@misc{DeMelMechleriDemisetal., author = {De Mel, Ishanki and Mechleri, Evgenia and Demis, Panagiotis and Dorneanu, Bogdan and Klymenko, Oleksiy and Arellano-Garc{\´i}a, Harvey}, title = {A Methodology for Global Sensitivity Analysis for the Operation of Distributed Energy Systems Using a Two-Stage Approach}, series = {2019 AIChE Annual Meeting}, journal = {2019 AIChE Annual Meeting}, isbn = {978-0-8169-1112-7}, abstract = {Optimisation-based models are often employed for the design and operation of distributed energy systems (DES). A two-stage approach often involves the optimisation of the design of a distributed energy system for a specified location or scale, and the subsequent optimisation of the operational model based on the structure recommended by the design model. The structure includes what types of generation and storage technologies should be used in the operation, related capacities and sizes, and potential locations. Often, both design and operational models are deterministic in nature, as either past or fictitious data is fed into the models to minimise an objective function such as the total cost or environmental impact due to carbon emissions. Consequently, the operational models encounter challenges when real-time data is fed, as time-variant input variables such as electricity demand, heating demand and solar insolation can be deemed uncertain. These variables could have unexpected and significant impacts on the total costs involved with the operation of distributed energy systems, leading to sub-optimality or even infeasibilities. Identifying these input variables, quantifying their uncertainties (which are then described in the models), and evaluating the influence of these variables on the outputs can lead to the design of more robust models. Such models can then be used to design and operate optimal distributed energy systems. This paper presents a novel methodology for using global sensitivity analysis (GSA) on an operational optimisation-based model of a distributed energy system. The operational model also utilises Model Predictive Control (MPC) rolling horizon concepts (as done by [1]) to determine hourly total operational costs. The paper also addresses how some challenges and limitations encountered in the operational model can be attributed to the deterministic design model on which the structure of the operational model has been based. Furthermore, the research explores how the design can be improved to support more robust operation. Another novel aspect of this paper highlights the use of the optimisation tool GAMS alongside SobolGSA, a global sensitivity analysis software [2]. This software uses the variance-based Sobol method to generate N samples and perform global sensitivity analysis, allowing users to understand how variations in the inputs can influence the outputs, whilst accounting for the different combinations of the uncertain parameters without varying one uncertain parameter at a time.}, language = {en} } @misc{MechleriShafieiDorneanuetal., author = {Mechleri, Evgenia and Shafiei, Zarif and Dorneanu, Bogdan and Arellano-Garc{\´i}a, Harvey and Klymenko, Oleksiy}, title = {A Blockchain Model for Residential Distributed Energy Resources Networks}, series = {2019 AIChE Annual Meeting}, journal = {2019 AIChE Annual Meeting}, isbn = {978-0-8169-1112-7}, abstract = {The energy production landscape is reshaped by distributed energy resources (DERs) {\^a}€" photovoltaic (PV) panels, combined heat and power (CHP), wind turbines (WT), fuel cells or battery storage systems, to name just a few [1]. Microgrids, collections of units or DERs that are locally controlled, close to the consumption point and cooperating with each other and the centralised grid [2], allow for the reduction in energy losses compared to traditional generation due to the close proximity to end users. Due to its volatility, the integration of this non-controllable generation poses severe challenges to the current energy system and ensuring a reliable balance of energy becomes an increasingly demanding task [3]. The optimal design and scheduling of the DERs and subsequent microgrid is of high importance in order to increase the reliability and determine their effectiveness in reducing losses, emissions and costs compared to conventional generation so that they may be implemented at faster rates to reduce global emissions and fossil fuel usage. In distributed energy systems, individual users typically have flexible tariffs while they also have the capability not only to use, but also to store and trade electric power. Direct transactions schemes can save money for end users, generate revenues for producers, reduce transmission losses and promote the use of renewable energy [4]. But it must be a robust, efficient and low-cost trading system to handle the rapid changes of information and value in the system. The blockchain technology can fulfil these requirements by enabling the implementation of optimal energy management strategies through distributed databases. Since its introduction as the underlying technology of Bitcoin, the blockchain technology has emerged from its use as a verification mechanism for cryptocurrencies and heads to a broader field of applications. Blockchain-based systems are basically a combination of a distributed ledger, a decentralised consensus mechanism, and cryptographic security measures [5]. More precisely, it allows the resolution of conflicts and dismantles information asymmetries by providing transparent and valid records of past transactions that cannot be altered retrospectively [6]. With the help of specific algorithms and applications, multiple operations can be performed automatically on the blockchain, using this information together with information from the Internet or the real world (e.g. on whether, energy pricing, etc.). Furthermore, smart contracts can be implemented between the nodes of the microgrid. This paper introduces a model for the implementation of a blockchain and smart contracts into the scheduling of a residential DER network. The blockchain is implemented in terms of energy rather than voltages [7], to allow for the decentralised operation of the microgrid without a centralised microgrid aggregator. Thus, the model will minimise only the operational cost. Furthermore, the DER network model is improved by the addition of more detailed transmission losses and costs within the microgrid and between the microgrid and the national grid. The resulted energy flows are stored and information on the availability/demand are exchanged between the network nodes. To appropriately compensate the DER operators in the microgrid for their services and to charge the consumers for withdrawals, nodal clearing prices are determined and implemented through smart contracts. The resulting MILP model minimises the overall investment and operating costs of the system.}, language = {en} } @misc{HajizeinalibiokiSebastiaSaezKlymenkoetal., author = {Hajizeinalibioki, Sahar and Sebastia-Saez, Daniel and Klymenko, Oleksiy and Arellano-Garc{\´i}a, Harvey}, title = {Investigation of Two-Phase Flow Characteristics in a Fractal-Branching Microchannel}, series = {AIChE Annual Meeting, November 10, 2019 to November 15, 2019}, journal = {AIChE Annual Meeting, November 10, 2019 to November 15, 2019}, isbn = {978-0-8169-1112-7}, abstract = {Inspiration from nature to solve advanced engineering problems has attracted the interests of engineers, designers and scientists. Biomimetics is to imitate and apply the elements, systems and mechanisms from nature to solve technological challenges as stated by Gleich et al. (2009). They also added that one of nature's solution which is being explored is fractal shapes. Fractal shapes appeared in a variety of cases such as snowflakes, blood vessels and plant root systems in nature. Fractal shapes consistently appear in situations which require mass or heat transfer throughout a large space. The optimal spreading and transfer throughout the space characteristics of fractal shapes, making them a practical solution to design more efficient heat and mass transfer devices. Fractal shapes were first employed to improve fluid mechanics designs by West et al. (1997) to minimise the workflow for bulk fluid transportation through a network of branching tubes. On the other hand, two-phase flow in microscale channels has great applicability due to its diverse range of applications. As expressed by Serizawa et al. (2002), modern and advanced technologies such as micro-electro-mechanical systems, chemical process engineering, medical engineering and electronic cooling utilise multiphase flow in microchannels. This work aims to investigate the application of nature-inspired fractal geometries as multiphase microscale flow passage using CFD analysis. ANSYS Fluent software has been utilised to investigate the flow characteristics numerically in order to improve the pressure drop and heat transfer. Also, this question will be raised whether two-phase flow patterns in fractal microchannels are different from straight channels or not.}, language = {en} } @misc{MerinoCarrascoDorneanuetal., author = {Merino, Manuel and Carrasco, Laura and Dorneanu, Bogdan and Manrique, Jose and Menzhausen, Robert and Arellano-Garc{\´i}a, Harvey}, title = {Control Strategies for a Vapour Compression Refrigeration System Used in Mango Exports: An Alternative to Traditional on-Off Controllers}, series = {AIChE Annual Meeting}, journal = {AIChE Annual Meeting}, isbn = {978-0-8169-1114-1}, abstract = {ropical fruits are important products on the global market. The change to a healthier nutrition, the development of new products and great availability led to a rise in their consumption during the last decade [1-2]. Due to their perishable nature they are stored at lower temperature. To achieve a rapid and efficient decrease in product temperature, refrigeration systems are employed, using vapor compression refrigeration plants. They consist of four main components: the compressor, the condenser, the expansion valve and the evaporator. Within the system a refrigerant is circulating. Though designed to satisfy maximum load, these plants usually work at part-load for much of their life, generally regulated by on/off cycles of the compressor, working at nominal frequency of 50 Hz [3]. The high cost involved in developing cold storage or controlled atmosphere storage is a pressing problem in several developing countries [4]. This contribution presents development and comparison of various strategies for the control of a refrigeration plant used for fruit cooling. The starting point is a model of the plant which is able to simulate both the chamber and the fruit temperature. The model is based on energy balances for each section of the refrigeration system and the fruits.}, language = {en} } @misc{MiahDorneanuMechlerietal., author = {Miah, Sayeef and Dorneanu, Bogdan and Mechleri, Evgenia and Arellano-Garc{\´i}a, Harvey}, title = {Multi-Objective Design Optimisation of a Distributed Energy System through 3E (economic, environmental and exergy) Analysis}, series = {2020 Virtual AIChE Annual Meeting, November 20, 2020}, journal = {2020 Virtual AIChE Annual Meeting, November 20, 2020}, isbn = {978-0-8169-1114-1}, abstract = {To facilitate the commitments of reducing greenhouse gas emissions will require the utilisation of renewable energy resources, as well as shifting away from a centralised generation. Distributed energy systems (DESs) are a promising alternative to conventional centralised layouts. Thus, there is a need for the development of models able to optimally design DES which show savings in cost as well as having a low carbon impact. Current literature focuses on the design optimisation of a DES through economical and environmental cost minimisation [1-4]. However, these two criteria alone do not show the complete picture and do not satisfy the long-term sustainability priorities. The inclusion of exergy analysis allows for the satisfaction of this criteria through the rational use of energy resources. The use of exergy analysis within DESs was first studied by [5], with a multiobjective approach whereby cost and exergy efficiency are considered. The novelty of this paper is twofold. The first is the investigation of exergy DES design optimisation through a multiobjective approach whilst considering the economic and environmental cost, thus making this work the first to simultaneously minimise three objective functions in the context of DES.}, language = {en} } @misc{DorneanuHeshmatMohamedetal., author = {Dorneanu, Bogdan and Heshmat, Mohamed and Mohamed, Abdelrahim and Ruan, Hang and Xiao, Pei and Gao, Yang and Arellano-Garc{\´i}a, Harvey}, title = {Stepping Towards the Industrial Sixth Sense}, series = {AIChE Annual Meeting, November 20, 2020}, journal = {AIChE Annual Meeting, November 20, 2020}, isbn = {978-0-8169-1114-1}, abstract = {Industry 4.0 is transforming chemical processes into complex, smart cyber-physical systems, by the addition of elements such as smart sensors, Internet of Things, big data analytics or cloud computing. Modern engineering systems and manufacturing processes are operating in highly dynamic environments, and exhibiting scale, structure and behaviour complexity. Under these conditions, plant operators find it extremely difficult to manage all the information available, infer the desired conditions of the plant and take timely decisions to handle abnormal operation1. Human beings acquire information from the surroundings through sensory receptors for vision, sound, smell, touch, and taste, the Five Senses. The sensory stimulus is converted to electrical signals as nerve impulse data communicated with the brain. When one or more senses fail, the humans are able to re-establish communication and improve the other senses to protect from incoming dangers. Furthermore, a mechanism of 'reasoning' has been developed during evolution, which enable analysis of present data and generation of a vision of the future, which might be called the Sixth Sense. As industrial processes are already equipped with five senses: 'hearing' from acoustic sensors, 'smelling' from gas and liquid sensors, 'seeing' from camera, 'touching' from vibration sensors and 'tasting' from composition monitors, the Sixth Sense could be achieved by forming a sensing network which is self-adaptive and self-repairing, carrying out deep-thinking analysis with even limited data, and predicting the sequence of events via integrated system modelling. This contribution introduces the development of an intelligent monitoring and control framework for chemical process, integrating the advantages of Industry 4.0 technologies, cooperative control and fault detection via wireless sensor networks.}, language = {en} } @misc{DorneanuMechleriArellanoGarcia, author = {Dorneanu, Bogdan and Mechleri, Evgenia and Arellano-Garc{\´i}a, Harvey}, title = {Towards smart distributed energy systems}, series = {Jahrestreffen der ProcessNet-Fachgemeinschaften "Prozess-, Apparate- und Anlagentechnik" (PAAT)}, journal = {Jahrestreffen der ProcessNet-Fachgemeinschaften "Prozess-, Apparate- und Anlagentechnik" (PAAT)}, pages = {1}, abstract = {A distributed energy resource (DER) system is an energy generation system located in the vicinity of the end users, simultaneously providing electricity, cooling and heating to meet the demands of the local users1. Unlike conventional, centralized energy supply, a DER system typically employs a wide range of technologies such as photovoltaics, wind turbines, gas turbines, biomass boilers, combined heating and power, absorption chillers, etc. In addition, energy storage technologies (batteries, hot/cold water storage) are available as well. DER systems can potentially play a vital role as the energy sector faces unprecedented challenges to reduce emissions by increasing energy generation using renewable and low-carbon energy resources. Different designs of the DER systems could lead to different performance in reducing the costs, the environmental impact or the use of primary energy. Hence, optimal design and management of complex DER systems are important tasks to promote their diffusion against the centralized grid. However, current operational models for DERs do not adequately analyse the complexity of such systems. This contribution presents a set of models for the optimal design and operation of residential DER systems, which build up on previous work in this field, and aims to provide a more holistic overview of such systems. For each node in the DER system, there is an option of installing the following ten technologies: wind turbines, photovoltaics arrays, combined heating and power units, absorption chillers, air-conditioning units, gas boilers, biomass boilers, gas heaters, batteries and thermal storage. Only one of each item may be installed in each home. There is also the option to connect a house to another via a combined hot and cold water pipeline and/or a microgrid cable, to share thermal and electrical energy, respectively. Due to increased availability of government incentives such as the feed-in tariffs (FIT) and renewable heat incentives (RHI) payments, these are included in the model as well. The increased penetration of Internet of Things technology and their potential to better control and optimize DER systems enable its use to help stabilize national grids. To this end, the models include the use of dynamic pricing, a strategy in which national grids publish in real time variable prices for electricity within given time periods. Furthermore, as current literature's focus on economic and environmental cost minimization, which do not satisfy long-term sustainability priorities through the rational use of energy resources, the introduction of a third criteria, exergy, is investigated. A third novelty of this contribution is the consideration of a multi-objective optimization which simultaneously includes the three objectives: the economic, the environmental and exergetic criteria in the design and operation of the residential DER system. Additionally, a novel methodology to analyse the effect of uncertain input variables on the total daily cost of the DER operational models. The methodology combines the operational model with model predictive control to predict the current state of the model. A subset of the model inputs (i.e., electricity demand, heating demand, and insolation) are considered uncertain. Global sensitivity analysis is conducted to quantify and understand how the uncertain variables influence, both individually and through interactions, the total daily cost. Finally, the implementation of blockchain technology and smart contracts within optimally designed and scheduled DER systems is investigated, to assess the advantages of smart technologies on the efficiency of residential DERs. Challenges, limitations and suggestions for improving the overall design and operation are also discussed in detail. All models are developed as mixed-integer linear programming models implemented and solved in GAMS, and show significant reduction of costs for all considered criteria when compared to the centralised grid and the classical approach towards the modelling of DER systems.}, language = {en} } @misc{GonzalezAriasGonzalezCastanoArellanoGarcia, author = {Gonzalez-Arias, Judith and Gonzalez-Castano, Miriam and Arellano-Garc{\´i}a, Harvey}, title = {Utilization of CO2-Rich Residues for Syngas Production: Strategies for Catalyst Design}, series = {AIChE Annual Meeting, November 15, 2021}, journal = {AIChE Annual Meeting, November 15, 2021}, isbn = {978-0-8169-1116-5}, abstract = {Compared to a Reverse Water Gas Shift (RWGS) process carried out under ideal conditions, the valorization of CO2-rich residues involve additional challenges. Indeed, for an ideal RWGS reaction unit, the CO2 methanation reaction and the constitution of carbon deposits via Boudouard reaction are the main side reactions to take into consideration. For CO2-rich residues derived from biomass treatment and heavy metal industries, the presence of CH4 and CO species (among others) constitute an, although often disregarded, much complex panorama where side reactions like CO methanation, dry reforming of methane, the forward Water Gas Shift reaction and the decomposition of CO and CH4 resulting in carbon deposits, are occurring to some extent within the catalytic reactor. This work aimed at designing advanced catalytic systems capable of converting the CO2/CO/CH4 feedstocks into syngas mixtures. Thus, with the RWGS reaction considered as the major process, this work focusses on the side reactions involving CO/CH4 species. In this context, a series Cu-MnOx/Al2O3 spinel derived catalysts were optimized for syngas production in presence of CO and CH4 fractions. Once the optimal active phase was determined, the optimal Cu contents and the impact of the support nature (Al2O3, SiO2-Al2O3 and CeO2-Al2O3) was evaluated for the valorization of realistic CO2-rich feedstocks. Remarkably, the obtained outcomes underline operative strategies for developing catalytic systems with advanced implementation potential. For that aim, the catalyst design should present, along with an active and selective phase for RWGS reaction, superior cooking resistances, activities towards methane reforming and low tendencies towards the forward WGS reaction. Further developments should tackle difficult tasks like improving the RWGS reaction rate while inhibiting the forwards WGS reaction as well as improving the CH4 conversion to CO without affecting the process selectivity. Strategies towards advancing catalytic systems capable of operating under variable conditions also arise as appealing routes.}, language = {en} } @misc{ArellanoGarciaElBariKalibeFanezouneetal., author = {Arellano-Garc{\´i}a, Harvey and El Bari, Hassan and Kalibe Fanezoune, Casimir and Dorneanu, Bogdan and Majozi, Thokozani and Elhenawy, Yasser and Bayssi, Oussama and Hirt, Ayoub and Peixinho, Jorge and Dhahak, Asma and Gadalla, Mamdouh A. and Khashaba, Nourhan H. and Ashour, Fatma}, title = {Catalytic Fast Pyrolysis of Lignocellulosic Biomass: Recent Advances and Comprehensive Overview}, series = {Journal of Analytical and Applied Pyrolysis}, volume = {Vol. 178}, journal = {Journal of Analytical and Applied Pyrolysis}, issn = {0165-2370}, doi = {10.1016/j.jaap.2024.106390}, abstract = {Using biomass as a renewable resource to produce biofuels and high-value chemicals through fast pyrolysis offers significant application value and wide market possibilities, especially in light of the current energy and environmental constraints. Bio-oil from fast-pyrolysis has various conveniences over raw biomass, including simpler transportation and storage and a higher energy density. The catalytic fast pyrolysis (CFP) is a complex technology which is affected by several parameters, mainly the biomass type, composition, and the interaction between components, process operation, catalysts, reactor types, and production scale or pre-treatment techniques. Nevertheless, due to its complicated makeup, high water and oxygen presence, low heating value, unstable nature, elevated viscosity, corrosiveness, and insolubility within conventional fuels, crude bio-oil has drawbacks. In this context, catalysts are added to reactor to decrease activation energy, substitute the output composition, and create valuable compounds and higher-grade fuels. The study aim is to explore the suitability of lignocellulosic biomasses as an alternative feedstock in CFP for the optimization of bio-oil production. Furthermore, we provide an up-to-date review of the challenges in bio-oil production from CFP, including the factors and parameters that affect its production and the effect of used catalysis on its quality and yield. In addition, this work describes the advanced upgrading methods and applications used for products from CFP, the modeling and simulation of the CFP process, and the application of life cycle assessment. The complicated fluid dynamics and heat transfer mechanisms that take place during the pyrolysis process have been better understood due to the use of CFD modeling in studies on biomass fast pyrolysis. Zeolites have been reported for their superior performance in bio-oil upgrading. Indeed, Zeolites as catalyses have demonstrated significant catalytic effects in boosting dehydration and cracking process, resulting in the production of final liquid products with elevated H/C ratios and small C/O ratios. Combining ex-situ and in-situ catalytic pyrolysis can leverage the benefits of both approaches. Recent studies recommend more and more the development of pyrolysis-based bio-refinery processes where these approaches are combined in an optimal way, considering sustainable and circular approaches.}, language = {en} } @misc{ArellanoGarciaSafdarShezadetal., author = {Arellano-Garc{\´i}a, Harvey and Safdar, Muddasar and Shezad, Nasir and Akhtar, Farid}, title = {Development of Ni-doped A-site lanthanides-based perovskite-type oxide catalysts for CO2 methanation by auto-combustion method}, series = {RSC Advances}, volume = {2024}, journal = {RSC Advances}, number = {14}, doi = {10.1039/d4ra02106a}, pages = {20240 -- 20253}, abstract = {Engineering the interfacial interaction between the active metal element and support material is a promising strategy for improving the performance of catalysts toward CO2 methanation. Herein, the Ni-doped rare-earth metal-based A-site substituted perovskite-type oxide catalysts (Ni/AMnO3; A = Sm, La, Nd, Ce, Pr) were synthesized by auto-combustion method, thoroughly characterized, and evaluated for CO2 methanation reaction. The XRD analysis confirmed the perovskite structure and the formation of nano-size particles with crystallite sizes ranging from 18 to 47 nm. The Ni/CeMnO3 catalyst exhibited a higher CO2 conversion rate of 6.6 × 10-5 molCO2 gcat-1 s-1 and high selectivity towards CH4 formation due to the surface composition of the active sites and capability to activate CO2 molecules under redox property adopted associative and dissociative mechanisms. The higher activity of the catalyst could be attributed to the strong metal-support interface, available active sites, surface basicity, and higher surface area. XRD analysis of spent catalysts showed enlarged crystallite size, indicating particle aggregation during the reaction; nevertheless, the cerium-containing catalyst displayed the least increase, demonstrating resilience, structural stability, and potential for CO2 methanation reaction.}, language = {en} } @misc{MedinaMendezDorneanuArellanoGarcia, author = {Medina M{\´e}ndez, Juan Ali and Dorneanu, Bogdan and Arellano-Garc{\´i}a, Harvey}, title = {Homogeneous modeling for laminar flows in structured catalysts: CO2 methanation}, series = {Book of Abstracts zur Jahrestagung der DECHEMA/VDI-Fachgruppe Fluidverfahrenstechnik, 04. - 06. M{\"a}rz 2024}, journal = {Book of Abstracts zur Jahrestagung der DECHEMA/VDI-Fachgruppe Fluidverfahrenstechnik, 04. - 06. M{\"a}rz 2024}, publisher = {Ruhr Universit{\"a}t}, address = {Bochum}, pages = {2}, language = {en} } @misc{MedinaMendezDorneanuArellanoGarcia, author = {Medina M{\´e}ndez, Juan Ali and Dorneanu, Bogdan and Arellano-Garc{\´i}a, Harvey}, title = {Homogeneous modeling for laminar flows in structured catalysts: CO2 methanation}, address = {Bochum}, pages = {1}, language = {en} } @misc{MedinaMendezDorneanuSchmidtetal., author = {Medina M{\´e}ndez, Juan Ali and Dorneanu, Bogdan and Schmidt, Heiko and Arellano-Garc{\´i}a, Harvey}, title = {Revisiting homogeneous modeling with volume averaging theory: structured catalysts for steam reforming and CO2 methanation}, series = {Journal of Physics: Conference Series}, volume = {2899/2024}, journal = {Journal of Physics: Conference Series}, issn = {1742-6596}, doi = {10.1088/1742-6596/2899/1/012004}, pages = {8}, abstract = {Progress in the modeling of structured catalysts is crucial for enhancing efficiency and scalability in industrial applications. Extensive research has investigated reactive flows over catalyst surfaces, covering chemical kinetics analysis and (direct) numerical simulations of the complete fluid flow in fixed-bed or structured catalysts. Nonetheless, this comes at a high computational cost. This study focuses on the homogeneous modeling of structured catalysts utilizing volume-averaging theory (VAT) as a more efficient method for representing the behaviour of such systems. We discuss modeling strategies for both 1-D and 3-D simulations. For steady 1-D flow simulations, we assess the influence of simplified gas chemical kinetics versus detailed surface chemistry, comparing with experimental data from the literature for a CO2 methanation processes. We also simulate 3-D flows of a steam reforming process, previously studied in the literature, using models which rely on different assumptions regarding the nature of the porous catalyst. Our findings reveal significant discrepancies based on different modeling assumptions, underscoring the necessity for accurate modeling of permeability and diffusivity tensors in homogeneous models.}, language = {en} } @misc{MedinaMendezDorneanuSchmidtetal., author = {Medina M{\´e}ndez, Juan Al{\´i} and Dorneanu, Bogdan and Schmidt, Heiko and Arellano-Garc{\´i}a, Harvey}, title = {Revisiting homogeneous modeling with volume averaging theory: structured catalysts for steam reforming and CO2 methanation}, series = {Book of Abstracts XXVI Fluid Mechanics Conference (FMC 2024), Warsaw, Poland, September 10-13, 2024}, journal = {Book of Abstracts XXVI Fluid Mechanics Conference (FMC 2024), Warsaw, Poland, September 10-13, 2024}, publisher = {University of Technology}, address = {Warsaw}, pages = {2}, language = {en} } @misc{DorneanuMappasVassiliadisetal., author = {Dorneanu, Bogdan and Mappas, Vassileios and Vassiliadis, Vassilios S. and Arellano-Garc{\´i}a, Harvey}, title = {Novel parametric gradient calculation method for multistage systems with generalized constraints}, series = {2024 AIChE Annual Meeting}, journal = {2024 AIChE Annual Meeting}, pages = {3}, abstract = {Sensitivity and gradient evaluations are essential for understanding the variability of a system subject to changes in input parameters, aiding in applications such as optimization, control, or decision-making processes (Castillo et al., 2008; Logsdon and Biegler, 1989, Horn and Tsai, 1967). Various approaches are available for the gradient evaluation in the simulation of large-scale steady-state systems, utilizing techniques such as automatic differentiation, sensitivity analysis, optimization or machine learning (Amaran et al., 2016). The term large-scale refers to problems with a substantial number of design variables, structural state variables, or constraint functions, or a combination thereof, necessitating significant high-performance parallel computing resources to solve within a reasonable timeframe (Kennedy and Martins, 2014). However, the evaluation of gradients in large-scale multistage systems simulation poses significant challenges due to computational complexity, numerical instability, scalability issues, and the limitations of the traditional differentiation techniques. Additionally, model complexity, sensitivity to noise, and data requirements of machine learning-based approaches further amplify these challenges. Overcoming these obstacles necessitates the development of efficient, scalable and robust gradient evaluation techniques that can effectively handle the characteristics of large-scale systems while offering reliable insights for a wide array of applications. This contribution focuses on re-examining and advancing the evaluation of parametric sensitivities within the context of simulating highly complex, hierarchical multiscale modular systems of very large size. The models being analyzed may necessitate sensitivity evaluations concerning their response to parametric inputs. These evaluations serve not only to test and verify their robustness, but also to integrate them into modular structures within a comprehensive optimization framework. Such an optimization framework aims to enhance system performance based on selected criteria, while simultaneously adhering to essential optimality constraints. While gradient-free optimization methods have been successfully applied to important design problems, their applications typically involve no more than O(102) design variables, and these methods exhibit very poor scalability with the dimensionality of the design variables (Kennedy and Martins, 2014). For large-scale, high-fidelity applications, gradient-based methods are deemed more suitable, although the challenges related to computational time and accuracy need to be addressed. To address these challenges, the use of either sensitivities or appropriately generalized adjoint equations for efficient calculation of constraint and objective functions gradients for generalized multistage systems, irrespective of whether they are dynamic in nature or they are steady-state. The proposed approach adopts a generalized modular strategy suitable for any type of system, starting from a traditional sensitivity-based calculations initially, and subsequently developing a novel generalized adjoint-based method. The resulting algorithm comprises a sequence of forward and backward sweep computational steps, which are entirely equivalent, and serve as a generalization of the adjoint-based calculation methods for gradients of constraints. These methods find application in various numerical analysis computations related to dynamical systems, including optimal control problems. It has to be noted that the model is regarded as a general modular representation of any coupled system, without making a distinction between dynamic or steady-state systems. In this context, a dynamic system is perceived as having state profiles as private internal variables, while interacting with its external environment through the input of initial conditions and parameter values. Its output consists of final conditions or any internal trajectory points that require reporting to the external environment during dynamic simulation. The proposed strategy using a novel adjoint scheme generalizes this approach to any multistage system model, of which the stages need not be of dynamic nature, such as in the use of adjoint equations in optimal control of multistage Differential- Algebraic Equation (DAE) systems (Morison and Sargent, 1986). The choice between the use of the adjoint- and the sensitivity-based approach depends on the balance between the number of constraints/functions requiring gradient evaluation, and the number of states in the underlying dynamical system. The adjoint-based approach may be advantageous when dealing with a smaller number of constraints than state variables that require gradient evaluation, whereas the sensitivity-based approach could be more computationally efficient for a larger number of constraints than state variables in the modular treatment of the underlying dynamic system. The simulation of a multistage system is demonstrated using an example consisting of steady-state feedforward blocks, employing both the sensitivity- and the proposed adjoint-based approach. The results obtained reveal that the numerical values derived from the gradient evaluation are identical for both methods. Therefore, it can be concluded that the newly introduced approach for general multistage sequential systems is entirely non-restrictive. This indicates its effectiveness and applicability, offering flexibility and robustness in gradient evaluation for such systems.}, language = {en} } @misc{SafdarDorneanuSantosdaSilvaetal., author = {Safdar, Muddasar and Dorneanu, Bogdan and Santos da Silva, Jefferson and Santos Mascarenhas, Artur Jose and Valverde Pontes, Karen and Arellano-Garc{\´i}a, Harvey}, title = {Advancements in CO2 methanation: customized heterogeneous Ni-Perovskite catalyst for sustainable SNG production}, series = {Annual Meeting on Reaction Engineering and Electrochemical Processes 2024}, journal = {Annual Meeting on Reaction Engineering and Electrochemical Processes 2024}, language = {en} } @misc{MappasDorneanuHeinzelmannetal., author = {Mappas, Vassileios and Dorneanu, Bogdan and Heinzelmann, Norbert and Schnitzlein, Klaus and Arellano-Garc{\´i}a, Harvey}, title = {A unified modular framework for modeling multiphase reactors}, series = {Annual Meeting of Process Engineering and Materials Technology 2024}, journal = {Annual Meeting of Process Engineering and Materials Technology 2024}, language = {en} } @misc{JafariShafieeDorneanuetal., author = {Jafari, Mitra and Shafiee, Parisa and Dorneanu, Bogdan and Arellano-Garc{\´i}a, Harvey}, title = {Towards efficient material design: use of machine learning to predict chemical reactions and retrosynthesis}, series = {Annual Meeting of Process Engineering and Materials Technology 2024}, journal = {Annual Meeting of Process Engineering and Materials Technology 2024}, language = {en} } @misc{YentumiJurischkaDorneanuetal., author = {Yentumi, Richard and Jurischka, Constantin and Dorneanu, Bogdan and Arellano-Garc{\´i}a, Harvey}, title = {Optimal design of a thermochemical hydrogen storage and release system via the reversible redox of iron oxide/iron}, series = {Annual Meeting of Process Engineering and Materials Technology 2024}, journal = {Annual Meeting of Process Engineering and Materials Technology 2024}, language = {en} } @misc{DorneanuVassiladisArellanoGarcia, author = {Dorneanu, Bogdan and Vassiladis, Vassilios S. and Arellano-Garc{\´i}a, Harvey}, title = {A novel approach to staggered training of deep learning networks}, series = {Annual Meeting of Process Engineering and Materials Technology 2024}, journal = {Annual Meeting of Process Engineering and Materials Technology 2024}, language = {en} } @misc{SafdarSafdarDorneanuetal., author = {Safdar, Muddasar and Safdar, Mutahar and Dorneanu, Bogdan and Arellano-Garc{\´i}a, Harvey}, title = {Process intensification by additive manufacturing strategies for power-to-X conversion application: Case studies}, series = {16th International Conference on Gas-Liquid and Gas-Liquid-Solid Reactor Engineering}, journal = {16th International Conference on Gas-Liquid and Gas-Liquid-Solid Reactor Engineering}, language = {en} }