ISSN:0008-4034    

DOI:10.1002/cjce.5450690101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:0008-4034    

DOI:10.1002/cjce.5450690102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper presents an overview and personnal perspective on recent developments and current practice in computer process model. The basic concepts behind conventional process control are reviewed to provide a starting point for the non‐control specialist and process engineer. The ensuing sections on Internal Model Control (IMC), Model Predictive Control (MPC) and adaptive control illustrate the evolution of control technology from the traditional multiloop strategies to the modern, multivariable, model‐based, computer control systems now being used in industry. The paper does not provide a complete, critical review of process control. However, the discussion and the recommended references should provide a good starting point for anyone wanting to become familiar with current practice and some of the new directions of process cont

ISSN:0008-4034    

DOI:10.1002/cjce.5450690103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper presents a method for Error‐in‐Variables Model (EVM) analysis when there is no prior knowledge of the error structure, but there is replication in the data. The method is presented, with examples, for cases where the error structure varies among the data, and for cases where the error structure is constant over all the data. The minimum amount of replication needed is discussed and posterior probability density functions are developed for the parameters. The results are an extension of the work of previous auth

ISSN:0008-4034    

DOI:10.1002/cjce.5450690104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractProcess computers routinely collect hundreds to thousands of pieces of data from a multitude of plant sensors every few seconds. This has caused a “data overload” and due to the lack of appropriate analyses very little is currently being done to utilize this wealth of information. Operating personnel typically use only a few variables to monitor the plant's performance. However, multivariate statistical methods such as PLS (Partial Least Squares or Projection to Latent Structures) and PCA (Principal Component Analysis) are capable of compressing the information down into low dimensional spaces which retain most of the information. Using this method of statistical data compression a multivariate monitoring procedure analogous to the univariate Shewart Chart has been developed to efficiently monitor the performance of large processes, and to rapidly detect and identify important process changes. This procedure is demonstrated using simulations of two processes, a fluidized bed reactor and an extractive distillation col

ISSN:0008-4034    

DOI:10.1002/cjce.5450690105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractMeasurements from industrial processes are often serially correlated. The impact of this correlation on the performance of the cumulative sum and exponentially weighted moving average charting techniques is investigated in this paper. It is shown that serious errors concerning the “state of statistical process control” may result if the correlation structure of the observations is not taken into account. The use of time series methods for coping with serially correlated observations is outlined. Paper basis weight measurements are used to illustrate the time series methodol

ISSN:0008-4034    

DOI:10.1002/cjce.5450690106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA methodology has been developed for the analysis of operational flexibility of a continuous processing plant. An application has been demonstrated for a multipurpose plant with uncertain operating conditions. A practical flexibility analysis procedure using a direct search optimization algorithm is proposed to solve the problem. The method provides a heuristic screening technique that makes it possible to avoid the exhaustive enumeration of every constraint vertex, while the direct search optimization offers a simple and effective means to identify bottlenecks. A refinery multiperiod plant problem has been investigated in order to highlight the procedures which lead to the construction of flexibility indices for each operating mode.

ISSN:0008-4034    

DOI:10.1002/cjce.5450690107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper presents the development of an expert system, called SIS (Separator Identification System), to generate near‐optimal separation sequences for any multicomponent mixture. SIS was designed based on a combination of heuristic and algorithmic approaches. Heuristics were used to select the location of the split. Algorithms were used to calculate physical properties of the multicomponent mixture. A fuzzy approach was used for the propagation of the truth function and uncertainty management. SIS was tested using four sample problems involving gas, liquid, and solid components. The separation sequences suggested by SIS were the same or similar to those found in process synthesis literatur

ISSN:0008-4034    

DOI:10.1002/cjce.5450690108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractIn this paper a diagnostic Knowledge Based Expert System (KBES) prototype for a nuclear Auxiliary Boiler Feed System (ABFS) was developed. A commercial Expert System shell accesses heuristic production rules to quickly resolve the majority of common faults. Supplementing this are a series of C functions which access the Fault Tree data base previously developed during the licensing process. These functions perform diagnostics, give detailed explanations of failure mechanisms, and identify system failure risks through examination of cut sets. The capture of both heuristic and Fault Tree information has resulted in a more exhaustive diagnostic tool with a domain of application unrestricted by the limitations of previous operator experience.

ISSN:0008-4034    

DOI:10.1002/cjce.5450690109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractCette publication montre que les algorithrnes de raisonnement qualitatif manipulent les qualitiés par une caractérisation des valeurs réelles. Un exemple simple fait ressortir la signification qualitative du raisonnement de QSIM (Qualitative SIMulation), son calcul par intervalles et ses limitations. Par la suite, on propose une extension de QSIM pour intégrer differentes connaissances (règles de production, raisonnernent qualitatif, ordre de grandeur, calcul quantitatit) dans un algorithme de simulation qualitative‐quantitative (QQSIM) en qualifiant les données sous forme d'intervalles. Cette extension permet l'utilisation du raisonnement qualitatif sur un système de traitement d'eaux usèes. Pour terminer, on montre que cette approche s'applique dans un contexte de systèm

ISSN:0008-4034    

DOI:10.1002/cjce.5450690110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY