Records with Subject: Reaction Engineering
Showing records 1 to 25 of 58. [First] Page: 1 2 3 Last
Approaches to Suppress CO₂-Induced Plasticization of Polyimide Membranes in Gas Separation Applications
Moli Zhang, Liming Deng, Dongxiao Xiang, Bing Cao, Seyed Saeid Hosseini, Pei Li
April 15, 2019 (v1)
Keywords: Carbon Dioxide, gas separation, membrane, plasticization, polyimide
Polyimides with excellent physicochemical properties have aroused a great deal of interest as gas separation membranes; however, the severe performance decay due to CO₂-induced plasticization remains a challenge. Fortunately, in recent years, advanced plasticization-resistant membranes of great commercial and environmental relevance have been developed. In this review, we investigate the mechanism of plasticization due to CO₂ permeation, introduce effective methods to suppress CO₂-induced plasticization, propose evaluation criteria to assess the reduced plasticization performance, and clarify typical methods used for designing anti-plasticization membranes.
Adsorption of Organic Constituents from Reverse Osmosis Concentrate in Coal Chemical Industry by Coking Coal
Hongxiang Xu, Qizheng Qin, Changfeng Zhang, Kejia Ning, Rong Zhao, Penghui Wang, Jiushuai Deng, Gen Huang
April 15, 2019 (v1)
Keywords: Adsorption, adsorption mechanism, aromatic structure, kinetics
To solve the unwieldy problem of coal chemical wastewater reverse osmosis concentrate (ROC), a novel treatment method in which coking coal was used to adsorb the organic from ROC and the adsorption mechanism involved was investigated. The results showed that the organic components in the ROC of coal chemical industry can be effectively absorbed by the coking coal and the total organic carbon, UV254 and chromaticity of treated ROC reduced by 70.18%, 70.15% and 59.55%, respectively, at the coking coal dosage of 80 g/L. The isothermal adsorption data were fitted to the Langmuir model well. The kinetics were expressed well by the quasi-second-order kinetic model. The intragranular diffusion model and the BET (Acronym for three scientists: Brunauer⁻Emmett⁻Teller) test showed that the adsorption occurred mainly on the surface of the coking coal and its macropores and mesopores. When the pollutants further diffused to the mesopores and micropores, the adsorption rate decreased. The result of... [more]
Efficient Removal of Hexavalent Chromium from Wastewater with Electro-Reduction
Hao Peng, Yumeng Leng, Qinzhe Cheng, Qian Shang, Jiancheng Shu, Jing Guo
April 15, 2019 (v1)
Keywords: acidic medium, chromium, electro-reduction
Removal of hexavalent chromium had attracted much attention as it is a hazardous contaminant. An electrocoagulation-like technology electro-reduction was applied. The chromium (VI) in the wastewater was reduced to chromium (III) by the electron supplied by electricity power and Fe2+, formed from corrosion of steel electrodes in acidic conditions. The mechanism and parameters affecting the reaction were investigated. The results optimized by response surface methodology indicated that the influence of single factor on the reduction efficiency followed the order: A: dosage of H₂SO₄ > C: reaction time > D: reaction temperature > B: current intensity. The reduction efficiency was hardly affected by current intensity, while it was increased with the increasing of reaction time and acid concentration. The reducing agent, Fe2+ an and extra free electron, acted as a reducing agent and could easily reduce hexavalent chromium to trivalent chromium at high temperatures in an acidic medium.
Effective Dye Degradation by Graphene Oxide Supported Manganese Oxide
Hayarpi Saroyan, George Z. Kyzas, Eleni A. Deliyanni
April 15, 2019 (v1)
Keywords: characterization, degradation, dyes, graphene oxide, manganese oxide, reuse
Graphene oxide (GO) was used as a support for manganese oxide (MnO₂) for the preparation of a nanocomposite catalyst for the degradation of an azo dye, Reactive Black 5 (RB5). The nanocomposite was characterized for the structure by XRD, for the morphology with SEM, and for the surface chemistry with FTIR and potentiometric titration measurements. The GO-MnO₂ nanocomposite presented a high catalytic activity for the degradation/oxidation of RB5 at ambient conditions, which was higher than that of the pure MnO₂ and could be attributed to the beneficial contribution of the manganese oxide and the graphene oxide.
Multi-Tubular Reactor for Hydrogen Production: CFD Thermal Design and Experimental Testing
Elvira Tapia, Aurelio González-Pardo, Alfredo Iranzo, Manuel Romero, José González-Aguilar, Alfonso Vidal, Mariana Martín-Betancourt, Felipe Rosa
April 15, 2019 (v1)
Keywords: Computational Fluid Dynamics, Computational Fluid Dynamics, hydrogen production, model, solar reactor, solar receiver, thermal energy
This study presents the Computational Fluid Dynamics (CFD) thermal design and experimental tests results for a multi-tubular solar reactor for hydrogen production based on the ferrite thermochemical cycle in a pilot plant in the Plataforma Solar de Almería (PSA). The methodology followed for the solar reactor design is described, as well as the experimental tests carried out during the testing campaign and characterization of the reactor. The CFD model developed for the thermal design of the solar reactor has been validated against the experimental measurements, with a temperature error ranging from 1% to around 10% depending on the location within the reactor. The thermal balance in the reactor (cavity and tubes) has been also solved by the CFD model, showing a 7.9% thermal efficiency of the reactor. CFD results also show the percentage of reacting media inside the tubes which achieve the required temperature for the endothermic reaction process, with 90% of the ferrite pellets inside... [more]
Optimization of Reaction Selectivity Using CFD-Based Compartmental Modeling and Surrogate-Based Optimization
Shu Yang, San Kiang, Parham Farzan, Marianthi Ierapetritou
April 9, 2019 (v1)
Keywords: CFD-simulation, compartmental modeling, competing reaction system, Mixing, model order reduction, Optimization, surrogate-based optimization
Mixing is considered as a critical process parameter (CPP) during process development due to its significant influence on reaction selectivity and process safety. Nevertheless, mixing issues are difficult to identify and solve owing to their complexity and dependence on knowledge of kinetics and hydrodynamics. In this paper, we proposed an optimization methodology using Computational Fluid Dynamics (CFD) based compartmental modelling to improve mixing and reaction selectivity. More importantly, we have demonstrated that through the implementation of surrogate-based optimization, the proposed methodology can be used as a computationally non-intensive way for rapid process development of reaction unit operations. For illustration purpose, reaction selectivity of a process with Bourne competitive reaction network is discussed. Results demonstrate that we can improve reaction selectivity by dynamically controlling rates and locations of feeding in the reactor. The proposed methodology inco... [more]
Photocatalytic Membranes in Photocatalytic Membrane Reactors
Pietro Argurio, Enrica Fontananova, Raffaele Molinari, Enrico Drioli
April 8, 2019 (v1)
Keywords: fine chemistry, photocatalytic membrane, photocatalytic membrane reactors, wastewater treatment
The present work gives a critical overview of the recent progresses and new perspectives in the field of photocatalytic membranes (PMs) in photocatalytic membrane reactors (PMRs), thus highlighting the main advantages and the still existing limitations for large scale applications in the perspective of a sustainable growth. The classification of the PMRs is mainly based on the location of the photocatalyst with respect to the membranes and distinguished in: (i) PMRs with photocatalyst solubilized or suspended in solution and (ii) PMRs with photocatalyst immobilized in/on a membrane (i.e., a PM). The main factors affecting the two types of PMRs are deeply discussed. A multidisciplinary approach for the progress of research in PMs and PMRs is presented starting from selected case studies. A special attention is dedicated to PMRs employing dispersed TiO₂ confined in the reactor by a membrane for wastewater treatment. Moreover, the design and development of efficient photocatalytic membran... [more]
Identifiability and Reconstruction of Biochemical Reaction Networks from Population Snapshot Data
Eugenio Cinquemani
April 8, 2019 (v1)
Keywords: flow-cytometry, moment equations, regulatory networks, reporter gene systems, statistical inference
Inference of biochemical network models from experimental data is a crucial problem in systems and synthetic biology that includes parameter calibration but also identification of unknown interactions. Stochastic modelling from single-cell data is known to improve identifiability of reaction network parameters for specific systems. However, general results are lacking, and the advantage over deterministic, population-average approaches has not been explored for network reconstruction. In this work, we study identifiability and propose new reconstruction methods for biochemical interaction networks. Focusing on population-snapshot data and networks with reaction rates affine in the state, for parameter estimation, we derive general methods to test structural identifiability and demonstrate them in connection with practical identifiability for a reporter gene in silico case study. In the same framework, we next develop a two-step approach to the reconstruction of unknown networks of inte... [more]
Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy
Chaoqi Shen, Kondo-Francois Aguey-Zinsou
February 27, 2019 (v1)
Keywords: activation energy, hydrogen storage, magnesium, nanosize, particle size
The kinetics of hydrogen absorption/desorption can be improved by decreasing particle size down to a few nanometres. However, the associated evolution of activation energy remains unclear. In an attempt to clarify such an evolution with respect to particle size, we electrochemically deposited Mg nanoparticles on a catalytic nickel and noncatalytic titanium substrate. At a short deposition time of 1 h, magnesium particles with a size of 68 ± 11 nm could be formed on the nickel substrate, whereas longer deposition times led to much larger particles of 421 ± 70 nm. Evaluation of the hydrogen desorption properties of the deposited magnesium nanoparticles confirmed the effectiveness of the nickel substrate in facilitating the recombination of hydrogen, but also a significant decrease in activation energy from 56.1 to 37.8 kJ·mol−1 H₂ as particle size decreased from 421 ± 70 to 68 ± 11 nm. Hence, the activation energy was found to be intrinsically linked to magnesium particle size. Such a re... [more]
Gas Hydrate Growth Kinetics: A Parametric Study
Remi-Erempagamo Tariyemienyo Meindinyo, Thor Martin Svartaas
February 27, 2019 (v1)
Keywords: factors that affect gas hydrate growth rate, mass and heat transfer, methane hydrate growth kinetics, reactor scale-up, stirring rate, temperature, water content
Gas hydrate growth kinetics was studied at a pressure of 90 bars to investigate the effect of temperature, initial water content, stirring rate, and reactor size in stirred semi-batch autoclave reactors. The mixing energy during hydrate growth was estimated by logging the power consumed. The theoretical model by Garcia-Ochoa and Gomez for estimation of the mass transfer parameters in stirred tanks has been used to evaluate the dispersion parameters of the system. The mean bubble size, impeller power input per unit volume, and impeller Reynold’s number/tip velocity were used for analyzing observed trends from the gas hydrate growth data. The growth behavior was analyzed based on the gas consumption and the growth rate per unit initial water content. The results showed that the growth rate strongly depended on the flow pattern in the cell, the gas-liquid mass transfer characteristics, and the mixing efficiency from stirring. Scale-up effects indicate that maintaining the growth rate per... [more]
Leaching of Metal Ions from Blast Furnace Slag by Using Aqua Regia for CO₂ Mineralization
Jun-Hwan Bang, Seung-Woo Lee, Chiwan Jeon, Sangwon Park, Kyungsun Song, Whan Joo Jo, Soochun Chae
February 27, 2019 (v1)
Keywords: blast furnace slag, calcium leaching, CO2 mineralization
Blast furnace slag (BFS) was selected as the source of Ca for CO₂ mineralization purposes to store CO₂ as CaCO₃. BFS was dissolved using aqua regia (AR) for leaching metal ions for CO₂ mineralization and rejecting metal ions that were not useful to obtain pure CaCO₃ (as confirmed by XRD analysis). The AR concentration, as well as the weight of BFS in an AR solution, was varied. Increasing the AR concentration resulted in increased metal ion leaching efficiencies. An optimum concentration of 20% AR was required for completely leaching Ca and Mg for a chemical reaction with CO₂ and for suppressing the leaching of impurities for the production of high-purity carbonate minerals. Increasing the liquid-to-solid ratio (L/S) resulted in the increased leaching of all metal ions. An optimum L/S of 0.3/0.03 (=10) was required for completely leaching alkaline-earth metal ions for CO₂ mineralization and for retaining other metal ions in the filtered residue. Moreover, the filtrate obtained using 20... [more]
Spark Ignition Engine Combustion, Performance and Emission Products from Hydrous Ethanol and Its Blends with Gasoline
Musaab O. El-Faroug, Fuwu Yan, Maji Luo, Richard Fiifi Turkson
February 27, 2019 (v1)
Keywords: combustion, emission, hydrous ethanol, performance, spark ignition engine
This paper reviews the serviceability of hydrous ethanol as a clean, cheap and green renewable substitute fuel for spark ignition engines and discusses the comparative chemical and physical properties of hydrous ethanol and gasoline fuels. The significant differences in the properties of hydrous ethanol and gasoline fuels are sufficient to create a significant change during the combustion phase of engine operation and consequently affect the performance of spark-ignition (SI) engines. The stability of ethanol-gasoline-water blends is also discussed. Furthermore, the effects of hydrous ethanol, and its blends with gasoline fuel on SI engine combustion characteristics, cycle-to-cycle variations, engine performance parameters, and emission characteristics have been highlighted. Higher water solubility in ethanol‑gasoline blends may be obviously useful and suitable; nevertheless, the continuous ability of water to remain soluble in the blend is significantly affected by temperature. Nearly... [more]
Experimental Investigation on Wall Film Distribution of Dimethyl Ether/Diesel Blended Fuels Formed during Spray Wall Impingement
Hanzhengnan Yu, Xingyu Liang, Gequn Shu, Xu Wang, Yuesen Wang, Hongsheng Zhang
February 5, 2019 (v1)
Keywords: dimethyl ether (DME)/diesel blended fuels, early injection, lubricating oil film, spray wall impingement, wall film characteristics
Dimethyl ether (DME)/diesel blended fuels are used to improve the emissions caused by spray wall impingement during the early injection period. However, experimental results have showed that the spray wall impingement still cannot be avoided due to the engine structure and low density of the in-cylinder charge at the early injection timing. Furthermore, the wall film formed in the spray wall impingement process directly affects fuel/air mixture formation, combustion, exhaust emissions and oil quality subsequently. In this paper, the wall film distribution of DME/diesel blended fuels formed during the spray wall impingement process has been experimentally investigated. The variations of wall film distribution, wall film area and average thickness with different injection pressures, impingement distances, impingement angles and blending ratios have been discussed under both dry wall and wet wall conditions. Results showed that the wall film distribution styles were mainly determined by t... [more]
Spray Formation of a Liquid Carbon Dioxide-Water Mixture at Elevated Pressures
Hakduck Kim, Changyeon Kim, Heechang Lim, Juhun Song
February 5, 2019 (v1)
Keywords: coal gasification, flash atomization, liquid carbon dioxide (LCO2), solubility, water-LCO2 mixture
Liquid carbon dioxide-assisted (LCO₂-assisted) atomization can be used in coal-water slurry gasification plants to prevent the agglomeration of coal particles. It is essential to understand the atomization behavior of the water-LCO₂ mixture leaving the injector nozzle under various conditions, including the CO₂ blending ratio, injection pressure, and chamber pressure. In this study, the flash-atomization behavior of a water-LCO₂ mixture was evaluated with regard to the spray angle and penetration length during a throttling process. The injector nozzle was mounted downstream of a high-pressure spray-visualization system. Based on the results, the optimal condition for the effective transport of coal particles was proposed.
Investigation the Influence of Different Salts on the Degradation of Organic Dyes Using Non-Thermal Plasma
Ahmed El-Tayeb, Ahmed H. El-Shazly, Marwa F. Elkady
January 31, 2019 (v1)
Keywords: corona discharge, dye decolorization, non-thermal plasma (NTP), ozone generation, pin-to-plate, wastewater treatment
In dye decolorization tests a non-thermal plasma (NTP) corona discharge generated by a high voltage pin-to-ground plate displayed 82% color removal within 11 min. Total color removal was accomplished after 28 min. Different salts such as KCl, NaCl, CaCl₂ and AlCl₃ were utilized to check the influence of conductivity changes on the dye decolorization process. Higher dye solution conductivity improved the color removal efficiency. The discharge energy and degradation efficiency were computed for diverse concentrations for NaCl, KCl, CaCl₂ and AlCl₃, whereby it was noticed that the salts generally have a small impact on the level of dye decolorization using corona discharge. In addition, the essential reactive species involved in the oxidation of organic dye compounds such as ozone (O₃) generated in treated water and hydrogen peroxide (H₂O₂) were investigated and the energetic species that produced the non-thermal plasma at the optimum operation time were determined. Energy yields for dec... [more]
Promoting Effect of Inorganic Alkali on Carbon Dioxide Adsorption in Amine-Modified MCM-41
Yang Teng, Lijiao Li, Gang Xu, Kai Zhang, Kaixi Li
January 31, 2019 (v1)
Keywords: alkali amounts, amine-modified MCM-41, CO2 adsorption, inorganic alkali
Three kinds of inorganic alkali are introduced into tetraethylenepentamine (TEPA) and polyethyleneimine (PEI)-modified MCM-41 as the CO₂ adsorbents. X-ray diffraction, N₂ adsorption, fourier-transform infrared and thermo gravimetric analysis are used to characterize the surface structures and the thermal stability of adsorbents. Chemical titration method is used to measure the alkali amounts of adsorbents. Thermo-gravimetric analysis with 10% CO₂/90% N₂ as the simulated flue gas is used to test the CO₂ adsorption performance of adsorbents. The results show that all three kinds of inorganic alkali-containing adsorbents exhibit higher CO₂ adsorption capability than traditional TEPA and PEI modified samples. Ca(OH)₂ and PEI modified samples exhibit the highest adsorption capacity and recyclable property. The introduction of inorganic alkali changes the chemical adsorption mechanism between CO₂ and adsorbent surface due to the increased hydroxyl groups. The CO₂ adsorption capacities have a... [more]
Laminar Flame Characteristics of C1⁻C5 Primary Alcohol-Isooctane Blends at Elevated Temperature
Qianqian Li, Wu Jin, Zuohua Huang
January 7, 2019 (v1)
Keywords: empirical correlation, isooctane, laminar flame speed, Markstein length, oxygen content, primary alcohol
The laminar combustion characteristics of blends of isooctane and C1⁻C5 primary alcohols (i.e., methanol, ethanol, n-propanol, n-butanol and n-pentanol) were investigated using the spherical expanding flame methodology in a constant volume chamber at various equivalence ratios and volume fractions of alcohol. The stretch effect was removed using the nonlinear methodology. The results indicate that the laminar flame speeds of alcohol-isooctane blends increase monotonously with the increasing volume fraction of alcohol. Among the five alcohols, the addition of methanol is identified to be the most effective in enhancing laminar flame speed. The addition of ethanol results in an approximately equivalent laminar flame speed enhancement rate as those of n-propanol, n-butanol and n-pentanol at ratios of 0.8 and 1.5, and a higher rate at 1.0 and 1.2. An empirical correlation is provided to describe the laminar flame speed variation with the volume fraction of alcohol. Meanwhile, the laminar f... [more]
High Pressure Oxydesulphurisation of Coal—Effect of Oxidizing Agent, Solvent, Shear and Agitator Configuration
Moinuddin Ghauri, Khurram Shahzad, Abrar Inayat, Zulfiqar Ali, Waqar Ali Khan, Javaid Akhtar, Keith R. Cliffe
January 7, 2019 (v1)
Keywords: Coal, organic sulphur, oxydesulphurisation, pyritic sulphur
The ambient temperature high pressure oxydesulphurisation technique was investigated to reduce the sulphur content. Prince of Wales coal was chosen for this study. The focus of the study was to investigate the reduction of both pyritic and organic sulphur while changing the KMnO₄/Coal ratio, agitation speed, agitator configuration, and shear. The effect of different concentrations of acetone as a solvent and effect of particle size on the sulphur removal was also studied by a series of experimental runs at ambient temperature. Heating value recovery was found to be increased with the decreased KMnO₄/Coal ratio and with decreased acetone concentration. It was found that sulphur removal was enhanced with the increase in shear using a turbine impeller. The effect of particle size was more significant on the pyritic sulphur removal as compared to the organic sulphur removal while heating value recovery was found to increase with decreased desulphurization tome for both, under atmospheric a... [more]
Investigation into the Catalytic Activity of Microporous and Mesoporous Catalysts in the Pyrolysis of Waste Polyethylene and Polypropylene Mixture
Kaixin Li, Shao Wee Lee, Guoan Yuan, Junxi Lei, Shengxuan Lin, Piyarat Weerachanchai, Yanhui Yang, Jing-Yuan Wang
November 28, 2018 (v1)
Keywords: catalytic pyrolysis, mesoporous catalyst, microporous catalyst, plastic recycling, polyethylene (PE), polypropylene (PP)
Catalytic pyrolysis behavior of synthesized microporous catalysts (conventional Zeolite Socony Mobil⁻5 (C-ZSM-5), highly uniform nanocrystalline ZSM-5 (HUN-ZSM-5) and β-zeolite), Mesoporous catalysts (highly hydrothermally stable Al-MCM-41 with accessible void defects (Al-MCM-41(hhs)), Kanemite-derived folded silica (KFS-16B) and well-ordered Al-SBA-15 (Al-SBA-15(wo)) were studied with waste polyethylene (PE) and polypropylene (PP) mixture which are the main constituents in municipal solid waste. All the catalysts were characterized by Brunauer-Emmett-Teller (BET), X-ray powder diffraction (XRD), and NH3-temperature programmed desorption (TPD). The results demonstrated that microporous catalysts exhibited high yields of gas products and high selectivity for aromatics and alkene, whereas the mesoporous catalysts showed high yields of liquid products with considerable amounts of aliphatic compounds. The differences between the microporous and mesoporous catalysts could be attributed to t... [more]
Hydrothermal Conversion of Neutral Sulfite Semi-Chemical Red Liquor into Hydrochar
Ramy Gamgoum, Animesh Dutta, Rafael M. Santos, Yi Wai Chiang
November 28, 2018 (v1)
Keywords: ash content, higher heating value, hydrochar, hydrothermal conversion, red liquor, thermogravimetric analysis
Hydrochar was produced from neutral sulfite semi-chemical (NSSC) red liquor as a possible bio-based solid fuel for use in power generation facilities. Hydrothermal conversion (HTC) experiments were conducted using a fixed liquor-to-water volume ratio of 1:8 and reaction time of 3 h. Solutions were processed using different chemical additives, pH and temperature conditions to determine the optimum conditions required for producing a high energy content solid fuel. The hydrochar samples produced were analyzed by ultimate, thermogravimetric (TGA) and Fourier transform infrared spectroscopy (FTIR) analyses to determine physicochemical properties that are important for utilization as a fuel. The residual process liquids were also analyzed to better understand the effect of HTC process conditions on their properties. It was determined that the optimum conditions for producing a solid fuel was at a reaction temperature of 250 °C, in the presence of acetic acid at pH 3. The maximum energy cont... [more]
Distribution of Clay Minerals in Light Coal Fractions and the Thermal Reaction Products of These Clay Minerals during Combustion in a Drop Tube Furnace
Sida Tian, Yuqun Zhuo, Zhonghua Zhan, Xinqian Shu, Zhizhong Kang
November 28, 2018 (v1)
Keywords: aluminosilicate components, ash formation, coal slagging characteristics, density separation, mineral matter distribution
To estimate the contribution of clay minerals in light coal fractions to ash deposition in furnaces, we investigated their distribution and thermal reaction products. The light fractions of two Chinese coals were prepared using a 1.5 g·cm−3 ZnCl₂ solution as a density separation medium and were burned in a drop-tube furnace (DTF). The mineral matter in each of the light coal fractions was compared to that of the relevant raw coal. The DTF ash from light coal fractions was analysed using hydrochloric acid separation. The acid-soluble aluminium fractions of DTF ash samples were used to determine changes in the amorphous aluminosilicate products with increasing combustion temperature. The results show that the clay mineral contents in the mineral matter of both light coal fractions were higher than those in the respective raw coals. For the coal with a high ash melting point, clay minerals in the light coal fraction thermally transformed more dehydroxylation products compared with those i... [more]
Experimental Attempts to Investigate the Influence of Petrographic Properties on Drying Characteristics of Lignite in Superheated Steam Atmosphere
Anna Sciazko, Yosuke Komatsu, Marcin Zakrzewski, Taro Akiyama, Akira Hashimoto, Naoki Shikazono, Shozo Kaneko, Shinji Kimijima, Janusz S. Szmyd, Yoshinori Kobayashi
November 27, 2018 (v1)
Keywords: drying characteristic, lignite upgrading, low-rank coal (LRC), superheated steam drying, Turow lignite
A superheated steam fluidized bed dryer (SSFBD) in a self-heat recuperative configuration has a great potential of improving thermal efficiency of a lignite-fired power plant by recovering both of latent heat of vaporization of water kept in the fuel and part of sensible heat during the fuel processing. However, the optimal design of the dryer requires the fundamental knowledge of drying characteristics in respect to the individual properties of the utilized fuel. Experimental investigation to determine the correlation between a specific coal properties originated from geological background and its drying characteristics is thus the major concern in this paper. The investigated lignite is a representative of Turoszow deposit in Poland. Experimental attempts unveiling drying kinetics were carried out for 5 mm and 10 mm diameter spherical samples in the superheated steam atmosphere in the temperature range of 110 °C⁻170 °C. Simultaneous and continuous measurements of changes in weight, s... [more]
Solar Hydrogen Production via a Samarium Oxide-Based Thermochemical Water Splitting Cycle
Rahul Bhosale, Anand Kumar, Fares AlMomani, Ujjal Ghosh, Mohammad Saad Anis, Konstantinos Kakosimos, Rajesh Shende, Marc A. Rosen
November 27, 2018 (v1)
Keywords: computational analysis, Hydrogen, samarium oxide, solar thermochemical, thermodynamics, water splitting
The computational thermodynamic analysis of a samarium oxide-based two-step solar thermochemical water splitting cycle is reported. The analysis is performed using HSC chemistry software and databases. The first (solar-based) step drives the thermal reduction of Sm₂O₃ into Sm and O₂. The second (non-solar) step corresponds to the production of H₂ via a water splitting reaction and the oxidation of Sm to Sm₂O₃. The equilibrium thermodynamic compositions related to the thermal reduction and water splitting steps are determined. The effect of oxygen partial pressure in the inert flushing gas on the thermal reduction temperature (TH) is examined. An analysis based on the second law of thermodynamics is performed to determine the cycle efficiency (ηcycle) and solar-to-fuel energy conversion efficiency (ηsolar−to−fuel) attainable with and without heat recuperation. The results indicate that ηcycle and ηsolar−to−fuel both increase with decreasing TH, due to the reduction in oxygen partial pre... [more]
Performance of Natural Ester as a Transformer Oil in Moisture-Rich Environments
Kapila Bandara, Chandima Ekanayake, Tapan Saha, Hui Ma
November 27, 2018 (v1)
Keywords: acidity, ageing, colour, dielectric dissipation factor (DDF), hydrolysis, mineral oil, natural ester (NE), oxidation, viscosity
Interest has risen among utilities in using natural ester (NE) insulating oils in transformers as a substitute for conventional mineral oil. However, present understanding on aging behaviour of NE-paper composite insulation system and knowledge on application of existing condition monitoring tools for NE-based insulation are inadequate. This limits the cost effective and reliable field applications of NE insulating oil. To pave the way the application of NE-based insulation in transformers, a systematic study has been performed to compare the aging behaviour of transformer grade pressboard (PB) impregnated in NE and conventional mineral oil. Applicability of a number of chemical and physical parameters, including acidity value, dielectric dissipation factor (DDF), viscosity, and colour for assessing the quality of NE insulating oil is also discussed in this paper. Comparisons are made based on the limiting values provided in the related IEEE Standard and properties of mineral oil under... [more]
An Experimental Study on the Potential Usage of Acetone as an Oxygenate Additive in PFI SI Engines
Lei Meng, Chunnian Zeng, Yuqiang Li, Karthik Nithyanandan, Timothy H. Lee, Chia-fon Lee
November 27, 2018 (v1)
Keywords: acetone, Ethanol, Gasoline, PFI, SI engine
To face the challenges of fossil fuel shortage and stringent emission norms, there is growing interest in the potential usage of alternative fuels such as bio-ethanol and bio-butanol in internal combustion engines. More recently, Acetone⁻Butanol⁻Ethanol (ABE), the intermediate product of bio-butanol fermentation, has been gaining a lot of attention as an alternative fuel. The literature shows that the acetone in the ABE blends plays an important part in improving the combustion performance and emissions, owing to its higher volatility. Acetone and ethanol are the low-value byproducts during bio-butanol production, so using acetone and ethanol as fuel additives may have both economic and environmental benefits. This study focuses on the differences in combustion, performance and emission characteristics of a port-injection spark-ignition engine fueled with pure gasoline (G100), ethanol-containing gasoline (E10 and E30) and acetone-ethanol-gasoline blends (AE10 and AE30 at A:E volumetric... [more]
Showing records 1 to 25 of 58. [First] Page: 1 2 3 Last
[Show All Subjects]