Historical simulation advantages

The simulation is performed in BEMFlow off-line. Afterwards, the simulation results are visualized with the help of BEMView, which animates the flow conditions in 3D (Fig. 1.20). The simulations have been run with different screw speeds in order to compare the respective flow conditions. The simulation expert, who took advantage of historical simulation data stored in TRAMP, provides his own contributions by recording animations as video clips, categoi izing and annotating them, and storing the annotated videos in the TRAMP database. 

For particular cases, it maybe required to add more complex phenomena with additional effects or more evolved descriptions of the same mechanisms. In general, however, reduced models are appropriate and desirable. Historically, this stemmed from the shorter computational effort and time required for the numerical solution of such models. Today this is also an advantage for optimization, control, and real-time simulation applications, and reliable simplified models are still used for almost all purposes due to the lower number of dimensionless parameters requiring estimation and to the success found in the description of experimental results. On the other hand, complex detailed models fulfill the most generic purpose of reactor simulation, which is related to the prediction of the actual behavior from fundamental, independently measured parameters. Therefore, it is important to understand the equivalence and agreement between both detailed and reduced models, so as to take advantage of their predictive power without unnecessary effort. 

Historically, the basis of gas permeation module design was first proposed by Weller and Steiner in 1950. Nowadays, modem computation techniques provide numerical solutions to the problems thanks to dedicated routines. Orthogonal collocation methods or perturbation methods " are reported to be particularly attractive when a minimum resolution time and computational efforts are required. Several of these routines have been implemented in commercial process simulation software, where advantage can be taken of thermodynamics or unit operation design packages in order to simulate hybrid or multi-stage operations with gas separation membranes. Nevertheless, much effort has been devoted to... 

The advantage of this method is that LP now reflects the actual capabihties of the unit and not the perceived capabilities based historical data or correlations. In addition, if the rigorous simulation is updated alongside with plant retrofits, we can modify the LP model quickly to track these retrofits. The workflow we describe in Figure 4.36 is easy to integrate into existing process simulation and LP software. Aspen HYSYS Petroleum Refining includes tools to automate the workflow and export the updated DELTA-BASE vectors to Aspen PIMS (LP software) directly. This automahon allows quick updates of the LP model to accurately reflect unit performance. 

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