scholarly journals Optimizing organic electrosynthesis through controlled voltage dosing and artificial intelligence

2019 ◽  
Vol 116 (36) ◽  
pp. 17683-17689 ◽  
Author(s):  
Daniela E. Blanco ◽  
Bryan Lee ◽  
Miguel A. Modestino
Keyword(s):  
Artificial Intelligence ◽  
High Current Density ◽  
Renewable Energy Sources ◽  
Energy Conversion Efficiency ◽  
Reaction Rates ◽  
Electrochemical Process ◽  
Transport Processes ◽  
Chemical Transformations ◽  
Low Solubility ◽  
Relative Selectivity

Organic electrosynthesis can transform the chemical industry by introducing electricity-driven processes that are more energy efficient and that can be easily integrated with renewable energy sources. However, their deployment is severely hindered by the difficulties of controlling selectivity and achieving a large energy conversion efficiency at high current density due to the low solubility of organic reactants in practical electrolytes. This control can be improved by carefully balancing the mass transport processes and electrocatalytic reaction rates at the electrode diffusion layer through pulsed electrochemical methods. In this study, we explore these methods in the context of the electrosynthesis of adiponitrile (ADN), the largest organic electrochemical process in industry. Systematically exploring voltage pulses in the timescale between 5 and 150 ms led to a 20% increase in production of ADN and a 250% increase in relative selectivity with respect to the state-of-the-art constant voltage process. Moreover, combining this systematic experimental investigation with artificial intelligence (AI) tools allowed us to rapidly discover drastically improved electrosynthetic conditions, reaching improvements of 30 and 325% in ADN production rates and selectivity, respectively. This powerful AI-enhanced experimental approach represents a paradigm shift in the design of electrified chemical transformations, which can accelerate the deployment of more sustainable electrochemical manufacturing processes.

Optimizing Organic Electrosynthesis through Controlled Voltage Dosing and Artificial Intelligence

2019 ◽  
Author(s):  
Daniela Blanco ◽  
Bryan Lee ◽  
Miguel Modestino
Keyword(s):  
Artificial Intelligence ◽  
High Current Density ◽  
Renewable Energy Sources ◽  
Energy Conversion Efficiency ◽  
Reaction Rates ◽  
Electrochemical Process ◽  
Transport Processes ◽  
New Paradigm ◽  
Low Solubility ◽  
Relative Selectivity

Organic electrocatalysis can transform the chemical industry by introducing new, electricity-driven processes that are more energy efficient and that can be easily integrated with renewable energy sources. However, their deployment is severely hindered by the difficulties of controlling selectivity and achieving a large energy conversion efficiency at high current density, due to the low solubility of organic reactants in practical electrolytes. This control can be improved by carefully balancing the mass transport processes and electrocatalytic reaction rates at the electrode diffusion layer through pulsed electrochemical methods. In this study, we explore these methods in the context of the electrosynthesis of adiponitrile, the largest organic electrochemical process in industry. Systematically exploring voltage pulses in the timescale between 5-150 ms, led to a 20% increase in production of ADN and a 250% increase in relative selectivity with respect to the state-of-the-art constant voltage process. Moreover, combining this systematic experimental investigation with artificial intelligence (AI) tools allowed us to rapidly discover drastically improved electrosynthetic conditions, reaching improvements of 30% and 325% in ADN production rates and selectivity, respectively. This powerful AI-enhanced experimental approach represents a new paradigm in electrocatalysis research that can accelerate the deployment of electrochemical manufacturing processes.

Optimizing Organic Electrosynthesis through Controlled Voltage Dosing and Artificial Intelligence

2019 ◽  
Author(s):  
Daniela Blanco ◽  
Bryan Lee ◽  
Miguel Modestino
Keyword(s):  
Artificial Intelligence ◽  
High Current Density ◽  
Renewable Energy Sources ◽  
Energy Conversion Efficiency ◽  
Reaction Rates ◽  
Electrochemical Process ◽  
Transport Processes ◽  
New Paradigm ◽  
Low Solubility ◽  
Relative Selectivity

Organic electrocatalysis can transform the chemical industry by introducing new, electricity-driven processes that are more energy efficient and that can be easily integrated with renewable energy sources. However, their deployment is severely hindered by the difficulties of controlling selectivity and achieving a large energy conversion efficiency at high current density, due to the low solubility of organic reactants in practical electrolytes. This control can be improved by carefully balancing the mass transport processes and electrocatalytic reaction rates at the electrode diffusion layer through pulsed electrochemical methods. In this study, we explore these methods in the context of the electrosynthesis of adiponitrile, the largest organic electrochemical process in industry. Systematically exploring voltage pulses in the timescale between 5-150 ms, led to a 20% increase in production of ADN and a 250% increase in relative selectivity with respect to the state-of-the-art constant voltage process. Moreover, combining this systematic experimental investigation with artificial intelligence (AI) tools allowed us to rapidly discover drastically improved electrosynthetic conditions, reaching improvements of 30% and 325% in ADN production rates and selectivity, respectively. This powerful AI-enhanced experimental approach represents a new paradigm in electrocatalysis research that can accelerate the deployment of electrochemical manufacturing processes.

scholarly journals CFD Modelling of a Hydrogen/Air PEM Fuel Cell with a Serpentine Gas Distributor

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 564
Author(s):  
Alessandro d’Adamo ◽  
Matteo Riccardi ◽  
Massimo Borghi ◽  
Stefano Fontanesi
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Catalyst Layer ◽  
Active Surface ◽  
Reaction Rates ◽  
Transport Processes ◽  
Proton Exchange ◽  
Sustainable Mobility ◽  
Cfd Modelling ◽  
Gas Distributor

Hydrogen-fueled fuel cells are considered one of the key strategies to tackle the achievement of fully-sustainable mobility. The transportation sector is paying significant attention to the development and industrialization of proton exchange membrane fuel cells (PEMFC) to be introduced alongside batteries, reaching the goal of complete de-carbonization. In this paper a multi-phase, multi-component, and non-isothermal 3D-CFD model is presented to simulate the fluid, heat, and charge transport processes developing inside a hydrogen/air PEMFC with a serpentine-type gas distributor. Model results are compared against experimental data in terms of polarization and power density curves, including an improved formulation of exchange current density at the cathode catalyst layer, improving the simulation results’ accuracy in the activation-dominated region. Then, 3D-CFD fields of reactants’ delivery to the active electrochemical surface, reaction rates, temperature distributions, and liquid water formation are analyzed, and critical aspects of the current design are commented, i.e., the inhomogeneous use of the active surface for reactions, limiting the produced current and inducing gradients in thermal and reaction rate distribution. The study shows how a complete multi-dimensional framework for physical and chemical processes of PEMFC can be used to understand limiting processes and to guide future development.

scholarly journals Multiscale in modelling and validation for solar photovoltaics

2018 ◽  
Vol 9 ◽  
pp. 10 ◽  
Author(s):  
Tareq Abu Hamed ◽  
Nadja Adamovic ◽  
Urs Aeberhard ◽  
Diego Alonso-Alvarez ◽  
Zoe Amin-Akhlaghi ◽  
...  
Keyword(s):  
Renewable Energy Sources ◽  
Energy Conversion Efficiency ◽  
Multiscale Simulation ◽  
Photovoltaic System ◽  
Environmental Footprint ◽  
Solar Photovoltaics ◽  
Operating Lifetime ◽  
The Cost ◽  
Multiscale Techniques

Photovoltaics is amongst the most important technologies for renewable energy sources, and plays a key role in the development of a society with a smaller environmental footprint. Key parameters for solar cells are their energy conversion efficiency, their operating lifetime, and the cost of the energy obtained from a photovoltaic system compared to other sources. The optimization of these aspects involves the exploitation of new materials and development of novel solar cell concepts and designs. Both theoretical modeling and characterization of such devices require a comprehensive view including all scales from the atomic to the macroscopic and industrial scale. The different length scales of the electronic and optical degrees of freedoms specifically lead to an intrinsic need for multiscale simulation, which is accentuated in many advanced photovoltaics concepts including nanostructured regions. Therefore, multiscale modeling has found particular interest in the photovoltaics community, as a tool to advance the field beyond its current limits. In this article, we review the field of multiscale techniques applied to photovoltaics, and we discuss opportunities and remaining challenges.

Self-dissociation and protonic charge transport in water and

1958 ◽  
Vol 247 (1251) ◽  
pp. 505-533 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Charge Transport ◽  
Proton Transport ◽  
Reaction Rates ◽  
Transport Processes ◽  
Electronic Charge ◽  
Kinetic Properties ◽  
Theoretical Treatment ◽  
Relaxation Techniques ◽  
Ionic Charge

A comprehensive survey on experimental techniques, results and theoretical interpretations concerning the self-dissociation and protonic charge transport in water and ice is given. Recent investigations of fast protolytic reactions in pure water and aqueous solutions by means of relaxation techniques complete our knowledge about state and kinetic properties of the proton in this medium. In comparison here with our experience regarding the same properties in ice crystals are far less complete, as usual techniques of aqueous solutions are not applicable. Direct measurements of individual properties of ‘excess’ and ‘defect’ protons in ice (mobilities, concentrations, reaction rates) are presented. The proton transport in hydrogen-bonded media is completely different from normal ionic migration and corresponds more to electronic transport processes in semi-conductors. Generally the proton transport through hydrogen bonds includes two processes: (1) The formation (or rearrangement) of (H-bond) structure with orientation, favourable for a proton transition, and (2) the charge transfer within the H bond. The first step is rate determining in water, whereas the second one is decisive for the charge transport in ice. The requirements for a theoretical treatment therefore are (1) for water: a theory of ‘structural diffusion’ of the H-bonded hydration complex of H 3 O + , and (2) for ice: a (quantum-mechanical) theory of the protonic motion within the potential well of the H bond. The mechanism of structural diffusion provides an explanation of the anomalous H 3 O + and OH - mobility and their recombination rate in water. The difference between protonic and normal ionic charge transport occurs most obviously in the absolute values of mobilities in ice. The proton mobility in ice differs by many orders of magnitude from that of normal ions, but only by a factor of about 50 from electronic mobilities in some metals and semi-conductors. Further arguments, demonstrating the analogy between protonic and electronic charge transport are given. The reaction kinetics of protolytic systems and the fast proton transport in H-bonded systems are of certain importance with respect to biological problems.

Evaluation of Lattice Boltzmann Method for Reaction-Diffusion Process in a Porous SOFC Anode Microstructure

2012 ◽  
Author(s):  
Hedvig Paradis ◽  
Bengt Sundén
Keyword(s):  
Porous Media ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Reaction Diffusion ◽  
Reaction Rates ◽  
Transport Processes ◽  
Microscopic Level ◽  
Reaction Diffusion Equation ◽  
Interaction Sites ◽  
Boltzmann Method

In the microscale structure of a porous electrode, the transport processes are among the least understood areas of SOFC. The purpose of this study is to evaluate the Lattice Boltzmann Method (LBM) for a porous microscopic media and investigate mass transfer processes with electrochemical reactions by LBM at a mesoscopic and microscopic level. Part of the anode structure of an SOFC for two components is evaluated qualitatively for two different geometry configurations of the porous media. The reaction-diffusion equation has been implemented in the particle distribution function used in LBM. The LBM code in this study is written in the programs MATLAB and Palabos. It has here been shown that LBM can be effectively used at a mesoscopic level ranging down to a microscopic level and proven to effectively take care of the interaction between the particles and the walls of the porous media. LBM can also handle the implementation of reaction rates where these can be locally specified or as a general source term. It is concluded that LBM can be valuable for evaluating the risk of local harming spots within the porous structure to reduce these interaction sites. In future studies, the information gained from the microscale modeling can be coupled to a macroscale CFD model and help in development of a smooth structure for interaction of the reforming reaction and the electrochemical reaction rates. This can in turn improve the cell performance.

Passive System for Bio-Recovery of Copper from Acid Mine Drainage

2015 ◽  
Vol 1130 ◽  
pp. 547-550 ◽  
Author(s):  
Alex Schwarz ◽  
Gustavo Chaparro ◽  
Norma Pérez
Keyword(s):  
Sulfate Reduction ◽  
Metal Toxicity ◽  
Mine Drainage ◽  
Metal Removal ◽  
Reaction Rates ◽  
Transport Processes ◽  
Precipitate Formation ◽  
Acid Mine ◽  
Biochemical Reactors ◽  
Diffusive Exchange

In Central Chile, acid mine drainages (AMDs) are characterized by high concentrations of copper, which can be recovered. Passive biochemical reactors are eco-friendly technologies for the treatment of AMD. They use organic substrate mixtures to drive microbial sulfate reduction and metal sulfide precipitate formation. The performance of conventional biochemical reactors, however, is limited by metal toxicity, and metal recovery is difficult. Diffusive exchange systems on the other hand can be tailored to resist metal toxicity. This is achieved by having separate zones for AMD movement and for sulfate reduction, and by allowing the diffusive exchange of solutes between these zones. Also, higher reaction rates are possible, because much finer organic materials can be utilized as substrates. A key innovation of this research is the use of vertical tubular screens to convey the AMD through the reactor while simultaneously allowing transverse diffusive exchange of dissolved species with the substrate. The tubular screens act as reactors for precipitate formation, settling and accumulation, from where precipitates can be periodically recovered. This design promotes higher reaction rates, eliminates clogging and facilitates the recovery of valuable metals. This work studied the performance of a 2-m long vertical diffusive exchange column. Detailed insight was gained into reactions and transport processes within the tubular screen by the use of several sampling points along the column. During the first two months the reactor was fed with increasing concentrations of sulfate only, to determine its sulfate reduction potential. Then the reactor was fed with AMD for three additional months. During the operation with AMD, significant metal removal occurred, and copper precipitates accumulated, and were recovered.

Dynamic Characteristics of Polymer Electrolyte Fuel Cell and Hydrogen Tank

2010 ◽  
Author(s):  
Yun Wang
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Dynamic Characteristics ◽  
Dynamic Models ◽  
Reaction Rates ◽  
Transport Processes ◽  
Water Dynamics ◽  
Polymer Electrolyte Fuel Cell ◽  
Limiting Factors ◽  
Electrochemical Double Layer

In this paper, we develop 3D dynamic models for polymer electrolyte fuel cells (PEFCs) and hydrogen tanks, respectively. The PEFC model considers the key components of a single PEFC and couples the various mechanisms that govern fuel cell transient including the electrochemical double-layer behavior, species transport, heat transfer, liquid water dynamics, and membrane water uptake. The hydrogen tank model includes a 3D description of the hydrogen discharging kinetics coupled with mass/heat transport in a LaNi5–based hydrogen tank. Efforts are made to discuss the dynamic characteristics of the PEFC and hydrogen tank together with the possible coupling of the two systems. Local electrochemical and hydride reaction rates, transport processes and associated limiting factors are investigated.

The Kinetics Effect in SOFCs on Heat and Mass Transfer Limitations: Interparticle, Interphase and Intraparticle Transport

2011 ◽  
Author(s):  
Hedvig Paradis ◽  
Martin Andersson ◽  
Jinliang Yuan ◽  
Bengt Sunde´n
Keyword(s):  
Mass Transfer ◽  
Kinetic Parameters ◽  
Heat And Mass Transfer ◽  
Electrochemical Reaction ◽  
Catalyst Particle ◽  
Reaction Rates ◽  
Transport Processes ◽  
Effect Of Temperature ◽  
Parameter Study ◽  
Time Saving

The transport processes in the porous, micro-structured electrodes are one of the least understood areas of research of the solid oxide fuel cell (SOFC). To enhance the knowledge of the transport process’ impact on the performance in the electrodes, the micro-structure needs to be modeled in detail. But at these smaller scales, it can be both cost and time saving to first conclude at which scales, the limiting action on the transport processes occurs. This study investigates the limiting effect of the kinetic parameters’ on the heat and mass transfer at interparticle, interphase and intraparticle transport level. The internal reaction and the electrochemical reaction rates are studied at three levels in the microscopic range or even smaller. At the intraparticle level the effect of temperature distribution, i.e., heat transfer, within a catalyst particle is often less limiting than the internal mass diffusion process, while at the interphase level the former is more limiting. In this study, no severe risk for transport limitations for the anode and the cathode of the SOFC was found with the chosen kinetic parameters. It was found that the reaction rates constitute the largest risk. A parameter study was conducted by increasing the steam reforming and the electrochemical reaction rates by a factor of 100 without any transport limitations for the same kinetic parameters. The result of this study provides one type of control of the kinetic parameters which in turn have an impact on the reforming reaction rates and the cell performance.

scholarly journals Experimental and Modeling Investigation of CO3=/OH– Equilibrium Effects on Molten Carbonate Fuel Cell Performance in Carbon Capture Applications

2021 ◽  
Vol 9 ◽  
Author(s):  
Timothy A. Barckholtz ◽  
Heather Elsen ◽  
Patricia H. Kalamaras ◽  
Gabor Kiss ◽  
Jon Rosen ◽  
...  
Keyword(s):  
Carbon Capture ◽  
High Current Density ◽  
Electrochemical Process ◽  
Operating Conditions ◽  
Cell Performance ◽  
Molten Carbonate Fuel Cell ◽  
Average Error ◽  
Molten Carbonate ◽  
Fuel Cell Performance ◽  
Electrochemical Model

Molten Carbonate Fuel Cells (MCFCs) are used today commercially for power production. More recently they have also been considered for carbon capture from industrial and power generation CO2 sources. In this newer application context, our recent studies have shown that at low CO2/H2O cathode gas ratios, water supplements CO2 in the electrochemical process to generate power but not capture CO2. We now report the direct Raman observation of the underlying carbonate-hydroxide equilibrium in an alkali carbonate eutectic near MCFC operating conditions. Our improved electrochemical model built on the experimental equilibrium data adjusts the internal resistance terms and has improved the representation of the MCFC performance. This fundamentally improved model now also includes the temperature dependence of cell performance. It has been validated on experimental data collected in single cell tests. The average error in the simulated voltage is less than 4% even when extreme operating conditions of low CO2 concentration and high current density data are included. With the improvements, this electrochemical model is suitable for simulating industrial cells and stacks employed in a wide variety of carbon capture applications.

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