scholarly journals Experimental Assessment of Perhydro-Dibenzyltoluene Dehydrogenation Reaction Kinetics in a Continuous Flow System for Stable Hydrogen Supply

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7613
Author(s):  
Sanghyoun Park ◽  
Mujahid Naseem ◽  
Sangyong Lee
Keyword(s):  
Continuous Flow ◽  
Fossil Fuels ◽  
Flow Reactor ◽  
Production Systems ◽  
Clean Energy ◽  
Operating Conditions ◽  
Dehydrogenation Reaction ◽  
Hydrogen Flow ◽  
Wide Range ◽  
Hydrogen Supply

The development of alternate clean energy resources is among the most pressing issues in the energy sector in order to preserve the global natural environment. One of the ideal candidates is the utilization of hydrogen as a primary fuel in lieu of fossil fuels. It can be safely stored in liquid organic hydrogen carrier (LOHC) materials and recovered on demand. A uniform supply of hydrogen is essential for power production systems for their smooth operation. This study was conducted to determine the operating conditions of the dehydrogenation of perhydro-dibenzyltoluene (H18-DBT) to ensure that hydrogen supply in a continuous flow reactor remains stable over a wide range of temperatures. The hydrogen flow rate from the dehydrogenation reaction was measured and correlated with the degree of dehydrogenation (DoD) evaluated from the refractive index of reactant liquid samples at various temperatures, WHSV and the initial reactant concentrations. Moreover, a kinetic model is presented holding validity up to a WHSV of 67 h−1. The results acquired present a range for an order of reaction from 2.3 to 2.4 with the required activation energy of 171 kJ/mol.

scholarly journals Overview of Maximum Power Point Tracking Techniques for PV System

2021 ◽  
Vol 242 ◽  
pp. 01004
Author(s):  
Khairul Eahsun Fahim ◽  
Shaikh M Farabi ◽  
Shaikh Shahrukh Farhan ◽  
Ishrat Jahan Esha ◽  
Taseen Muhtadi
Keyword(s):  
Fossil Fuels ◽  
Clean Energy ◽  
Maximum Power ◽  
Pv System ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Wide Range ◽  
Alternative Sources ◽  
Power Point

Fossil fuel is one of the major sources of the world’s energy generation. Greenhouse gases are increasing in the atmosphere due to the excessive use of fossil fuels. To tackle global warming and the shortage of natural gases, researchers are always looking for alternative sources of clean energy. Solar energy is becoming popular due to its inexhaustible nature. To get the most of out of a solar system and to generate maximum power, it is important to operate the panel at maximum power point. In other words, it can be said that MPP techniques are used to maximize the output power. There is a wide range of MPPT algorithm available to calculate MPP. This paper gives a broad overview of the existing MPPT techniques used in practice.

scholarly journals Factors influencing the production of Hidrogen by fermentative processes

2016 ◽  
Vol 2 (1) ◽  
pp. 101
Author(s):  
Liliane Poleto ◽  
Flaviane Eva Magrini ◽  
Lademir Luiz Beal ◽  
Suelen Osmarina Paesi
Keyword(s):  
Energy Production ◽  
Fossil Fuels ◽  
State Of The Art ◽  
Calorific Value ◽  
Clean Energy ◽  
Operating Conditions ◽  
Industrial Wastes ◽  
Production Of Hydrogen ◽  
Points Of View ◽  
Social Environmental

<p><strong>Abstract - </strong>Growing concern about finding suitable replacements for fossil fuels has encouraged the search for new clean energy production processes. Hydrogen has been highlighted as an ideal form of energy because this molecule does not contribute to the greenhouse effect and it possesses a high calorific value. The microbiological production of this gas is a process that can become sustainable from social, environmental and economic points of view once the microorganisms isolated from the environment can use agro-industrial wastes as substrate. Various microorganisms are described in the literature as producers of hydrogen from several types of substrates, especially species from the genera <em>Clostridium </em>and <em>Enterobacter</em>. However, various scientific factors and fermentation operating conditions that will steer the metabolic pathway to the production of hydrogen should be analyzed. The objective of this work is to contribute to the state of the art by reviewing recent studies involving the microbiological production of hydrogen and the main aspects involved in biotechnological process.</p>

scholarly journals Using Machine Learning Tools to Predict Compressor Stall

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Samuel M. Hipple ◽  
Harry Bonilla-Alvarado ◽  
Paolo Pezzini ◽  
Lawrence Shadle ◽  
Kenneth M. Bryden
Keyword(s):  
Machine Learning ◽  
Power Systems ◽  
Gas Turbine ◽  
Clean Energy ◽  
Operating Conditions ◽  
Learning Tools ◽  
Power Sources ◽  
Load Following ◽  
Wide Range ◽  
Compressor Surge

Abstract Clean energy has become an increasingly important consideration in today’s power systems. As the push for clean energy continues, many coal-fired power plants are being decommissioned in favor of renewable power sources such as wind and solar. However, the intermittent nature of renewables means that dynamic load following traditional power systems is crucial to grid stability. With high flexibility and fast response at a wide range of operating conditions, gas turbine systems are poised to become the main load following component in the power grid. Yet, rapid changes in load can lead to fluid flow instabilities in gas turbine power systems. These instabilities often lead to compressor surge and stall, which are some of the most critical problems facing the safe and efficient operation of compressors in turbomachinery today. Although the topic of compressor surge and stall has been extensively researched, no methods for early prediction have been proven effective. This study explores the utilization of machine learning tools to predict compressor stall. The long short-term memory (LSTM) model, a form of recurrent neural network (RNN), was trained using real compressor stall datasets from a 100 kW recuperated gas turbine power system designed for hybrid configuration. Two variations of the LSTM model, classification and regression, were tested to determine optimal performance. The regression scheme was determined to be the most accurate approach, and a tool for predicting compressor stall was developed using this configuration. Results show that the tool is capable of predicting stalls 5–20 ms before they occur. With a high-speed controller capable of 5 ms time-steps, mitigating action could be taken to prevent compressor stall before it occurs.

scholarly journals A Comprehensive Review on Thermal Coconversion of Biomass, Sludge, Coal, and Their Blends Using Thermogravimetric Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Zeeshan Hameed ◽  
Salman Raza Naqvi ◽  
Muhammad Naqvi ◽  
Imtiaz Ali ◽  
Syed Ali Ammar Taqvi ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Sewage Sludge ◽  
Fossil Fuels ◽  
Synergistic Effects ◽  
Clean Energy ◽  
Thermal Conversion ◽  
Operating Conditions ◽  
Decomposition Mechanism ◽  
Sustainable Environment ◽  
Vital Resource

Lignocellulosic biomass is a vital resource for providing clean future energy with a sustainable environment. Besides lignocellulosic residues, nonlignocellulosic residues such as sewage sludge from industrial and municipal wastes are gained much attention due to its large quantities and ability to produce cheap and clean energy to potentially replace fossil fuels. These cheap and abundantly resources can reduce global warming owing to their less polluting nature. The low-quality biomass and high ash content of sewage sludge-based thermal conversion processes face several disadvantages towards its commercialization. Therefore, it is necessary to utilize these residues in combination with coal for improvement in energy conversion processes. As per author information, no concrete study is available to discuss the synergy and decomposition mechanism of residues blending. The objective of this study is to present the state-of-the-art review based on the thermal coconversion of biomass/sewage sludge, coal/biomass, and coal/sewage sludge blends through thermogravimetric analysis (TGA) to explore the synergistic effects of the composition, thermal conversion, and blending for bioenergy production. This paper will also contribute to detailing the operating conditions (heating rate, temperature, and residence time) of copyrolysis and cocombustion processes, properties, and chemical composition that may affect these processes and will provide a basis to improve the yield of biofuels from biomass/sewage sludge, coal/sewage sludge, and coal/biomass blends in thermal coconversion through thermogravimetric technique. Furthermore, the influencing factors and the possible decomposition mechanism are elaborated and discussed in detail. This study will provide recent development and future prospects for cothermal conversion of biomass, sewage, coal, and their blends.

Uncertainty in High-Pressure Stator Performance Measurement in an Annular Cascade at Engine-Representative Reynolds and Mach

2021 ◽  
Author(s):  
Lakshya Bhatnagar ◽  
Guillermo Paniagua ◽  
David G. Cuadrado ◽  
Papa Aye N. Aye-Addo ◽  
Antonio Castillo Sauca ◽  
...  
Keyword(s):  
High Pressure ◽  
Uncertainty Analysis ◽  
Production Systems ◽  
Single Point ◽  
Measurement Data ◽  
Operating Conditions ◽  
Development Programs ◽  
Wide Range ◽  
Annular Cascade ◽  
Flow Blockage

Abstract The betterment of the turbine performance plays a prime role in all future transportation and energy production systems. Precise uncertainty quantification of experimental measurement of any performance differential is therefore essential for turbine development programs. In this paper, the uncertainty analysis of loss measurements in a high-pressure turbine vane are presented. Tests were performed on a stator geometry at engine representative conditions in a new annular turbine module called BRASTA (Big Rig for Annular Stationary Turbine Analysis) located within the Purdue Experimental Turbine Aerothermal Lab. The aerodynamic probes are described with emphasis on their calibration and uncertainty analysis, first considering single point measurement, followed by the spatial averaging implications. The change of operating conditions and flow blockage due to measurement probes are analyzed using CFD, and corrections are recommended on the measurement data. The test section and its characterization are presented, including calibration of the sonic valve. The sonic valve calibration is necessary to ensure a wide range of operation in Mach and Reynolds. Finally, the vane data are discussed, emphasizing their systematic and stochastic uncertainty.

scholarly journals Uncertainty in High-Pressure Stator Performance Measurement in an Annular Cascade At Engine-Representative Reynolds and Mach

2021 ◽  
Author(s):  
Lakshya Bhatnagar ◽  
Guillermo Paniagua ◽  
David Gonzalez Cuadrado ◽  
Nyansafo Aye-Addo ◽  
Antonio Castillo Sauca ◽  
...  
Keyword(s):  
High Pressure ◽  
Uncertainty Analysis ◽  
Production Systems ◽  
Single Point ◽  
Measurement Data ◽  
Operating Conditions ◽  
Development Programs ◽  
Wide Range ◽  
Annular Cascade ◽  
Flow Blockage

Abstract The betterment of the turbine performance plays a prime role in all future transportation and energy production systems. Precise uncertainty quantification of experimental measurement of any performance differential is therefore essential for turbine development programs. In this paper, the uncertainty analysis of loss measurements in a high-pressure turbine vane are presented. Tests were performed on a stator geometry at engine representative conditions in a new annular turbine module called BRASTA (Big Rig for Annular Stationary Turbine Analysis) located within the Purdue Experimental Turbine Aerothermal Lab. The aerodynamic probes are described with emphasis on their calibration and uncertainty analysis, first considering single point measurement, followed by the spatial averaging implications. The change of operating conditions and flow blockage due to measurement probes are analyzed using CFD, and corrections are recommended on the measurement data. The test section and its characterization are presented, including calibration of the sonic valve. The sonic valve calibration is necessary to ensure a wide range of operation in Mach and Reynolds. Finally, the vane data are discussed, emphasizing their systematic and stochastic uncertainty.

Comparison of Deterministic and Linear Cosine Spatial Filtering of Transmission Electron Micrographs

1972 ◽  
Vol 30 ◽  
pp. 596-597
Author(s):  
David A. Ansley
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Spatial Filter ◽  
Operating Conditions ◽  
Objective Lens ◽  
List Type ◽  
Spatial Filters ◽  
Transmission Electron ◽  
Wide Range

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

Renewable Energy from Agricultural Waste

2018 ◽  
Vol 69 (6) ◽  
pp. 1363-1366 ◽  
Author(s):  
Stefania Daniela Bran ◽  
Petre Chipurici ◽  
Mariana Bran ◽  
Alexandru Vlaicu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gas Chromatography ◽  
Continuous Flow ◽  
Laboratory Experiments ◽  
Fermentation Process ◽  
Flow Reactor ◽  
Agricultural Waste ◽  
Continuous Flow Reactor ◽  
Natural Support ◽  
Co2 Flow

This paper has aimed at evaluating the concentration of bioethanol obtained using sunflower stem as natural support, molasses as carbon source and Saccharomyces cerevisiae yeast in a continuous flow reactor. The natural support was tested to investigate the immobilization/growth of S. cerevisiae yeast. The concentration of bioethanol produced by fermentation was analyzed by gas chromatography using two methods: aqueous solutions and extraction in organic phase. The CO2 flow obtained during the fermentation process was considered to estimate when the yeast was deactivated. The laboratory experiments have highlighted that the use of plant-based wastes to bioconversion in ethanol could be a non-pollutant and sustainable alternative.

Nitrogen Removal from Anaerobically-Treated Leachate

1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis
Keyword(s):  
Nitrogen Removal ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Anaerobic Filter ◽  
Ph Values ◽  
Wide Range ◽  
Ammonia Desorption ◽  
Effects Of Ph

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.

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