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About this book

This collection addresses the need for sustainable technologies with reduced energy consumption and pollutants and the development and application of alternative sustainable energy to maintain a green environment and energy supply. Contributions focus on energy-efficient technologies including innovative ore beneficiation, smelting technologies, and recycling and waste heat recovery, as well as emerging novel energy technologies. Papers also cover various technological aspects of sustainable energy ecosystems, processes that improve energy efficiency, reduce thermal emissions, and reduce carbon dioxide and other greenhouse emissions.

Papers from the following symposia are presented in the book:

Energy Technologies and Carbon Dioxide Management

Solar Cell Silicon

Advanced Materials for Energy Conversion and Storage

Table of Contents

Frontmatter

2019 Energy Technologies and Carbon Dioxide Management Symposium

Frontmatter

Analysis on Energy Efficiency and Optimization of HIsmelt Process

HIsmelt process is a clean and efficient iron-making technology. The production of the first HIsmelt commercial plant of China, which was built in 2016, is stable at present, and remarkable results have been achieved in environmental protection and production cost aspects. The energy efficiency and its main influencing factors of HIsmelt process were systematically analyzed in this paper, combining with China’s HIsmelt plant production practice. It has been pointed out that the main restrictive factors are the high efficient utilization of high temperature and low calorific value SRV off-gas to further improve the energy efficiency of HIsmelt . It introduced the process improvement and optimization of the HIsmelt plant in China, around the hot air blast position control, iron ore powder preheating , gas purification, and waste heat recovery.
Chao-zhen Cao, Yu-jie Meng, Fang-xing Yan, Dian-wei Zhang, Xin Li, Fu-ming Zhang

The Characterizations of Hydrogen from Steam Reforming of Bio-Oil Model Compound in Granulated Blast Furnace Slag

The purpose of this research investigating the characterizations of steam reforming of bio-oil model compound in granulated BF (blast furnace) slag was to recover waste heat and obtain hydrogen . The results indicated that hydrogen yield and hydrogen fraction first increased and then decreased with the increase of temperature. When S/C increased, hydrogen yield and hydrogen fraction increased. But they decreased with the increasing LHSV. Hydrogen yield and hydrogen fraction were 1.68 m3 per kg of bio-oil model compound and 65.39% at the optimum condition with the temperature, S/C and LHSV reaching 750 °C, 9, and 0.9 h−1, respectively. Granulated BF slag containing metallic oxides as CaO and Fe2O3 could promote hydrogen yield and hydrogen fraction, so it was regarded as an excellent heat carrier for the reaction of steam reforming of bio-oil model compound .
Xin Yao, Qingbo Yu, Guowei Xu, Qin Qin, Ziwen Yan

Feasibility of a District Heating System in Fjardabyggd Using Waste Heat from Alcoa Fjardaal

The Alcoa Fjarðaál smelter in Iceland consumes 4600 GWh annually to produce aluminum. About 50% of the total energy absorbed by the cells is reduced to waste heat of which roughly 40% is currently lost through exhaust gases . The exhaust gases leave the cells at about 110 °C before entering the gas treatment center (GTC). The feasibility of operating heat exchangers upstream of GTCs has been demonstrated at other smelters. Reyðarfjordur, which is 5.5 km from Fjarðaál currently uses electricity for domestic heating, like other surrounding communities. Previous research has shown that the waste heat from Fjarðaál is more than enough to supply space heating for the local community. This paper will address the technical challenges and suggest solutions to deliver heat in a closed-loop heating circuit from the Fjarðaál plant to Reydarfjordur and estimate the total investment cost for the heat regeneration system.
Leo Blaer Haraldsson, Gudrun Saevarsdottir, Maria S. Gudjonsdottir, Gestur Valgardsson

Research and Application on Waste Heat Recycling and Preheating Technology of Iron-Making Hot Blast Stove in China

China is the country with the largest steel output in the world. During the process of iron making, the blast furnace consumes a lot of energy. The hot blast stove system is an important system for providing high-temperature hot air to the blast furnace, and its energy utilization efficiency has an important influence on energy conservation and emission reduction. This paper analyzed and compared the use effect, thermal efficiency, technical characteristics, and development prospects of different waste heat recycling technology, based on the research and application of different waste heat recovery and utilization methods of hot blast stove system in different projects, such as tubular heat exchangers, heat pipe exchangers, plate heat exchangers, preheating furnaces, and combined preheating methods. Furthermore, this paper gave some recommendations for the future development path of waste heat recycling technology of hot blast stove system.
Xin Li, Fuming Zhang, Guangyu Yin, Chaozhen Cao

Influence of Proportion of Pellet on Burden Distribution

Based on the movement analysis of burden in charging, a mathematical model of bell-less burden distribution is established to study the burden distribution in the furnace. The mathematical model consists of three sub-models: the material trajectory model, burden profile model, and burden descent model. The novel fitting formula that chute inclination angle and ratio of mixed ore affect the inner angle and outer angle of repose is proposed. The influence of pellet and sinter shapes on the inner angle and outer angle of repose of the ore is considered by introducing a correction coefficient. The modified fitting relation is applied to the mathematical model for bell-less blast furnace to analyze the influence of the proportion of pellet on the surface shape and radial distribution of ore–coke ratio under the same burden matrix. The influence rule of mixed ore ratio on burden distribution is obtained, which provides basis for adjusting the upper part of blast furnace.
Jiansheng Chen, Haibin Zuo, Jingsong Wang, Qingguo Xue, Jiapeng Liang

High-Temperature Online Reforming of Converter Gas with Coke Oven Gas

A large amount of by-product gas containing abundant physical heat and excessive quantity of carbon dioxide (CO2) is generated during the iron and steel production. Through the high-temperature online reforming of the by-product gas with coke oven gas , generated physical heat and CO2 can be completely utilized to achieve efficient use of energy and reduction of CO2 emission, respectively, and high-quality chemical synthesis gas can be acquired simultaneously. The thermodynamic behavior of the reforming of converter gas with coke oven gas was analyzed based on Gibbs energy minimization method. The thermodynamic calculation model was proposed and utilized to describe the effect of temperature, pressure, and ratio of converter gas to coke oven gas on conversion rate of CO2 and methane (CH4) and ratio of H2 to CO of the product gas. High temperature and low pressure were found to be the favorable thermodynamic condition for reforming process. Ratio of H2 to CO of product gas was significantly influenced by initial composition of reactant gases. Moreover, the reforming reaction was investigated by performing the mixed reforming experiments under the condition of high temperature to provide theoretical and experimental basis for the realization of industrialization.
Binglang Ren, Lin Lin, Jingsong Wang

Preparation and Characterization of Manganese-Based Catalysts for Removing NO Under Low Temperatures

Selective catalytic reduction of NOx with loaded urea (urea-SCR) is a promising technology to remove NOx from the low-temperature metallurgical sintering flue gas. In present work, a series of nutshell-based activated carbon (nu-AC) supported MnOx catalysts with loading urea were synthesized by ultrasound-assisted impregnation, and the physicochemical properties of catalysts were detected by XRD, SEM , EDS, GFAAS, BET, and XPS. Besides, NO adsorption capacity and the influences of reaction temperature, activated carbon particle size, metal oxides loading, and urea loading on catalytic activity were studied through experiment. The results of NO adsorption tests show that the adsorption capacity of nu-AC is limited, and the adsorption capacity decreases with increasing temperature. Catalytic performance test results indicate that the catalyst with 12% MnOx and 6% urea shows the best performance, giving nearly 90% NO conversion at 50 °C. Finally, the reaction mechanism of low-temperature urea-SCR for manganese-based catalyst was discussed.
Kaijie Liu, Qingbo Yu, Junbo San, Zhicheng Han, Qin Qin

Simultaneous CO2 Sequestration of Korean Municipal Solid Waste Incineration Bottom Ash and Encapsulation of Heavy Metals by Accelerated Carbonation

The aim of this work was to evaluate the amount of CO2 that could be sequestered with a view to decrease greenhouse gas emissions and investigate the feasibility of modernizing some specific properties of the municipal solid waste incineration bottom ash with accelerated carbonation. Municipal solid waste incineration (MSWI) fly ash and bottom ashes are the byproducts of the incineration combustion process. We collected the different samples from four incineration plants located in Seoul. Some of the Korean MSWI byproducts contain heavy metals . Here, we reported encapsulation effect of some heavy metals such as arsenic (As), chromium (Cr), cadmium (Cd), lead (Pb), and nickel (Ni) in MSWI ashes by accelerated carbonation process. The carbonation reaction would promote CO2 sequestration . In this paper, we reported the simultaneous CO2 sequestration of municipal solid waste incineration byproducts and encapsulation studies of heavy metals . The investigations were carried out at the bench scale. Finally, an efficient removal of heavy metals (90–95%) was achieved.
T. Thriveni, Ch. Ramakrishna, Ahn Ji Whan

Effect of Biomaterial (Citrullus Lanatus Peels) Nanolubricant on the Thermal Performance and Energy Consumption of R600a in Refrigeration System

The study experimentally investigated the combinatorial impact of bio-based nanoparticles from agriculture waste of Citrullus Lanatus (watermelon) peels on the improvement of thermal performance and energy consumption of R600a as an alternative refrigerant to environment malignant R134a in a domestic refrigeration system. The thermodynamic system includes Copeland 46B/R600a or R134a as control and bio-based nanolubricant /R600a at different concentrations as test samples. The outcome showed that despite the results of coefficient of performance and pull-down time for the conventional R134a refrigerant fluid system, the R600a and its nanorefrigerant fluid variants performed better in terms of energy consumption, cooling capacity, and quantity of heat absorbed and expelled. Thus, reconfiguration of the thermodynamic system with bio-based nanoparticles had effect on the performance and improvement of R600a as a worthy refrigerant alternative to R134a.
Oluseyi O. Ajayi, Caleb C. Aba-Onukaogu, Enesi Y. Salawu, F. T. Owoeye, D. K. Akinlabu, A. P. I. Popoola, S. A. Afolalu, A. A. Abioye

Performance and Energy Consumption Analyses of R290/Bio-Based Nanolubricant as a Replacement for R22 Refrigerant in Air-Conditioning System

The study investigated the comparative thermal performance and energy saving abilities of environment-malignant R22 and eco-friendly R290 refrigerants in a domestic air-conditioning system. It focused on studying the effect that the thermodynamic (fluid) system has on the performance indices of the refrigerants. The fluid system was reconfigured to include bio-based (Citrullus Lanatus peels (watermelon peels)) nanoparticles, dispersed in Capella D oil at different concentrations of (0.05, 0.1, and 0.2) vol%. Various performance analyses such as cooling capacity (CC), energy consumption, coefficient of performance (COP), thermal conductivity and viscosity were considered. The results showed that R22 performed better than R290 in terms of COP and CC while R290 was preferred considering energy consumption and other thermodynamic performance variables. However, when the thermodynamic system was reconfigured to contain the bio-based nanoparticles, the outcome showed that the nanoparticles subsequently improved the overall thermodynamic performance and energy consumption of R290.
Oluseyi O. Ajayi, Teddy I. Okolo, Enesi Y. Salawu, F. T. Owoeye, D. K. Akinlabu, E. T. Akinlabi, S. T. Akinlabi, S. A. Afolalu

Characterizations of Manganese-Based Desulfurated Sorbents for Flue-Gas Desulfurization

For the application of dry flue-gas desulfurization , Mn2O3/SiC desulfurated sorbents with various manganese contents are prepared by the sol–gel method . The desulfurization performance of the sorbents is evaluated by a fixed-bed reactor with the simulated flue gas. X-ray diffraction and scanning electron microscope are adopted to characterize the crystalline phases and microstructure of the sorbents, respectively. For all the sorbents, the SO2 removal efficiency is above 93%, attributed to the nanoscale oval-shaped Mn2O3. For the sorbent with a manganese content of 50%, its breakthrough time reaches 27 min, benefiting from the uniform dispersion of SiC and Mn2O3. Compared to the sorbents with SiC , the breakthrough time of pure Mn2O3 is much shorter, resulting from the agglomeration of active component. Choosing Mn2O3 as the active component and SiC as the supporter to remove SO2 from flue gas has the obvious advantages of high SO2 removal efficiency rate.
Yanni Xuan, Qingbo Yu, Kun Wang, Wenjun Duan, Qin Qin

The Manganese-Based Zirconium (Zr) and Chromium (Cr) Polymeric Pillared Interlayered Montmorillonite for the Low-Temperature Selective Catalytic Reduction of NOx by Ammonia (NH3) in Metallurgical Sintering Flue Gas

The manganese-based Zr and Cr polymeric pillared interlayered montmorillonite (Mn/Zr-Cr-PILM) with various Zr/Cr ratio as carrier supported MnOx were used in the selective catalytic reduction of NOx by NH3 (NH3-SCR) in metallurgical sintering flue gas. The X-ray diffraction (XRD), N2 adsorption–desorption isotherm, and ammonia temperature-programmed desorption (NH3-TPD) were used to analyze the catalyst physicochemical property. The Mn/Zr-Cr-PILM (1:3) had the highest NOx conversion between 140 and 180 °C compared with other catalysts. This was due to the large specific surface area and a large amount of Lewis acid sites provided more reaction platform and more adsorption sites for the catalytic reaction. However, as the proportion of Cr increased in Mn/Zr-Cr-PILM, the N2 selectivity of the catalyst decreased rapidly with the increasing temperature, except for Mn/Zr-Cr-PILM (3:1). It may be that the entry of chromium oxide into the zirconium oxide crystal phase in Mn/Zr-Cr-PILM (3:1) inhibited the production of N2O for increasing the N2 selectivity.
Zhicheng Han, Qingbo Yu, Kaijie Liu, Huaqing Xie, Qin Qin

Characterization of Polymeric Solutions with TiO2 Photocatalytic Conversion Efficiency Exposed to Different CO2 Sources

Atmospheric pollution is the main environmental and health hazard in several countries, and the World Health Assembly approved the WHA68.8 resolution in which were PM10, PM2.5, NO2, O3, and SO2 are identified as the main regulated atmospheric pollutants. Thus, the present paper characterizes the photocatalytic reaction efficiency of two polymeric solutions (used as vinylic and waterproofing paint ) that have TiO2 as photocatalytic active when being exposed to different CO2 sources . Using an Air Pollution Monitor for measuring NOx, SOx, and CO2, the decreasing of this pollutant was proved. In addition, SEM (Scanning Electron Microscopy) was used for measuring the adherence quality of the paint to the substrate and the changes in the surfaces where the solutions were applied. It was found the conversion velocity was greater when the CO2 was emitted by a vehicle than when coming from a polymer combustion.
Aline Hernández, Natalia Loera, Gerardo Pérez, Francisco Blockstrand

Comparison Between Lactuca sativa L. and Lolium perenne: Phytoextraction Capacity of Ni, Fe, and Co from Galvanoplastic Industry

Heavy metals stay in the environment for large periods of time, which contribute to them being highly toxic and are associated to illness in human beings and biodiversity reduction. The present paper used Lactuca sativa L. and Lolium perenne to remove heavy metals from galvanoplastic waste polluted soil. Nickel, Cobalt, and Iron (adsorbents) from galvanoplastic waste were chosen as parameters in the biosorbents (roots, stem, and leaves). Particle size phytoextracted by L. sativa L. and L. perenne were analyzed using SEM (Scanning Electron Microscopy) and Atomic Absorption Spectroscopy (AA). It was determined that L. sativa L. has a greater absorption capacity, but a lower intrinsic velocity than L. perenne . The greatest survival time was presented by L. perenne .
Aline Hernández, Natalia Loera, María Contreras, Luis Fischer, Diana Sánchez

Determination of Crystallite Size and Its Effect on Sulfur Content, CO2 Reactivity, and Specific Electrical Resistance of Coke

The average crystallite size (LC) is an important property of carbon materials for aluminum electrolysis. LC is a useful factor to characterize the petroleum coke (PC) calcination level and in some cases to estimate the baking level of anodes. CO2 reactivity of coke and specific electrical resistance (SER) are two important parameters in manufacturing of anode in aluminum industries. In addition, the amount of sulfur and calcination temperature of coke is very effective factors playing an impressive role in the quality of anode. It is demonstrated that coke calcination with different sulfur levels can affect LC , CO2 reactivity, and specific electrical resistance (SER). Many types of coke samples calcinated in different temperatures were examined in this study. The results showed that increasing sulfur percentage will lead to rise in LC level; however, it had a reverse effect on both CO2 and SER reactivity. All obtained results were compared and the researchers believe that the best range of LC is between 29.5  and 33.5 A°.
Saeb Sadeghi, Mohsen Ameri Siahooei, Sid Hadi Sajadi, Borzu Baharvand

Determination of Limiting Current Density, Plateau Length, and Ohmic Resistance of a Heterogeneous Membrane for the Treatment of Industrial Wastewaters with Copper Ions in Acid Media

In the last years, the electrodialysis process has been considered as an alternative to the chemical precipitation for the treatment of wastewaters from electroplating industries due to some limitations involved in the precipitation, as the sludge formation. For the success of the electrodialysis , some membranes properties have to be evaluated and the chronopotentiometry technique can be used. Hence, the present paper aimed at using chronopotentiometry for determining the limiting current density, plateau length, and ohmic resistance of the cationic heterogeneous HDX100 membrane by constructing current–voltage curves. The synthesized solution of the effluent from the electroplating industry evaluated was prepared with copper sulfate and sulfuric acid (2 g Cu2+/L and pH 2). The chronopotentiometric curves were also evaluated for the study of the precipitate formation. According to the results, typical curves of monopolar membranes were obtained and the properties could be effectively determined by chronopotentiometry .
K. S. Barros, J. A. S. Tenório, V. Pérez-Herranz, D. C. R. Espinosa

Effect of pH and Potential in Chemical Precipitation of Copper by Sodium Dithionite

The aim of this work was to study the effect of pH and potential in copper precipitation from nickel laterite leach solution. A synthetic solution was prepared to simulate the real conditions and sodium dithionite was used as reducing agent. The effect of pH was studied between pH 0.50 and 3.50. Sodium dithionite 1 mol/L was added to decrease the potential. The stirring speed was 45 rpm and reaction time was 45 min. Results indicated that copper precipitation decreased when pH increases. Copper precipitation was selective in 240 mV at pH 0.50–1.50. Co-precipitation was observed in experiments performed in pH above 2.00.
I. A. Anes, A. B. Botelho Junior, D. C. R. Espinosa, J. A. S. Tenório

Study of Separation Between CO with H2 on Carbon Nanotube by Monte Carlo Simulation in Aluminum Smelter

CO is very toxic gas, hence the separation of this gas is very important. In this study, the separation of CO and H2 has been studied. Prevent the emission of carbon monoxide in the environment is very important. In this study, Lennard–Jones potential was used for gas–gas and gas–carbon nanotube interactions, and the potential parameters for the carbon–gas and carbon–carbon interactions were obtained from the Lorenz–Berthelot combining rules. The study has been done by using the equation state of Virial and finding the second coefficient in Virial equation. Final steps were the inside density, outside density, and total density of nanotubes, and my calculation result shows that this separation is possible.
Mohsen Ameri Siahooei, Borzu Baharvand, Alireza Fardani, Mokhita Vahedi Zade, Sid Hadi Sajadi

Vinylic and Waterproofing Paint with TiO2 as Photocatalytic Active Effects in Lolium Perenne Germination

There are studies that show the presence of TiO2 nanoparticles may have ecotoxic consequences in vegetable species germination process, even though benefits of TiO2 have been found as a photocatalytic active for CO2 conversion into O2 reducing the concentration of this greenhouse effect gas. The present paper aims to analyze the Lolium perenne germination and its growing when being exposed to vinylic and waterproofing paint with TiO2 active, concentration curves of CO2 and O2 were determined, in addition to L. perenne growing as being exposed to the active. Seeds, seedling, and the former L. perenne plant were analyzed to determine the presence of Ti using SEM and EDS-RX microanalysis to determine if it is possible to use TiO2 as a CO2 remediator without repercussions in vegetable species such as L. perenne .
Aline Hernández, Natalia Loera, Gerardo Pérez, Francisco Blockstrand

Solar Cell Silicon

Frontmatter

The Influence of Boron Dopant on the Structural and Mechanical Properties of Silicon: First Principles Study

Boron (B) is usually used to produce p-type silicon to form the base layer in wafer-based silicon solar cells . The main objective of this work is to investigate the influence of B doping on the structural and mechanical properties of silicon . Using CASTEP program, which uses the density functional theory (DFT), with a plane wave basis, the structural, electronic, and mechanical properties of pure Si and the solid solution Si1−xBx (0.0001 ≤ x ≤ 0.05) were studied. The structure, density of states, band structure, and elastic properties were computed. It is found that as B concentration increases, the lattice constant increases, Bulk modulus (B), Shear modulus (G), and Young modulus (E) decreases. The ratio G/B decreases and Poisson’s ratio (ν) increases. The decrease of G/B and increase of ν mean that brittleness of Si decreases by increasing B concentration.
Shadia Ikhmayies, Yasemin Ö. Çiftci

The Influence of Phosphorus Dopant on the Structural and Mechanical Properties of Silicon

Phosphorus (P) is widely used as n-type dopant for silicon (Si) to form the emitter layer in wafer-based silicon solar cells . The main purpose of this work is to investigate the influence of P doping on the structural and mechanical properties of silicon . CASTEP program, which uses the density functional theory (DFT), with a plane-wave basis, is used to study the structural, electronic, and mechanical properties of undoped and P-doped Si (Si1−xPx for 0.0001 ≤ x ≤ 0.05). The density of states (DOS), band structure, elastic constants, bulk modulus \( \left( B \right) \), Young’s modulus (E), Shear modulus \( \left( G \right) \), and Poisson’s ratio (v) were all calculated. It is found that brittleness of Si increased by P doping .
Shadia Ikhmayies, Yasemin Ö. Çiftci

Simple and Highly Effective Purification of Metallurgical-Grade Silicon Through Metal-Assisted Chemical Leaching

The present study proposed a simple and highly effective method for removal of impurities from large-sized particle metallurgical-grade silicon (MG-Si) powders based on metal-assisted chemical leaching (MACL). The various leaching approaches (MACL, HF + H2O2 leaching, HF leaching, HCl leaching) were investigated for leaching behaviors of the main impurities (Fe, Al, Ca, Ti, Ni, V, Mn, and Cu). The leaching results show that the order of impurities’ removal efficiency, from highest to lowest, is MACL > HF − H2O2 leaching > HF leaching > HCl leaching. After MACL, The numerous micro-scale “channels” introduced by MACL which are beneficial for the removal of impurities, especially for the non-dissolving metal impurities, such as copper , calcium, and aluminum. It should be noted that the small amount of Cu mainly come from residual Cu nanoparticle and can be removed by simple acid washing.
Fengshuo Xi, Shaoyuan Li, Wenhui Ma, Kuixian Wei, Jijun Wu, Keqiang Xie, Yun Lei, Zhengjie Chen, Jie Yu, Xiaohan Wan, Bo Qin

Wettability Behavior of Si/C and Si–Sn Alloy/C System

During the Si growth process in the zone melting directional solidification experiment, the wettability behavior of Si source/solvent metal and solvent metal/seed substrate is an important issue for Si purification and growth. In this work, the wettability behavior of Si/C and Si-90 wt% Sn alloy/C system was studied by using the sessile drop method. The results show that Si and Si–Sn alloy wet C substrate , and the wettability gradually improves with the holding time due to the generation of a SiC layer in the metal/C interface and the infiltration Si or Si–Sn alloy into C substrate . Moreover, the addition of Sn into Si melt is beneficial for Si to wet C substrate , because Sn hinders the generation of SiC and Si promotes Sn wetting C substrate .
Yaqiong Li, Lifeng Zhang

Phase Diagrams of Al–Si System

Thermo-Calc software was used to deduce the phase diagram of the Al–Si binary system , which is a necessary step to understand the more complicated systems containing Si–Al binary. The phase diagram contains two solid solution phases (α-Al) (FCC_Al) and diamond cubic Si (Diamond-A4), a liquid phase, and three mixed phases; FCC_Al + Diamond-A4, liquid + FCC_Al, and liquid + Diamond A4. The melting points of Al and Si are 932.77 and 1687.73 K (659.62 and 1414.58 °C), respectively. From the phase diagram, the eutectic reaction occurs at 12.49 mass percent Si and 850.22 K (577.07 °C). The maximum solubility of Si in Al occurs at the eutectic temperature and 1.547 mass percent Si, and that of Al in Si occurs at 0.1576 Al mass percent at 950.22 K (677.07 °C).
Shadia Ikhmayies

The Separation of Refined Silicon by Gas Pressure Filtration in Solvent Refining Process

The separation of refined silicon by gas pressure filtration combined with solvent refining was studied. The purified silicon grains were separated by gas pressure filtration under a pressure differential of 0.2 MPa. In all of the systems, Al–40%Si, Sn–40%Si, Cu–40%Si, and Fe–80%Si, the effect of separation temperature (T) on separation efficiency was evaluated. In Al–40%Si alloy, the silicon content in separated silicon was 91.3 wt% and the recovery rate of silicon was 97.6%, at T = 600 °C. In Sn–40%Si alloy, almost all of the silicon was retained, and the silicon content in separated silicon was 79.4 wt% at T = 600 °C. For Cu–40%Si alloy and Fe–80%Si alloy, the silicon content in separated silicon was over 75 wt% under high superheat. With efficient removal of impurities, the combination of gas pressure filtration and solvent refining is a promising method.
Tianyang Li, Lei Guo, Zhe Wang, Zhancheng Guo

5th Symposium on Advanced Materials for Energy Conversion and Storage

Frontmatter

Comparison of Solar-Selective Absorbance Properties of TiN, TiNxOy, and TiO2 Thin Films

TiN , TiNxOy , and TiO2 thin films share many properties such as electrical, and optical properties . In this work, a comparison is made between TiN , TiNxOy , and TiO2 thin films deposited by RF magnetron sputtering (reactive sputtering) using the same pure titanium target, Argon (Ar) flow rate, nitrogen flow rates, and deposition time. In the case of TiNxOy thin film, oxygen is pumped in addition. TiO2 is obtained by annealing the sputtered TiN thin films, which were subsequently annealed at 800 °C for 2 h in air after sputtering. The optical properties of the thin films were characterized by a spectrophotometer, and Fourier-transform infrared spectroscopy (FTIR). The morphology and structure were studied by scanning electron microscope (SEM ), atomic force microscope (AFM), and X-ray diffraction (XRD). The results show that TiN and TiNxOy thin films have metal-like behaviour with some similarities in structure and microstructure and differences in optical absorbance. After annealing the TiN layer, the optical absorbance of the TiO2 is equal to 94% with a stable profile at ultraviolet, visible, and near infrared ranges.
Hanan Abd El-Fattah, Iman El Mahallawi, Mostafa Shazly, Waleed Khalifa

Electrophoretically Deposited Copper Manganese Spinel Coatings for Prevention of Chromium Poisoning in Solid Oxide Fuel Cells

Cr2O3 scales formed on ferritic steel interconnects in intermediate temperature solid oxide fuel cell (SOFC) stacks have the problem of Cr-poisoning that can deteriorate cell performance. Applying a protective coating on the surface of the interconnects is an effective strategy to solve this problem. (CuMn)3O4 spinel is a potential candidate-coating material. In this study, the performance of the CuMn1.8O4 at 750 °C, the conductivities of the reaction layer formed between the coating and Cr2O3 scale, and the reduction of Cr ion diffusivity in Ni-doped (CuMn)3O4 were explored. CuMn1.8O4 coatings were found to be good Cr diffusion barriers at 750 °C, with the coatings also acting as an excellent Cr getter. The conductivities of the reaction layer were found to be at least two orders of magnitude higher than that of Cr2O3, indicating the formation of the reaction layer is favorable compared to the thickening of the Cr2O3 scale at the coating/alloy interface. Ni-doped of (CuMn)3O4 decreased the diffusivity of Cr, making (CuMnNi)3O4 a promising candidate-coating material.
Zhihao Sun, Srikanth Gopalan, Uday B. Pal, Soumendra N. Basu

Observations on Accelerated Oxidation of a Ferritic Stainless Steel Under Dual Atmosphere Exposure Conditions

Iron-base alloys, conventionally used for the fabrication of cell-to-cell interconnects , undergo localized oxide scale overgrowth when exposed to a bipolar atmospheric condition, in which one side of the metal is exposed to a reducing gas and the opposing side is exposed to an oxidant. The phenomenon, coined “dual atmosphere corrosion”, is prevalent in many electrochemical and thermochemical systems where separation of fuel and oxidant gas streams is required. It is apparent that hydrogen exposure and the existence of a dual atmosphere plays a key role, as metals exposed to single atmospheres of reducing or oxidizing gases do not show the extent of oxide scale overgrowth . The exact role that hydrogen plays in accelerated iron oxide growth on the air-exposed side of metals , however, remains largely unknown. Experimental results from oxidation tests conducted on a select ferritic stainless steel under dual atmosphere exposure conditions are presented. After 50 h in dual atmosphere , the ferritic steel had an extensive iron oxide scale with a particular needle-like growth morphology. In comparison, the same steel in dry air for 50 h only showed uniform scale growth and absence of iron oxide nodules. These results along with thermodynamic driving forces are discussed in regard to metal oxidation and active species involved in oxidation. Current hypotheses regarding the role of hydrogen in dual atmosphere corrosion are also discussed.
Michael Reisert, Ashish Aphale, Prabhakar Singh

DOC-Stabilized PVAc/MWCNTs Composites for Higher Thermoelectric Performance

Novel technologies of energy generation are being developed nowadays to keep pace with the increasing energy crisis. Thermoelectric materials have the capability of harvesting waste heat and efficiently converting into useful electrical current. In this work, a commercial polymer is developed to be adopted for thermal electrical energy conversion. Low thermal conductivity Polyvinyl Acetate is used to host multi-walled carbon nanotubes (MWNTs) with different weight percentages (10–70) wt% with the addition of semiconducting Sodium Deoxycholate (DOC) as a nanofiller stabilizer. DOC was found to have a dual role in improving the dispersion of the nanotubes and stabilizing the composite, and hence resulting in higher thermoelectric performance. The composite with 70 wt% MWNTs showed the highest electrical conductivity of 171.7 S/m at 100 ℃ while the 50 wt% composite recorded the greatest power factor of 0.008 µW/mK2 at the same temperature.
Hussein Badr, Mahmoud Sorour, Shadi Foad Saber, Iman S. El-Mahallawi, Fawzi A. Elrefaie

Synthesis and Electrocatalytic Properties of Ni–Fe-Layered Double Hydroxide Nanomaterials

Designing efficient electrocatalysts for oxygen evolution reaction (OER) is very important for renewable energy storage. Layered double hydroxides (LDHs) attract widespread attention because of their excellent performance in electrochemical oxygen evolution. In this paper, the layered catalyst materials with different ratio of Ni and Fe were synthesized by one-pot hydrothermal synthesis technique. It was found that the Ni–Fe-layered double hydroxides with a ratio of 3:1 had a higher catalytic activity for oxygen evolution with an overpotential of 366 mV and a Tafel slope of 38.34 mV dec−1. The Ni–Fe compound with the ratio of 3:1 hold a higher electrical conductivity when the Ni–Fe LDH was calcinated at 600 °C and nitrogen protection conditions, resulting in a higher catalytic activity for oxygen evolution reactions. And its overpotential is 270 mV and the Tafel slope is 32.8 mV dec−1.
Mengxin Miao, Xiaobo Han, Rulong Jia, Wei Ma, Guihong Han

Backmatter

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