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In this study, we used the thermoeconomic theory to evaluate the impact of residue cost formation on the cost of electricity generated from natural gas burned in a gas turbine that applied sequential combustion; we also analyzed the impact of the combustion process on the additional fuel consumption to compensate for a malfunction component. We used the Alstom GT24 gas turbine, which applied sequential combustion and generated 235 MW of power. Thermoeconomic analysis indicated that the exergy cost of power generation was 626.33 MW (30.42% corresponded to irreversibility costs, and 29.22% and 2.84% corresponded to the formation costs of physical and chemical residues, respectively). The exergoeconomic production cost of gas turbine was 10,098.71 USD/h, 34.76% from external resources and 65.24% from capital and operating costs. Thermoeconomic diagnosis revealed that a compressor deterioration (of 1-% drop in the isentropic efficiency) resulted in an additional fuel consumption of 4.05 MW to compensate for an increase in irreversibilities (1.97 MW) and residues (2.08 MW); the compressor generated the highest cost (49.9% of additional requirement). Thus, our study can identify the origin of anomalies in a gas-turbine system and explain their effects on the rest of the components.

This chapter presents the design, operation, and integral evaluation of a sugarcane molasses biorefinery, for the production of l -lysine, lactic acid, polyhydroxybutyrate, and other by-products (such as the recovery of residual biomass). A systematic approach, based on modeling and simulation tools, is presented with two main contributions: (a) the development of operation strategies for fermentation reactors, in order to increase the yield and productivity of the products and (b) the proposal of a technical-economic-environmental strategy, to evaluate the profitability and sustainability of a multi-product biorefinery. The proposed multicriteria evaluations are useful both to evaluate the performance of various process options from various points of view and to support decision-making at the initial stage of designing a biorefinery. The results show the operation regions of the fermentation reactors and the integral evaluation of a complete flowsheet to achieve a conceptual design of a biorefinery that is profitable with low environmental impact.

A simple Gibbs energy-driving force method for the design of non-reactive and reactive distillation columns has been developed. Based on the binary driving force concept and the equilibrium Gibbs energy computation, a systematic procedure for the design of non-reactive distillation columns (NRDC) and reactive distillation columns (RDC) is proposed. The design method exploits the connection between the driving force values and the equilibrium Gibbs energy to determine the number of stages, the optimal feed location, and the heat required at the top and bottom of the column and the minimum reflux ratio. The final design guarantees an optimal operation since maximum thermodynamic efficiency is achieved. The maximum thermodynamic efficiency criterion is equivalent to the minimum entropy condition required for a stable operation of the distillation columns. The method is applied for the design of two non-reactive systems: a) Benzene-Toluene ideal system and b) Ethanol-Water non-ideal system. A reactive distillation column considering the isomerization of n-butane in the presence of an inert compound is designed. The optimal thermal feed condition obtained through the maximum separation efficiency guarantees that the final designs obtained correspond to the minimum energy requirements for the design target of separation.

Nowadays, sensitivity analysis (SA) is a methodology commonly used to identify important parameters that determine the behavior of the model. The SA of a model allows to determine how uncertainties in the model responses (outputs) can be assigned to the values of the model parameters (input variables). The related literature indicates that there are several methods to perform SA. This work addresses the benchmarking of four widely used methods for Global SA (GSA): Sobol-Jansen, Sobol-Baudin, Sobol-Owen and Sobol 2007, based on the concept of performance profile introduced by Dolan and More (2002) and the extension by Mahajan et al. (2012). For the previous methods, a set of 21 models and their variations were considered, which correspond to various applications in chemical engineering (such as heap leaching, water distribution network, milling, flotation circuit, among others). These comparisons show that the Sobol-Jansen method has the best performance profile because it is the first to perform GSA in 83% of the models considered. The four SA methods analyzed proved to be quite stable since they performed the SA in 100% of the models tested.

This paper considers the criterion of minimum compression work to derive an expression for the interstage pressure of a multistage compressor with intercooling that includes the gas properties, pressure drops in the intercoolers, different suction gas temperatures, and isentropic efficiencies in each compression stage. The analytical expression for the interstage pressures is applied to estimate the number of compression stages and to evaluate its applicability in order to estimate interstage pressures in the operation of multistage compressors, which can be especially useful when their measurements are not available.

The primary management of the organic fraction of municipal solid waste (OFMSW) was commonly composting, landfill or incineration, while now the anaerobic digestion of OFMSW offers the possibility of a clean and renewable energy source. This work presents the modelling and simulation of an OFMSW biorefinery to produce biogas, fertiliser and bioethanol. The conceptual design of the biorefinery begins with an anaerobic digestion to degrade OFMSW and produce biogas. The resulting solid fibres and the effluent are sent to the subsequent stages to produce fertiliser from the solid waste and anhydrous bioethanol from the fermentation broth. The process simulations are based on an anaerobic biorefinery capable to treat 1,000 tonnes per day of OFMSW generated in CDMX. The main results show the yields are 73 kg ethanol, 54 kg biogas and 59 kg fertiliser per tonne of dry waste.

La biomasa es una de las materias primas mas prometedoras utilizada en una biorrefineria, ya que produce un balance neutro de CO 2 . Mientras que la bioeconomia es un nuevo enfoque que enfatiza el uso eficiente y sostenible de los procesos de produccion de la biomasa para obtener productos quimicos, materiales y energia. Bajo este enfoque, en este trabajo se presenta el diseno de una biorrefineria de melaza de cana de azucar para producir acido lactico y un suplemento alimenticio. El analisis del diseno se presenta en dos partes, primero se hace un analisis dinamico del reactor de fermentacion para dos modos de operacion (lote y lote alimentado), utilizando un factor de enriquecimiento asociado a la concentracion de nutrientes, y logrando una productividad maxima de acido lactico de 2.4 g/L/h y un rendimiento de 0.97 kg producto/kg sustrato. En la segunda parte, se analiza un diseno conceptual industrial de la biorrefineria, evaluando diversos criterios tecnicos, economicos y ambientales para determinar la sostenibilidad del proceso de produccion. Con el mejor diseno del proceso (en modo lote alimentado) se obtiene un costo de produccion unitario de 0.66 US$/kg, con una tasa de retorno de la inversion de 62.2% en un periodo de recuperacion de 1.61 anos, y con un indice de impacto ambiental bajo de 0.18 PEI/kg.

PHB (polyhydroxybutyrate) is a biodegradable polymer that can replace petrochemical polymers due to its properties and applications. However, its commercial use remains limited because of its high production cost. In this work, factors affecting the PHB fermentation reactor and its impact on the production cost are studied. The production process considers the sucrose fermentation with Azohydromonas australica, followed by the PHB purification and drying. The proposed methodology is divided into two stages: firstly, the analysis of the reactor where it is necessary to define the operation mode and the operating conditions to achieve high product yield and productivity; and secondly, the analysis of production process using technical, economic and environmental criteria to evaluate the process conceptual design. The proposed methodology can reduce complex efforts to achieve an efficient fermentation and validate the design of PHB production process, thereby enabling a biopolymer production with a competitive cost and low environmental impact. The best operation mode for the fermentation reactor was fed-batch, whose feeding strategy allowed to achieve satisfactory technical-economic-environmental results for the PHB production plant: product yield of 0.36 g PHB/g sucrose, productivity of 1.6 g/L/h, production cost of 2.6 USD/kg PHB, return on investment of 34.2%, payback period of 2.9 yr, emissions of 1.7 kg CO2/kg PHB, energy consumption of 10.1 MJ/kg PHB and process requirement of 16.9 kg water/kg PHB.

L-Lysine is an essential amino acid that can be produced by chemical processes from fossil raw materials, as well as by microbial fermentation, the latter being a more efficient and environmentally friendly procedure. In this work, the production process of L-lysine-HCl is studied using a systematic approach based on modeling and simulation, which supports decision making in the early stage of process design. The study considers two analysis stages: first, the dynamic analysis of the fermentation reactor, where the conversion of sugars from sugarcane molasses to L-lysine with a strain of Corynebacterium glutamicum is carried out. In this stage, the operation mode (either batch or fed batch) and operating conditions of the fermentation reactor are defined to reach the maximum technical criteria. Afterwards, the second analysis stage relates to the industrial production process of L-lysine-HCl, where the fermentation reactor, upstream processing, and downstream processing are included. In this stage, the influence of key parameters on the overall process performance is scrutinized through the evaluation of several technical, economic, and environmental criteria, to determine a profitable and sustainable design of the L-lysine production process. The main results show how the operating conditions, process design, and selection of evaluation criteria can influence in the conceptual design. The best plant design shows maximum product yield (0.31 g L-lysine/g glucose) and productivity (1.99 g/L/h), achieving 26.5% return on investment (ROI) with a payback period (PBP) of 3.8 years, decreasing water and energy consumption, and with a low potential environmental impact (PEI) index.

An intensified three-step reaction-separation process for the production of bio-jet diesel from tryglycerides and petro-diesel mixtures is proposed. The intensified reaction-separation process considers three sequentially connected sections: (1) a triglyceride hydrolysis section with a catalytic heterogeneous reactor, which is used to convert the triglycerides of the vegetable oils into the resultant fatty acids. The separation of the pure fatty acid from glycerol and water is performed by a three-phase flash drum and two conventional distillation columns, (2) a co-hydrotreating section with a reactive distillation column used to perform simultaneously the deep hydrodesulphurisation (HDS) of petro-diesel and the hydrodeoxigenation (HDO), decarbonylation and decarboxylation of the fatty acids, and (3) an isomerization-cracking section with a hydrogenation catalytic reactor coupled with a two-phase flash drum is used to produce bio-jet diesel with the suitable fuel features required by the international standards. Intensive simulations were carried out and the effect of several operating variables of the three sections (triglyceride-water feed ratio, oleic acid-petro-diesel feed ratio, hydrogen consumption) on the global intensified process was studied and the optimal operating conditions of the intensified process for the production of bio-jet diesel were achieved.

An integrated reactive separation process for the production of jet diesel from vegetable oils and gasoil mixture has been developed. The integrated reactive separation process consider three interconnected sections: 1) a triglyceride hydrolysis section consisting of a catalytic heterogeneous reactor which is used to transform the triglycerides of the vegetable oils or animal fats to the corresponding fatty acids and a coupled decanter-distillation column to separate the fatty acids from glycerol and water; 2) a co-hydrotreating section where a reactive distillation column is proposed to perform the deep hydrodesulfurization (HDS) of gasoil and the hydrodeoxigenation (HDO) and the decarbonilation of the fatty acids simultaneously and 3) a isomerization section where a catalytic reactor is used to produce the jet diesel with the appropriate fuel properties. Through intensive simulations the effect of the different operating variables of the three sections were studied. Results show that for the first section the water excess and the operating pressure are key variables for the transformation of the triglycerides. For the reactive distillation column for the HDS of gasoil and HDO of the fatty acids, it is very important to maintain the hydrogen excess in the feed with a low reflux ratio to allow the release of the light gases produced and, to guarantee the deep HDS of gasoil and the complete transformation of the vegetable oils. Finally, the isomerization reactor must be carefully operated with respect to the amount of light hydrocarbons compounds allowed in the mixture to be cracked and isomerized.

In this work, a monitoring strategy is presented to infer unmeasured concentrations and estimate the kinetic parameter of inhibition in an enzymatic reactor. The reaction corresponds to the hydrolysis of cellulose to produce glucose, in batch and isothermal conditions. The strategy is based on a softsensor that consists of a model-based state estimator and considering only density measurements. The reactor model and the softsensor performances are validated with experimental data, obtaining satisfactory estimates. The strategy could be extended to other bioreactors.

At present, technological innovation can be used as a tool in the teaching-learning process through the implementation and use of an interactive virtual laboratory. Large-scale resources could be simulated, overcoming the drawbacks associated with the physical space, infrastructure and instrumentation required to carry out process engineering practices at different levels (laboratory, pilot and industrial). In this type of laboratory, students can enter a virtual environment where they must apply the acquired knowledge to select solution options and make decisions in situations similar to a real environment, allowing them to experience the resulting consequences. The LaVIP (for its acronym in Spanish for Virtual Laboratory of Process Engineering) is being developed at the Universidad Autonoma Metropolitana (Cuajimalpa Campus), where practices are being implemented that support undergraduate degrees such as chemical engineering, biological engineering and related. In particular, this work shows the methodology used for the development and implementation of the LaVIP, as well as the results of an interactive virtual practice for an isothermal batch reactor where an enzymatic hydrolysis reaction occurs. The LaVIP is accessed through a website, which includes the information architecture of an educational platform that guides the user, providing tools to: (i) motivate and involve the student in the development of a practice in a quasi-real environment, and (ii) improve teaching and evaluate learning. The educational platform is developed using usability techniques, maintaining indispensable characteristics such as access security, an intuitive environment, access to information (offering resources such as glossary, help, descriptions, etc.), student progress monitoring, and a simple administration portal. The functions and executable programs of process engineering practices are developed using the Matlab Production Server application. This tool provides web clients, which through a process and administration server allow users to run programs developed in Matlab without having an own license. The main server is able to generate scripts, which are used in the website developed in the standard HTML5 language. As case study, the calculations and analysis of an isothermal batch reactor where the enzymatic hydrolysis of cellulose to produce glucose is carried out. The kinetics is Michaelis-Menten type and the main objective is to determine the values of the kinet (1) trial and error, where the kinetic parameters are estimated from a plot of experimental data; (2) linear regression, where the parameters are calculated from the linearization of the Michaelis-Menten equation; and (3) optimization, where an objective function is minimized to determine the optimal parameter values. So far, LaVIP has its own systematic development process for lab practice implementation. Currently its use is internal and being in evaluation. In the future, more practices will be added and LaVIP use will open for other institutions.

This work studies the effect of the heat integration on the production process of 2G bioethanol by using simulation tools, focusing mainly on the economic analysis viability of the process to reduce the use of energy resources. The study considers wheat straw as raw material, and two different pretreatment processes (dilute acid and steam-explosion) are analysed. Pinch analysis is employed to identify heat sources and sinks in bioethanol production process, to supply the process with heating and cooling using heat exchangers, reducing the external energy input use. The results of this analysis are compared for both pretreatments, together with economic evaluations. The results provided screening options during the early process design stage. In the future, they will be used to optimize the heat exchange network and incorporate life-cycle assessment to calculate rigorously the profitability and sustainability of the production process.

The problem of designing a saturated output-feedback controller to stabilize a class of continuous three-state bioreactors with Haldane inhibited kinetics is addressed. The reactor must be maintained about the (locally stable but possibly structurally unstable) steady-state with maximum production rate by manipulating the substrate feed rate on the basis of a biomass measurement. The consideration of the problem in the light of bioreactor (bifurcation and invariant set) dynamical and (passivity and observability) structural characteristics leads to a saturated linear dynamic OF control design with: (i) PI scheme with observer-based antiwindup protection, (ii) simple construction and tuning, and (iii) closed-loop robust stability conditions in terms of control gains and limits. The PI controller recovers (up to observer convergence and saturation) the behavior of a model-based nonlinear state-feedback passive stabilizing controller equivalent to an exact nonlinear model-based predictive controller with infinite-time receding horizon. The proposed approach is illustrated with a representative case example through numerical simulations.

A simple computational procedure to determine reactive critical points of kinetically controlled reacting mixtures was developed. The thermodynamic analysis considers the simultaneous calculation of the reactive and non-reactive residue curve maps using the Peng–Robinson equation of state and the Heidemann and Khalil method for the computation of critical points. Two kinetically controlled reactive systems were considered: (i) the reversible esterification reaction of acetic acid with ethanol in the presence of CO2 and, (ii) the irreversible hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene with tetralin as solvent for the production of ultra low sulfur diesel. It was found that the amount of catalyst loaded (α) into the reacting vessel plays a key role for the existence of the reactive critical points for the deep HDS of diesel while for the esterification reactions has little significance. Also, results showed that, while the catalyst loaded does not have any influence on the existence of the reactive critical point for the esterification reactive system (TC ∼ 566 K; PC ∼ 68 atm; xHAc ∼ 0.39, xEtOH ∼ 0.26, xEtAc ∼ 0.15, x H 2 O ∼ 0 .19 , and x CO 2 ∼ 0 .01 ), it moves the range of temperature where a maximum liquid composition of ethyl acetate can be obtained. Several critical points for the hydrodesulfurization of 4,6-DMDBT were found with different α values.

The problem of designing a saturated Output-Feedback (OF) controller for a three species continuous fermenter with substrate and product-inhibited kinetics is addressed. The reactor must be operated at maximum production rate by manipulating the feed rate on the basis of a (biomass, substrate or reaction rate) measurement. The combination of global dynamics concepts with State-Feedback (SF) and OF nonlinear control tools yields a linear dynamical OF saturated control design with: (i) robust stability conditions in terms of the controller gains and saturation limits, and (ii) simple tuning guidelines. The linear OF saturated controller: (i) recovers, in a practical stability sense, the behavior of a globally stabilizing nonlinear robust SF saturated controller, and (ii) becomes a linear PI controller in the absence of saturation. The proposed approach is illustrated and tested with a representative example through simulations.

A systematic study of the operating conditions and parameter sensibility under which multiple steady states may occur in a reactive distillation column (RDC) for diesel deep hydrodesulfurization is presented. The multiplicity analysis is performed through bifurcation diagrams for two feed case scenarios. The main variables that affect the steady state behavior are the reflux ratio, the hydrocarbon feed flowrate, the reboiler heat duty, and the catalyst load (liquid holdup). For the first case only a single steady state was found, while in the second case input and output multiplicities were determined. It is shown that the introduction in the feed of the recalcitrant 4,6-DMDBT, plays a crucial role in the RDC design and operation. A set of values of the bifurcation parameters for an appropriate operation of the RDC are recommended to avoid the multiplicity region and to reach the required output targets.

The problem of regulating the biomass growth rate at its maximum value in an open-loop unstable, continuous, non-monotonic biological reactor using biomass measurement and manipulation of substrate feed rate is considered. An Output-Feedback controller is designed exploiting the reactor open-loop stability and inherent observability properties and the relative degree structure to obtain robust and non-wasteful closed-loop performance. The resulting controller has a high degree of independency with respect to the kinetic growth rate expression, thus ensuring robustness against typical model uncertainties. A representative case example with non-monotonic Haldane kinetics is employed to test the proposed controller, in absence and presence of modeling and measurement errors.

Petroleum is currently the primary raw material for the production of fuels and chemicals. Consequently, our society is highly dependent on fossil non-renewable resources. However, renewable raw materials are recently receiving increasing interest for the production of chemicals and fuels, so a new industrial system based on biomass, an inexpensive, abundant and renewable raw material, is being established with sustainability as the main driving force [1]. The processing facilities for the production of multiple products (including biofuels and chemicals) from biomass are referred as biorefineries [2]. The optimal synthesis of biorefinery networks problem is defined as: given a set of biomass derived feedstock and a set of desired final products and specifications, determine a flexible, sustainable and innovative processing network with the targets of minimum cost and sustainable development taking into account the available technologies, geographical location, future technological developments and global market changes. The problem of optimal design of biorefinery networks is solved in this work through three different stages: (i) synthesis stage, (ii) design stage, and (iii) innovation stage. At the synthesis stage, the considered alternatives are represented in a superstructure, from which a mixed-integer linear or nonlinear programming (MILP or MINLP) problem is derived and solved in order to find the optimal processing network for a pre-defined objective function. Next, at the design stage, the selected processing network is simulated and analyzed and targets for improvement are identified. Finally, a more sustainable design is achieved at the innovation stage by generating innovative solutions that satisfy the targets from the design stage. This work is concerned with the first stage: the synthesis stage. Various biorefinery processing alternatives are represented in a superstructure and the associated data is collected and stored in a database. Once a specific biorefinery synthesis problem is formulated, the superstructure is reduced in order to include only the relevant alternatives. The superstructure is reduced based on constraints from the problem formulation, such as location or raw material. The reduced superstructure is then represented using mathematical models - the modelling approach by Quaglia et al. [3] is used - and solved to find the optimal network. The applicability of the proposed approach is shown through a practical case study for the production of valuable products (i.e. lysine and lactic acid) from sugarcane molasses; these alternatives are considered with respect to availability and demands in Mexico [4].

The advances in computer science and computational algorithms for process modelling, process simulation, numerical methods and design/synthesis algorithms, makes it advantageous and helpful to employ computer-aided modelling systems and tools for integrated process analysis. This is illustrated through the study of a copolymerization process, where operational problems due to their complex nonlinear behaviour are usually encountered, indicating thereby, the need for the development of an appropriate process model that can describe the dynamic behaviour over the complete range of conversion. This will allow analysis of the process behaviour, contribute to a better understanding of the polymerization process, help to avoid unsafe conditions of operation, and to develop operational and optimizing control strategies. In this work, through a computer-aided modeling system ICAS-MoT, two first-principles models have been investigated with respect to design and operational issues for solution copolymerization reactors in general, and for the methyl methacrylate/vinyl acetate system in particular. The Model 1 is taken from literature and is commonly used for low conversion region, while the Model 2 has been derived in this work and covers the complete range of conversion. The performances of the two models are compared with respect to the steady state and dynamic behaviour of the polymerization process. The model analyses highlight the influence of the reaction mechanism, the transport phenomena, the process design and conditions of operation on the polymer grade and the production rate.

In this work, a software sensor is presented in order to monitor the pollutant concentrations in an activated sludge process for industrial and municipal wastewater treatment. The software sensor consists of a model-based state estimator to infer the (unmeasured) biodegradable substrate and ammonia concentrations, based on a reduced process model with approximated model parameters and considering only on-line measurements of dissolved oxygen and nitrate concentrations. The software sensor performance is showed with experimental data from a real process and it is compared versus a complex process model, obtaining good estimated concentrations. Results show that not always the use of complex models is the best way to obtain a good process representation for monitoring and control purposes

In this work the problem of on-line monitoring of product quality and production rate in a copolymer reactor is addressed, using an estimation scheme with secondary measurements of density, refractive index, temperature, and volume. Three different estimator structures are studied: (a) the nominal detectability structure that underlines the extended Kalman filter and Luenberguer observers, (b) a passive estimation structure with estimation degrees equal to one, and (c) a hybric structure that combines the detectability and passive structures in low and high gain, respectively. The nominal detector maximizes the reconstruction rate, the passive estimator maximizes the robustness, and the cascade (hybrid) design achieves a suitable compromise between them. The approach is illustrated with a case study and simulations.

L-Lysine is an essential amino acid which can be produced by chemical processes from fossil raw materials, as well as by microbial fermentation, the latter being a more economical procedure. In the present work the fermentation process of L-lysine from sugarcane molasses is studied, using modelling and dynamic simulation tools to compare batch and fed-batch process, as well as to determine feasible operating regions in terms of productivity, product yield and fermentation time. These results will be used in the future for economic analysis, optimization studies and environmental impact.

Within a nonlinear geometric-type state-inference framework, this work studies the problem of estimating the states of a solution copolymerization reactor from measurements of temperature, density, vapor pressure, and volume. With this estimation technique: a observable/detectable plant can be handled, there is convergence criteria, and there is a simple and systematic tuning procedure. The reactor has ten states, and two estimators are considered; one with observability index four, and another with index seven. The estimator with low observability index shows more tolerance to modeling errors.

The article contains sections titled: 1. Introduction 2. Process Synthesis and Design 2.1. Objective of Process Synthesis and Design 2.2. Generic Problem Definition 2.3. Process Synthesis–Design Methods 2.4. Challenges and Opportunities 3. Process Integration–Energy 3.1. Process Integration–Introduction to Key Concepts and Major Topics 3.1.1. Design of Heat Exchanger Networks (HENs) 3.1.2. Correct Heat Integration 3.1.3. Use of Optimization in Process Integration 3.1.4. Use of Exergy in Process Integration 3.1.5. Heat Recovery in Batch Processes 3.1.6. Expansions of the Pinch Concept 3.1.7. Concluding Remarks and Future Directions 3.2. Introduction to the Synthesis of Heat Exchanger Networks 3.2.1. Problem Statement 3.2.2. Minimum Utility Cost 3.2.2.1. Partition of Temperature Scale 3.2.2.2. Linear Programming Transshipment Model 3.2.2.3. Illustration 3.2.3. Minimum Number of Matches 3.2.4. Derivation of Optimal HEN Structure 3.2.4.1. Problem Statement 3.2.4.2. HEN superstructure 3.2.4.3. Mathematical Formulation of the HEN Superstructure 3.2.5. Simultaneous HEN Synthesis Approach 4. Process Intensification 4.1. Introduction 4.2. Definition of PI 4.3. Process Systems Engineering (PSE) and Process Intensification (PI) 4.3.1. Synthesis and Design 4.3.2. Modeling and Simulation 4.4. Analysis and Verification 4.5. Perspective 5. Reactive Distillation Processes 5.1. Graphical Design Methods 5.1.1. Element Balances and Equilibrium Condition 5.1.2. Design of Reactive Distillation Columns 5.1.2.1. Binary-Element Reactive Systems 5.1.2.2. The Reactive Equilibrium Curve 5.1.2.3. Constant Total Element Mass Overflow Assumption (CTEMO) 5.1.2.4. The Reactive McCabe–Thiele Diagram 5.1.2.5. Accounting Heat Effects: The Reactive Ponchon–Savarit Diagram 5.1.3. Application Examples 5.1.4. Conclusions 5.2. New Applications 5.2.1. Clean Fuels, Challenges and Opportunities 5.2.2. Methodology 5.2.3. Case Study: Production of Ultra-Clean Diesel 5.2.3.1. The Reaction System (Stage 1) 5.2.3.2. Model Formulation: Batch Reactive Distillation Process (Stage 2) 5.2.3.3. Conceptual design of a reactive distillation column (Stage 3) 5.2.3.4. Rigorous Simulation of Reactive Distillation Process (Stage 3) 5.2.4. Conclusions 6. Chemical Product Synthesis/Design 6.1. Introduction 6.2. Design, Synthesis, and Formulation 6.2.1. Mathematical Formulation of the Chemical Product Design Problem 6.2.2. Database Searches 6.2.3. Enumeration & Generation 6.2.4. Optimization 6.3. Tools for Product Design 6.3.1. Computer-Aided Mixture/Blend Design (CAMbD) 6.3.2. Computer-Aided Molecular Design (CAMD) 6.3.3. Design of Structured Chemical Products 6.4. Example: Design of an Insect Repellent 6.5. Conclusions and Future Directions 7. Approaches to Pharmaceutical Product Design 7.1. Introduction 7.2. General Concepts in Pharmaceutical Product Design 7.3. Design and Development of Active Pharmaceutical Ingredient 7.3.1. Overview 7.3.2. Ligand Screening 7.3.3. Structure-Based Drug Design 7.4. Pharmaceutical Formulation Design 7.4.1. Overview 7.4.2. Formulation Properties and Selection 7.4.3. Computer-Aided Molecular Design of Excipients 7.5. Example: Formulation Design to Minimize Aggregation of Protein Drugs 7.5.1. Overview 7.5.2. Prediction of Protein Aggregation 7.5.3. Design of Excipients for the Minimization of Aggregation 7.6. Conclusions and Future Directions 8. Acknowledgments

Motivated by the importance of the pretreatment step for the production of biobased products (such as bioethanol), this paper addresses the problem of modelling, design and optimization of operating conditions of a non-isothermal continuous reactor where the acid pretreatment of lignocellulosic biomass takes place. The reactor model is developed using material and energy balances, including a rigorous reaction mechanism. Process design and operating conditions are first studied by analysing the steady-state behaviour (including state multiplicity) and transient behaviour, and then solving the optimization problem to maximize sugar production and minimize lignin retention.

The objective of this work is the viscosity prediction of the main fatty compounds derived from castor oil (i.e. fatty acids, triacylglycerols and methyl esters) extending a predictive method based on group contribution that was previously reported. The missing values of viscosity parameters for the hydroxyl functional group are evaluated through optimization using available experimental data for castor oil and its biodiesel. The optimization problem is proposed for three different functional groups and is solved using Successive Quadratic Programming method. Best viscosity values for castor oil and its biodiesel are obtained with parameter estimation for the group CH-OH.

The objective of this work is to study the design and operation of a dilute acid pretreatment reactor for lignocellulosic biomass. An isothermic continuous reactor model is developed based on rigorous mass balances. Then the process design and operation are studied through steady state analysis, together with an optimization problem that maximizes the reaction rates of the sugar production and of lignin elimination. The results are presented in terms of flowrates of fermentable sugars and acid soluble ligning, defining operating ranges for an efficient continuous process.

In the acid pretreatment of lignocellulosic biomass, a first drawback that must be solved is the removal of lignin and hemicellulose through hydrolysis reactions. In this work, the influence of several operating conditions, as well as the reactor design (batch or continuous), for the dilute acid pretreatment is analyzed. Rigorous kinetic modeling is considered and simulation tools are employed. The results give guidelines for improving the process efficiency (i.e. high conversions and low reaction times).

The design, operation and control of reactive distillation columns are more complex than those involved for either reactors or conventional distillation columns. Therefore, a good un derstanding of the process helps to avoid unsafe operation conditions and further facilitates various, subsequent studies such as control, monitoring, data reconciliation, parameter estimation and optimization of existing plants. In this work the study of the steady state and dynamic behavior as well as the analysis of some controllability issues for reactive distillation columns, based on the applicability of the (equilibrium) element-based approach and thermodynamic issues, are presented. The MTBE process is selected as case study, so that previous reported, results can be compared and verified. Results are obtained using ICAS and ASPEN simulators.

The development of an appropriate model for copolymerisation reactors that can describe the process behaviour over the complete range of conversion contributes to a better understanding of the polymerisation process, helps to avoid unsafe operating conditions and to develop operational and optimizing control strategies. The aim in this work is to study the design and operational issues of a copolymerisation reactor through a systematic model-based (open-loop) nonlinear analysis. The performance of two first-principles models are compared with respect to the steady state and dynamic behaviour of the polymerisation process. The analysis highlights the influence of the reaction mechanism, the transport phenomena, the process design and operating conditions on the polymer grade and the production rate.

Muchos plásticos comerciales y de ingeniería son industrialmente producidos en reactores de copolimerización en solución. El propósito fundamental de la copolimerización, a escala comercial, es mejorar las propiedades fisicas, químicas, y mecánicas de un homopolímero. Debido a esto, el conocimiento de las propiedades instantáneas del copolímero (tales como: la conversión, la composición de copolímero, los pesos moleculares, la fracción de sólidos, etc.) durante su proceso de producción es importante para monitorear y controlar los indices de desempeño relacionados a la seguridad, la operabilidad, la productividad, y el grado o calidad del producto. En esta tesis se presenta una metodología para abordar los problemas de estimación y de control en reactores continuos de copolimerización en solución. El objetivo principal es el diseño de estimadores y controladores (geométricos) no lineales que permitan inferir propiedades no medibles en tiempo real (como son la fracción de sólidos, la composición instantánea, la conversión, el peso molecular peso-promedio, y la velocidad de producción del copolímero), empleando un modelo dinámico del proceso en combinación con una retroalimentación de salidas medibles en línea (seleccionando mediciones continuas, instantáneas y de bajo costo, como son densidad, índice de refracción, temperatura, y volumen) La metodología propuesta aborda tres aspectos principalmente. Primero, el estudio de los reactores continuos de copolimerización en solución. Donde la finalidad es describir, entender, caracterizar e interpretar el comportamiento dinámico del reactor mediante un sistema de ecuaciones diferenciales no lineales. Segundo, el esquema de estimación no lineal (a lazo abierto). En el cual se desarrolla un estimador geométrico no lineal, con las siguientes características: (a) construcción sistemática, (b) diseño con criterio de convergencia, (c) técnica de sintonización simple y sistemática (mediante la asignación de polos, de forma similar a las técnicas de control y filtrado lineal convencional), y (d) la estructura de estimabilidad (i.e., grado de observabilidad y partición de los estados observables - no observables) como grado de libertad del diseño. Y tercero, el esquema d e control no lineal con retroalimentación d e mediciones. El cual se construye a partir de la combinación del estimador de estados a lazo abierto, con el control no lineal con retroalimentación de estados; mostrando características similares al estimador (en cuanto a diseño, construcción, sintonización, y convergencia). Los esquemas de estimación y control propuestos son implementados para la copolimerización de metil metacrilato - acetato de vinilo, con acetato de etilo como solvente, y AIBN como iniciador. Los resultados muestran la factibilidad de inferir y regular las variables de calidad, seguridad, y velocidad de producción a partir de mediciones secundarias en línea. Tanto el estimador como el controlador no lineal muestran robustez ante errores en las condiciones iniciales, cambios en las entradas exógenas, errores en los parámetros del modelo, y ruido en las mediciones.

In this work, an exergoeconomic analysis is performed on a vapor compression refrigeration system using R134a. A productive structure is proposed and the exergetic and exergoeconomic costs balances are implemented with and without considering the components allocation costs of the residue formation process. A parametric analysis is carried out to evaluate the behavior of the exergetic and exergoeconomic operation costs, the coefficient of performance and the exergetic efficiency depending on the change in the ambient temperature, the refrigeration temperature, the adiabatic efficiency and the refrigeration capacity. The results show the system product costs (cooling effect) considering the residue costs is 56.8 % greater than the product cost obtained by discarding them. The parametric analysis shows that the exergetic and exergoeconomic operation costs are mainly affected by the change in the ambient temperature followed by the change in the refrigeration temperature. Resumen En este trabajo se realiza un análisis exergoeconómico a un sistema de refrigeración por compresión de vapor con R134a. Se plantea la estructura productiva y se obtienen los modelos matemáticos de los costos exergéticos y exergoeconómicos con y sin imputación del costo del residuo a los equipos. Se hace un análisis paramétrico para evaluar los costos de operación exergéticos y exergoeconómicos, el coeficiente de operación y la eficiencia exergética en función de la temperatura ambiente, la temperatura de refrigeración, la eficiencia de compresión isoentrópica y la potencia frigorífica. Los resultados muestran que al comparar los costos de operación del producto del sistema, considerando el análisis con imputación del costo del residuo, éstos aumentan 56.8 %; así mismo, los costos de operación se incrementan en mayor proporción con la temperatura ambiente que con la variación de la temperatura de refrigeración considerando como objetivo productivo la producción del frío.

La biomasa es una de las materias primas más prometedoras utilizada en una biorrefinería, ya que produce un balance neutro de CO2. Mientras que la bioeconomía es un nuevo enfoque que enfatiza el uso eficiente y sostenible de la biomasa para obtener productos químicos, materiales, y energía. Algunos productos químicos de base biológica como aminoácidos, enzimas, ácidos orgánicos, antibióticos son excelentes ejemplos de la utilización de procesos biológicos para una gran escala sostenible y económica producción. El principal objetivo de este trabajo es presentar y analizar el diseño (como selección de insumos, equipo, operaciones y método de operación), operación (diagrama del proceso), síntesis (configuración del proceso) y evaluación integral (mediante criterios técnicos, económicos y ambientales) del proceso de producción en una biorrefinería de melaza de caña de azúcar. Las principales contribuciones son: (i) el desarrollo de estrategias de operación para un reactor de fermentación con el fin de aumentar el rendimiento y la productividad del producto, y (ii) la propuesta de una metodología de evaluación técnico-económica y ambiental detallada, útil para decidir la rentabilidad y sostenibilidad de un bioproceso industrial. La metodología se basa en un enfoque sistemático, empleando herramientas de modelado y simulación, que apoyan la toma de decisiones en la etapa inicial del diseño de una biorrefinería. La metodología considera dos pasos de análisis: en primer lugar, el análisis dinámico de la etapa reactiva. Aquí se estudia el efecto de las condiciones de operación sobre los criterios técnicos, en segundo lugar, se realiza el análisis del proceso de producción industrial, en el que se incluyen la etapa reactiva junto con los procesos corriente arriba y corriente abajo. En este segundo análisis se estudia la influencia del modo de operación y la capacidad instalada de la planta sobre el rendimiento global de la biorrefinería. La metodología se aplica a varios escenarios en una biorrefinería de melaza de caña de azúcar para producir L-lisina, ácido láctico y polihidroxibutirato. La influencia de los parámetros clave en el desarrollo de los procesos es crucial en la evaluación de criterios técnicos, económicos y ambientales, para determinar un diseño rentable y sostenible de la biorrefinería. De los casos estudiados, el mejor diseño de biorrefinería se logra para el proceso de producción de ácido láctico, obteniendo como criterios técnicos: máximo rendimiento de YOP = 0.97 kg/kg y productividad de Pr = 1.7 kg/L/h; como económicos: máximos retorno sobre la inversión de RSI = 62.2% y periodo de recuperación de PR = 1.61 años; y finalmente como criterios ambientales: un gasto energético de E = 0.29 MJ/Kg y un índice de impacto ambiental de PEI= 0.18 PEI/kg. Los resultados determinan las regiones de operación para lograr un diseño conceptual de una biorrefinería que sea rentable con bajo impacto ambiental.