One of the major problems faced in managing biomass waste to higher quality products is choosing the right technology.Wastes are used as an alternative fuel,with increase in the calorific value.Hydrothermal carboniza...One of the major problems faced in managing biomass waste to higher quality products is choosing the right technology.Wastes are used as an alternative fuel,with increase in the calorific value.Hydrothermal carbonization(HTC)is a biomass conversion technology,used to obtain solid fuel.This study aims to utilize of Calophyllum inophyllum as an alternative solid fuel through HTC.The calorific value and proximate of the hydrochar will be determined and analyzed to find out its quality.The experiments were carried out at temperature variations of 160℃,190℃,and 220℃ and holding times of 30 and 60 minutes.The results show that an increase in temperature and holding time causes a decline in the moisture content 1.87%,volatile matter 54.03%,and ash content 12.35%,respectively,leading to elevations in the fixed carbon at 31.75%.In addition,the highest calorific value of 4149 Kcal/Kg was produced at a temperature of 220℃,within a holding time of 60 minutes.The results showed a significant increase in the quality of solid fuels between 3500–4611 Kcal/Kg in accordance with the American Standard Testing and Materials(ASTM).Therefore,this research leads to an important finding that Calophyllum inophyllum waste through the HTC process can be used as an alternative fuel to substitute lignite coal,which is environmentally friendly.展开更多
This paper is intended to source literature, identifying the adverse impacts on human health, from the pollutants released from residential burning from both fossil fuel and biomass sources. The literature sourced was...This paper is intended to source literature, identifying the adverse impacts on human health, from the pollutants released from residential burning from both fossil fuel and biomass sources. The literature sourced was ascertained through the conduction of a systematic literature review. The author assessed peer-reviewed English language articles, which had been published within the last five years. The studies reviewed indicated a clear increase in the burning of residential solid fuels. The findings suggest that residential solid fuel combustion is occurring in developed countries, primarily as a secondary source of heating during the winter months. The study concluded that similarly to bituminous coal, the domestic burning of wood also had adverse effects on human health. The intentions of UK Climate Change Act 2008 are to achieve an 80% reduction by the year 2050 in the net carbon account from the 1990 baseline. It is recommended for countries to meet the European 2050 targets, long-term measures need to be adopted. This includes switching from residential solid fuel burning to heating methods such as oil and gas, which are necessary in improving overall air quality and public health.展开更多
In sludge treatment, drying sludge using typical technology with high water content to a water content of approximately 10% is always difficult because of adhesive characteristics of sludge in drying. Many methods hav...In sludge treatment, drying sludge using typical technology with high water content to a water content of approximately 10% is always difficult because of adhesive characteristics of sludge in drying. Many methods have been applied, including direct and indirect heat drying, but these approaches of reducing water content to below 40% after drying are very inefficient in energy utilization of drying sludge. In this study, fry-drying technology with a high heat transfer coefficient of approximately 500 W/m2·°C was used to dry swine excreta, sewage and industrial sludge. Also waste oil was used in the fry-drying process, and because the oil’s boiling point is between 240°C and 340°C and the specific heat is approximately 60% of that of water. In the fry-drying system, the sludge is input by molding it into a designated form after heating the waste oil at temperatures between 130°C and 150°C. At these temperatures, the heated oil rapidly evaporates the water contained in the sludge, leaving the oil itself. After approximately 8 - 10 min, the water content of the sludge was less than 10%, and its heating value surpassed 20,000 kJ/kg. Indeed, this makes the organic sludge appropriate for use as a solid fuel. The dried swine excreta, sewage and industrial sludge can be used in an incinerator like low-rank coal or solid fuel.展开更多
Ferrous iron oxides, present in abundant minerals such as olivines, can be oxidized to ferric iron oxide to produce more energy per unit oxygen than carbon and hydrogen. These “geofuels” are essentially inexhaustibl...Ferrous iron oxides, present in abundant minerals such as olivines, can be oxidized to ferric iron oxide to produce more energy per unit oxygen than carbon and hydrogen. These “geofuels” are essentially inexhaustible. Energy might be extracted from geofuels by using the ferrous iron oxide to reduce fluids for use in a fuel cell. Water can be reduced by geofuels, producing hydrogen fuel. Ferrous iron oxide containing rocks are abundant, but diluted with inert oxides. Exploiting them requires new technologies to extract the energy and handle the oxidized mineral residues.展开更多
Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs s...Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas sealing.To solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output voltage.This work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical studies.Finally,the challenges and future development of tubular SIS-SOFCs are also discussed.The findings of this work can help guide the direction and inspire innovation of future development in this field.展开更多
For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion b...For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference cell.The LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged cell.The microstructural and activity de-gradations are attributed to Ni migration and coarsening.展开更多
Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)...Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.展开更多
Iron ore sintering process is the main CO_(2) emission source throughout the integrate steelworks,which primarily comes from the combustion of solid fuels.Improving the combustion efficiency and reducing the solid fue...Iron ore sintering process is the main CO_(2) emission source throughout the integrate steelworks,which primarily comes from the combustion of solid fuels.Improving the combustion efficiency and reducing the solid fuel consumption are important ways to reduce the CO_(2) emission in the sintering process.Around the efficient combustion of fuel,the migration behavior and combustion characteristics of solid fuel in the granulation process were investigated.The results indicated that during the granulation process,fuel particles with size less than 0.5 mm mainly migrated into the granules with grain size of 1-3,3-5 and 5-8 mm;fuel particles with size of 0.5^(-1)mm mainly migrated into granules of 1-3 mm;fuel particles with size of 1-3,3-5 and 5-8 mm mainly entered the granules with the same grain size.With the increase in fuel particles grain size from-0.5 to+8 mm,the combustion efficiency exhibited a firstly-increasing and then decreasing tendency,while the NO_(x) exhibited a decreasing tendency.Potential reason can be described that finer fuel particles(-1 mm)easily distributed in the outer layer of the granules,which combusted fiercely due to its larger specific surface area,leading to the development of incomplete combustion and the conversion of fuel nitrogen;the combustion efficiency of larger fuel particles was restricted by the inner diffusion of O_(2),which then contributed to the reduction of NO_(x) under the inadequate combustion atmosphere.展开更多
A total of 37.5 million tons of palm empty fruit bunches(EFBs)produced in Indonesia in 2018 have the potential to be used as an alternative eco-friendly solid fuel.However,a pretreatment process is necessary to increa...A total of 37.5 million tons of palm empty fruit bunches(EFBs)produced in Indonesia in 2018 have the potential to be used as an alternative eco-friendly solid fuel.However,a pretreatment process is necessary to increase the heating value and reduce the po-tassium content of EFBs.Several methods can be employed to improve the characteristics of EFBs as a solid fuel,such as drying and torrefaction to increase the heating value and the leaching process for reducing the potassium content of EFBs.The main concept of increasing the heating value is to increase the fuel content,which is carbon.Through drying,the carbon ratio can be increased by reducing the moisture content and,through torrefaction,the carbon ratio could be increased due to the decomposition of ligno-cellulose.A simple way to reduce the potassium content of EFBs is the leaching process.Two types of leaching treatment have been studied before:soaking and stirring treatment.This study reviews those methods to make EFBs more suitable as a solid fuel with a high heating value and less potassium content.Increasing the carbon content in EFBs is crucial for enhancing their heating value as a fuel.Drying and torrefaction decrease the moisture content and modify the chemical structure,resulting in higher carbon ratios.The leaching process effectively reduces the potassium content of EFBs and stirring treatment is more effective than immersion treat-ment.Torrefaction positively affects leaching by decreasing the potassium content,while hydrophobicity may hinder leaching by re-pelling water.The high moisture content of leached EFBs requires additional energy for evaporation during torrefaction,resulting in a lower energy density yield compared with raw EFBs.Adjustments may also be required to account for the decreased mineral content,which functions as a torrefaction catalyst in EFBs that have not been leached.展开更多
Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects o...Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.展开更多
Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscalin...Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests.展开更多
This article delivers a robust overview of potential electrode materials for use in symmetrical solid oxide fuel cells(S-SOFCs),a relatively new SOFC technology.To this end,this article provides a comprehensive review...This article delivers a robust overview of potential electrode materials for use in symmetrical solid oxide fuel cells(S-SOFCs),a relatively new SOFC technology.To this end,this article provides a comprehensive review of recent advances and progress in electrode materials for S-SOFC,discussing both the selection of materials and the challenges that come with making that choice.This article discussed the relevant factors involved in developing electrodes with nano/microstructure.Nanocomposites,e.g.,non-cobalt and lithiated materials,are only a few of the electrode types now being researched.Furthermore,the phase structure and microstructure of the produced materials are heavily influenced by the synthesis procedure.Insights into the possibilities and difficulties of the material are discussed.To achieve the desired microstructural features,this article focuses on a synthesis technique that is either the most recent or a better iteration of an existing process.The portion of this analysis that addresses the risks associated with manufacturing and the challenges posed by materials when fabricating S-SOFCs is the most critical.This article also provides important and useful recommendations for the strategic design of electrode materials researchers.展开更多
This paper presents a review of low molecular weight alkane-fed solid oxide fuel cells(SOFCs),which,unlikely the conventional use of SOFCs for only power production,are utilized to cogenerate produce useful chemicals ...This paper presents a review of low molecular weight alkane-fed solid oxide fuel cells(SOFCs),which,unlikely the conventional use of SOFCs for only power production,are utilized to cogenerate produce useful chemicals at the same time.The cogeneration processes in SOFC have been classified according to the different types of fuel.C_(2)and C_(3)alkenes and synthesis gas are the main cogenerated chemicals together with electricity.The chemicals and energy cogeneration in a fuel cell reactor seems to be an effective alternative to conventional reactors for only chemicals production and conventional fuel cells for only power production.Although,the use of SOFCs for chemicals and energy cogeneration has proved successful in the industrial setting,the development of new catalysts aimed at obtaining the desired chemicals together with the production of a high amount of energy,and optimizing SOFC operation conditions is still a challenge to enhance system performance and make commercial applications workable.展开更多
Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface bet...Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface between the cathode and electrolyte is important for facilitating ORR kinetics and hence improving the electrochemical performance.We developed the yttria-stabilized zirconia(YSZ)nanofiber(NF)-based composite cathode,where the oxygen vacancy concentration is controlled by varying the dopant cation(Y2O3)ratio in the YSZ NFs.The composite cathode with the optimized oxygen vacancy concentration exhibits maximum power densities of 2.66 and 1.51 W cm^(−2)at 700 and 600℃,respectively,with excellent thermal stability at 700℃ over 500 h under 1.0 A cm^(−2).Electrochemical impedance spectroscopy and distribution of relaxation time analysis revealed that the high oxygen vacancy concentration in the NF-based scaffold facilitates the charge transfer and incorporation reaction occurred at the interfaces between the cathode and electrolyte.Our results demonstrate the high feasibility and potential of interface engineering for achieving IT-SOFCs with higher performance and stability.展开更多
Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to inve...Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to investigate the thermal responses of a tubular methanol-fueled SOFC.Results show that unlike the low-temperature condition of 873 K,where the peak temperature gradient occurs at the cell center,it appears near the fuel inlet at 1073 K because of the rapid temperature rise induced by the elevated current density.Despite the large heat convection capacity,excessive air could not eff ectively eliminate the harmful temperature gradient caused by the large current density.Thus,optimal control of the current density by properly selecting the operating potential could generate a local thermal neutral state.Interestingly,the maximum axial temperature gradient could be reduced by about 18%at 973 K and 20%at 1073 K when the air with a 5 K higher temperature is supplied.Additionally,despite the higher electrochemical performance observed,the cell with a counter-fl ow arrange-ment featured by a larger hot area and higher maximum temperature gradients is not preferable for a ceramic SOFC system considering thermal durability.Overall,this study could provide insightful thermal information for the operating condition selection,structure design,and stability assessment of realistic SOFCs combined with their internal reforming process.展开更多
Carbon dissolution from solid fuels used in a COREX gasifier was investigated in a high-temperature furnace to investigate the influences of temperature, carbon structure and ash properties of solid fuels into molten ...Carbon dissolution from solid fuels used in a COREX gasifier was investigated in a high-temperature furnace to investigate the influences of temperature, carbon structure and ash properties of solid fuels into molten iron on carbon dissolution behavior. The results showed that the final carbon content of molten iron and dissolution reaction rate of carbon increased as the temperature increased. However, the dissolution behavior of different solid fuels varied with their properties. At the same temperature, the dissolution reaction rate of solid fuel from high to low was coke, semi-coke and lump coal. The apparent reaction rate constants of solid fuel were calculated using the piecewise fitting method based on the experimental data. The analyzed results showed that the dissolution rates of solid fuels had a good correlation with their microcrystalline structures. Moreover, the carbon crystallite structures of solid fuels used in COREX had greater influence on dissolution behavior than their ash properties.展开更多
Solid oxide fuel cell(SOFC) technology and its status and problems were briefly described.Several topics for furtherresearch and development were proposed.
Residential low efficient fuel burning is a major source of many air pollutants produced during incomplete combustions, and household air pollution has been identified as one of the top environmental risk factors. Her...Residential low efficient fuel burning is a major source of many air pollutants produced during incomplete combustions, and household air pollution has been identified as one of the top environmental risk factors. Here we compiled literature-reported emission factors of pollutants including carbon monoxide(CO), total suspended particles(TSPs), PM2.5, organic carbon(OC),elemental carbon(EC) and polycyclic aromatic hydrocarbons(PAHs) for different household energy sources, and quantified the potential for emission reduction by clean fuel adoption. The burning of crop straws, firewood and coal chunks in residential stoves had high emissions per unit fuel mass but lower thermal efficiencies, resulting in high levels of pollution emissions per unit of useful energy, whereas pelletized biofuels and coal briquettes had lower pollutant emissions and higher thermal efficiencies. Briquetting coal may lead to 82%–88% CO, 74%–99%TSP, 73%–76% PM2.5, 64%–98% OC, 92%–99% EC and 80%–83% PAH reductions compared to raw chunk coal. Biomass pelletizing technology would achieve 88%–97% CO, 73%–87% TSP, 79%–88%PM2.5, 94%–96% OC, 91%–99% EC and 63%–96% PAH reduction compared to biomass burning. The adoption of gas fuels(i.e., liquid petroleum gas, natural gas) would achieve significant pollutant reduction, nearly 96% for targeted pollutants. The reduction is related not only to fuel change, but also to the usage of high efficiency stoves.展开更多
Traditional disposal methods of biomass and plastic waste,such as landfill,combustion,and compost,no longer meet the requirements of carbon reduction,carbon neutrality,and sustain-able society due to low utilization e...Traditional disposal methods of biomass and plastic waste,such as landfill,combustion,and compost,no longer meet the requirements of carbon reduction,carbon neutrality,and sustain-able society due to low utilization efficiency and severe pollution.As a green,efficient and environmentally-friendly method,hydrothermal technology has been paid much attention to and has already been applied to recycle or reuse various plastic and biomass wastes.No matter for the single or mixed type of waste,it is expected to achieve efficient recycling and obtain value-added products through the hydrothermal process.This review summarized the basic knowledge of hydrothermal technology and the possible reaction mechanism of biomass and plastics un-der hydrothermal conditions and listed the previous reports on the application of hydrothermal technology for converting wastes of biomass,plastic,and biomass/plastic mixtures to solid fuels.Moreover,regarding the future of hydrothermal technology,four points related to reaction mech-anism,synergistic effect,catalysis,and scaled-up application,were provided for consideration.展开更多
Carbon-fueled solid oxide fuel cells(CF-SOFCs)can electrochemically convert the chemical energy in carbon into electricity,which demonstrate both superior electrical efficiency and fuel utilisation compared to all oth...Carbon-fueled solid oxide fuel cells(CF-SOFCs)can electrochemically convert the chemical energy in carbon into electricity,which demonstrate both superior electrical efficiency and fuel utilisation compared to all other types of fuel cells.However,using solid carbon as the fuel of SOFCs also faces some challenges,the fluid mobility and reactive activity of carbon-based fuels are much lower than those of gaseous fuels.Therefore,the anode reaction kinetics plays a crucial role in determining the electrochemical performance of CF-SOFCs.Herein,the progress of various anodes in CF-SOFCs is reviewed from the perspective of material compositions,electrochemical performance and microstructures.Challenges faced in developing high performance anodes for CF-SOFCs are also discussed.展开更多
基金This article has been funded from research activities entitled Increasing Geothermal Technology Education and Public Outreach for Communities as Supporters for the Development of 35 MW Geothermal Power Plants according to research contract No.452/UN27.21/PN/2020(Featured Research Grants)PNBP funding sources for Budget Year 2020.
文摘One of the major problems faced in managing biomass waste to higher quality products is choosing the right technology.Wastes are used as an alternative fuel,with increase in the calorific value.Hydrothermal carbonization(HTC)is a biomass conversion technology,used to obtain solid fuel.This study aims to utilize of Calophyllum inophyllum as an alternative solid fuel through HTC.The calorific value and proximate of the hydrochar will be determined and analyzed to find out its quality.The experiments were carried out at temperature variations of 160℃,190℃,and 220℃ and holding times of 30 and 60 minutes.The results show that an increase in temperature and holding time causes a decline in the moisture content 1.87%,volatile matter 54.03%,and ash content 12.35%,respectively,leading to elevations in the fixed carbon at 31.75%.In addition,the highest calorific value of 4149 Kcal/Kg was produced at a temperature of 220℃,within a holding time of 60 minutes.The results showed a significant increase in the quality of solid fuels between 3500–4611 Kcal/Kg in accordance with the American Standard Testing and Materials(ASTM).Therefore,this research leads to an important finding that Calophyllum inophyllum waste through the HTC process can be used as an alternative fuel to substitute lignite coal,which is environmentally friendly.
文摘This paper is intended to source literature, identifying the adverse impacts on human health, from the pollutants released from residential burning from both fossil fuel and biomass sources. The literature sourced was ascertained through the conduction of a systematic literature review. The author assessed peer-reviewed English language articles, which had been published within the last five years. The studies reviewed indicated a clear increase in the burning of residential solid fuels. The findings suggest that residential solid fuel combustion is occurring in developed countries, primarily as a secondary source of heating during the winter months. The study concluded that similarly to bituminous coal, the domestic burning of wood also had adverse effects on human health. The intentions of UK Climate Change Act 2008 are to achieve an 80% reduction by the year 2050 in the net carbon account from the 1990 baseline. It is recommended for countries to meet the European 2050 targets, long-term measures need to be adopted. This includes switching from residential solid fuel burning to heating methods such as oil and gas, which are necessary in improving overall air quality and public health.
文摘In sludge treatment, drying sludge using typical technology with high water content to a water content of approximately 10% is always difficult because of adhesive characteristics of sludge in drying. Many methods have been applied, including direct and indirect heat drying, but these approaches of reducing water content to below 40% after drying are very inefficient in energy utilization of drying sludge. In this study, fry-drying technology with a high heat transfer coefficient of approximately 500 W/m2·°C was used to dry swine excreta, sewage and industrial sludge. Also waste oil was used in the fry-drying process, and because the oil’s boiling point is between 240°C and 340°C and the specific heat is approximately 60% of that of water. In the fry-drying system, the sludge is input by molding it into a designated form after heating the waste oil at temperatures between 130°C and 150°C. At these temperatures, the heated oil rapidly evaporates the water contained in the sludge, leaving the oil itself. After approximately 8 - 10 min, the water content of the sludge was less than 10%, and its heating value surpassed 20,000 kJ/kg. Indeed, this makes the organic sludge appropriate for use as a solid fuel. The dried swine excreta, sewage and industrial sludge can be used in an incinerator like low-rank coal or solid fuel.
文摘Ferrous iron oxides, present in abundant minerals such as olivines, can be oxidized to ferric iron oxide to produce more energy per unit oxygen than carbon and hydrogen. These “geofuels” are essentially inexhaustible. Energy might be extracted from geofuels by using the ferrous iron oxide to reduce fluids for use in a fuel cell. Water can be reduced by geofuels, producing hydrogen fuel. Ferrous iron oxide containing rocks are abundant, but diluted with inert oxides. Exploiting them requires new technologies to extract the energy and handle the oxidized mineral residues.
基金supported by the National Natural Science Foundation of China (Nos.21701083 and 22179054).
文摘Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas sealing.To solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output voltage.This work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical studies.Finally,the challenges and future development of tubular SIS-SOFCs are also discussed.The findings of this work can help guide the direction and inspire innovation of future development in this field.
基金the National Key R&D Program of China(No.2018YFB1502201)the Guangdong Basic and Applied Basic Research Foundation,China(No.2020A1515010551).
文摘For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference cell.The LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged cell.The microstructural and activity de-gradations are attributed to Ni migration and coarsening.
基金supported by the National Natural Science Foundation of China(22279025,21773048)the Natural Science Foundation of Heilongjiang Province(LH2021A013)+1 种基金the Sichuan Science and Technology Program(2021YFSY0022)the Fundamental Research Funds for the Central Universities(2023FRFK06005,HIT.NSRIF202204)。
文摘Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.
基金supported by the National Natural Science Foundation of China(No.52274344)Provincial Natural Science Foundation of Hunan(No.2022JJ30723)+1 种基金Independent Exploration and Innovation Project of graduate students of Central South University,Hunan Provincial Science and Technology Achievement Transformation and Industrialization Program(No.2020GK4055)China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202118).
文摘Iron ore sintering process is the main CO_(2) emission source throughout the integrate steelworks,which primarily comes from the combustion of solid fuels.Improving the combustion efficiency and reducing the solid fuel consumption are important ways to reduce the CO_(2) emission in the sintering process.Around the efficient combustion of fuel,the migration behavior and combustion characteristics of solid fuel in the granulation process were investigated.The results indicated that during the granulation process,fuel particles with size less than 0.5 mm mainly migrated into the granules with grain size of 1-3,3-5 and 5-8 mm;fuel particles with size of 0.5^(-1)mm mainly migrated into granules of 1-3 mm;fuel particles with size of 1-3,3-5 and 5-8 mm mainly entered the granules with the same grain size.With the increase in fuel particles grain size from-0.5 to+8 mm,the combustion efficiency exhibited a firstly-increasing and then decreasing tendency,while the NO_(x) exhibited a decreasing tendency.Potential reason can be described that finer fuel particles(-1 mm)easily distributed in the outer layer of the granules,which combusted fiercely due to its larger specific surface area,leading to the development of incomplete combustion and the conversion of fuel nitrogen;the combustion efficiency of larger fuel particles was restricted by the inner diffusion of O_(2),which then contributed to the reduction of NO_(x) under the inadequate combustion atmosphere.
基金This study was supported financially by Institut Teknologi Bandung as part of the research,community service and innovation program(PPMI)2021.
文摘A total of 37.5 million tons of palm empty fruit bunches(EFBs)produced in Indonesia in 2018 have the potential to be used as an alternative eco-friendly solid fuel.However,a pretreatment process is necessary to increase the heating value and reduce the po-tassium content of EFBs.Several methods can be employed to improve the characteristics of EFBs as a solid fuel,such as drying and torrefaction to increase the heating value and the leaching process for reducing the potassium content of EFBs.The main concept of increasing the heating value is to increase the fuel content,which is carbon.Through drying,the carbon ratio can be increased by reducing the moisture content and,through torrefaction,the carbon ratio could be increased due to the decomposition of ligno-cellulose.A simple way to reduce the potassium content of EFBs is the leaching process.Two types of leaching treatment have been studied before:soaking and stirring treatment.This study reviews those methods to make EFBs more suitable as a solid fuel with a high heating value and less potassium content.Increasing the carbon content in EFBs is crucial for enhancing their heating value as a fuel.Drying and torrefaction decrease the moisture content and modify the chemical structure,resulting in higher carbon ratios.The leaching process effectively reduces the potassium content of EFBs and stirring treatment is more effective than immersion treat-ment.Torrefaction positively affects leaching by decreasing the potassium content,while hydrophobicity may hinder leaching by re-pelling water.The high moisture content of leached EFBs requires additional energy for evaporation during torrefaction,resulting in a lower energy density yield compared with raw EFBs.Adjustments may also be required to account for the decreased mineral content,which functions as a torrefaction catalyst in EFBs that have not been leached.
基金supported by the National Key R&D Program of China(No.2018YFB1502202)the Fundamental Research Funds for the Central Universities(No.FRF-GF-20-09B).
文摘Performance degradation shortens the life of solid oxide fuel cells in practical applications.Revealing the degradation mechanism is crucial for the continuous improvement of cell durability.In this work,the effects of cell operating conditions on the terminal voltage and anode microstructure of a Ni-yttria-stabilized zirconia anode-supported single cell were investigated.The microstructure of the anode active area near the electrolyte was characterized by laser optical microscopy and focused ion beam-scanning electron microscopy.Ni depletion at the anode/electrolyte interface region was observed after 100 h discharge tests.In addition,the long-term stability of the single cell was evaluated at 700℃for 3000 h.After an initial decline,the anode-supported single cell exhibits good durability with a voltage decay rate of 0.72%/kh and an electrode polarization resistance decay rate of 0.17%/kh.The main performance loss of the cell originates from the initial degradation.
基金financially supported by the National Key R&D Program of China (No. 2018YFB1502203-1)the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120087)the Stable Supporting Fund of Shenzhen, China (No. GXWD20201230155427003-202007 28114835006)
文摘Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests.
基金the Fundamental Research Grant Scheme (FRGS),grant No.FRGS/1/2021/TK0/UKM/01/5 funded by the Ministry of Higher Education (MOHE)。
文摘This article delivers a robust overview of potential electrode materials for use in symmetrical solid oxide fuel cells(S-SOFCs),a relatively new SOFC technology.To this end,this article provides a comprehensive review of recent advances and progress in electrode materials for S-SOFC,discussing both the selection of materials and the challenges that come with making that choice.This article discussed the relevant factors involved in developing electrodes with nano/microstructure.Nanocomposites,e.g.,non-cobalt and lithiated materials,are only a few of the electrode types now being researched.Furthermore,the phase structure and microstructure of the produced materials are heavily influenced by the synthesis procedure.Insights into the possibilities and difficulties of the material are discussed.To achieve the desired microstructural features,this article focuses on a synthesis technique that is either the most recent or a better iteration of an existing process.The portion of this analysis that addresses the risks associated with manufacturing and the challenges posed by materials when fabricating S-SOFCs is the most critical.This article also provides important and useful recommendations for the strategic design of electrode materials researchers.
文摘This paper presents a review of low molecular weight alkane-fed solid oxide fuel cells(SOFCs),which,unlikely the conventional use of SOFCs for only power production,are utilized to cogenerate produce useful chemicals at the same time.The cogeneration processes in SOFC have been classified according to the different types of fuel.C_(2)and C_(3)alkenes and synthesis gas are the main cogenerated chemicals together with electricity.The chemicals and energy cogeneration in a fuel cell reactor seems to be an effective alternative to conventional reactors for only chemicals production and conventional fuel cells for only power production.Although,the use of SOFCs for chemicals and energy cogeneration has proved successful in the industrial setting,the development of new catalysts aimed at obtaining the desired chemicals together with the production of a high amount of energy,and optimizing SOFC operation conditions is still a challenge to enhance system performance and make commercial applications workable.
基金supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean government (MSIT)(Nos. 2022R1A2C3012372 and 2022R1A4A1031182)Korea Institute for Advancement of Technology(KIAT)Competency Development Program for Industry Specialists of Korean Ministry of Trade,Industry and Energy Grant funded by the Korea Government(MOTIE)(No. P0008458, The Competency Development Program for Industry Specialist and No. P0017120, HRD program for Foster R&D specialist of parts for ecofriendly vehicle (xEV))
文摘Sluggish oxygen reduction reaction(ORR)kinetics are a major obstacle to developing intermediate-temperature solid-oxide fuel cells(IT-SOFCs).In particular,engineering the anion defect concentration at an interface between the cathode and electrolyte is important for facilitating ORR kinetics and hence improving the electrochemical performance.We developed the yttria-stabilized zirconia(YSZ)nanofiber(NF)-based composite cathode,where the oxygen vacancy concentration is controlled by varying the dopant cation(Y2O3)ratio in the YSZ NFs.The composite cathode with the optimized oxygen vacancy concentration exhibits maximum power densities of 2.66 and 1.51 W cm^(−2)at 700 and 600℃,respectively,with excellent thermal stability at 700℃ over 500 h under 1.0 A cm^(−2).Electrochemical impedance spectroscopy and distribution of relaxation time analysis revealed that the high oxygen vacancy concentration in the NF-based scaffold facilitates the charge transfer and incorporation reaction occurred at the interfaces between the cathode and electrolyte.Our results demonstrate the high feasibility and potential of interface engineering for achieving IT-SOFCs with higher performance and stability.
基金by the Project of Strategic Importance Funding Scheme from The Hong Kong China Polytechnic University(No.P0035168)the National Natural Science Foundation of China(No.51806241).
文摘Thermal management in solid oxide fuel cells(SOFC)is a critical issue due to non-uniform electrochemical reactions and convective fl ows within the cells.Therefore,a 2D mathematical model is established herein to investigate the thermal responses of a tubular methanol-fueled SOFC.Results show that unlike the low-temperature condition of 873 K,where the peak temperature gradient occurs at the cell center,it appears near the fuel inlet at 1073 K because of the rapid temperature rise induced by the elevated current density.Despite the large heat convection capacity,excessive air could not eff ectively eliminate the harmful temperature gradient caused by the large current density.Thus,optimal control of the current density by properly selecting the operating potential could generate a local thermal neutral state.Interestingly,the maximum axial temperature gradient could be reduced by about 18%at 973 K and 20%at 1073 K when the air with a 5 K higher temperature is supplied.Additionally,despite the higher electrochemical performance observed,the cell with a counter-fl ow arrange-ment featured by a larger hot area and higher maximum temperature gradients is not preferable for a ceramic SOFC system considering thermal durability.Overall,this study could provide insightful thermal information for the operating condition selection,structure design,and stability assessment of realistic SOFCs combined with their internal reforming process.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China (Nos. 51704216, 51474164 and U201760101) and China Postdoctoral Science Foundation (No. 2016M602378).
文摘Carbon dissolution from solid fuels used in a COREX gasifier was investigated in a high-temperature furnace to investigate the influences of temperature, carbon structure and ash properties of solid fuels into molten iron on carbon dissolution behavior. The results showed that the final carbon content of molten iron and dissolution reaction rate of carbon increased as the temperature increased. However, the dissolution behavior of different solid fuels varied with their properties. At the same temperature, the dissolution reaction rate of solid fuel from high to low was coke, semi-coke and lump coal. The apparent reaction rate constants of solid fuel were calculated using the piecewise fitting method based on the experimental data. The analyzed results showed that the dissolution rates of solid fuels had a good correlation with their microcrystalline structures. Moreover, the carbon crystallite structures of solid fuels used in COREX had greater influence on dissolution behavior than their ash properties.
文摘Solid oxide fuel cell(SOFC) technology and its status and problems were briefly described.Several topics for furtherresearch and development were proposed.
基金Funding for the study was supported by the United Nation Foundation (No. RFP 13-1)the National Natural Science Foundation (No. 41301554)Jiangsu Natural Science Foundation (No. BK20131031)
文摘Residential low efficient fuel burning is a major source of many air pollutants produced during incomplete combustions, and household air pollution has been identified as one of the top environmental risk factors. Here we compiled literature-reported emission factors of pollutants including carbon monoxide(CO), total suspended particles(TSPs), PM2.5, organic carbon(OC),elemental carbon(EC) and polycyclic aromatic hydrocarbons(PAHs) for different household energy sources, and quantified the potential for emission reduction by clean fuel adoption. The burning of crop straws, firewood and coal chunks in residential stoves had high emissions per unit fuel mass but lower thermal efficiencies, resulting in high levels of pollution emissions per unit of useful energy, whereas pelletized biofuels and coal briquettes had lower pollutant emissions and higher thermal efficiencies. Briquetting coal may lead to 82%–88% CO, 74%–99%TSP, 73%–76% PM2.5, 64%–98% OC, 92%–99% EC and 80%–83% PAH reductions compared to raw chunk coal. Biomass pelletizing technology would achieve 88%–97% CO, 73%–87% TSP, 79%–88%PM2.5, 94%–96% OC, 91%–99% EC and 63%–96% PAH reduction compared to biomass burning. The adoption of gas fuels(i.e., liquid petroleum gas, natural gas) would achieve significant pollutant reduction, nearly 96% for targeted pollutants. The reduction is related not only to fuel change, but also to the usage of high efficiency stoves.
文摘Traditional disposal methods of biomass and plastic waste,such as landfill,combustion,and compost,no longer meet the requirements of carbon reduction,carbon neutrality,and sustain-able society due to low utilization efficiency and severe pollution.As a green,efficient and environmentally-friendly method,hydrothermal technology has been paid much attention to and has already been applied to recycle or reuse various plastic and biomass wastes.No matter for the single or mixed type of waste,it is expected to achieve efficient recycling and obtain value-added products through the hydrothermal process.This review summarized the basic knowledge of hydrothermal technology and the possible reaction mechanism of biomass and plastics un-der hydrothermal conditions and listed the previous reports on the application of hydrothermal technology for converting wastes of biomass,plastic,and biomass/plastic mixtures to solid fuels.Moreover,regarding the future of hydrothermal technology,four points related to reaction mech-anism,synergistic effect,catalysis,and scaled-up application,were provided for consideration.
基金financially supported by the National Natural Science Foundation of China(Grant nos.21376001,21576028 and 21506012)。
文摘Carbon-fueled solid oxide fuel cells(CF-SOFCs)can electrochemically convert the chemical energy in carbon into electricity,which demonstrate both superior electrical efficiency and fuel utilisation compared to all other types of fuel cells.However,using solid carbon as the fuel of SOFCs also faces some challenges,the fluid mobility and reactive activity of carbon-based fuels are much lower than those of gaseous fuels.Therefore,the anode reaction kinetics plays a crucial role in determining the electrochemical performance of CF-SOFCs.Herein,the progress of various anodes in CF-SOFCs is reviewed from the perspective of material compositions,electrochemical performance and microstructures.Challenges faced in developing high performance anodes for CF-SOFCs are also discussed.