Industrial process models fidelity

Since the advent of efficient and robust simulation and optimization solution engines" and flowsheeting software packages that allow for relatively easy configuration of complex models, numerous integrated, high fidelity, and multiscale process model applications have been deployed in industrial plants to monitor performance and to determine and capture improvements in operating profit. 

High-fidelity models for industrial catalytic reactors can be incorporated into these flowsheet simulators via a number of techniques depending on the characteristics of the flowsheet simulator. In some steady-state flowsheet simulators, there is a built-in facility for the user to add his own module. In such cases, the high-fidelity reactor model can be added as one of these special modules. The reactor model in this case can make full use of the physical properties database available in the simulator. However, in most flowsheet simulators, this facility is not available in such cases, the module can be used with the flowsheet simulator on the basis that the output variables from the last unit preceding the catalytic reactor is used as an input file to the catalytic reactor model, and when the calculations for the reactor are complete, the output file from the reactor model is used as an input file to the unit next to the reactor in the process flowsheet. Clearly, this last technique is less efficient and takes more effort to implement than in the first case. 

Industrial applications began in the 1970s. This was made possible by the development of highly selective polyvinyl alcohol composite membranes. The process is clearly discussed by Sander and Soukup. They provide engineering performance curves for removing water from an ethanol-water mixture. The curves show how the temperature and ethanol concentration of the feed affect the flux of water through the membrane and the composition of the permeate stream. These performance curves are used in this chapter to provide a simple pervaporation model that captures the behavior of the process with sufficient fidelity for use in control studies. 

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