abstract
The present dissertation made in the company EGEO Solventes S.A, had as major goal the optimization of the single staged discontinuous columns by making a viability study on the usage of packing on said columns and subsequent analysis and result comparison with and without packing usage. Being a company that operates on solvent recovery by using industrial separation equipment, and is always keen on maximizing the overall efficiency of their site, the study done in the present dissertation aims to take advantage on the latest technology available on process simulation and modelling in order to assist the company in the pursuit of one of their main goals: continuous improvement. The work started by rigorously profiling a real single staged discontinuous column to obtain valuable experimental data which was proven fundamental to make some important calculations and to feed the simulator’s input fields that was going to be used in the present study. Two very different kind of dirty mixes were chosen to profiling analysis to reach a wider array of results: A product often produced by the company for selling as a company-branded product, and a new product composed by an unfrequently seen mix that would be returned to the client after processing. It was registered instant distillate volumetric flow rate values, distillate, bottom, mid and top temperatures, operational and condensate pressures, distillate density, mixing compositions, and other miscellaneous data this way allowing to have a good initial solid ground to tighten the simulation iterations to more realistic values. With this data, it was also possible to calculate the value of an important input parameter, HETP, that was to be used in the simulator. After successfully profiling the operation method of the single staged discontinuous columns, stage two of the present work began: Process modelling and packing usage simulation while comparing the results in the software Aspen Plus®. By using every collected data so far and converging the modelling results, using the following iterative calculations, to a realistic scenario, it was possible to conclude about the viability study. Since the packing section is too small and the inevitable increased pressure drop, caused by the usage of the packing, data showed that, for optimal volumetric flow rate, there was flooding occurrence. Trying to manoeuvre the problem, lower volumetric flow rates were tested as well but, due to improper equilibrium between the vaporization rate and the volumetric feeding rate, the column dried up. For lower volumetric flow rates, there is a greater amount of vaporization occurrence when comparing to the volumetric feeding rate. By means of simulation and modelling, it was shown that the usage of a packing bed on the single stages discontinuous columns is unreliable. Additional calculations were made to allow an estimation of a minimum acceptable diameter that would not flood the column at various volumetric flow rates. The values were presented as suggestions for future modifications if needed
authors
José Frederico Barroso Ramalho
supervisors
Lina Manuela Marques Raimundo , Francisco Avelino Da Silva Freitas
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