In a production facility for oleo chemical products, a pretreatment step is used to condition raw feed oils for downstream processes.
In a two-step distillation process, light ends and heavy ends are removed using two columns.
During the change from one feed oil to the other, the process leaves the steady state condition. The conditioned oil produced meanwhile does not achieve the downstream process requirements and must be recycled or discarded.
Thus, production time, energy and feed are wasted during the feed change. Minimizing the changeover time reduces these losses.
PSC2015’s goal is to find optimal trajectories for the operation parameters in order to minimize the changeover time for a given feed change and with given product specifications in a defined two-step distillation process.
Find the entire process and a more detailed description of the challenge in our scientific paper and our blog!
Download the summary of the task here.
Download the scientific paper here.
Download the CHEMCAD flowsheet here.
The CHEMCAD Job is set up in a way that the dynamic calculation ends automatically when all product specifications are met. The decision variables can be controlled via the Data Map “Design Variable Control”. To open the Data Map MS-Excel file in CHEMCAD, go to the menu Tools -> Excel Data Map -> Edit Data Map.
Select “Open” for access to the ramp parameters. Change the values in the green cells. To run the simulation, go back to CHEMCAD and klick the “Run Dynamic Simulation” button.
If the run terminates successfully, the product changeover time is transferred back to MS-Excel. The parameters that you enter in the web interface will be processed in the same way. Thus, be careful not to change the original simulation file, as you might get different results which cannot be reproduced by Chemstations.
Make a copy of the original simulation file to play around with and to get a better feeling of the dynamic process behavior. In your copy, deactivate the Data Map function for editing the parameter directly in CHEMCAD via menu Tools -> Excel Data Map -> Execution Rules.
To determine the winner of the Process Simulation Cup, the parameters you specify are run on a Chemstations server and in our original simulation file. The parameter set which leads to the shortest changeover time wins. In the case where the same changeover time is calculated, Chemstations will reduce the simulation step size to determine a more accurate changeover time.
Be aware of the plant constraints! Runtimes (minutes) in which the available condenser duties are exceeded (3 MW and 0.5 MW as described in table 4 of the scientific paper) are added to the final changeover time (“penalty minutes”).
27 February 2015: Soft-Launch of the PSC2015 at the Symposium Teaching Process Simulation in Berlin
5 February 2016: Submission closing day for PSC2015.
19 February 2016: Award Ceremony at the Computer-Aided Process Optimization Symposium
26 February 2016: Launch of the PSC2016 at the Symposium Teaching Process Simulation in Berlin