焦炉集气管压力的智能协调控制

设计了一种集气管压力的智能协调控制方案,解决焦炉集气管压力之间耦合严重,稳定性较差,极易出现压力振荡现象。综合考虑多集气管及风机、回流的特性,集气管翻板阀采用双模式PID算法,风机或回流阀进行整体吸力的协调控制,同时引入了振荡检测机制,并对压力振荡进行抑制。该控制方案的效果已在焦化企业现场得到了实践验证,并在多个现场应用。     

一种基于多尺度分析的多变量统计过程监测方法

现有的多尺度主元分析方法为监测具有多尺度特性的工业过程提供了一种有效途径,但该方法还存在以下两个问题：一是采用了重构步骤使得需要建立的监测模型数大大增加;二是采用Haar小波进行小波变换,而Haar小波不连续从而对信号特征的刻画能力比较弱,为此,本文提出了根据故障尺度特征的分布特点修改原有的多尺度主元分析的框架,去除了重构步骤并具体给出了突变故障和振荡故障的定位和跟踪方法,还提出了采用sym小波进行多尺度分析并解决了边界效应的处理和信号对齐的计算等问题,在一个标准的CSTR仿真过程中验证了所提方法的有效性。     

系统的控制策略对多变量统计监控性能的影响

为分析系统控制策略对复杂工业过程多变量统计监控的影响,以模拟实际复杂系统特征的标准问题Tennessee Eastman（TE）过程为测试对象,在基本控制、分散控制和厂级控制3种典型控制策略下,比较了各种控制策略的异同及其对于故障的抑制能力.采用故障检出率作为监控性能指标,详细分析了不同控制策略对基于主元分析（PCA）和基于数据相异度的两种具有代表性的多变量统计监控方法的影响.对TE过程20种故障的仿真结果表明,控制策略对监控方法性能的影响十分明显,针对控制策略的特点来选择合适的建模变量和模型参数能有效地提高故障检出率.     

焦炉集气管压力的智能协调控制

设计了一种集气管压力的智能协调控制方案,解决焦炉集气管压力之间耦合严重．稳定性较差,极易出现压力振荡现象。综合考虑多集气管及风机、回流的特性,集气管翻板阀采用双模式PID算法,风机或回流阀进行整体吸力的协调控制,同时引入了振荡检测机制,并对压力振荡进行抑制。该控制方案的效果己在焦化企业现场得到了实践验证,并在多个现场应用。     

复杂故障判定的基于结构化残差的多层次分析法

In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured residuals cannot isolate complex faults.This paper presents a multi-level strategy for complex fault isolation.An extraction procedure is employed to reduce the complex faults to simple ones and assign them to several levels.On each level,faults are isolated by their different responses in the structured residuals.Each residual is obtained insensitive to one fault but more sensitive to others.The faults on different levels are verified to have different residual responses and will not be confused.An entire incidence matrix containing residual response characteristics of all faults is obtained,based on which faults can be isolated.The proposed method is applied in the Tennessee Eastman process example,and the effectiveness and advantage are demonstrated.     

具有不确定性的聚烯烃牌号切换过程动态优化

聚烯烃生产经常需要进行牌号切换操作,最优牌号切换策略能在保证生产安全的前提下减少切换过程中的经济损失.由于实际生产中存在不确定性,基于理论模型的最优解无法保证最优的切换结果,甚至使牌号切换失败.对此,有学者将最优性条件校正策略引入牌号切换问题中,在克服不确定性方面体现出较好效果.从最优输入轨迹中提取合理的解模型是校正策...     

基于ARX-NNPLS模型的优化策略及在聚合物牌号切换过程中的应用(英文)

Since it is often difficult to build differential algebraic equations (DAEs) for chemical processes, a new data-based modeling approach is proposed using ARX (AutoRegressive with eXogenous inputs) combined with neural network under partial least squares framework (ARX-NNPLS), in which less specific knowledge of the process is required but the input and output data. To represent the dynamic and nonlinear behavior of the process, the ARX combined with neural network is used in the partial least squares (PLS) inner model between input and output latent variables. In the proposed dynamic optimization strategy based on the ARX-NNPLS model, neither parameterization nor iterative solving process for DAEs is needed as the ARX-NNPLS model gives a proper representation for the dynamic behavior of the process, and the computing time is greatly reduced compared to conventional control vector parameterization method. To demonstrate the ARX-NNPLS model based optimization strategy, the polyethylene grade transition in gas phase fluidized-bed reactor is taken into account. The optimization results show that the final optimal trajectory of quality index determined by the new approach moves faster to the target values and the computing time is much less.     

带路径约束的聚烯烃牌号切换操作优化方法

产品多样化需求使得聚烯烃生产过程中经常需要进行牌号切换操作。以往关于牌号切换优化的研究大多只关心切换过程结束后聚合物质量指标是否达到目标牌号值,对过渡过程中质量指标及状态变量的波动情况缺少关注,而过程的波动会影响到最终产物的质量性质和操作平稳性。为此,本文以聚乙烯气相流化床反应器为对象,通过在牌号切换优化命题中加入关于熔融指数等的路径约束,防止过渡过程中的状态变量剧烈波动影响聚合物树脂质量。为求解此类带路径约束的动态优化问题,对常规的控制变量参数化方法进行了改进,通过求解微分代数方程(DAE方程)将路径约束转化为控制变量约束。仿真结果表明,加入路径约束可以有效避免牌号切换中变量的剧烈波动,增强过程平稳性。