scholarly journals Performance of rGO/TiO2 Photocatalytic Membranes for Hydrogen Production

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 218 ◽  
Author(s):  
Juan Corredor ◽  
Eduardo Perez-Peña ◽  
Maria J. Rivero ◽  
Inmaculada Ortiz
Keyword(s):  
Hydrogen Production ◽  
High Performance ◽  
Large Scale ◽  
Membrane Surface ◽  
Life Time ◽  
Dip Coating ◽  
Production Of Hydrogen ◽  
Nafion Membranes ◽  
The Matrix ◽  
Low Efficiency

Although there are promising environmental and energy characteristics for the photocatalytic production of hydrogen, two main drawbacks must be overcome before the large- scale deployment of the technology becomes a reality, (i) the low efficiency reported by state of the art photocatalysts and, (ii) the short life time and difficult recovery of the photocatalyst, issues that need research and development for new high performance catalysts. In this work 2% rGO/TiO2 composite photocatalysts were supported over Nafion membranes and the performance of the photocatalytic membrane was tested for hydrogen production from a 20% vol. methanol solution. Immobilization of the composite on Nafion membranes followed three different simple methods which preserve the photocatalyst structure: solvent-casting (SC), spraying (SP), and dip-coating (DP). The photocatalyst was included in the matrix membrane using the SC method, while it was located on the membrane surface in the SP and DP membranes showing less mass transfer limitations. The performance of the synthesized photocatalytic membranes for hydrogen production under UVA light irradiation was compared. Leaching of the catalytic membranes was tested by measuring the turbidity of the solution. With respect to catalyst leaching, both the SC and SP membranes provided very good results, the leaching being lower with the SC membrane. The best results in terms of initial hydrogen production rate (HPR) were obtained with the SP and DP membrane. The SP was selected as the most suitable method for photocatalytic hydrogen production due to the high HPR and the negligible photocatalyst leaching. Moreover, the stability of this membrane was studied for longer operation times. This work helps to improve the knowledge on the application of photocatalytic membranes for hydrogen production and contributes in facilitating the large-scale application of this process.

Nickel Multi-walled Carbon Nanotube Composite Electrode for Hydrogen Generation

2012 ◽  
Vol 1387 ◽  
Author(s):  
Nitin Kalra ◽  
Kalathur Santhanam ◽  
David Olney
Keyword(s):  
Carbon Nanotube ◽  
Hydrogen Production ◽  
Large Scale ◽  
Coulombic Efficiency ◽  
Superior Performance ◽  
Efficient Production ◽  
Scale Production ◽  
Production Of Hydrogen ◽  
Carbon Nanotube Composite ◽  
Decomposition Of Water

ABSTRACTThe electrochemical decomposition of water is an attractive method, however, the performance of the electrodes and efficiencies are of great concern in its large scale production. In this context, we wish to report here the superior performance of Ni-multiwalled carbon nanotube composite as cathode in the decomposition of water. The current voltage curves recorded with this electrode in different media showed a significant electrocatalysis in the reduction of hydrogen ion; the background electrolysis is shifted in the anodic direction. The nanocomposite composition has been found to be crucial in the efficient production of hydrogen. A coulombic efficiency of about 68% has been obtained at this electrode with a hydrogen production rate of 130L/m2 d. This electrode is more efficient than the 316L stainless steel (composition in percentage: C 0.019, Cr 17.3, Mo 2.04, Ni 11.3, Mn 1.04, N 0.041, Fe bulk) cathode that produces 10 ml/h at an area of 20 cm2 (5L/m2.h) (2). The results obtained with different electrolytes, performance variation with electrode composition, and current densities will be presented. The trials carried out using solar panel instead of DC power source showed similar hydrogen production rates and efficiencies.

Fuzzy rules based efficient event-driven simulation of blockchain-based applications

2021 ◽  
pp. 1-7
Author(s):  
Wei Zhou
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Fuzzy Rule ◽  
Data Access ◽  
Simulation Method ◽  
Actual System ◽  
Internet Service ◽  
Event Driven ◽  
Block Chain ◽  
Low Efficiency

Decentralized application (DAPP), replacing traditional business logic and data access layer with block chain, is a new form of Internet service. Testing DAPP requires large-scale distributed systems. Performing experiments in a real system is costly and difficult. This article carefully analyses the process of block generation and synchronization and explains the reasons for the low efficiency of block chain system simulation. We incorporate fuzzy rule based model for enhancing the logging system in blockchain. Rules based on fuzzy are utilized inside system of fuzzy logic to obtain outcome on basis of input variables. The data of Ethereum and Bitcoin proves that the block generation interval conforms to the exponential distribution, and the real PoW calculation can be replaced with random numbers. Both block verification and network propagation processes have latency, which can be simulated with asynchronous messaging. Based on the above analysis, this article proposes a high-performance simulation method based on event-driven model, which is suitable for describing the communication and synchronization behave our of block chain networks. The method can effectively describe the block generation, the synchronization process between nodes, and supports different equity proof forms. Using this method, the performance of the PoW systemis tested. Under the ecs.c6.xlargeinstance,the simulation running speed reaches 782 times of actual system. Further experiments show that this method can be efficiently used in larger-scale networks and is an effective tool for DAPP developing and testing.

Study on the Key Technology for Large-Scale High-Performance CNC Vertical Broaching Machine

2013 ◽  
Vol 705 ◽  
pp. 483-486
Author(s):  
Guo Jin Chen ◽  
Jing Ni ◽  
Ting Ting Liu ◽  
Ming Xu ◽  
Lu Gao Lin
Keyword(s):  
High Performance ◽  
Optimization Design ◽  
Large Scale ◽  
Mechanical Performance ◽  
Operational Reliability ◽  
Enterprise Management ◽  
Low Grade ◽  
Intelligent Monitoring ◽  
Low Efficiency ◽  
Enterprise Resource Optimization

For the general broaching machines problems of structure bulkiness, poor cylinder synchronization, lack of optimization design, low-grade control system, low efficiency and operational reliability, the paper studied the structural optimization technology of the large-scale high-performance CNC vertical broaching machine, designed the new 360-degree high-load lateral rotary table, the axial-rotary multi-pass joint of the anti-leakage and the elastic-contact, and the modular slider rails, so as to improve the mechanical performance, the working stability and reliability. The remote network intelligent monitoring system and the multi-function data acquisition processor for the developed CNC broaching machine, realize the enterprise management information, the enterprise resource optimization, and the automation and intelligence of the manufacturing process.

scholarly journals The calculation of specific heats for some important solid components in hydrogen production process based on CuCl cycle

2014 ◽  
Vol 18 (3) ◽  
pp. 823-831 ◽  
Author(s):  
Jurij Avsec
Keyword(s):  
Mathematical Model ◽  
Hydrogen Production ◽  
Thermodynamic Properties ◽  
Large Scale ◽  
Solid Phase ◽  
Statistical Thermodynamics ◽  
Thermochemical Cycle ◽  
Direct Production ◽  
Production Of Hydrogen ◽  
The Mathematical Model

Hydrogen is one of the most promising energy sources of the future enabling direct production of power and heat in fuel cells, hydrogen engines or furnaces with hydrogen burners. One of the last remainder problems in hydrogen technology is how to produce a sufficient amount of cheap hydrogen. One of the best options is large scale thermochemical production of hydrogen in combination with nuclear power plant. copper-chlorine (CuCl) cycle is the most promissible thermochemical cycle to produce cheap hydrogen.This paper focuses on a CuCl cycle, and the describes the models how to calculate thermodynamic properties. Unfortunately, for many components in CuCl cycle the thermochemical functions of state have never been measured. This is the reason that we have tried to calculate some very important thermophysical properties. This paper discusses the mathematical model for computing the thermodynamic properties for pure substances and their mixtures such as CuCl, HCl, Cu2OCl2 important in CuCl hydrogen production in their fluid and solid phase with an aid of statistical thermodynamics. For the solid phase, we have developed the mathematical model for the calculation of thermodynamic properties for polyatomic crystals. In this way, we have used Debye functions and Einstein function for acoustical modes and optical modes of vibrations to take into account vibration of atoms. The influence of intermolecular energy we have solved on the basis of Murnaghan equation of state and statistical thermodynamics.

scholarly journals Optimization of Oxygen Evolution Reaction with Electroless Deposited Ni–P Catalytic Nanocoating

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3010
Author(s):  
Sergio Battiato ◽  
Mario Urso ◽  
Salvatore Cosentino ◽  
Anna Lucia Pellegrino ◽  
Salvo Mirabella ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
High Performance ◽  
Large Scale ◽  
Low Cost ◽  
Water Electrolysis ◽  
Synthetic Approach ◽  
Low Efficiency ◽  
Electrochemical Water Splitting

The low efficiency of water electrolysis mostly arises from the thermodynamic uphill oxygen evolution reaction. The efficiency can be greatly improved by rationally designing low-cost and efficient oxygen evolution anode materials. Herein, we report the synthesis of Ni–P alloys adopting a facile electroless plating method under mild conditions on nickel substrates. The relationship between the Ni–P properties and catalytic activity allowed us to define the best conditions for the electroless synthesis of highperformance Ni–P catalysts. Indeed, the electrochemical investigations indicated an increased catalytic response by reducing the thickness and Ni/P ratio in the alloy. Furthermore, the Ni–P catalysts with optimized size and composition deposited on Ni foam exposed more active sites for the oxygen evolution reaction, yielding a current density of 10 mA cm−2 at an overpotential as low as 335 mV, exhibiting charge transfer resistances of only a few ohms and a remarkable turnover frequency (TOF) value of 0.62 s−1 at 350 mV. The present study provides an advancement in the control of the electroless synthetic approach for the design and large-scale application of high-performance metal phosphide catalysts for electrochemical water splitting.

Preliminary Cost Estimates for Massive Hydrogen Production Using SI Process

2008 ◽  
Author(s):  
K. J. Yang ◽  
K. Y. Lee ◽  
T. H. Lee
Keyword(s):  
Hydrogen Production ◽  
Large Scale ◽  
Fossil Fuels ◽  
Production Costs ◽  
Scale Production ◽  
Cost Estimates ◽  
Production Of Hydrogen ◽  
Major Factors ◽  
The Cost ◽  
Hydrogen Systems

As a preliminary study of cost estimates for nuclear hydrogen systems, the hydrogen production costs of the nuclear energy sources benchmarking GT-MHR and PBMR are estimated in the necessary input data on a Korean specific basis. G4-ECONS was appropriately modified to calculate the cost for hydrogen production of SI process with VHTR as a thermal energy source rather than the LUEC. The estimated costs presented in this paper show that hydrogen production by the VHTR could be competitive with current techniques of hydrogen production from fossil fuels if CO2 capture and sequestration is required. Nuclear production of hydrogen would allow large-scale production of hydrogen at economic prices while avoiding the release of CO2. Nuclear production of hydrogen could thus become the enabling technology for the hydrogen economy. The major factors that would affect the cost of hydrogen were also discussed.

scholarly journals Development of a Spatial Domain Decomposition Scheme for Monte Carlo Neutron Transport

2018 ◽  
Author(s):  
Manuel García ◽  
Diego Ferraro ◽  
Victor Hugo Sanchez-Espinoza ◽  
Luigi Mercatali ◽  
Jaakko Leppänen ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Domain Decomposition ◽  
High Performance ◽  
Large Scale ◽  
Neutron Transport ◽  
Spatial Domain ◽  
Parallel Execution ◽  
Monte Carlo Code ◽  
Processing Scheme ◽  
Low Efficiency

The computing power available nowadays to the average Monte-Carlo-code user is sufficient to perform large-scale neutron transport simulations, such as full-core burnup or high-fidelity multiphysics. In practice however, software limitations in the majority of the available Monte Carlo codes result in a low efficiency when running in High Performance Computing (HPC) environments, the main issues being inadequate memory utilization and poor scalability. The traditional parallel processing scheme based of splitting particle histories among processes requires domain replication across nodes, and therefore the memory demand for each computing node does not scale, and a memory bottleneck appears for large-scale problems. The scalability of this approach usually limits the resources that can be used efficiently to a small number of nodes/processors. Consequently, massively parallel execution is not viable with particle-based parallelism, at least not by itself. In this work we propose a Spatial Domain Decomposition (SDD) approach to develop an efficient and scalable Monte Carlo neutron transport algorithm. Breaking down the geometry into subdomains, a distributed memory scheme can be used to reduce the in-node memory demand, allowing the simulation of large-scale memory-intensive problems. Additionally, with an efficient neutron tracking algorithm the overall speedup can be significantly improved.

scholarly journals Study of Activity and Super-Capacitance Exhibited by Bifunctional Raney 2.0 Catalyst for Alkaline Water-Splitting Electrolysis

Hydrogen ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 1-17
Author(s):  
William J. F. Gannon ◽  
Charles W. Dunnill
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
High Performance ◽  
Large Scale ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
Bifunctional Electrocatalyst ◽  
Energy Capture ◽  
A New Technique ◽  
Alkaline Electrolysis

Low-cost, high-performance coatings for hydrogen production via electrolytic water-splitting are of great importance for de-carbonising energy. In this study the Raney2.0 coating was analysed using various electrochemical techniques to assess its absolute performance, and it was confirmed to have an extremely low overpotential for hydrogen evolution of just 28 mV at 10 mA/cm2. It was also confirmed to be an acceptable catalyst for oxygen evolution, making it the highest performing simple bifunctional electrocatalyst known. The coating exhibits an extremely high capacitance of up to 1.7 F/cm2, as well as being able to store 0.61 J/cm2 in the form of temporary hydride deposits. A new technique is presented that performs a best-fit of a transient simulation of an equivalent circuit containing a constant phase element to cyclic voltammetry measurements. From this the roughness factor of the coating was calculated to be approximately 40,000, which is the highest figure ever reported for this type of material. The coating is therefore an extremely useful improved bifunctional coating for the continued roll-out of alkaline electrolysis for large-scale renewable energy capture via hydrogen production.

scholarly journals Aplikasi Direct Matrix Converter pada Pengendali Kecepatan Motor Induksi 3 Fase menggunakan Modulasi Venturini

2020 ◽  
Vol 8 (3) ◽  
pp. 518
Author(s):  
GAMAR BASUKI ◽  
ERA PURWANTO ◽  
HARY OKTAVIANTO ◽  
MENTARI PUTRI JATI ◽  
MOCHAMAD ARI BAGUS NUGROHO
Keyword(s):  
Induction Motor ◽  
Power Factor ◽  
High Performance ◽  
Power Factor Correction ◽  
Matrix Converter ◽  
Motor Controller ◽  
The Matrix ◽  
Low Efficiency ◽  
Converter Matrix ◽  
Converter Testing

ABSTRAKMotor induksi yang paling banyak digunakan juga memiliki kekurangan seperti losses yang cukup tinggi, power factor correction, dan efisiensi yang rendah. Oleh karena itu, dibutuhkan pengendali motor induksi yang memiliki performa dan efisiensi yang tinggi. Salah satu jenis AC – AC konverter yang mempunyai efisiensi, lifetime, kekompakan dan faktor daya mendekati unity yang akan digunakan sebagai pengendali motor induksi adalah matrix converter. Metode venturini digunakan sebagai modulasi pada matrix converter. Untuk itu dalam penelitian ini dilakukan pembuatan simulasi menggunakan simulink MATLAB dan hardware matrix converter. Pengujian matrix converter menggunakan modulasi venturini sebagai pengendali motor induksi telah dilakukan dengan motor dapat berputar mencapai kecepatan nominal sebesar 1440 Rpm sesuai nameplate dan motor juga dapat berputar dibawah frekuensi nominal. Dengan penelitian ini, pengendalian motor induksi dapat lebih efisien dalam penggunaannya di berbagai bidang.Kata kunci: Matrix converter, metode venturini, motor induksi. ABSTRACTThe most widely used induction motors also have disadvantages such as fairly high losses, power factor correction, and low efficiency. From this disadvantages, we need an induction motor controller that has high performance and efficiency. One type of AC-AC converter that has efficiency, lifetime, compactness and power factor approach to unity that will be used as an induction motor controller is a matrix converter. The Venturini method is used as modulation in the matrix converter. For this reason, in this study, simulation was made using MATLAB simulink and hardware matrix converter. Matrix converter testing using venturini modulation as an induction motor controller has been done with the motor can be rotate reaching a nominal speed of 1440 Rpm according to nameplate and the motor can also rotate below the nominal frequency. It is expected that induction motor controller can be more efficient in their use in various fields.Keywords: Matrix converter, venturini method, induction motor

scholarly journals Production of Hydrogen from Coke Oven Gas in JSW Group

2020 ◽  
Vol 3 (1) ◽  
pp. 9-20
Author(s):  
Tomasz Szeszko
Keyword(s):  
Hydrogen Production ◽  
High Purity ◽  
Large Scale ◽  
Target Location ◽  
Negative Impact ◽  
Coke Oven ◽  
Transport Sector ◽  
Market Demand ◽  
Coke Oven Gas ◽  
Production Of Hydrogen

AbstractThe publication analyses the possibility of separating hydrogen from coke oven gas for further use in the transport sector in the FCEV segment (fuel cell electric vehicles). The construction of the separation installation using the PSA (pressure swing adsorption) method guaranteeing high purity of hydrogen was assumed, according to the requirements of ISO 14678-2:2012 and SAE J-2719 standards. The PSA technology is widely used in industrial gas separation processes, however, due to the composition of coal gas, which apart from hydrogen and methane consists of impurities in the form of hydrocarbons, sulphur compounds, chlorine, etc., it needs to be adapted to the needs of separation of hydrogen from coke oven gas. The study shows the total possible hydrogen production potential and then, in agreement with the JSW Group’s Coking Plants, limits were set for hydrogen production in PSA technology at Przyjaźń, Jadwiga and Radlin Coking Plants, without the negative impact of the separation installation on technological processes associated with coke oven battery firing, operation of existing power units, gas compression systems and taking into account securing the needs of external customers for coke oven gas. Additionally, in order to determine the Polish market demand for high-purity hydrogen, an analysis was carried out which indicates that in 2030 the share of FCEVs will be 2%, so the demand for hydrogen in this segment would be negligible compared to the supply of hydrogen produced in a large-scale installation. Due to the need to build such a market and adapt the parameters of the installation to the variable parameters of coke oven gas, the pilot scale of the installation and the target location of the installation at the Przyjaźń Coking Plant were indicated as the most optimal.

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