情况,通过在升温反应前预先向反应釜内充入一定压力氮气的方法提高反应压力,在此基础上对比了不同初始压力下PA10T聚合反应的温度和压力随反应时间的变化情况,并绘制了PA10T聚合反应温度–压力相图。结果表明,在设定的反应温度范围内(220~270℃),反应温度与压力对PA10T的相对黏度和端基含量影响很小;PA10T聚合物溶液在230~250℃范围内(尤其在240℃时),处于热力学不稳定状态,在反应釜内长时间停留容易发生相分离,导致放料困难。通过降低反应温度至220℃或提高反应温度至260℃以上以及提高反应釜内初始压力两种途径,可大幅度延长相分离出现的时间,保持PA10T聚合物溶液处于均相状态,解决放料困难问题。     

煤焦油基沥青的热缩合聚合反应研究

本文以改质沥青为原料,采用直接热缩合聚合和催化热缩合聚合反应的方法,在高压反应釜中,氮气气氛保护进行热缩合聚合反应,合成出沥青中间相。考查了不同热缩合温度和不同恒温时间对合成煤沥青中间相的影响,用软化点测定仪对煤沥青的软化点进行了测定,并利用偏光显微镜对中间相的光学结构进行了观察。研究结果表明:采用直接热缩合聚合反应,在热缩合温度400℃下,恒温时间为5h,得到软化点为250℃的光学各向异性含量较高的优质中间相。催化热缩合可以降低煤沥青热缩合聚合反应的温度,控制反应温度为330℃,反应时间7h时,得到软化点263℃的光学各向异性含量较高的优质中间相。     

HRY-03S型高温荷软蠕变试验机计算机控制系统

HRY－03S型高温荷软蠕变试验机采用STD型工控计算机控制，升温温差±2℃，恒温温差±1℃，温度测量分辨率0．5℃，位移测量分辨率0．0025mm，实验结果自动处理，实验结束自动停机。     

氯乙烯悬浮聚合反应温度的微机控制

我公司1995年8月完成万吨/年PVC树脂生产装置的技改。在本次技改中,我厂与天津大沽化工厂协作,采用微机控制氯乙烯悬浮聚合反应温度技术。经工业生产装置验证表明,在恒温阶段,其控制偏差由技改前的±0.5℃稳定在±0.2℃以内,保证了PVC树脂的产品质量,缩短了聚合反应周期,节约了能源,减轻了工人的劳动强度。 氯乙烯聚合反应温度的控制见图1。图1中:U_0为蒸汽加热阀,U_1为循环冷水阀,U_2为回水阀,其工艺要求如图2所示。     

超临界乙醇抽提洗油组分的工艺研究

以超临界乙醇为抽提溶剂,采用恒容升温法对洗油组分中的氧芴、芴及苊进行超临界乙醇抽提工艺研究,对抽提产物进行GC分析,计算其超临界溶解度和抽提百分比.结果表明,氧芴与芴在超临界乙醇中的溶解性接近,均在反应温度为255℃,反应压力为7.0 MPa达到最大超临界溶解度;在反应温度为265℃,反应压力为11.0 MPa时超临界乙醇抽提百分比达到最高;苊在超临界乙醇中的抽提效果规律性不明显;超临界乙醇抽提洗油效果差异性明显;抽提完成后溶剂易于回收利用.     

ES纤维专用PP生产工艺控制

在间歇式液相本体法聚丙烯(PP)装置上,探讨了CS-1型和N-Ⅲ型高效催化剂的性能及催化效果,研究了氢气压差、反应温度、反应压力等因素对PP产品质量的影响.结果表明,采用N-Ⅲ型高效催化剂,控制氢气压差为14 MPa、反应温度为73～78℃、反应压力为3.6 MPa时,得到的PP产品质量最佳,可满足皮芯型双组分复合纤维专用PP的质量要求.     

基于Aspen Polymer的聚酯聚合反应研究及流程模拟

通过Aspen Polymer对对苯二甲酸和乙二醇进行逐步聚合生成聚酯的反应进行了研究。并采用间歇反应器模块分析了进料比、压力、温度对反应的影响,结果表明进料比为1.2～2.0是比较合适的,低压高温有利于聚合反应的进行。但过低的压力导致较低的反应速率而使反应时间增加,过高的温度也导致副产物大幅度增加。因此选择压力为0.001～0.2MPa,温度为260～285℃,在间歇反应器内进行逐步降压和逐步升温反应,并在此基础上,设计模拟了压力逐步降低、温度逐步升高的连续生产工艺流程并进行优化。经过优化后的连续生产工艺流程最终反应器出口聚合度达到121.1。     

超低聚合度的PVC树脂及其生产方法

专利申请号:CN200910167753.0公开号:CN101665548申请日:2009.09.25公开日:2010.03.10申请人:四川金路集团股份有限公司本发明公开了一种超低聚合度的PVC树脂及其生产方法。本发明采用聚合方法进行聚合反应,反应温度60～64℃,反应压力小于1.0MPa,在聚合反应开     

On-line multivariable adaptive control of a binary distillation column

An experimental evaluation of the simultaneous control of top and bottom product compositions of a binary distillation column utilizing multi-variable self-tuning control algorithms is presented. The study was carried out using an 8-tray, 22.86 cm diameter methanol–water pilot scale column with continuous capacitance analysis of top product composition and bottom composition analyzed on a 3 minute cycle, by a gas chromatograph. Column control is studied for ±25% step disturbances in feed flow rate. Terminal composition regulation using both ‘positional’ and ‘incremental’ forms of a generalized minimum variance self-tuning control algorithm is compared with that achieved using a conventional digital PI/PID multiloop control strategy.     

NONLINEAR MODEL PREDICTIVE CONTROL

Nonlinear Model Predictive Control (NMPC), a strategy for constrained, feedback control of nonlinear processes, has been developed. The algorithm uses a simultaneous solution and optimization approach to determine the open-loop optimal manipulated variable trajectory at each sampling instant. Feedback is incorporated via an estimator, which uses process measurements to infer unmeasured state and disturbance values. These are used by the controller to determine the future optimal control policy. This scheme can be used to control processes described by different kinds of models, such as nonlinear ordinary differential/algebraic equations, partial differential/algebraic equations, integra-differential equations and delay equations. The advantages of the proposed NMPC scheme are demonstrated with the start-up of a non-isothermal, non-adiabatic CSTR with an irreversible, first-order reaction. The set-point corresponds to an open-loop unstable steady state. Comparisons have been made with controllers designed using (1) nonlinear variable transformations, (2) a linear controller tuned using the internal model control approach, and (3) open-loop optimal control. NMPC was able to bring the controlled variable to its set-point quickly and smoothly from a wide variety of initial conditions. Unlike the other controllers, NMPC dealt with constraints in an explicit manner without any degradation in the quality of control. NMPC also demonstrated superior performance in the presence of a moderate amount of error in the model parameters, and the process was brought to its set-point without steady-state offset.     

模糊控制的现状与工程应用关键问题研究

详细阐述了模糊控制技术的研究现状,包括经典模糊控制、智能模糊控制和复合模糊控制。研究分析了模糊控制技术在工程应用中存在的若干问题,包括模糊控制规则和参数优化问题、强耦合多变量问题和模糊控制稳态精度问题,并根据目前国内外模糊控制技术的研究趋势,指出了模糊控制技术未来的研究方向。     

裂解炉的先进控制

介绍了中国石油大庆石化公司化工一厂乙烯装置GK一Ⅵ型裂解炉的主要控制方案，并结合工艺操作具体说明控制方案的实现过程。     

Generic model control — A case study

This paper outlines the use of a process model directly in a control algorithm. The process considered, a forced circulation single-stage evaporator, is a nonlinear interacting process. The control strategy employing a process model derived from fundamental mass and energy balances is shown to outperform single loop and predictive control strategies by a significant amount. The control structure is first presented in general form and then specifically applied to this process.     

Two-degree-of-freedom output feedback controllers for nonlinear processes

In this work, a nonlinear output feedback control algorithm is proposed, in the spirit of model-state feedback control. The structure provides state estimates using a process model, the measured output, and the residual between the model output and the measured output. These estimates will track the process states at a rate determined by a set of tunable parameters. An algebraic transformation of the state estimates is incorporated in the control structure to ensure that the input/output gain of the observer matches the model upon which the static state feedback control law is based. The transformed states are then used in the control law. This leads to a controller of minimal order possessing integral action. The control structure is shown to have the same properties as the standard model-state feedback structure. The resulting algorithm is a two-degree of freedom control law, in the sense that the control action is not a function of the error only, but the output and the set point are processed in different ways. Finally, a simulation example using an exothermic CSTR operating at an open-loop unstable steady state is used to demonstrate the closed-loop performance of the proposed method.     

轮胎硫化生产过程的模糊控制

分析轮胎硫化生产过程的特点,建立了硫化罐温度和压力控制的多维模糊控制数学模型,设计了适合该模型的控制算法,并在实际工程中予以实现。实践表明该控制方法具有较好的鲁棒性和较好的控制效果,并具有一定的推广价值。     

大时滞过程中的智能复合控制方法及应用

针对复杂工业过程中通常存在的大时滞现象,本文介绍了几种智能复合控制方法,并对其应用进行举例说明。     

Two-degree-of-freedom output feedback controllers for discrete-time nonlinear systems

A discrete-time, model-based output feedback control structure for nonlinear processes is developed in the present work. The structure makes use of a closed-loop observer, while at the same time it guarantees that the overall feedback controller possesses integral action. An algebraic transformation is applied on the observer states to insure that the input/output gain of the observer matches the model upon which the static state feedback control law is based. The resulting control algorithm is a two-degree-of-freedom control law, in the sense that the output and the set point are processed in different ways. The control structure is shown not only to have the same properties as the standard model-state feedback structure, but also that it emerges from a model algorithmic control framework. Finally, a simulation example using an exothermic CSTR operating at an open-loop unstable steady state is used to evaluate the closed-loop performance of the proposed method.     

粗轧控制系统的设计与应用

结合生产实际,对粗轧控制系统进行综合设计。介绍粗轧控制系统的结构,以及粗轧核心APC控制、粗轧RAWC控制和带铜SSC控制的控制思想并给出相应控制算法。