http://hdl.handle.net/2117/3142 2013-06-19T06:29:07Z http://hdl.handle.net/2117/18629 Title: Prospective and perspective review in integrated supply chain modelling for the chemical process industry Authors: Lainez Aguirre, José Miguel; Puigjaner Corbella, Lluís Abstract: There is a large body of work on modelling and optimisation of the supply chain in the chemical process industry. This review summarises the most recent concepts and structural components constituting the SC. It describes the enlarged scope presently attributed to supply chain management, which departs from classical approaches focused on operations to a more integrated conception that jointly considers necessary decisions from other business functional areas (e.g. corporate finances, new product development, environmental management), as well as captures the complex dynamics characterizing the supply chain management (SCM) problem. Moreover, new perspectives come into focus for enterprise-wide decision-making through the use of ontologies that provide a general model representation for different decision-support levels at different time and space scales. 2013-04-05T08:18:14Z http://hdl.handle.net/2117/18627 Title: Simultaneous production and logistics operations planning in semicontinuous food industries Authors: Kopanos, Georgios; Puigjaner Corbella, Lluís; Georgiadis, Michael C. Abstract: The production and logistics operations planning in real-life single- or multi-site semicontinuous food industries is addressed in this work. A discrete/continuous-time mixed integer programming model, based on the definition of families of products, is developed for the problem in question. A remarkable feature of the proposed approach is that in the production planning problem timing and sequencing decisions are taken for product families rather than for products. However, material balances are realized for every specific product, thus permitting the detailed optimization of production, inventory, and transportation costs. Changeovers are also explicitly taken into account and optimized. Moreover, alternative transportation modes are considered for the delivery of final products from production sites to distribution centers. The efficiency and the applicability of the proposed approach is demonstrated by solving to optimality two industrial-size case studies, for an emerging real-life Greek dairy industry. 2013-04-05T07:52:31Z http://hdl.handle.net/2117/18611 Title: Efficient mathematical frameworks for detailed production scheduling in food processing industries Authors: Kopanos, Georgios; Puigjaner Corbella, Lluís; Georgiadis, Michael C. Abstract: The production scheduling of a real-world multistage food process is considered in this work. An efficient mixed integer programming (MIP) continuous-time model is proposed to address the production problem under study. The overall mathematical framework relies on an efficient modeling approach of the sequencing decisions, the integrated modeling of all production stages, and the inclusion of a set of strong tightening constraints. The simultaneous optimization of all processing stages aims at facilitating the interaction among the different departments of the production facility. Moreover, an alternative MIP-based solution strategy is proposed for dealing with large-scale food processing scheduling problems. Although this method may no guarantee global optimality, it favors low computational requirements and solutions of very good quality. Several problem instances are solved to reveal the salient computational performance and the practical benefits of the proposed MIP formulation and solution strategy. 2013-04-04T12:15:07Z http://hdl.handle.net/2117/17095 Title: Design of regional and sustainable bio-based networks for electricity generation using a multi-objective MILP approach Authors: Pérez Fortes, María del Mar; Lainez Aguirre, José Miguel; Arranz Piera, Pol; Velo García, Enrique; Puigjaner Corbella, Lluís Abstract: Biomass energy systems can be employed to meet the requirements of distributed energy systems in rural as well as urban contexts, whether this is an electrification or a microgeneration project. This work is focused on a mathematical programming approach applied to bio-based supply chains that use locally available biomass at or near the point of use in order to produce electricity or other bioproduct. The problem of designing and planning a regional biomass supply chain is formulated as a MO-MILP (multi-objective mixed integer linear program), which takes into account three main objectives: economic, environmental and social criteria. The model supports decision-making about location and capacity of technologies, connectivity between the supply entities, biomass storage periods, matter transportation and biomass utilisation. The advantages of this approach are highlighted by solving a case study of a specific district in Ghana. The aim is to determine the most suitable biomass and electricity network among the different communities. The technology considered to transform the biomass into electricity is gasification combined with a gas engine. 2012-12-11T10:29:29Z http://hdl.handle.net/2117/16775 Title: Identification of volatile organic compounds (VOC) emitted from three European orchid species with different pollination strategies : two deceptive orchids (Himantoglossum robertianum and Ophrys apifera) and a rewarding (Gymnadenia conopsea) Authors: Gallego Piñol, Eva; Gelabert, A.; Roca Mussons, Francisco Javier; Perales, Francisco; Guardino, X. Abstract: Volatile organic compounds (VOC) emission was evaluated in the inflorescences of three species of the family Orchidaceae: Himantoglossum robertianum, Ophrys apifera and Gymnadenia conopsea, that comprise three different pollination strategies: non-rewarding food deceptive, non-rewarding sexually deceptive and nectar rewarding, respectively. VOC were dynamically sampled in custom packed glass multi-sorbent cartridge tubes (Carbotrap, Carbopack X and Carboxen 569). A modified Tedlar® gas sampling bag was placed in vivo covering the inflorescence of the studied orchid, a design that prevents the dilution of the VOC mixture emitted by the flower. Multi-sorbent bed tubes were analysed through automatic thermal desorption coupled with a capillary gas chromatography/mass spectrometry detector. A total of 106 different VOC were found in the scents emitted by the three different studied orchids. A 54% of these compounds had already been identified in floral scents. Generally, only 3 compounds were highly abundant in each species: α-pinene, β-pinene and limonene in Himantoglossum robertianum; 1-butanol, butyl ether and caryophyllene in Ophrys apifera; and phenethyl acetate, eugenol and benzaldehyde in Gymnadenia conopsea. The employment of the presented methodology 2012-10-22T11:41:44Z http://hdl.handle.net/2117/16665 Title: Ontological framework for enterprise-wide integrated decision-making at operational level Authors: Muñoz, Edrisi; Capón García, Elisabet; Espuña Camarasa, Antonio; Puigjaner Corbella, Lluís Abstract: In the domain of chemical process engineering, there is an increased interest in the integration of the enterprise hierarchical levels for decision-making purposes. At the scheduling level, decisions on the allocation of tasks to resources, sequencing and timing of tasks must be managed. However, such decisions are directly related to other enterprise actions, such as control and planning, but they are difficult to coordinate because they are modeled at different time and space scales, and their goals are not the same. In order to achieve integrated decisions supported by high quality information, there is a need to improve and develop robust computational tools and consistent models. In general, scheduling optimization approaches for decision-making differ depending on problem features, such as physical layout or time representation. Therefore, this work focuses on providing a framework based on a semantic model that captures the diversity in scheduling problem representation. Such semantic model uses the master recipe concept from the ANSI/ISA-88 standard perspective and encapsulates the scheduling decision task features. As a result, by the use of a single representation approach, any scheduling problem can be modeled and solved by its adequate optimization tool. The potential of a general model representation is presented by means of several case studies related to the scheduling function. Such case studies shed light to the model capabilities to represent different kinds and particular scheduling problems, achieving integration at the different decision support levels. 2012-10-08T09:55:28Z http://hdl.handle.net/2117/16655 Title: Fault diagnosis of a benchmark fermentation process: a comparative study of feature extraction and classification techniques Authors: Monroy, Isaac; Villez, Kris; Graells Sobré, Moisès; Venkatasubramanian, Venkat Abstract: This paper investigates fault diagnosis in batch processes and presents a comparative study of feature extraction and classification techniques applied to a specific biotechnological case study: the fermentation process model by Birol et al. (Comput Chem Eng 26:1553–1565, 2002), which is a benchmark for advanced batch processes monitoring, diagnosis and control. Fault diagnosis is achieved using four approaches on four different process scenarios based on the different levels of noise so as to evaluate their effects on the performance. Each approach combines a feature extraction method, either multi-way principal component analysis (MPCA) or multi-way independent component analysis (MICA), with a classification method, either artificial neural network (ANN) or support vector machines (SVM). The performance obtained by the different approaches is assessed and discussed for a set of simulated faults under different scenarios. One of the faults (a loss in mixing power) could not be detected due to the minimal effect of mixing on the simulated data. The remaining faults could be easily diagnosed and the subsequent discussion provides practical insight into the selection and use of the available techniques to specific applications. Irrespective of the classification algorithm, MPCA renders better results than MICA, hence the diagnosis performance proves to be more sensitive 2012-10-05T10:42:20Z http://hdl.handle.net/2117/15563 Title: Simultaneous evaluation of odor episodes and air quality in urban areas by multi-sorbent sampling and TD-GC/MS analysis Authors: Gallego Piñol, Eva; Roca Mussons, Francisco Javier; Perales Lorente, José Francisco; Guardino Solà, Xavier Abstract: A validated analytical method, based on thermal desorption (TD) coupled to gas chromatography (GC) and mass spectrometry (MS), is used for air-quality measurements of volatile organic compounds in indoor and outdoor air, including alkanes, aromatic hydrocarbons, aldehydes, alcohols, chlorides, esters, ketones, terpenes, amides, carbon disulfide and isocyanates. 2012-03-13T14:40:32Z http://hdl.handle.net/2117/15377 Title: Production scheduling in multiproduct multistage semicontinuous food processes Authors: Kopanos, Georgios; Puigjaner Corbella, Lluís; Georgiadis, Michael C. Abstract: This works presents a novel mixed-integer programming framework and a solution strategy for the optimal production scheduling of multiproduct and multistage food process industries, such as ice-cream production facilities, studied in detail. The overall mathematical framework relies on an efficient modeling approach of the sequencing decisions, the integrated modeling of all production stages, and the inclusion of strong valid integer cuts in the formulation. The simultaneous optimization of all processing stages increases the plant production capacity, reduces the production cost for final products, and facilitates interaction among the different departments of the production facility. Several instances of a real-life industrial case study concerning ice-cream production have been solved to optimality to illustrate the applicability and efficiency of the overall modeling and solution approach. 2012-02-27T12:03:47Z http://hdl.handle.net/2117/15376 Title: Resource-constrained production planning in semicontinuous food industries Authors: Kopanos, Georgios; Puigjaner Corbella, Lluís; Georgiadis, Michael C. Abstract: The resource-constrained production planning problem in semicontinuous multiproduct food industries is addressed. In particular, the case of yogurt production, a representative food process, in a real-life dairy facility is studied in detail. The problem in question is mainly focused on the packing stage, whereas timing and capacity constraints are imposed with respect to the batch stage to ensure the generation of feasible production plans. A novel mixed discrete/continuous-time mixed-integer linear programming model, based on the definition of families of products, is proposed. Timing and sequencing decisions are taken for product families rather than for products; thus, reducing significantly the model size. Additionally, material balances are realized for every particular product, permitting the detailed optimization of inventory and operating costs. Packing units operate in parallel and share resources. Qualitative as well as quantitative objectives are considered. Several industrial case studies, including also some unexpected events scenarios, have been solved to optimality. 2012-02-27T11:46:13Z http://hdl.handle.net/2117/14736 Title: Scheduling and control decision-making under an integrated information environment Authors: Muñoz Mata, Edrisi; Capón García, Elisabet; Moreno Benito, Marta; Espuña Camarasa, Antonio; Puigjaner Corbella, Lluís Abstract: The complexity of decision-making in process industries and the need of highly competitive organizations require new supporting tools to coordinate and optimize the information flow among decision levels. This work presents a framework for integrating the scheduling and control decision levels by means of an ontology, which allows and coordinates the information exchange among the different modeling paradigms/conventions currently used for the enterprise-wide optimization (EWO). The scheduling of two multiproduct batch plants with increasing complexity is presented for illustrating the proposed working procedure. 2012-01-23T12:19:21Z http://hdl.handle.net/2117/14735 Title: Advanced simulation environment for clean power production in IGCC plants Authors: Pérez Fortes, María del Mar; Bojarski, Aarón David; Puigjaner Corbella, Lluís Abstract: Oxygen-blown biomass integrated gasification combined cycle (IGCC) plants are one of the most promising options for clean energy generation with CO2 abatement potential. However, the integrated nature of IGCC leads to difficult design problems. In this study, we present an advanced simulation environment for the preliminary design and retrofit of IGCC plants. We describe the modelling approach, the model validation strategy and the plant behaviour, as determined by sensitivity analyses. The simulation environment uses Pareto curves to examine various co-gasification and co-production case studies in terms of technical, economic and environmental performance. It serves as a decision support tool in the design stage, which can be used to explore ways to improve plant performance and to analyse the influence of raw materials and the unit’s operational parameters. The test and validation results are discussed. 2012-01-23T12:00:21Z http://hdl.handle.net/2117/14671 Title: Enhanced plant fault diagnosis based on the characterization of transient stages Authors: Monroy, Isaac; Benítez Iglesias, Raúl; Escudero Bakx, Gerard; Graells Sobré, Moisès Abstract: This paper introduces a data-based fault diagnosis system that includes an enhanced characterization of faults during transient stages. First, data under abnormal operating conditions (AOC) is projected onto a reference PCA model constructed with data under normal operating conditions (NOC). T2 and Q-statistic measures of this first PCA model are both used to detect the fault and to estimate the duration and delay of its transient evolution. After a dimensionality reduction, a second NOC PCA model is used to process data before diagnosing the faults by standard classification methods such as Artificial Neural Networks (ANN) or Support Vector Machines (SVM). A quantitative validation of the procedure has been carried out using simulated on-line data sets of the Tennessee Eastman Process (TEP). Results indicate that the incorporation of transient data in models improves the overall diagnosis performance, regardless of the particular choice between the statistical methods or the classification methods. 2012-01-19T12:10:25Z http://hdl.handle.net/2117/13514 Title: Multiobjective optimization of multiproduct batch plants scheduling under environmental and economic concerns Authors: Capón García, Elisabet; Bojarski, Aarón David; Espuña Camarasa, Antonio; Puigjaner Corbella, Lluís Abstract: In batch process scheduling, production trade-offs arise from the simultaneous consideration of different objectives. Economic goals are expressed in terms of plant profitability and productivity, whereas the environmental objectives are evaluated by means of metrics originated from the use of life cycle assessment methodology. This work illustrates a novel approach for decision making by using multiobjective optimization. In addition, different metrics are proposed to select a possible compromise based on the distance to a nonexistent utopian solution, whose objective function values are all optimal. Thus, this work provides a deeper insight into the influence of the metrics selection for both environmental and economic issues while considering the trade-offs of adopting a particular schedule. The use of this approach is illustrated through its application to a case study related to a multiproduct acrylic fiber production plant, special attention is put to the influence of product changeovers. 2011-10-17T08:16:07Z http://hdl.handle.net/2117/13135 Title: Improved short-term batch scheduling flexibility using variable recipes Authors: Capón García, Elisabet; Moreno Benito, Marta; Espuña Camarasa, Antonio Abstract: Batch scheduling and control decision levels are usually optimized separately, even though integrated decisions would potentially increase the overall performance of the plant. This work aims at including in the scheduling problem the operating conditions related to the control function, which are traditionally optimized and fixed beforehand, to shed light to the benefits that may be obtained when using variable recipes in contrast to fixed nominal recipes. A multiproduct and amultipurpose plant illustrate the proposed approach. In both cases, the potential benefits are confirmed resulting in clear advantages regarding overall economic benefit, when the variable recipes are introduced. Thus, the presented approach gives rise to new tradeoffs, since it allows new improvement opportunities associated with quality, safety, or changing operating policies, which are usually considered separately. 2011-08-29T18:58:36Z