ParamIni_LL_NRTL: Graphical User Interface (GUI) for the Selection of NRTL Initial Parameters for the Correlation of Ternary Liquid-Liquid Equilibrium Data (Type I, II, III and 0 (LL island), i.e. with 1, 2, 3 or 0 binary pairs partially miscibles)

The correlation of liquid-liquid equilibrium data is still currently a problem not fully resolved, especially for complex systems such as, those involving ionic liquid, where the high nonlinearity and non-convexity of the equations involved produce convergence problems, with a strong dependence on the initialization values used of the obtained solution. To avoid this situation, for the NRTL model, we have analyzed more than 200 LLE ternary systems (including type I, II, III and 0 or island, following the Treybal classification, Figure 1) in order to obtain a good representation of the different possible binodal curves and tie triangles that this model can reproduce satisfactorily, in a wide enough interval of values of the different parameters (taui,j, taui,j). All these systems have been parametrized regarding the main characteristics of the corresponding LLE, such as the number of binary subsystems partially miscible, the size and middle point of the binary tie-lines, the slope of the tie-lines, the location of the plate point, etc. With this parametrization, we have created a database and a new graphical user interface, GUI, that allows loading a set of liquid-liquid experimental data to obtain, using optimization algorithms and machine learning techniques, a consistent set of initial NRTL parameters that predicts a parametrized LLE near the experimental one. This set of parameters can be used now in any correlation data algorithm (using the corresponding equilibrium condition: isoactivity, minimum of the global Gibbs energy of mixing, or the Gibbs energy of mixing minor common tangent plane) to obtain the final rigorous solution. We believe that the present work can help researchers, professionals and students, in the task of correlating experimental liquid-liquid equilibrium data, in order to obtain consistent binary interaction parameters, taking into account that the correct calculation of the phase equilibrium is a key point in the optimal (efficient and sustainable) design of the corresponding processes and equipment. Related references: *Should we trust all the published LLE correlation parameters in phase equilibria? Necessity of their Assessment Prior to Publication. Fluid Phase Equilibria. 2017, 433, 243-252 (http://dx.doi.org/10.1016/j.fluid.2016.11.009). *GE Models and Algorithms for Condensed Phase Equilibrium Data Regression in Ternary Systems: Limitations and Proposals. The Open Thermodynamics Journal. 2011, 5, (Suppl 1-M5) 48-62 (http://dx.doi.org/10.2174/1874396X01105010048). * Checking Liquid-Liquid Critical Point Conditions and their Application in Ternary Systems. Industrial & Engineering Chemistry Research. 2012, 51(13), 5098-5102 (http://dx.doi.org/10.1021/ie202793r). *LLE data correlation using NRTL model for different types of binary systems: UCST, LCST and closed miscibility loops. Industrial & Engineering Chemistry Research. 2020, 59(17), 8469-8479 (https://doi.org/10.1021/acs.iecr.0c00141). * GMcal_TieLinesLL: Graphical User Interface (GUI) for Topological Analysis of Calculated GM Surfaces and Curves, including Tie-Lines, Hessian Matrix, Spinodal Curve, Plait Point Location, Miscibility Boundaries, etc. for Binary and Ternary Liquid-Liquid Equilibrium (LLE) Data. RUA 2015-2022. http://hdl.handle.net/10045/51725. *GMcal_TieLinesVL: Graphical User Interface (GUI) for the Topological Analysis of Experimental and Calculated GM Functions for Binary and Ternary (isobaric or isothermal) Vapor-Liquid Equilibrium (VLE) Data (including Tie-Lines, Derivatives, Distillation Boundaries, etc.). RUA 2022. http://hdl.handle.net/10045/122857. * Boundaries_LL_NRTL Graphical User Interface (GUI) for the Characterization of the NRTL model: Binary Spinodal Surfaces (in the tau(i,j)-tau(j,i)-xi space), LLE Maps and Miscibility Boundaries. RUA 2022 (http://hdl.handle.net/10045/121471). * What does the NRTL model look like? Determination of boundaries for different fluid phase equilibrium regions. AIChE Journal. 2022, e17805 (https://dx.doi.org/10.1002/aic.17805).University of Alicante y Ministerio de Ciencia e Innovación. PID2021-124139NB-C21: SUS4Energy, 2022/00666/001 (AEI)

Structural considerations in zeotropic distillation sequences with multiple feeds

The separation of multiple feed streams with some common components using sequences of distillation columns produces a rich space of alternatives that must be considered. In this work, we present the main structural characteristics of sequences generated when we want to take advantage of the synergies of common components in multiple feed streams to reduce both, energy consumption and the total number of distillation columns. In general, the sequence of separation tasks of the whole system can be obtained from the sequences of separation tasks of each one of the feeds. However, the integration in actual columns is not so straightforward and we must consider aspects like the optimal location of feeds in multiple-feed columns; and the alternatives of integration of common sub-mixtures (when possible) in actual columns. Besides, the optimal sequence of separation tasks for each feed is not necessarily the same when all of them are considered simultaneously. We show that the minimum number of actual columns, without considering further intensification, depends on the number of components in each feed and on the possibilities of integration of common sub-mixtures, so we extend the concepts of regular and basic column sequences to deal with these new situations. The examples show the potential savings in energy and number of columns compared to maintain isolated each feed; mixing the feed streams or an incorrect integration.The authors acknowledge financial support to the “Generalitat Valenciana” under project PROMETEO 2020/064

Graphical User Interface (GUI): ParamIni_LL_NRTL

33rd European Symposium on Computer Aided Process Engineering (ESCAPE33), June 18-21, 2023, Athens, Greece (Theme 8. Education and knowledge transfer: Poster 43,Board 107).In the present work, the NRTL model has been analyzed to obtain a good representation of the different ternary liquid-liquid equilibria that this thermodynamic model can reproduce satisfactorily. To do that, the main characteristics of different possible binary subsystems, ternary binodal curves (location in the composition diagram, size, tie-lines orientation, and plait point location), and LLLE tie triangles have been evaluated. With more than two hundred systems studied, the different behaviors have been parametrized to create, as the main objective of the present work, a database and a graphical user interface associated (ParamIni_LL_NRTL, Labarta et al. 2022. RUA: http://hdl.handle.net/10045/130017). This resource (publicly available for teaching and research uses) allows, given a set of ternary experimental LLE data to obtain by comparison with the elements of the database, a consistent set of initial NRTL parameters (taui,j, alfai,j) to start the corresponding correlation data procedure with enough guarantees.The authors gratefully acknowledge the financial support by the Ministry of Science and Innovation from Spain, under the project PID2021-124139NB-C21: SUS4Energy, 2022/00666/001 (AEI)

Procedure for evaluating and refurbishing envelopes of obsolete buildings in warm regions

This research develops a procedure to evaluate and refurbish obsolete buildings obliged to comply with the Spanish Technical Building Code. This procedure matches the building typologies selected to the optimal solution for each case. The analysis focuses on buildings constructed between the 1960s and the 1980s in Castellón, Spain. The buildings selected are representative of the period, of compact cities, and of the Mediterranean climate region. Three types of intervention on the envelope have been considered. The analysis for the most appropriate intervention in each case was based on economic, environmental, technical, and social factors. It shows that the best solution for Terraced Houses (TH) and Multi-family Houses (MH) is exterior refurbishment with additional insulation on the façade. This solution is achieved at reasonable cost by reducing one-third of the primary energy consumed. The best solution for Apartment Blocks (AB) is exterior retrofitting with ventilated façades, which offers the best performance from a technical, environmental, and economic perspective. In all cases, interior retrofitting is ruled out given that exterior retrofitting with additional insulation provides greater energy savings at a similar cost.This study was funded by the project: Study of existing building envelopes and analysis of retrofit solutions, conventional and innovative, by means of multi-criteria analysis, from Jaume I University (Castellón de la Plana, Spain) [grant number P1·1A2013-08]

Rigorous design of distillation columns using surrogate models based on Kriging interpolation

The economic design of a distillation column or distillation sequences is a challenging problem that has been addressed by superstructure approaches. However, these methods have not been widely used because they lead to mixed-integer nonlinear programs that are hard to solve, and require complex initialization procedures. In this article, we propose to address this challenging problem by substituting the distillation columns by Kriging-based surrogate models generated via state of the art distillation models. We study different columns with increasing difficulty, and show that it is possible to get accurate Kriging-based surrogate models. The optimization strategy ensures that convergence to a local optimum is guaranteed for numerical noise-free models. For distillation columns (slightly noisy systems), Karush–Kuhn–Tucker optimality conditions cannot be tested directly on the actual model, but still we can guarantee a local minimum in a trust region of the surrogate model that contains the actual local minimum.The authors gratefully acknowledge the financial support of the Ministry of Economy and Competitiveness of Spain, under the project CTQ2012-37039-C02-02

Hybrid simulation-equation based synthesis of chemical processes

A challenging problem in the synthesis and design of chemical processes consists of dealing with hybrid models involving process simulators and explicit constraints. Some unit operations in modular process simulators are slightly noisy or require large CPU times to converge. In this work, this problem is addressed by combining process simulators and surrogate models. We have replaced some unit operations, which cannot be used directly with a gradient-based optimization, by surrogate models based on Kriging interpolation. To increase the robustness of the resulting optimization model, we perform a degree of freedom analysis and aggregate (or disaggregate) parts of the model to reduce the number of independent variables of the Kriging surrogate models (KSMs). Thus, the final model is composed of KSMs, unit operations (maintained in the process simulator) and also explicit equations. The optimization of the well-known vinyl chloride monomer (VCM) production process is performed to test the proposed approach. The effect of the heat integration is also studied. In addition, the economic feasibility of the optimized process is calculated assuming uncertainty in raw material and product prices.The authors gratefully acknowledge the financial support by the Ministry of Economy and Competitiveness from Spain, under the project CTQ2016-77968-C3-02-P (AEI/FEDER, UE), and Call 2013 National Sub-Program for Training, Grants for pre-doctoral contracts for doctoral training (BES-2013-064791)

Rigorous Design of Complex Distillation Columns Using Process Simulators and the Particle Swarm Optimization Algorithm

We present a derivative-free optimization algorithm coupled with a chemical process simulator for the optimal design of individual and complex distillation processes using a rigorous tray-by-tray model. The proposed approach serves as an alternative tool to the various models based on nonlinear programming (NLP) or mixed-integer nonlinear programming (MINLP) . This is accomplished by combining the advantages of using a commercial process simulator (Aspen Hysys), including especially suited numerical methods developed for the convergence of distillation columns, with the benefits of the particle swarm optimization (PSO) metaheuristic algorithm, which does not require gradient information and has the ability to escape from local optima. Our method inherits the superstructure developed in Yeomans, H.; Grossmann, I. E.Optimal design of complex distillation columns using rigorous tray-by-tray disjunctive programming models. Ind. Eng. Chem. Res.2000, 39 (11), 4326–4335, in which the nonexisting trays are considered as simple bypasses of liquid and vapor flows. The implemented tool provides the optimal configuration of distillation column systems, which includes continuous and discrete variables, through the minimization of the total annual cost (TAC). The robustness and flexibility of the method is proven through the successful design and synthesis of three distillation systems of increasing complexity.The authors would like to acknowledge financial support from the Spanish “Ministerio de Ciencia e Innovación” (CTQ2009-14420-C02-02 and CTQ2012-37039-C02-02)

Optimal carbon dioxide and hydrogen utilization in carbon monoxide production

Carbon monoxide is the building block of many relevant chemical products. However, the relatively high emissions (1.396–2.322 kg CO2-eq/kg CO) of its synthesis and separation process result in high emitting derivatives. Therefore, reducing CO synthesis emissions is the first step towards more sustainable end products. In order to tackle this problem, we propose a carbon monoxide synthesis and purification superstructure. We perform multi-objective optimizations minimizing the cost and emission of the final CO product across several case scenarios. Results show that the minimum cost solutions are achieved using partial oxidation of methane (POX) as the syngas synthesis process and cryogenic distillation as the CO separation technology. Emissions can be decreased using dry methane reforming (DMR) and pressure swing adsorption (PSA) but costs increase dramatically. Optimal H2 utilization results in a reverse water gas shift (RWGS) reactor where CO2 is consumed to produce additional CO. Off-gas valorization is key to further reducing the synthesis cost and emissions.The authors gratefully acknowledge financial support to the Spanish «Ministerio de Economía, Industria y Competitividad» under project CTQ2016-77968-C3-2-P (AEI/FEDER, UE). The authors would also like to thank «Generalitat Valenciana: Conselleria de Educación, Investigación, Cultura y Deporte» for the Ph.D grant (ACIF/2016/ 062)

Symbolic Perdurance in the Use of an Iberian Necropolis. The Funerary Building in Cerro del Santuario (Baza, Granada)

En este trabajo presentamos una serie de reflexiones interpretativas respecto a un edificio localizado durante las excavaciones que Francisco Presedo desarrolló entre 1968 y 1971 en la necrópolis ibérica de Cerro del Santuario en Baza (Granada), y que fue interpretado como una construcción romana sin más. La limpieza de estructuras llevada a cabo por nuestro equipo durante el año 2013 nos ha permitido establecer una nueva línea interpretativa, y considerar la posibilidad de que se trate de un monumento funerario turriforme.We present a series of interpretative reflections on a building discovered during the excavations carried out by Francisco Presedo in the Iberian necropolis of Cerro del Santuario in Baza (Granada). This building was simply considered as a regular Roman construction until the recent works carried out by our team in 2013. A new line of interpretation has now been established, which considers that this building may be a Roman tower-shaped funerary monument