scholarly journals Straight-Parallel Electrodes and Variable Gap for Hydrogen and Oxygen Evolution Reactions

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
María J. Lavorante ◽  
Carla Y. Reynoso ◽  
Juan I. Franco
Keyword(s):  
Energy Consumption ◽  
Electrical Resistance ◽  
Negative Electrode ◽  
Water Electrolysis ◽  
Alkaline Water Electrolysis ◽  
Stainless Steel 316L ◽  
Reduction Of Energy Consumption ◽  
The One ◽  
Definition Of ◽  
The Cost

The challenges to be overtaken with alkaline water electrolysis are the reduction of energy consumption, the maintenance, and the cost as well as the increase of durability, reliability, and safety. Having these challenges in mind, this work focused on the reduction of the electrical resistance of the electrolyte which directly affects energy consumption. According to the definition of electrical resistance of an object, the reduction of the space between electrodes could lower the electrical resistance but, in this process, the formation of bubbles could modify this affirmation. In this work, the performance analyses of nine different spaces between stainless steel 316L electrodes were carried out, although the spaces proposed are not the same as those from the positive electrode (anode) to the separator and from the separator to the negative electrode (cathode). The reason why this is studied is that stoichiometry of the reaction states that two moles of hydrogen and one mole of oxygen can be obtained per every two moles of water. The proposed spaces were 10.65, 9.20, 8.25, 7.25, 6.30, 6.05, 4.35, 4.15, and 3.40 millimetres. From the nine different analysed distances between electrodes, it can be said that the best performance was reached by one of the smallest distances proposed, 4.15 mm. When the same distance between electrodes was compared (the same and different distance between electrodes and separator), the one that had almost twice the distance (negative compartment) presented an increase in current density of approximately 33% with respect to that where both distances (from electrodes to separator) are the same. That indicates that the stichometry of the electrolysis reaction influenced the performance.

scholarly journals Non-Precious Electrodes for Practical Alkaline Water Electrolysis

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1336 ◽  
Author(s):  
Alejandro N. Colli ◽  
Hubert H. Girault ◽  
Alberto Battistel
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Water Electrolysis ◽  
Industrial Applications ◽  
Alkaline Water Electrolysis ◽  
Stainless Steel 316L ◽  
Experimental Conditions ◽  
Alkaline Water ◽  
Cell Components

Water electrolysis is a promising approach to hydrogen production from renewable energy sources. Alkaline water electrolyzers allow using non-noble and low-cost materials. An analysis of common assumptions and experimental conditions (low concentrations, low temperature, low current densities, and short-term experiments) found in the literature is reported. The steps to estimate the reaction overpotentials for hydrogen and oxygen reactions are reported and discussed. The results of some of the most investigated electrocatalysts, namely from the iron group elements (iron, nickel, and cobalt) and chromium are reported. Past findings and recent progress in the development of efficient anode and cathode materials appropriate for large-scale water electrolysis are presented. The experimental work is done involving the direct-current electrolysis of highly concentrated potassium hydroxide solutions at temperatures between 30 and 100 °C, which are closer to industrial applications than what is usually found in literature. Stable cell components and a good performance was achieved using Raney nickel as a cathode and stainless steel 316L as an anode by means of a monopolar cell at 75 °C, which ran for one month at 300 mA cm−2. Finally, the proposed catalysts showed a total kinetic overpotential of about 550 mV at 75 °C and 1 A cm−2.

scholarly journals Stainless Steel Cyclic Voltammograms in Dioscorea Opposita Flour Media

2021 ◽  
Vol 6 (3) ◽  
pp. 535-542
Author(s):  
Isana Supiah Yosephine Louise ◽  
Siti Marwati ◽  
S. Sulistyani ◽  
Heru Pratomo Al ◽  
Felix Arie Setiawan
Keyword(s):  
Stainless Steel ◽  
Energy Consumption ◽  
Water Electrolysis ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Cyclic Voltammograms ◽  
Electrolysis Process ◽  
Dioscorea Opposita ◽  
The Media ◽  
The Cost

Improving the efficiency of hydrogen gas production in the water electrolysis process draws great attention from many scholars. To improve the efficiency of the process and reduction in the cost, stainless steel has been widely implemented in the industrial water electrolysis process. Electrolyte modification is also one of the methods to improve the water electrolysis process. The study used Dioscorea opposita tuber flour as a media addition in an alkaline solution. The efficiency of water electrolysis was evaluated by cyclic voltammetry. The result showed that the activity of the electrode and energy consumption were increased with values of 29 and 23%, respectively, by adding 3 g of the media. However, no media addition showed the lowest energy consumption regarding overpotential value. In general, the Dioscorea opposita tuber flour tends to cover the electrode and reduce the activity. Moreover, the utilization of wastewater from Dioscorea opposita flour industry is still beneficial to produce hydrogen gas instead of using freshwater.

scholarly journals Regression analysis of the influence of auger surface hardness on its wear during dehydration of solid waste in a garbage truck

2021 ◽  
Vol 101 (3) ◽  
pp. 48-55
Author(s):  
O. Bereziuk ◽  
V. Savulyak ◽  
V. Kharzhevskyi ◽  
◽  
Keyword(s):  
Wear Resistance ◽  
Regression Analysis ◽  
Energy Consumption ◽  
Solid Waste ◽  
Surface Hardness ◽  
Household Waste ◽  
Graphical Dependence ◽  
Friction Path ◽  
Reduction Of Energy Consumption ◽  
The Cost

The article is dedicated to the study of the influence of the surface hardness of the auger on its wear during dehydration of solid waste in the garbage truck. Using the method of regression analysis, the logarithmic dependencies of auger wear depending on the hardness of its surface for different values of the friction path are determined. Graphical dependences of augur wear depending on the hardness of its surface for different values of the friction path are made up, and it confirms sufficient convergence of the obtained dependencies. Carried out additional regression analysis allowed to obtain the dependence of wear of the auger depending on the hardness of its surface and the friction path, which showed that during two weeks of operation and wear of the auger during dehydration of solid waste in the garbage truck increasing the surface hardness of the auger from 2310 MPa to 10050 MPa reducing the rate of growth of energy consumption of solid waste dehydration from 16.7 % to 1.5 %, and, consequently, to reduce the cost of the process of their dehydration in the garbage truck. The graphical dependence of the reduction of energy consumption of dehydration of solid household waste due to the increase in the hardness of the auger surface during its two-week wear is presented. It was established the expediency of further research to determine the rational material of the auger and ways to increase its wear resistance

scholarly journals Temperature Effect on Permeate Water in Batch Electrodialysis Reversal

2021 ◽  
Author(s):  
Germán Eduardo Dévora-Isiordia ◽  
Alejandra Ayala-Espinoza ◽  
Luis Alberto Lares-Rangel
Keyword(s):  
Energy Consumption ◽  
Temperature Effect ◽  
Operating Conditions ◽  
Optimal Operating ◽  
Different Temperatures ◽  
Agricultural Use ◽  
Reduction Of Energy Consumption ◽  
Increasing Temperature ◽  
The Cost ◽  
High Degree

Currently, a large part of the wells for agricultural use located in the state of Sonora are overexploited, which generates a high degree of saline intrusion and abandonment by nearby communities. In this paper the temperature effect on the final concentration of permeate water was evaluated through voltage and intel concentration variations in a batch electrodialysis reversal process (EDR), in order to identify optimal operating conditions with emphasis on the reduction of energy consumption and cost of desalinated water. Thirty-six samples were prepared: eighteen 2,000 mg/L total dissolved solids (TDS) samples and eighteen 5,000 mg/L TDS samples; brackish well water of 639 mg/L TDS and synthetic salt were mixed to obtain those concentrations. 3 different temperatures (25, 30, 35 °C) and 2 different voltages (10 and 20 V) were tested for each sample. The best salt removal occurred in the 20 V arrays, with 18.34% higher removal for 2,000 mg/L TDS experiments and 25.05% for 5,000 mg/L experiments (average between the 25 to 35 °C tests). Temperature positively affected EDR, especially in the experiments at 10 V voltage, where increasing 10 °C increased its efficiency by 10.83% and 24.69% for 2,000 and 5,000 mg/L TDS, respectively. Energy consumption was lower with increasing temperature (35 °C), as it decreased by 1.405% and 1.613% for 2,000 and 5,000 mg/L TDS concentrations, respectively (average between 10 and 20 V tests), decreasing the cost per m3 of water.

scholarly journals Arrayed Cobalt Phosphide Electrocatalyst Achieves Low Energy Consumption and Persistent H2 Liberation from Anodic Chemical Conversion

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Kai Zhang ◽  
Gong Zhang ◽  
Qinghua Ji ◽  
Jiuhui Qu ◽  
Huijuan Liu
Keyword(s):  
Energy Consumption ◽  
High Efficiency ◽  
Hydrogen Adsorption ◽  
Water Electrolysis ◽  
Clean Energy ◽  
Chemical Conversion ◽  
Water Dissociation ◽  
Hydrogen Purification ◽  
Alkaline Water Electrolysis ◽  
Cobalt Phosphide

AbstractElectrochemical reduction of water to hydrogen (H2) offers a promising strategy for production of clean energy, but the design and optimization of electrochemical apparatus present challenges in terms of H2 recovery and energy consumption. Using cobalt phosphide nanoarrays (Co2P/CoP NAs) as a charge mediator, we effectively separated the H2 and O2 evolution of alkaline water electrolysis in time, thereby achieving a membrane-free pathway for H2 purification. The hierarchical array structure and synergistic optimization of the electronic configuration of metallic Co2P and metalloid CoP make the Co2P/CoP NAs high-efficiency bifunctional electrocatalysts for both charge storage and hydrogen evolution. Theoretical investigations revealed that the introduction of Co2P into CoP leads to a moderate hydrogen adsorption free energy and low water dissociation barrier, which are beneficial for boosting HER activity. Meanwhile, Co2P/CoP NAs with high capacitance could maintain a cathodic H2 evolution time of 1500 s at 10 mA cm−2 driven by a low average voltage of 1.38 V. Alternatively, the energy stored in the mediator could be exhausted via coupling with the anodic oxidation of ammonia, whereby only 0.21 V was required to hold the current for 1188 s. This membrane-free architecture demonstrates the potential for developing hydrogen purification technology at low cost.

scholarly journals Lignin-Assisted Water Electrolysis for Energy-Saving Hydrogen Production With Ti/PbO2 as the Anode

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiayi Li ◽  
Wei Zhou ◽  
Yuming Huang ◽  
Jihui Gao
Keyword(s):  
Energy Consumption ◽  
Hydrogen Production ◽  
Electricity Consumption ◽  
Cell Voltage ◽  
Linear Sweep Voltammetry ◽  
Water Electrolysis ◽  
High Energy ◽  
Alkaline Water Electrolysis ◽  
Lignin Concentration ◽  
Slow Kinetics

Replacing the oxygen evolution reaction (OER), which is of high energy consumption and slow kinetics, with the more thermodynamically favorable reaction at the anode can reduce the electricity consumption for hydrogen production. Here we developed a lignin-assisted water electrolysis (LAWE) process by using Ti/PbO2 with high OER overpotential as the anode aimed at decreasing the energy consumption for hydrogen production. The influence of key operating parameters such as temperature and lignin concentration on hydrogen production was analyzed. Compared with alkaline water electrolysis (AWE), the anode potential can be decreased from 0.773 to 0.303 (V vs. Hg/HgO) at 10 mA/cm2 in LAWE, and the corresponding cell voltage can be reduced by 546 mV. With increasing the temperature and lignin concentration, current density and H2 production rate were efficiently promoted. Furthermore, the anode deactivation was investigated by analyzing the linear sweep voltammetry (LSV) and cyclic voltammetry (CV) tests. Results showed that the anode deactivation was affected by the temperature.

The approach to increasing the efficiency of convolution algorithms in modern high-availability systems

2021 ◽  
Author(s):  
E.I. Goncharov ◽  
P.L. Iljin ◽  
V.I. Munerman ◽  
T.A. Samoylova
Keyword(s):  
Artificial Intelligence ◽  
Information Systems ◽  
Three Dimensional ◽  
High Availability ◽  
Technical Problems ◽  
Convolution Operation ◽  
Multidimensional Matrices ◽  
The One ◽  
Definition Of ◽  
The Cost

Most modern high-availability information systems are either based on systems that are classified as artificial intelligence, or to a large extent include them as components. The solution of many problems of artificial intelligence is based on the use of algorithms that implement the convolution operation (for example, algorithms for training neural networks). The article proposes an approach that, on the one hand, provides a strict formalization of this operation based on the algebra of multidimensional matrices, and on the other hand, due to this, it provides such practical advantages as simplifying and reducing the cost of developing such information systems, as well as reducing the execution time of queries to them. due to the simplicity of the development of parallel algorithms and programs and the efficient use of parallel computing systems. Convolution is an indispensable operation for solving many scientific and technical problems, such as machine learning, data analysis, signal processing, image processing filters. An important role is played by multidimensional convolutions, which are widely used in various subject areas. At the same time, due to the complexity of the algorithms that implement them, in practice even three-dimensional convolutions are used much less frequently than one- and two-dimensional ones. Replacing a multidimensional convolution operation with a sequence of convolution operations of lower dimensions significantly increases its computational complexity. The main reason for this lies in the absence of a unified strict definition of the operation and overload in mathematics of the term «convolution». Therefore, the article discusses a multidimensional-matrix computation model, which allows one to effectively formalize problems whose solution uses multidimensional convolution operations, and to implement an effective solution to these problems due to the natural parallelism inherent in the operations of the algebra of multidimensional matrices.

Understanding functional illiteracy from a policy, adult education, and cognition point of view: Towards a joint referent framework

2019 ◽  
Vol 30 (2) ◽  
pp. 109-122
Author(s):  
Aleksandar Bulajić ◽  
Miomir Despotović ◽  
Thomas Lachmann
Keyword(s):  
Adult Education ◽  
Operational Definition ◽  
Literacy Skills ◽  
Point Of View ◽  
Industrialized Countries ◽  
Functional Illiteracy ◽  
Scale Levels ◽  
Components Of Reading ◽  
The One ◽  
Definition Of

Abstract. The article discusses the emergence of a functional literacy construct and the rediscovery of illiteracy in industrialized countries during the second half of the 20th century. It offers a short explanation of how the construct evolved over time. In addition, it explores how functional (il)literacy is conceived differently by research discourses of cognitive and neural studies, on the one hand, and by prescriptive and normative international policy documents and adult education, on the other hand. Furthermore, it analyses how literacy skills surveys such as the Level One Study (leo.) or the PIAAC may help to bridge the gap between cognitive and more practical and educational approaches to literacy, the goal being to place the functional illiteracy (FI) construct within its existing scale levels. It also sheds more light on the way in which FI can be perceived in terms of different cognitive processes and underlying components of reading. By building on the previous work of other authors and previous definitions, the article brings together different views of FI and offers a perspective for a needed operational definition of the concept, which would be an appropriate reference point for future educational, political, and scientific utilization.

Modelling and control of an alkaline water electrolysis process

2018 ◽  
Vol 1 (2) ◽  
pp. 9-14
Author(s):  
Marisol Cervantes-Bobadilla ◽  
Ricardo Fabricio Escobar Jiménez ◽  
José Francisco Gómez Aguilar ◽  
Tomas Emmanuel Higareda Pliego ◽  
Alberto Armando Alvares Gallegos
Keyword(s):  
Process Model ◽  
Water Electrolysis ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
Electrolysis Process ◽  
Linear Dynamic ◽  
Energy Current ◽  
Identification Technique ◽  
Nonlinear Static ◽  
And Control

In this research, an alkaline water electrolysis process is modelled. The electrochemical electrolysis is carried out in an electrolyzer composed of 12 series-connected steel cells with a solution 30% wt of potassium hydroxide. The electrolysis process model was developed using a nonlinear identification technique based on the Hammerstein structure. This structure consists of a nonlinear static block and a linear dynamic block. In this work, the nonlinear static function is modelled by a polynomial approximation equation, and the linear dynamic is modelled using the ARX structure. To control the current feed to the electrolyzer an unconstraint predictive controller was implemented, once the unconstrained MPC was simulated, some restrictions are proposed to design a constrained MPC (CMPC). The CMPC aim is to reduce the electrolyzer's energy consumption (power supply current). Simulation results showed the advantages of using the CMPC since the energy (current) overshoots are avoided.

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