An operational model for the optimal operation of the freeze-drying process

[Abstract] In this work an operational mathematical model for the freeze-drying process is derived. The model describes the state variables related to product quality and stability. Computational issues associated to the presence of a moving front are approached by using the Landau transform. Unknown model parameters are estimated using experimental data. The model is used to design optimal operation policies that reduce the process duration ensuring product quality

Modelos operacionais para aplicacións en tempo real de sistemas de proceso distribuídos non liñais e de fronteira móbil

222 páginasThermal processes are widely employed in both Food and Biotechnology industries. Nevertheless, their operation and decision making is still ruled by rigid procedures which are difficult to adapt to sudden changes in the production conditions or to disturbances in the process caused by unforeseen events. Besides, it must be considered too, that in most of the cases, those operation policies have been not designed according to optimality principles, and therefore there exist opportunities to improve not only the process costs but also the final product quality. It is in this framework where the development and implementation of real-time oriented mathematical models, which would be employed as the core of computational tools and methods for optimal on-line control processes, constitutes an invaluable mechanism. Many are the advantages related to process modelling: from providing a virtual environment where evaluate new procedures and equipment to predict the effects of failures or malfunctioning conditions on quality product. However the specific requirements of real-time tasks call for low-dimensional models aimed at reducing the computational times associated to its numerical solving. In response to this need, the concept of operational model emerges in the sense of a simplified while accurate representation of the system, based on first-principles, whose structure and dimensionality enable its role as the body of control and optimisation on-line schemes which would supply with the desired flexibility to the operation process. Thus, the objectives of this dissertation will be, in one hand, to provide with the insights of the methodology proposed, and in the other, to show the applicability and advantages of this integral modelling approach by means of examples consisting of real-time applications for different processes of interest in Food and/or Biotechnology industries.Financiamento prestado polo programa FPI do MINECO, polo 7º Programa Marco da Union Europea (Proxecto CAFE - Large Collaborative Project: KBBE-2007-2-3-01) e polo proxecto SMARTQC (Proxecto do antigo MICINN AGL2008-05267-C03-01)Peer reviewe

Time-scale modeling and optimal control of freeze-drying

12 páginas, 1 apéndice, 16 figuras, 6 tablasFreeze–drying is considered to be an attractive dehydration method of preserving the quality of high value foods products. Unfortunately, it is an expensive operation, which calls for efficient tools capable of minimizing time and/or energy while preserving product quality. In this work, time-scale analysis has been applied to a detailed first-principle-based model. From such analysis a simplified model, capable of describing freeze–drying at the time scales relevant to quality, has been proposed. The model has been solved by the Finite Element method, showing good agreement with the results in literature. Likewise, the efforts associated with the computation of optimal operation policies have been reduced. In this regard, different operational scenarios that take into account shelf temperature (TL) and chamber pressure (Pc) have been considered on a simulation basis. In all cases the resulting optimal control profiles obtained led to significant reductions of cycle time while ensuring product quality.7th Framework Programme of the European Union (CAFE Project – Large Collaborative Project: KBBE-2007-2-3–01); Spanish Government (MICINN Project AGL2008-05267-C03–01); Xunta de Galicia (IDECOP 08DPI007402PR)Peer reviewe

Model reduction as a tool for robust predictive control: Application to OPR

6 páginasThe production of some chemicals or pharmaceuticals has been improved over the years by the development of a new concept of reactors, the reactor-heat exchangers, that overcome the classical constrains affecting many reaction units related to dissipation of heat and dilution/separation of products. The aim of this work is to propose a methodology for robust predictive control which aims at capturing the slow and most relevant, dynamics of the system. This model reduction constitutes the preliminary step to apply a real time optimization (RTO) framework for the robust control of reaction systems. The Open Plate Reactor (OPR) developed by the Swedish company Alfa Laval is used as a benchmark to validate the proposed methodologyPeer reviewe

Non invasive on-line estimation of temperature distribution in freeze-drying processes

Proceedings of the 11th International Congress on Engineering and Food (ICEF11), Athens, Greece, 2011Freeze-drying is a dehydration process often employed in high added-value food and biochemical goods.This technique facilitates the later re-hydration of the resulting product while it helps to maintain its organoleptic and nutritional properties. In order to preserve quality, as well as to reduce the costs of a high demanding energy and time consuming process, the proper handling of the product temperature during the operation course becomes critical. Direct – invasive – measurement methods are potentially dangerous to product integrity what calls for new non-invasive strategies as the one proposed in this work. Our approach combines the mathematical modelling of the leading physical phenomena involved in freeze-drying together with experimental data obtained from pressure rise disturbances in the drying chamber. The data collected from pressure essays are employed to complete the partial differential equation system describing heat transfer mechanism. Numerical issues usually related to solving moving boundary problems, as it is the freeze-drying case, are overcome by applying coordinate transformations which lead to a fixed reference frame. On this new framework, order reduction methods can be used as a tool not only to simplify the system analysis and control but to minimize the computational effort as well, especially when 2D or 3D spatial domains with complex geometries are involvedThe authors acknowledge the financial support received from the 7th Framework Programme of the European Union (CAFE Project – Large Collaborative Project KBBE-2007-2-3-01) and the Spanish Ministry of Science and Innovation (MICINN Project AGL2008-05267-C03-01)N

A novel approach for optimal operation of freeze-drying processes based on time-scale model decomposition

2 pages.-- Proceedings of the 11th International Congress on Engineering and Food (ICEF11), Athens, Greece, 2011Freeze-drying (lyophilisation) constitutes an attractive dehydration method for valuable food products as this technology is capable of preserving their quality and biological activity, extending their shelf life as well. However, it is known to be a high energy and time consuming process. This translates into an expensive operation which calls for efficient optimal decision making tools able to minimize time-energy while preserving (maximizing) product qualitThe authors acknowledge the financial support received from the 7th Framework Programme of the EU (CAFE Project: KBBE-2007-2-3-01) and the Spanish Government (MICINN Project AGL2008-05267-03-01)N

Model identification and on-line optimal control of food processes

12 páginas, 5 figuras.-- V International Conference on Computational Methods for Coupled Problems in Science and Engineering COUPLED PROBLEMS 2013, held in Ibiza, Spain, 17-19 June 2013Food processes are coupled systems that involve heat, mass and momentum transfer together with kinetic processes related to quality and safety. This work is devoted to illustrate how model-based techniques o er the possibility to rationally optimise processes even in real time. The contribution is mainly based on our group experience and illustrates concepts with several examples such as the refrigeration of fruits, the deep-fat frying of potato chips, the freeze-drying of dairy products and the thermal processing of packaged foodsEU [CAFE FP7-KBBE-2007-1(212754)], Spanish Ministry of Science and Innovation [SMART-QC AGL2008-05267-C03-01], Xunta de Galicia [IDECOP 08DPI007402PR] and CSIC [PIE 201270E075]. A. Arias-Mendez and E. Lopez-Quiroga acknowledge nancial support through JAE-pre and FPI programmes, respectivelyPeer reviewe

An operational model for the optimal operation of the freeze-drying process

8 pages, 4 figures, 2 tables.-- XL Jornadas de Automática: libro de actas, Ferrol, 4-6 de septiembre de 2019.-- Atribución-NoComercial-CompartirIgual 4.0In this work an operational mathematical model for the freeze-drying process is derived. The model describes the state variables related to product quality and stability. Computational issues associated to the presence of a moving front are approached by using the Landau transform. Unknown model parameters are estimated using experimental data. The model is used to design optimal operation policies that reduce the process duration ensuring product qualityThe authors acknowledge the financial support received from E.U. H2020 research and innovation programme (CoPro project, No 723575) and E.U. 7th Framework Programme (CAFE Project, KBBE-2007-2-3-01)Peer reviewe

An Operational Model for the Optimal Operation of the Freeze-Drying Process

Poster.-- Encontros IIM Primeira fase, 12 de decembro de 2019Peer reviewe

Abundancia de flebótomos de yungas y chaco semiárido y su posible asociación con la vegetación arbórea en el norte de Argentina

La presencia y abundancia de flebótomos se relacionada con la cobertura y densidad de la vegetación. El objetivo del trabajo fue estudiar la presencia y abundancia de flebótomos y su asociación con el tipo de vegetación en las Yungas y Chaco Semiárido de Orán, Salta. Se capturaron flebótomos e identificaron plantas arbóreas en: Selva Pedemontana (SP),Selva Montana (SM) y Bosque Montano (BM) y Chaco Semiárido (CH). Mediante Modelos Lineales Generalizados y Mixtosse comparó la abundancia media (ab) de flebótomos entre SP, SM, BM y CH; y entre especies de flebótomos por estrato. Se realizó la correlación de Spearman entre las abundancias de especies arbóreas y de flebótomos (totales y por especie).La abundancia absoluta de flebótomos fue: SP (2074), SM (21), BM (5) y CH (191). Se observó diferencias significativas(p<0,05) entre las ab de flebótomos de SP, CH, SM y BM. La ab en SP fue: Nyssomyia neivai (93,13), Migonemyia migonei(7,13), complejo cortelezzii (Evandromyia cortelezzii/Ev. sallesi: 1,69), (p<0,05). En CH complejo cortelezzii (4,78) fuemayor a Mg. migonei (1,33) y Ny. neivai (0,56) (p<0,05). Se observó asociación positiva entre Ny. nevai con: Inga saltensis,Myrsine laetevirens, Sebastiana brasiliensis y Tipuana tipu; complejo cortelezzii con: Prosopis nigra, P. ruscifolia, Ruprechtiatriflora, Tabebuia nodosa y Ziziphus mistol; y Mg. migonei con: I. saltensis, S. brasiliensis y T. tipu. Ny. neivai fue la especiecon mayor distribución, se registró desde el CH, hasta SM. Complejo cortelezzii y Mg. migonei estuvieron presentes en CHy SP. La correlación entre flebótomos y plantas puede deberse a que ciertos árboles podrían servir de refugio, criaderoso fuente de alimento azucarado. Las especies de flebótomos informadas tienen importancia epidemiológica. El presente estudio podría contribuir a la orientación de medidas focales de control de poblaciones de flebótomos y a la prevención de la leishmaniasis teniendo en cuenta la vegetación circundanteFil: Copa, Griselda Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Sede Regional Orán. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: Almazán, María Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Sede Regional Orán. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: Benci Arqued, José Gabriel. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Chambi, Janet. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Hoyos, Carlos Lorenzo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Sede Regional Orán. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: López Quiroga, Inés Raquel. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaFil: Escalada, Andres S.. Universidad Nacional de Salta. Sede Regional Orán. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: Abán Moreyra, Daira Nahir. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaFil: Aramayo, Estefanía. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaFil: Barroso, Paola Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Marco, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Nasser, Julio Rubén. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaFil: Gil, José Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaVIII Congreso Argentino De ParasitologíaCorrientesArgentinaAsociación Parasitológica Argentin