Browsing by Author "Minceva, Mirjana"
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- Advances in simulated moving bed chromatographic separationsPublication . Gomes, Pedro Sá; Minceva, Mirjana; Pais, Luís S.; Rodrigues, AlírioThe development of some unconventional Simulated Moving Bed (SMB) strategies, such as the introduction of nonsynchronous inlet/outlet shifts (the Varicol process), variable flux or variable composition in the inlet/outlet streams (PowerFeed and Modicon, respectively), and also the use of multiple feed or distributed feed, have increased the potential of this technique for a wide range of binary separations. For multiple component separations, different strategies has been investigated, including a cascade of SMB, more complex SMB units composed by several adsorption zones, and the JO process operating in two different separation steps.
- Cyclic steady state of simulated moving bed processes for enantiomers separationPublication . Minceva, Mirjana; Pais, Luís S.; Rodrigues, AlírioSimulated moving bed (SMB) technology developed by UOP in early 1960s has expanded greatly in the last decade, finding new applications in the area of natural products, fine chemistry and pharmaceutical industry. SMB processes are periodic processes designed to operate in cyclic steady state (CSS) and, therefore, the correct determination of CSS is needed for the assessment of the SMB performance. Two approaches can be used for determination of CSS: the dynamic simulation until CSS is reached and direct prediction of CSS. The direct prediction of CSS could be obtained in two ways: (i) considering that at CSS the spatially distributed SMB unit state at the end of the cycle is identical to that at its beginning (Method 1); or (ii) considering that at CSS the spatially distributed SMB unit state at the end of a switching time interval is identical to the state at the beginning of the interval, apart from a shift of exactly one column length (Method 2). The mathematical models assume axial dispersion flow and linear driving force (LDF) approximation for intraparticle mass transfer. Mathematical models were solved using the g (general Process Modelling System) software package. Both approaches (dynamic simulation and direct CSS prediction) were applied to the prediction of cyclic steady state of SMB unit for 1,1′-bi-2-naphthol enantiomers separation. The direct CSS predictions were compared with the standard dynamic simulation CSS prediction in terms of accuracy of SMB performance and computing time requirements; the Method 2 for CSS prediction is more efficient than the standard dynamic simulation.
- Simulated moving bed technology: principles, design and process applicationsPublication . Rodrigues, Alírio; Pereira, Carla S.M.; Minceva, Mirjana; Pais, Luís S.; Ribeiro, Ana Mafalda; Ribeiro, António E.; Silva, Marta S.P.; Graça, Nuno S.; Santos, João CarlosThis book is a result of more than 20 years research on Simulated Moving Bed (SMB) processes at the Laboratory of Separation and Reaction Engineering (LSRE) and teaching at undergraduate level at the Department of Chemical Engineering (ChE), Faculty of Engineering of University of Porto (FEUP), graduate courses at Technical University (TU) Eindhoven and TU Delft, and an in-house course for Companhia Petroquímica do Nordeste (COPENE) (now Brazchem) and Petrogal. I graduated in ChE at University of Porto (U. Porto) in 1968, having never heard about SMB during those years. I heard about PAREX (and other Sorbex processes) in Nancy during my thesis work (1970e1973) with P. Le Goff and D. Tondeur. I found the idea of SMBdturning fixed-bed operation into continuous processesda bright one. After my African endeavors (teaching at the University of Luanda in Angola and military service there), I landed again at FEUP in August 1976 as an Assistant Professor. An optional course on Petroleum Refining for Chemical Engineering (ChE) was offered to undergraduate students given by Lopes Vaz from Petrogal. He was working in Lisbon but coming to Porto every Saturday morning to teach that course. I asked permission to attend. Lopes Vaz was a very good lecturer. It was an opportunity to learn details of the PAREX unit existing in the aromatics plant in the Refinery of Petrogal in Matosinhos. After the Revolution of April 1974, FEUP began offering evening courses allowing people with a “technical engineer” degree to get a diploma of Chemical Engineering (ChE) from U. Porto by following an additional two-year program. One of my students at that time was Soares Mota working for Petrogal and taking care of the PAREX unit. In 1978, I organized my first NATO Advanced Study Institute (ASI) on “Percolation Processes: Theory and Applications.” One of the lecturers I invited was D. Broughton from UOP (one of the inventors of SMB). He could not come, but instead A. De Rosset lectured in that ASI. I had the opportunity to travel to Des Plaines (Illinois) to visit Universal Oil Products (UOP) and meet D. Broughton at lunch. It was a business trip that I remember because I met some leaders in the Adsorption area (Vermeulen and Klein from University of California (UC) Berkeley, Wankat from Purdue, etc.). In 1984, an opportunity arose for funding to work on PAREX and ISOMAR processes when Veiga Sim~ao was Minister of Industry and Energy (MIE). He launched some Contracts for Industrial Development (CDIs) and I took the initiative of encouraging several engineers from Petrogal to join that initiative. The funding was supposed to be equivalent to 100,000 euro, but when the MIE came to Porto for the signing ceremony it seems he decided not to sign that CDI. I just found those documents while cleaning my office.
- The concept of separation volume for the design of SMB processesPublication . Rodrigues, Alírio; Pais, Luís S.; Azevedo, Diana C.S.; Minceva, Mirjana