Design And Development Of An Environment For Graphically Modeling And Simulating Chemical Systems

Chemical model is important for analyzing system dynamic properties,controlling, safety evaluation and operator training. But chemical object iscomplex system of material, energy and message. Its model building needsdeep special knowledge, software design and development skill, which limitquality and rate for simulator development. To solve the problem, this papercarries the following study:(1) This paper establishes basic models of chemical system.These chemical models are established based on chemical engineeringprinciple, using expression concepts of stream and accumulator, and uniforminterface. The models mainly include material property calculation models, oilsystem characterization models, chemical unit operation models (pipe, pump,compressor, vessel, distillation column, heater, flash separation, PID, logicunit and so on).(2) This paper proposes a particular format of multi-input multi-outputHammerstein model, and improved new neural dynamic method to identifyHammerstein model parameters. For making up the disadvantages of the mechanical models, the paperproposes a particular format of multi-input multi-output Hammerstein model.The improved new neural dynamic algorithm with the idea of alternatingiteration is used to identify two sets of the model parameters. The algorithmwith high accuracy and convergence rate is applicable for online identification.The paper also proposes a new hybrid modeling method, based on themulti-input multi-output Hammerstein model, which was to build an errormodel between actual system and basic system. Since the new neural dynamicmethod can adjust Hammerstein model parameters online, the hybrid modelcan be used to simulate dynamics of complex process in a large scale. Therationality and efficiency of presented method are demonstrated by simulationexamples.(3) This paper describes structure of the simulator platform in detail,firstly gives the idea of six levels, and builds chemical platform.This paper analyzes demand of chemical system modeling and simulating.Based on this, it concludes six levels for establishing chemical platform,which include running level, flowsheet level, equipment level, unit level,process control level, material property level. Based on these six levels, thispaper designs and builds chemical modeling and simulating platform.Modeling function allows users build model graphically, initialize modelparameter, edit model properties and serialize model data. Simulating functionincludes instructor, process running and instrument data checking. (4) This paper successfully establishes the petroleum tower andatmospheric distillation tower using the platform. The simulation resultdiagram shows great rationality and efficiency. Users can build chemicalsystem models without much deep knowledge.