Nicolas J. Scenna

Universidad Tecnológica Nacional (UTN-Rosario) · CAIMI - Departamento de Ingeniería Química

Un adecuado diseño del layout de planta contribuye a reducir costos y el riesgo tecnológico. En las últimas décadas surgieron modelos de optimización de layout basados en programación matemática buscando minimizar costos o el riesgo (o bien restringiéndolo). El denominador común de estas formulaciones es que el diseño interno de las instalaciones e...

El conocimiento de las consecuencias ocasionadas por los accidentes industriales de las últimas décadas hace imperante la propuesta de nuevas metodologías para minimizar los daños. Uno de los eventos más peligrosos son las explosiones BLEVE (Boiling Liquid Expanded Vapour Explosion) y la inmediata formación de una bola de fuego, dado que el campo d...

Optimal revamping, sizing, and operation of an existing gas-turbine combined-cycle dual-purpose power/desalination plant – simultaneous electricity and freshwater generation – which operates with a heat recovery steam generation with one-pressure level (1P-HRSG) and a multi-stage flash desalination process, is addressed. The sizes and configuration...

En los últimos años, debido al gran número de accidentes catastróficos en el sector industrial, la obtención de una metodología cuya aplicación contribuya a la mitigación de los daños causados ha adquirido gran importancia. En este trabajo, se obtienen dos correlaciones que describen el comportamiento de un evento específico (explosión tipo BLEVE)...

A new mathematical framework for optimal synthesis, design, and operation of triple-pressure steam-reheat combined-cycle power plants (CCPP) is presented. A superstructure-based representation of the process, which embeds a large number of candidate configurations, is first proposed. Then, a generalized disjunctive programming (GDP) mathematical mo...

En este trabajo se presentan brevemente los avances y resultados desarrollados en el marco de la tesis doctoral titulada “Metodología para la Optimización de Layout y Síntesis de Procesos Considerando el Riesgo Tecnológico”. A través de la misma se pretende desarrollar un algoritmo eficiente que permita la obtención de la distribución óptima de las...

Un problema ingenieril resiliente es la gran cantidad de accidentes tecnológicos asociados a la manipulación de sustancias peligrosas que se encuentran en el inventario de la mayoría de las industrias. Estos accidentes, de acuerdo a su nivel de gravedad, han ocasionado una gran cantidad de muertos y heridos como así también cuantiosas pérdidas econ...

Los principios del diseño inherentemente seguro imponen la consideración del riesgo desde etapas tempranas del diseño. La consideración del mismo generalmente es realizada en las últimas etapas, independientemente de la optimización de layout, aun cuando existe una estrecha relación entre ambas. En este trabajo se aborda dicha problemática, proponi...

En el presente informe se presenta una metodología para el diseño de procesos basada en riesgo y una herramienta informática, llamada CEIBO, que permite aplicarla. También se muestra un caso de estudio donde se aplica CEIBO al diseño de un parque de tanques de almacenamiento.

Se implementa un modelo que representa en forma simplificada una corriente superficial de agua, ya sea natural o artificial, sobre la que se simula un vertido de una sustancia contaminante de características conservativas. Se comparan los resultados obtenidos para diferentes escenarios (ancho del canal, rugosidad, concentración inicial, pendiente d...

A través del presente trabajo se presentan modelos de programación mixta entera lineal (MILP), con el objetivo optimizar por un lado la síntesis de la playa de almacenamiento de sustancias peligrosas (en este caso inflamables) considerando la posibilidad de incendio de trinchera (trench fire) y por otro, la distribución del layout general de planta...

This paper presents a risk-based design procedure of ammonia based refrigeration processes taking into account the allocation of the manufacturing plant and the surrounding environment vulnerability at early stages of process design. In addition , the proposed design framework allows the integration of a process simulator with vulnerability assessm...

This work deals with the development and implementation of mathematical models in the General Algebraic Modeling System (GAMS) environment for optimization purposes, involving extrinsic functions that are executed outside GAMS from dynamic-link libraries (DLL) implemented in the programming language C. Three DLL libraries are developed to calculate...

An optimization study of membrane-based separation systems for carbon dioxide capture from flue gas of power plants is conducted, considering the possibility of employing up to four stages and using diverse options to create the required driving force. By proposing a superstructure-based model, the number of stages, recycle options, use of feed com...

This work deals with the optimization of two-stage membrane systems for H2 separation from off-gases in hydrocarbons processing plants to simultaneously attain high values of both H2 recovery and H2 product purity. First, for a given H2 recovery level of 90%, optimizations of the total annual cost (TAC) are performed for desired H2 product purity v...

This paper fits into the process system engineering field by addressing the optimization of a two-stage membrane system for H2 separation in refinery processes. To this end, a nonlinear mathematical programming (NLP) model is developed to simultaneously optimize the size of each membrane stage (membrane area, heat transfer area, and installed power...

This work presents an exhaustive three dimensional mathematical model to describe chicory root cubes drying process (Cichorium intybus L.) using a Fick's diffusion model considering a variable diffusion path length in three dimensions. Experimental data obtained at laboratory scale is used to validate the proposed model. Experiments are conducted u...

The effect of the drying conditions on the retention quality for dried chicory roots (Cichorium intibyus L.) was investigated. Cubes of chicory roots were dried using hot air and vacuum dryers at 60 and 80 °C. Two different air velocities (0.2 and 0.7 m/s) were used in the hot air dryer, and two vacuum pressures (25 and 50 mmHg absolute) were set i...

The main objective of this manual is to provide to all the users the basic steps to use thermodynamic libraries in GAMS employing extrinsic functions. The steps are presented using specific cases including examples. However, it should be mentioned that the developed libraries can be used for any chemical/industrial process, according to the necess...

This article shows the development of optimization models using extrinsic functions for GAMS. Precisely, different dynamic link libraries have been implemented for the calculation of thermodynamic properties in GAMS environment. A simple case study taken from Perry's Chemical Engineers' Handbook, Sec. 13 Pg. 34 corresponding to the Example 3 is use...

This paper deals with the optimization of the coupling between a natural gas combined cycle (NGCC) plant and a post-combustion CO2 capture process by minimizing the mitigation cost – defined as the ratio between the cost of electric power generation and the amount of CO2 emitted per unit of total net electric power generated – while satisfying the...

Conventional and ultrasound assisted extraction of anthocyanins from grape pomace are here analyzed and compared. Mathematical modeling is used firstly to represent the extraction process and determine the associated mass transport parameters, and afterwards, to obtain useful predictions on how the system behaves under different operating condition...

Water consumption required during the leaching stage in the surimi manufacturing process strongly depends on the design and the number and size of stages connected in series for the soluble protein extraction target, and it is considered as the main contributor to the operating costs. Therefore, the optimal synthesis and design of the leaching stag...

This paper applies mathematical programming and superstructure-based optimization approaches todesign multi-stage membrane systems for CO2capture, with the aim to systematically determine theoptimal number of membrane stages, membrane areas, power requirements, the location of recyclestreams, and operating conditions that satisfy desired CO2recover...

In any system, there are some properties, quantities or relationships that remain unchanged despite the applied transformations (system invariants). For a batch reaction system with n linearly independent reactions and m components (n<m) there exist linear combinations of the concentrations that are unaffected by the reaction progress, i.e. so-call...

This paper addresses the optimal arrangement and design of a dual pressure heat recovery steam generator coupled to two steam turbines. A superstructure that embeds various alternative configurations is optimized considering the following two single objective functions: (a) the maximization of the total net power generation for a given total heat t...

This paper focuses on the optimization of the specific total annual cost (operating costs and investments) of a post-combustion CO2 capture plant with chemical absorption and on the sensitivity analyses of all of the model parameters. Using a mathematical programming approach and a detailed model the optimal design of the entire process (absorption...

In this paper, we introduce an optimization strategy in order to comprehensively quantify the impact of availability and maintenance notions during the early stages of synthesis and design of a new natural gas combined cycle power plant. A detailed state-space approach is thoroughly discussed, where influence of maintenance funds on each component'...

Due to the importance of the natural watercourses preservation, a mathematical model of heat and mass transfer dynamics of a fixed-geometry watercourse is fully developed. The mathematical model is derived from first principles and consists of both partial differential and algebraic equations. Semi empirical equations are applied to calculate the p...

This paper deals with the simultaneous optimization of the operating conditions and sizes of each one of the process units of a natural gas combined cycle coupled to a postcombustion CO2 capture system. Precisely, from the mathematical models previously developed by the authors for each stand-alone process, a new optimization nonlinear programming...

This work presents a mathematical model to simulate the extraction process of soluble protein from sabalo (Prochilodus platensis) during the surimi elaboration. The mathematical model consists of both partial differential and algebraic equations. Central finite difference method and the explicit scheme were applied to discretize the partial differe...

This paper presents a disjunctive mathematical model for the optimal design of air cooled heat exchangers. The model involves seven discrete decisions which are related to the selection of the type of the finned tube, number of tube rows, number of tube per row, number of passes, fins per unit length, mean fin thickness and the type of the flow reg...

This work deals with optimization of a hybrid system for simultaneous bio-hydrogen production and C-N removal by a combined anaerobic-aerobic treatment method. The global model couples kinetics, hydrodynamics and bioparticle subsystem for each reactor model. An existing set of experimental data is used for model validation. Fluctuating operation co...

To guarantee acceptable hard candy quality during the cooling stage, the distribution of the product’s temperature throughout the cooling tunnel must be controlled. Hence, the product’s quality depends on the operating conditions of the cooling process and the air conditioning system. In this paper, hard candy quality, operating policies and produc...

The leaching stage in the manufacturing process of surimi gel requires a large amount of wash water contributing to a high operating cost. Therefore, the minimization of the wash water demand is essential for a low cost operation. In this paper, a complete mathematical model for the simultaneous optimization of the process configuration and the ope...

Optimal power plant designs are achieved by means of a proposed multiperiod non-linear programming formulation that utilizes the net present value as objective function, while construction, operation and dismantling of the generation facility are accounted for. In addition, optimal operative characteristics are also established for each operative t...

Fossil fuel power plants are one of the major sources of electricity generation, although invariably release greenhouse gases. Due to international treaties and countries regulations, CO2 emissions reduction is increasingly becoming key in the generators’ economics. NGCC power plants constitute a widely used generation technology, from which CO2 ca...

This work deals with optimization of biological hybrid systems based on both anaerobic and aerobic sequential batch reactors (SBRs). The global model can address the differences between aerated and anaerobic systems by assigning adequate parameter values related to the presence of oxygen in the medium, aeration and sedimentation times, and selectin...

This paper deals with the simultaneously optimization of operating conditions (pressures, temperatures and flow-rates) and dimensions (diameter and height) of the amine regeneration unit in the postcombustion CO2 capture process. The proposed model takes into account the effect of kinetic reactions on the mass transfer, the hydraulics of the random...

In this work, the e�ect of the number of (active redundant) capture trains on the system performance, coupled to a 800 MW natural gas combined cycle power plant is studied, while considering technological restrictions which limit the amount of ue gas that can be treated by a given absorption- desorption loop. Both design and operation mode of such...

The post combustion process based on the CO2 absorption using amine aqueous solution is one of the more attractive options to drastically reduce greenhouse gas emissions from electric power sector. However, the solvent regeneration is highly energy intensive affecting the total operating cost significantly. The CO2 removal target depends on the abs...

On large industrial scales, the cooling stage in the production process of hard candies is one of the most critical unit operations because many quality problems such as deformation, fragility and aggregation may appear in this stage. Therefore, the optimization of the operating conditions of the cooling tunnel plays an essential role from a qualit...

Hard candies are classic examples of sugar glasses. Apparently, they are solids, butactually, in fact they are supercooled liquids in a non-crystalline state. Despite theirsimple composition, different process aspects are strongly influenced by themicrostructural characterization of hard candies. In the confectionary industry, severalprocess operat...

A comprehensive and simplified rate based mathematical model of a packed column for CO2 capture using aqueous MEA amine solution is developed. The absorption unit model takes into account the effect of kinetic reactions on the mass transfer, the thermodynamic non-idealities, the hydraulics of the random packing and the absorber dimensions (diameter...

This paper deals with the simultaneously optimization of operating conditions (pressures, temperatures and flow-rates) and dimensions (diameter and height) of the amine regeneration unit in the post-combustion CO 2 capture process. The proposed model takes into account the effect of kinetic reactions on the mass transfer, the hydraulics of the rand...

The aim of this paper is to develop an optimization NLP mathematical model to determine the best operating conditions for the amine regeneration unit of the CO2 post-combustion process. The amine regeneration is an energy intensive process and its optimization is the most important key to obtain cost-effective designs. Thus, an objective function d...

This paper deals with the modeling and optimization of the chemical absorption process to CO2 removal using monoethanolamine (MEA) aqueous solution. Precisely, an optimization mathematical model is proposed to determine the best operating conditions of the CO2 post-combustion process in order to maximize the CO2 removal efficiency. Certainly, the f...

This paper presents optimal operating conditions for the post-combustion CO2 capture process utilizing aqueous amine solutions obtained using a process simulator (HYSYS). Three alkanolamine solutions (Methyldiethanolamine MDEA, DiEthanolAmine DEA and MDEA–DEA mixture) are considered to study the performance of the capture process.The design problem...

Optimal combined cycle gas turbine power plants characterized by minimum specific annual cost values are here determined for wide ranges of market conditions as given by the relative weights of capital investment and operative costs, by means of a non-linear mathematical programming model. On the other hand, as the technical optimization allows id...

The aim of this paper is to present a coupling model for calculating both the hydrodynamic and anaerobic digestion processes in expanded granular sludge bed (EGSB) bioreactors for treating wastewaters. The bioreactor is modeled as a dynamic (gas–solid–liquid) three-phase system. An existing set of experimental data of three case studies based on th...

This work deals with modeling and operation optimization of biological sequential batch reactors (SBR). The SBR is a fill-and-draw biological sludge system for wastewater treatment. In this system, wastewater is added to a single batch reactor, treated to remove undesirable components, and then, discharged. In this paper, a global model of a gas-so...

This paper deals with the optimal design of Mechanical Vapor Compression (MVC) desalination process. Precisely, a detailed mathematical model of the process and a deterministic global optimization algorithm are applied to determine the optimal design and operating conditions for the system. The resulting model involves the real-physical constraints...

On large industrial scales, the cooling stage in the production process of hard candies is one of the most critical unit operations. The main problems affecting final hard candies quality as regards the cooling process are: deformation, fragility and aggregation. The main operating conditions of the cooling stage are temperature and velocity of coo...

In this paper, glass transition temperature (Tg) and microstructure of hard candy honey flavored have been investigated using differential scanning calorimetry (DSC) data and scanning electron microscopy images (SEM) respectively. Precisely, the glass transition temperature can be used as reference temperature to determine the operating mode of pro...

In the present work, a previous superstructure model developed for simultaneous optimization of the process configuration and equipment dimensions, i.e., optimal process synthesis and design and the operation conditions of activated sludge wastewater treatment plants, is extended to account for phosphorus as well as nitrogen removal. Along the acti...

In this work, a rigorous model describing the processes taking place in hollow fiber modules for reverse osmosis desalination is analyzed. The Kimura–Sourirajan model is used for describing transport phenomena through the membrane. The concentration polarization phenomenon is mathematically described using the film theory, while the Hagen–Poiseuill...

Optimal designs of a CCGT power plant characterized by maximum second law efficiency values are determined for a wide range of power demands and different values of the available heat transfer area. These thermodynamic optimal solutions are found within a feasible operation region by means of a non-linear mathematical programming (NLP) model, where...

This paper presents an equilibrium stage mathematical model to optimize the operating conditions to remove CO2 from flue-gases using MonoEthanolAmine (MEA) aqueous solution in a stage column. For the modeling, the absorption column is divided into a number of segments assuming that liquid and gas phases are well mixed. The number of stages of the c...

This paper presents an equilibrium stage mathematical model to optimize the operating conditions to remove CO2 from flue-gases using MonoEthanolAmine (MEA) aqueous solution in a stage column. For the modeling, the absorption column is divided into a number of segments assuming that liquid and gas phases are well mixed. The number of stages of the c...

This paper presents a NLP mathematical model to optimize the operating conditions of the chemical absorption process to CO2 removal using MEA aqueous solution. The optimization design problem is to maximize the CO2 absorption efficiency to reach desired CO2 reduction targets. The entire post-combustion CO2 process is modeled in detail. Temperature,...

In the present work, a life cycle oriented approach is used for designing power plants in a way they can satisfy the desired demand along the whole time horizon, while a selected performance indicator of the project is optimized. As case study, optimal design characteristics as well as optimal values of long term operation parameters of a GT + 1PSH...

In this paper, a mathematical model of CO2 chemical absorption system using MDEA (MethylDiEthanolAmine) and PZ (Piperazine) aqueous solutions is investigated. Precisely, the complex reactive absorption behavior is modeled by an NLP mathematical model. The resulting mathematical model is implemented in GAMS and CONOPT is used as NLP solver. The prop...

In the present work, a previous superstructure model developed for simultaneous optimization of the process configuration and equipment dimensions- i.e., process synthesis and design- and the operation conditions of activated sludge wastewater treatment plants (Alasino et al., 2007) will be extended to account for phosphorus as well as nitrogen rem...

In a previous work, a methodology developed for modeling anaerobic fluidized bed (AFB) reactors was presented. The aim of this work is to extend this methodology for modeling upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors, and compare and discuss model hypotheses and simulation results. A set of experimental...

Seawater desalination is one of the main alternatives to overcome the problem of fresh water supply. Thermal and membrane processes are the conventional technologies widely used to obtain potable water from the sea.Hybrid desalination plants integrating reverse osmosis (RO) and multi stage flash (MSF) systems result interesting alternatives. The hy...

In this paper, desalination systems integrating thermal and membrane processes are investigated. Specifically, a hybrid desalination plant integrating reverse osmosis (RO) and multi stage flash (MSF) systems is mathematically modeled. The non linear programming problem is developed in order to optimize the configuration and operating conditions in...

It is known that pollutants can be dispersed from the emission sources by the wind, or settled on the ground. Particle size, stack height, topography and meteorological conditions strongly affect particulate matter (PM) dispersion. In this work, an impact distance calculation methodology considering different particulate sizes is presented. A Gauss...

In this paper, a mathematical optimization model for the optimal design of industrial furnaces/fired heaters is presented. Precisely, a detailed Mixed Integer Nonlinear Programming (MINLP) model including operational and geometric constraints is developed to get an efficient furnace design. Discrete decisions connected with the geometric design suc...

This work deals with an experimental and theoretical investigation of fluidized bed anaerobic biofilm reactors (FBABRs). The bioreactors are modeled as dynamic three-phase systems. Biochemical transformations are assumed occurring only in the fluidized bed zone but not in the free-support material zone. The biofilm process model is coupled to the s...

A mathematical model for the optimization of the mechanical vapor compression (MVC) desalination process is presented. The mathematical model involves the real physical constraints for the evaporation process. Nonlinear equations in terms of chemical–physical properties and design equations are used to model the process. A general algebraic modelin...

This paper is about the sensitivity of detection of multiple solutions to the structures or parameters incorporated in the equation system that represents a distillation column. The performance of different column simulation models, generally carried out in commercial simulators, is tested to detect multiplicity. The influence of the physicochemica...

The main purpose of this paper was to present a heterogeneous model of a three-phase solid–liquid–gas system to investigate the hydrodynamics and biological behavior and the system performance of anaerobic fluidized bed reactors (AFBRs). The Anaerobic Digestion Model No. 1 (ADM1) was selected to describe the substrate degradation scheme and was app...

Este trabajo presenta un modelo matemático que permite optimizar el porcentaje de absorción de CO2 presente en la corriente de gases de combustión cuando ésta reacciona químicamente con una solución de amina, precisamente con MonoEtanolAmina (MEA). El modelo resultante, el cual es del tipo determinístico y no-convexo, está constituido por las restr...

An optimization model based on a superstructure embedding several activated sludge process configurations for nutrient removal is formulated and solved. Simultaneous optimization of the process configuration (process synthesis) and operation conditions for given wastewater specifications and influent flow rate in steady state operation are investig...

The impact of start-up procedures on the behaviour of simple distillation columns with multiple steady states is analyzed. A well-known system with hysteresis is studied in this paper and transient responses for a binary distillation column yielding different steady states during the start-up operation are shown. Several dynamic simulation results...

The operability of azeotropic distillation columns with multiplicity is analysed during start-up by dynamic simulation. Different steady states can be reached by applying different start-up configurations and/or policies. The well-known benzene-heptane-acetone (BHA) system is studied. The process by which the column reaches these steady states can...

The main purpose of this paper is to analyze the adequacy of some hypotheses assumed in the literature for modeling mass transfer phenomena and hydrodynamics in bioreactors. Four different hydrodynamic models were investigated to simulate the dynamic behavior of an anaerobic fluidized bed reactor (AFBR). A total developed flow condition and the ass...

In this paper a new version of the Outer Approximation for Global Optimization Algorithm by Bergamini et al. [Bergamini, M.L., Aguirre, P., & Grossmann, I.E. (2005a). Logic based outer approximation for global optimization of synthesis of process networks. Computers and Chemical Engineering 29, 1914] is proposed, in order to speed up the convergenc...

In this paper a methodology for MSF process optimization taken into account process availability will be presented. The process optimal operative conditions, and the optimal equipment allocation in stand-by units when necessary will be performed, given a process model and cost data.