Plantwide Control and Simulation of Sulfur-Iodine Thermochemical Cycle Process for Hydrogen Production

A PWC structure has developed for an industrial scale SITC plant. Based on the performance evaluation, it has been shown that the SITC plant developed via the proposed modified SOC structure can produce satisfactory performance – smooth and reliable operation. The SITC plant is capable of achieving a thermal efficiency of 69%, which is the highest attainable value so far. It is worth noting that the proposed SITC design is viable on the grounds of economic and controllability

Integrated design and control of chemical processes : part I : revision and clasification

[EN] This work presents a comprehensive classification of the different methods and procedures for integrated synthesis, design and control of chemical processes, based on a wide revision of recent literature. This classification fundamentally differentiates between “projecting methods”, where controllability is monitored during the process design to predict the trade-offs between design and control, and the “integrated-optimization methods” which solve the process design and the control-systems design at once within an optimization framework. The latter are revised categorizing them according to the methods to evaluate controllability and other related properties, the scope of the design problem, the treatment of uncertainties and perturbations, and finally, the type the optimization problem formulation and the methods for its resolution.[ES] Este trabajo presenta una clasificación integral de los diferentes métodos y procedimientos para la síntesis integrada, diseño y control de procesos químicos. Esta clasificación distingue fundamentalmente entre los "métodos de proyección", donde se controla la controlabilidad durante el diseño del proceso para predecir los compromisos entre diseño y control, y los "métodos de optimización integrada" que resuelven el diseño del proceso y el diseño de los sistemas de control a la vez dentro de un marco de optimización. Estos últimos se revisan clasificándolos según los métodos para evaluar la controlabilidad y otras propiedades relacionadas, el alcance del problema de diseño, el tratamiento de las incertidumbres y las perturbaciones y, finalmente, el tipo de la formulación del problema de optimización y los métodos para su resolución

Diseño y simulación de controladores inteligentes aplicados a procesos industriales

El presente proyecto tiene por objetivo general desarrollar sistemas de apoyo para la toma de decisiones en procesos industriales, enfocados principalmente a los sistemas de control inteligente. Estos sistemas son cada vez más necesarios debido a la complejidad creciente de los escenarios planteados por la globalización, la competencia, los avances tecnológicos, los problemas ambientales y sociales, entre otros. Concretamente, el Control Inteligente es un procedimiento computacional, capaz de conducir eficientemente un sistema complejo a un objetivo, aún con una representación incompleta, inadecuada y/o bajo especificaciones imprecisas; es decir, actúa apropiadamente en un entorno con incertidumbre. Bajo estas premisas, se puede considerar que proporciona perspectivas interesantes al ser capaz de suministrar metodologías que permiten realizar de forma automática algunas de las tareas realizadas típicamente por los humanos. El desarrollo de Controladores Inteligentes requiere significativos esfuerzos de investigación interdisciplinarios para integrar conceptos y métodos de áreas tales como control, identificación, estimación, además de otras áreas tales como teoría de la comunicación, ciencias de la computación, inteligencia artificial e investigación operativa.Eje: Procesamiento de Señales y Sistemas de Tiempo RealRed de Universidades con Carreras en Informática (RedUNCI

Diseño y simulación de controladores inteligentes aplicados a procesos industriales

El presente proyecto tiene por objetivo general desarrollar sistemas de apoyo para la toma de decisiones en procesos industriales, enfocados principalmente a los sistemas de control inteligente. Estos sistemas son cada vez más necesarios debido a la complejidad creciente de los escenarios planteados por la globalización, la competencia, los avances tecnológicos, los problemas ambientales y sociales, entre otros. Concretamente, el Control Inteligente es un procedimiento computacional, capaz de conducir eficientemente un sistema complejo a un objetivo, aún con una representación incompleta, inadecuada y/o bajo especificaciones imprecisas; es decir, actúa apropiadamente en un entorno con incertidumbre. Bajo estas premisas, se puede considerar que proporciona perspectivas interesantes al ser capaz de suministrar metodologías que permiten realizar de forma automática algunas de las tareas realizadas típicamente por los humanos. El desarrollo de Controladores Inteligentes requiere significativos esfuerzos de investigación interdisciplinarios para integrar conceptos y métodos de áreas tales como control, identificación, estimación, además de otras áreas tales como teoría de la comunicación, ciencias de la computación, inteligencia artificial e investigación operativa.Eje: Procesamiento de Señales y Sistemas de Tiempo RealRed de Universidades con Carreras en Informática (RedUNCI

Diseño y simulación de controladores inteligentes aplicados a procesos industriales

El presente proyecto tiene por objetivo general desarrollar sistemas de apoyo para la toma de decisiones en procesos industriales, enfocados principalmente a los sistemas de control inteligente. Estos sistemas son cada vez más necesarios debido a la complejidad creciente de los escenarios planteados por la globalización, la competencia, los avances tecnológicos, los problemas ambientales y sociales, entre otros. Concretamente, el Control Inteligente es un procedimiento computacional, capaz de conducir eficientemente un sistema complejo a un objetivo, aún con una representación incompleta, inadecuada y/o bajo especificaciones imprecisas; es decir, actúa apropiadamente en un entorno con incertidumbre. Bajo estas premisas, se puede considerar que proporciona perspectivas interesantes al ser capaz de suministrar metodologías que permiten realizar de forma automática algunas de las tareas realizadas típicamente por los humanos. El desarrollo de Controladores Inteligentes requiere significativos esfuerzos de investigación interdisciplinarios para integrar conceptos y métodos de áreas tales como control, identificación, estimación, además de otras áreas tales como teoría de la comunicación, ciencias de la computación, inteligencia artificial e investigación operativa.Eje: Procesamiento de Señales y Sistemas de Tiempo RealRed de Universidades con Carreras en Informática (RedUNCI

Fluidized bed plants for heat and power production in future energy systems

Fluidized bed (FB) plants are used for heat and power production in several energy systems around the world, with particular importance in systems using large shares of renewable solid fuel, e.g., biomass. These FB plants are traditionally operated for base-load electricity production or for heat production, and thus characterized by relatively small and slow load changes. In parallel, as the transition towards energy systems with net-zero emissions increases the share of variable renewable energy (VRE) sources, the need for implementing variation management strategies at various timescales arises – giving heat and power plants the possibility to adapt their operations to accommodate the inherent variability of VRE sources. Following this, FB technology is envisioned for a wide range of novel applications expected to play significant roles in the decarbonization of energy systems, such as thermochemical energy storage and carbon capture and storage. In this context, research efforts are needed to investigate the technical and economic features of FB plants in energy systems with high levels of VRE.The aim of this thesis is to elucidate the capabilities of FB plants for heat and power production in net-zero emissions energy systems. For this purpose, two main pathways are explored: i) transient operation as fuel-fed plants, and ii) the potential conversion into decarbonized plants, i.e., into VRE-fed layouts providing dispatchable outputs.For fuel-fed FB plants, a dynamic model of biomass-fired FB plants has been developed, considering the two types of FB boilers (BFB and CFB) and including validation against steady-state and transient operational data collected from two commercial plants. As a novelty of this work the model describes both the gas (in-furnace) and water-steam sides such that the interactions between the two can be assessed. The results of the simulations show that i) the characteristic times for the gas side are shorter in BFB furnaces than in CFBs, albeit these times are for both furnace types not longer than those for the water-steam side; ii) the computed timescales for the dynamics of FB plants fall well within those required for offering complementing services to the grid; and iii) the use of control and operational strategies for the water-steam side can confer capabilities superior to fuel-feeding control in terms of avoiding undesirable unburnt emissions and providing temporary overload operation. The retrofit of fuel-fed FB plants into poly-generation facilities cogenerating a combustible biogenic gas is also assessed, revealing that partial combustion of this gas can be used to provide faster inherent dynamics than the original configuration.For VRE-fed FB layouts, techno-economic process modeling has been carried out for large-scale deployment of solar- and electricity-charging processes based on three different chemical systems: i) carbonation/calcination (calcium); ii) thermally reduced redox (cobalt oxides); and iii) chemically reduced redox (iron oxides). One attractive aspect of these layouts is the possibility to build part of them by retrofitting current fuel-fed FB plants. While the technical assessment for solar applications indicates that cobalt-based layouts offer the highest levels of efficiency and dispatchability, calcium-based processes present better economics owing to the use of inexpensive calcium material. The results also show that electricity-charged layouts such as iron looping can play an important role in the system providing variation management strategies to the grid while avoiding costly H2 storage. Further, the economic performances of VRE-fed FB layouts are benefitted by the generation of additional services and products (e.g., carbon capture and on-demand production of H2), and by scenarios with high volatility of the electricity prices

Design of Control Configurations for Complex Process Networks

University of Minnesota Ph.D. dissertation.May 2015. Major: Chemical Engineering. Advisor: Prodromos Daoutidis. 1 computer file (PDF); xi, 194 pages.Tight integration is the rule rather than the exception in chemical and energy plants. Despite the significant economic benefits which result from efficient utilization of energy/material resources, effective control of plants with such integration becomes challenging; the network-level dynamics emerging from process interconnections and the model complexity of such plants limit the effectiveness of decentralized control approaches traditionally followed in plant-wide control. The development of effective control methods for complex integrated plants is a challenging, open problem. This thesis proposes methods to develop effective control strategies for two classes of process networks. In the first part of the thesis, a class of process networks, in which slow network-level dynamics is induced by large rates of energy and/or material recycle, is considered. A graph theoretic algorithm is developed for such complex material integrated process networks to i) identify the material balance variables evolving in each time scale, and ii) design hierarchical control structures by classifying potential manipulated inputs and controlled outputs in each time scale. The application of a similar algorithm developed for energy integrated networks to representative chemical processes is also presented. The second part of the thesis focuses on generic process networks where tight integration is not necessarily reflected on a segregation of energy and/or material flows. A method is developed to systematically synthesize control configurations with favorable structural coupling, using relative degree as a measure of such coupling. Hierarchical clustering methods are employed to generate a hierarchy of control configurations ranging from fully decentralized ones to a fully centralized one. An agglomerative hierarchical clustering method is first developed, in which groups of inputs/outputs are merged successively to form fewer and larger groups that are strongly connected topologically. Then, a divisive hierarchical clustering method is developed, in which groups of inputs/outputs are decomposed recursively into smaller groups. The developed methods are applied to typical chemical process networks

Equation-oriented modeling, simulation, and optimization of integrated and intensified process and energy systems

Process intensification, defined as unconventional design and/or operation of processes that results in substantial performance improvements, represents a promising route toward reducing capital and operating expenses in the chemical/petrochemical process industry, while simultaneously achieving improved safety and environmental performance. In this dissertation, intensification is approached from three different angles: reactor design and control, process flowsheet design and optimization, and production scheduling and control. In the first part of the dissertation, three novel concepts for improving the controllability of intensified microchannel reactors are introduced. The first concept is a latent energy storage-based temperature controller, where a phase change material is confined within the walls of an autothermal reactor to improve local temperature control. The second concept is a segmented catalyst layer which modulates the rate of heat generation and consumption along the length of an autothermal reactor. Finally, the third concept is a thermally actuated valve, which uses small-scale bimetallic strips to modulate flow in a microchannel reactor in response to temperature changes. The second part of the dissertation introduces a novel framework for equation-oriented flowsheet modeling, simulation and optimization. The framework consists of a pseudo-transient reformulation of the steady-state material and energy balance equations of process unit operations as differential-algebraic equation (DAE) systems that are statically equivalent to the original model. I show that these pseudo-transient models improve the convergence properties of equation-oriented process flowsheet simulations by expanding the convergence basin in comparison to conventional steady state equation-oriented simulators. A library of pseudo-transient unit operation models is developed, and several case studies are presented. Models for more complex unit operations such as a pseudo-transient multistream heat exchanger and a dividing-wall distillation column are later introduced, and can easily be included in the flowsheet optimization framework. In the final part of the dissertation, a paradigm for calculating the optimal production schedule in a fast changing market situation is introduced. This is accomplished by including a model of the dynamics of a process and its control system into production scheduling calculations. The scheduling-relevant dynamic models are constructed to be of lower order than a detailed dynamic process model, while capturing the closed-loop behavior of a set of scheduling-relevant variables. Additionally, a method is given for carrying out these production scheduling calculations online and in "closed scheduling loop,"' i.e., recalculating scheduling decisions upon the advent of scheduling-relevant process or market events. An air separation unit operating in a demand response scenario is used as a representative case study.Chemical Engineerin