Multi-Resolution Modeling Of Material Flow For Petrochemical Production Processes

To meet the demand of modeling for enterprise-wide optimization and control system, it is often necessary to build an enterprise model with different levels of detail. Multi-Resolution Modeling (MRM), which combines and executes multiple models of the same enterprise jointly, has attracted more and more attention. Previous MRM approaches have encountered problems such as model formalization, model evaluation, high cost of modeling and mapping inconsistency. After a survey of major issues in Multi-Resolution modeling, we eliminate these problems by showing how to achieve MRM correctly, consistently and inexpensively. The main contributions in this dissertation are listed as follows:The formalization description of enterprise modeling is the foundation of MRM theory. Previous MRM formalization descriptions, such as DEVS and UNIFY, have encountered problems when they are applied in enterprise modeling. After analysis of the shortcomings of these descriptions, a kind of MRM formalization description base on the Multi-Node Structured System(MNSS) is proposed, which extends the definition and classification of node's property to provide both analysis function and descriptive function in enterprise models. The nodes in a MNSS have the same or similar resolution and are related one another to model an enterprise in the given level of detail. MRM formalization description proposed in this dissertation involves several layer of MNSS with different resolution depending on the demand of enterprise modeling.MRM evaluation is very important for effective modeling, but it is still a blank in this area until now. A set of model evaluation index, including consistency, completeness, correctness and observably, is established for MRM.To achieve effective MRM, the dissertation focus on the relationship between structure and properties of the MNSSs at different levels of resolution. Two kinds of multi-resolution modeling strategy suitable for model reuse and cost-efficient modeling are proposed. A hierarchical modeling method is also proposed to maximize the overall observability of the MRM with given modeling cost.An approach for hierarchical material flow modeling and its formalization description based on MRM were introduced in the integrated automation system for petrochemical industry. A Conversion method of material flow topography from its hierarchical formalization model is also proposed. A kind of space aggregation algorithm based on the material flow topography of the logistics associated matrix is designed to achieve the consist mapping of homomorphism and isomorphism in material flow MRM.The method of material flow MRM has been successfully applied in the design and implementation of the MES system in a real petrochemical enterprise. The on-line consistency verification of the hierarchical material flow model have been conducted in the MES system and satisfactory results are observed. Finally, the material flow MRM has been successfully applied in the Intelligent Plant Experimental System.