PTA中的PT酸控制

分析了PTA中PT酸的来源,PT酸与PTA结晶过程的结晶原理,结晶过的可变因素冷却速度和溶剂比。从进料、结晶温度、浆料流速和停留时间等几个方面进行控制,降低了PTA中的PT酸含量。确保PTA中PT酸品质指标合格。     

PTA工艺进展与污染控制

PTA生产工艺同污染之间存在较大关联性。PTA生产工艺发展很快,但污染治理却相对滞后。由于PTA废水的毒理性和处理难度,废水治理仍是国内不少PTA企业不得不面对的环保焦点。     

浅论控制PTA产品粒度分布的途径

本文针对扬子石化公司化工厂PTA装置目前PTA产品粒度分布现状,通过采用正交试验方法对结晶器工艺参数进行了调优,并对正交试验结果进行方差分析指出了影响PTA小颗粒分布的最主要因素是,对第一结晶器温度和第二结晶器温度的控制。经过装置试运行后,已基本控制住PTA产品粒度的分布。     

PTA色泽质量的表征及控制

针对现有的精对苯二甲酸(PTA)的色泽质量表征方法及控制指标的局限性,提出了采用PTA的三刺激值a~*,b~*,L~*值及紫外透过率(340 nm)表征PTA的色泽质量。PTA生产中必须控制有机多环副产物产生和金属元素的含量,产品的色泽质量才能有效控制。用a~*值、b~*值、L~*值及紫外透过率能较全面、正确地表征PTA的色泽质量,但a~*值、b~*值应控制在一个合适范围,而L~*值和紫外透过率应大于一定值,PTA才能较好地满足聚酯生产的需要。     

PTA装置氧化反应系统开车过程逻辑控制优化

介绍了PTA装置的氧化反应系统工艺过程及控制原理,讨论了基于传统DCS控制系统的氧化反应系统开车过程中的存在的问题。针对上述问题,运用逻辑代数提出了将反应过程规律和设备运行规律之间的关系进行逻辑化处理的解决方案,提前预防事故和故障,避免事后制定反事故措施和消除缺陷。方案实施效果表明:PTA装置氧化反应系统采用开车过程逻辑控制方案后,节约了开车时间并减少了开车错误的发生。为避免开车错误指明方向并提供了方法。     

PTA溶剂脱水塔先进控制与在线优化

从PTA溶剂脱水塔的工艺操作特点出发，运用RMPCT多变量预测控制软件，建立以塔顶与塔釜组分为被控变量，以塔釜温度回路设定值和回流量为操纵变量的溶剂脱水塔先进控制与在线优化系统．稳定溶剂脱水塔的操作，综合降低塔的酸耗和蒸汽消耗，取得满意的控制效果。     

浆料配制工序取消PTA秤后的控制优化

主要针对PET装置的浆料配制工艺过程中,PTA称量装置出现故障时,现场取消了PTA称量装置,并在生产上实现平稳控制而作出的一系列控制优化。     

探讨控制PTA产品质量新途径

文章叙述了PTA工艺流程,介绍了PTA产品质量重要指标B-值,指出了产生B-值的原因,影响因素,建立B值的控制模型,寻找到了控制产品的B-值的新途径。     

PTA产品中PT酸含量的控制

通过对辽阳石化新建53万t／a PTA装置运行状况的研究,探讨了PT酸产生机理,并对PT酸分离过程进行了分析。探索出影响PTA产品中PT酸含量的主要因素为氧化中间产品CTA中4-CBA的含量、结晶器操作温度、离心分离效果等。提出了工艺控制的重点,以保证PTA中PT酸含量达到优等品指标。     

TA浆料浓度模型预测控制

分析PTA装置精制工段TA浆料浓度配置单元的系统特性 ,讨论原控制方案中PID控制的不足 ,针对打浆水、喷淋水以及某些未知扰动对浆料浓度的影响 ,采用模型预测控制技术并记录为实施模型预测控制而进行的相关测试数据。     

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。     

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.     

污水处理智能控制系统的研究进展

本文综述了国内外污水处理自动控制技术的发展现状，重点介绍了模糊控制、神经网络控制、模糊神经控制以及专家控制的最新进展以及在污水处理过程中的应用。并结合国内外研究动态简要分析了污水处理智能控制的重要性和今后的发展方向。     

暖通空调系统基于SMITH预估自校正控制算法

目前暖通空调控制系统中普遍存在运行效率低下、能耗浪费严重的现象,主要原因在于暖通系统本身具有时变、时滞等非线性特性,使得传统的控制方法无法取得良好的控制性能。如何克服暖通空调系统时变和时滞特性所带来的不利影响,是提高暖通空调系统控制回路性能的重要途径之一。本文设计了一种基于SMITH预估的自校正控制算法,首先通过在线辨识包含时滞参数在内的暖通空调对象模型,进而采用SMITH预估器对时滞进行补偿,而SMITH预估器中的PI控制器则用于提高鲁棒性,并实现控制器参数的实时更新。仿真结果表明该算法性能要优于传统的控制方法。     

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.     

ADAPTIVE CONTROL OF A BATCH REACTOR

A globally stable adaptive predictive control system (APCS) is evaluated by application to a simulated PVC batch reactor. The reactor is run under APCS control with the objective of either temperature setpoint tracking or constant reaction rate. The batch nature of this system makes it possible to learn about the physical problem from successive runs. This knowledge is incorporated into the control strategy to improve the performance of the reactor. The problem of excessive manipulation of the control variable has been recognized and resolved by using control weighting. Performance of the adaptive technique is compared with previous results using self-tuning and PID control of the same reactor. APCS provides good, robust control despite the nonlinear dynamics of the system.     

压缩机组速度控制方案研究

以丙烯压缩机组为例,详细论述基于TRICON TS3000系统的压缩机速度控制方案,介绍了压缩机工作原理及速度控制过程。结合丙烯压缩机升速曲线,将压缩机的运行状态分成多个模式进行阐述,确定不同模式下的目标转速范围,将动态的目标值作为速度控制给定值。经过运算,控制调速器的开关大小,进而调整蒸汽量的大小,实现转速控制。     

模糊控制在聚合装置的应用

介绍了模糊控制在我厂聚丙烯聚合装置的投用，并结合聚合的工艺特点详细介绍了模糊控制的理论和对聚合的模糊控制方案。     

基于IMC结构的PID-GPC的鲁棒性分析

Proportion integral differential generalized predictive control(PID-GPC),a new type of generalized predictive control(GPC) is introduced,and its quality is analyzed with internal model contron(IMC).A very important characteristic,which distinguishes GPC from ordinary IMC,and the robust effect are found.At the same time,a robust region is obtained according to the control laws,so that the defect that the robust analysis could be carried out only with stable models is vercome.It is verified that the robustness of PID-GPC is stronger than general GPC.     

Analysis of the lumped and distributed optimal temperature trajectories for packed bed reactors with concentration dependent catalyst deactivation

Algorithms published previously by the authors for solving the problem of spatially uniform and non-uniform temperature optimal control in tubular fixed bed reactors have been applied to three systems with series catalyst deactivation and different ratios between the activation energies of the main and deactivation reactions. The optimal temperature and conversion trajectories as well as the maximum production obtained have been compared at the same final duration of operation. Systems with slow deactivation obtain maximum production with spatially uniform control, whilst for systems with rapid deactivation the temperature trajectory distributed both in space and time improves the production obtained with lumped control.