Initial conditions in terms of temperature and vapor or liquid molar flowrate profiles may be provided directly by the user or may be generated internally by the PRO/II initial estimate generator (IEG). Four different models are available for the IEG.
SIMPLE - The vapor rates are calculated from simple mass balance. Temperatures are determined by estimating the product compositions and determining the bubble points or dew points as appropriate. The resulting profiles are linear.
CONVENTIONAL - Uses the Fenske shortcut model for conventional columns or flash for absorber/strippers. This method is the most general and generally applicable IEG, and is recommended for most two product distillation problems. CONV will use product specifications (if applicable to shorcut model) and/or product rates to get a Fenske model for initial profiles.
REFINE - Uses the Fenske shortcut model for multiproduct separations normally found in refinery units like crude units and FCC main fractionators. REFI will use product specifications (if applicable to shorcut model) and/or product rates to get a Fenske model for initial profiles.
CHEMICAL - Uses a multiflash technique (series of L/F flashes up and down colum) to bring the temperature, flow, and composition profiles closer to the final solution before the column algorithm takes over. This method is CPU intensive and is recommended for difficult, highly non-ideal distillation problems.
About PRO/II: PRO/II is the major product in the Process Engineering Suite (PES). This process simulation software optimizes plant performance by improving process design, operational analysis, and performing engineering studies. It is designed to perform rigorous heat and material balance calculations for a wide range of chemical processes. PRO/II allows users to evaluate the use of heat integration with case studies, rigorously evaluate process improvements with the help of a process flow diagram (PFD), or model crude distillation units. PRO/II offers a wide variety of thermodynamic models to virtually every industry and is incredibly cost effective, decreasing both capital and operating costs.
Technical Support: As always, feel free to reach out to your local technical support team for more information.
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