Production of petrochemical catalysts accounts for one of the largest shares of platinum group metals(PGMs) consumption;thus,recycling of spent petrochemical catalysts holds great economic value.Conventionally,PGMs ar...Production of petrochemical catalysts accounts for one of the largest shares of platinum group metals(PGMs) consumption;thus,recycling of spent petrochemical catalysts holds great economic value.Conventionally,PGMs are recovered through hydrometallurgical processes which have a low recovery efficiency and produce a large amount of waste.In this regard,this paper proposed a method to use iron-capturing PGMs based on CaO-Al_(2)O_(3)-Na_(2)O slag.This method avoided the formation of Fe-Si alloy and achieved efficient enrichment of PGMs.The droplet force model showed that the recovery efficiency of PGMs could be improved if the slag had low density and low viscosity.Based on this result,FactSage software optimized the composition of slag.Furthermore,the effect of B_(2)O_(3) on the 1400 ℃ liquidus of CaO-Al_(2)O_(3)-Na_(2)O_(3)-B_(2)O_(3) phase diagram was revealed.Moreover,it was found that the recovery efficiency of PGMs exceeded 99% under the following optimized conditions:basicity of 1.0,20 wt%Na_(2)O,15 wt% B_(2)O_(3),15 wt% Fe,3 wt% C and a temperature range of 1400-1500℃.The thermodynamic model revealed the mechanism of iron capture.Different chemical bonds prevented the formation of bonds between the alloy and slag,resulting in the separation of the slag from the alloy.PGMs particles and iron microspheres had significant surface Gibbs free energy.Only when iron microspheres and PGMs particles collided and fused with each other to reduce their surface area could the Gibbs free energy of the system be reduced.展开更多
Lithium-sulfur batteries(LSBs)have a high theoretical capacity,which is considered as one of the most promising high-energy-density secondary batteries due to the double electrons reaction of sulfur.However,the shuttl...Lithium-sulfur batteries(LSBs)have a high theoretical capacity,which is considered as one of the most promising high-energy-density secondary batteries due to the double electrons reaction of sulfur.However,the shuttle effects of lithium polysulfides(Li PSs)and sluggish redox kinetics lead to their materials capacity loss and cycle stability deterioration,which restrains LSBs commercialization.Metallic compounds as additions can improve the electrochemical performance of the Li-S system,through the trap of Li PSs and accelerate the conversion of the soluble Li PSs.Among of them,the iron group elements(Fe,Ni,Co)-based compounds are the promising materials for the LSBs,due to their unique outer electronic structure and its tunable properties,low cost,abundant in the earth,environmental benignity,controllable and scalable prepared,and so on.In this review,we have made a summary for iron-based compounds to capture Li PSs according to lithium bond,sulfur bond and magnetic force.The type of iron-based compound including oxides,sulfides,nitrides,phosphides,carbides,and so on,and we have investigated the electrocatalytic mechanism of these materials.Besides,some improvement strategies are proposed,such as the engineering of the special micro/nanostructure,defect concentrations,band structures,and heterostructures.We hope to shed an in-depth light on the rationally design and fabrication of robust,commercial and stable materials for high-performance LSBs.展开更多
The capture efficiency describes the capability of a sink,such as a grain boundary(GB),dislocation,and void,to absorb point defects(PDs).The bias defines the difference in capture efficiency between the absorption of ...The capture efficiency describes the capability of a sink,such as a grain boundary(GB),dislocation,and void,to absorb point defects(PDs).The bias defines the difference in capture efficiency between the absorption of a vacancy and dumbbell at a sink.Complete kinetic information on PDs,including diffusion barriers and diffusion orientations,as well as accurate saddle points,are needed to determine the capture efficiency and bias at a sink accurately,which is computationally demanding.In the present study,the Self-Evolving Atomistic Kinetic Monte Carlo(SEAKMC)method was used to investigate the defect dynamics of PDs near different types of grain boundaries(GBs)(with both 100 and 110 families)accurately in body-centered cubic(BCC)iron(Fe).The capture efficiency,sink strength,and bias factor of different types of GBs were determined in Fe,which,different from traditional rate theory estimation,showed a distinct capture efficiency,sink strength,and bias in different GBs.The results demonstrate a strong positive correlation between the capture efficiency and the GB strain width,instead of the GB misorientation,GB energy,or GB-PD binding energy,which have been investigated previously.This work provides valuable insight into the radiation-induced microstructural evolution of GBs.展开更多
Chemical looping combustion （CLC） of carbonaceous compounds has been proposed, in the past decade, as an efficient method for CO2 capture without cost of extra energy penalties. The technique involves the use of a m...Chemical looping combustion （CLC） of carbonaceous compounds has been proposed, in the past decade, as an efficient method for CO2 capture without cost of extra energy penalties. The technique involves the use of a metal oxide as an oxygen carrier that transfers oxygen from combustion air to fuels. The combustion is carried out in a two-step process： in the fuel reactor, the fuel is oxidized by a metal oxide, and in the air reactor, the reduced metal is oxidized back to the original phase. The use of iron oxide as an oxygen carrier has been investigated in this article. Particles composed of 80 wt% Fe2O3, together with Al2O3 as binder, have been prepared by impregnation methods. X-ray diffraction （XRD） analysis reveals that Fe2O3 does not interact with the Al2O3 binder after multi-cycles. The reactivity of the oxygen carrier particles has been studied in twenty-cycle reduction-oxidation tests in a thermal gravimetrical analysis （TGA） reactor. The components in the outlet gas have been analyzed. It has been observed that about 85% of CH4 converted to CO2 and H2O during most of the reduction periods. The oxygen carrier has kept quite a high reactivity in the twenty-cycle reactions. In the first twenty reaction cycles, the reaction rates became slightly higher with the number of cyclic reactions increasing, which was confirmed by the scanning electron microscopy （SEM） test results. The SEM analysis revealed that the pore size inside the particle had been enlarged by the thermal stress during the reaction, which was favorable for diffusion of the gaseous reactants into the particles. The experimental results suggested that the Fe2O3/Al2O3 oxygen carrier was a promising candidate for a CLC system.展开更多
碳捕集利用与封存(简称CCUS)技术是钢铁行业实现碳中和目标的可行选择,但是我国钢铁生产以高炉-转炉长流程生产为主,产生碳排放的工序众多且碳浓度较低,目前仍缺少经济高效的碳捕集方案。在此背景下,通过引入气化炉用于重整炉顶煤气,改...碳捕集利用与封存(简称CCUS)技术是钢铁行业实现碳中和目标的可行选择,但是我国钢铁生产以高炉-转炉长流程生产为主,产生碳排放的工序众多且碳浓度较低,目前仍缺少经济高效的碳捕集方案。在此背景下,通过引入气化炉用于重整炉顶煤气,改进现有炉顶煤气循环-氧气高炉工艺的炉顶煤气循环方式,耦合富氧燃烧碳捕集技术,提出一种基于重整煤气喷吹-氧气高炉的富氧燃烧碳捕集方案,并利用Aspen Plus建模计算和碳流分析评估了该方案的节能减排潜力。结果表明:富氧燃烧碳捕集技术与氧气高炉低碳冶炼工艺有着良好的承接性与耦合性,两者耦合能够降低钢铁行业碳捕集的难度;富氧燃烧单位CO_(2)的捕集能耗为2623.91 kJ/kg,比现有的醇胺法的碳捕集能耗低51.4%,比变压吸附法的碳捕集能耗低26.2%;生产每吨钢材可通过富氧燃烧捕集到1.5 t CO_(2),有望实现钢铁生产过程的CO_(2)净零排放。总的来说,该方案能够在高炉低碳冶炼的基础上进行低成本、大规模的碳捕集,是钢铁行业绿色低碳转型的可行方案。展开更多
The over-consumption of fossil fuels resulted in the large quantity emission of carbon dioxide （CO2）, which was the main reason for the climate change and more extreme weathers. Hence, it is extremely pressing to ex...The over-consumption of fossil fuels resulted in the large quantity emission of carbon dioxide （CO2）, which was the main reason for the climate change and more extreme weathers. Hence, it is extremely pressing to ex- plore efficient and sustainable approaches for the carbon-neutral pathway of CO2 utilization and recycling. In our recent works with this context, we developed successfully a novel ＂chemical vapor deposition integrated process （CVD-IP）＂ technology to converting robustly CO2 into the value-added solid-form carbon materials, The monometallic FeNi0-Al2O3 （FNi0） and bimetallic FeNix-Al2O3 （FNi2, FNi4, FNi8 and FNi20） samples were synthesized and effective for this new approach. The catalyst labeled FNi8 gave the better performance, exhibited the single pass solid carbon yield of 30%. These results illustrated alternative promising cases for the CO2 capture utilization storage （CCUS）, by means of the CO2 catalytic conversion into the solid-form nano carbon materials.展开更多
2011年中期,浦项产业科学研究院在浦项厂建立了氨水捕集CO_2的中试工厂,高炉煤气处理能力为1 000 Nm^3/h,每天可生产10 t CO_2产品;装置运行中,通过废热回收系统提供吸收剂溶液再生所需的热能或蒸汽。技术数据显示,该套设备的CO_2去除...2011年中期,浦项产业科学研究院在浦项厂建立了氨水捕集CO_2的中试工厂,高炉煤气处理能力为1 000 Nm^3/h,每天可生产10 t CO_2产品;装置运行中,通过废热回收系统提供吸收剂溶液再生所需的热能或蒸汽。技术数据显示,该套设备的CO_2去除率大于90%,CO_2产品纯度大于95%。该研究也是韩国海洋水产部推进的"CO_2海洋捕集封存技术"一部分,目前的研究方向主要是优化运输和封存CO_2的离岸基础设施。展开更多
The chemical looping concept provided a novel way to achieve carbon separation during the production of energy or substances. In this work, hydrogen generation with inherent CO2 capture in single packed bed reactor vi...The chemical looping concept provided a novel way to achieve carbon separation during the production of energy or substances. In this work, hydrogen generation with inherent CO2 capture in single packed bed reactor via this concept was discussed. Two oxygen carriers, Fe203 60 wt.% and Fe2O3 55 wt.%/CuO 5 wt.% supported by Al2O3, were made by ball milling method. First, according to the characteristics of the reduction breakthrough curve, a strict fuel supply strategy was selected to achieve simultaneous CO2 capture and HE production. Then, in the long term tests using CO as fuel, it was proved that CuO addition improved hydrogen generation with the maximum intensity of 3700 μmol H2·g^-1 Fe2O3 compared with Fe-Al of 2300 μmol HE.g^-1 Fe2O3. The overall CO2 capture efficiency remained 98%- 98.8% over 100 cycles. Moreover, the reactivity of deactivated materials was recovered nearly like that of fresh ones by sintering treatment. Finally, two kinds of complex gases consist of CO, HE, CH4 and CO2 were utilized as fuels to test the feasibility. The results showed all components could be completely converted by Fe-Cu- Al in the reduction stage. The intensity of hydrogen production and the overall CO2 capture efficiency were in the range of 2000-2400 μnol H2^g^-1 Fe2O3 and 89%, 95%, respectively.展开更多
Neutron radiative capture cross sections of <sup>56</sup>Fe（n,γ）<sup>57</sup>Fe reaction have beenmeasured in two incident energy ranges,from 9.3 to 16.0 MeV at 90° and from 9.0 to20.0 ...Neutron radiative capture cross sections of <sup>56</sup>Fe（n,γ）<sup>57</sup>Fe reaction have beenmeasured in two incident energy ranges,from 9.3 to 16.0 MeV at 90° and from 9.0 to20.0 MeV at 55° and 125°.Time-of-flight technique is used to discriminate neutronsand gamma rays.The asymmetry of fore and aft γ-ray in this reaction is obtained.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.U2002212 and 52204412)the National Key R&D Program of China (Nos. 2019YFC1907101,2019YFC1907103 and 2021YFC1910504)+3 种基金Key R&D Program of Ningxia Hui Autonomous Region (No. 2020BCE01001)Guangdong Basic and Applied Basic Research Foundation (No.2020A1515110408)Foshan Science and Technology Innovation Special Foundation (No.BK21BE002)the Fundamental Research Funds for the Central Universities (No.FRF-TP20-031A1)。
文摘Production of petrochemical catalysts accounts for one of the largest shares of platinum group metals(PGMs) consumption;thus,recycling of spent petrochemical catalysts holds great economic value.Conventionally,PGMs are recovered through hydrometallurgical processes which have a low recovery efficiency and produce a large amount of waste.In this regard,this paper proposed a method to use iron-capturing PGMs based on CaO-Al_(2)O_(3)-Na_(2)O slag.This method avoided the formation of Fe-Si alloy and achieved efficient enrichment of PGMs.The droplet force model showed that the recovery efficiency of PGMs could be improved if the slag had low density and low viscosity.Based on this result,FactSage software optimized the composition of slag.Furthermore,the effect of B_(2)O_(3) on the 1400 ℃ liquidus of CaO-Al_(2)O_(3)-Na_(2)O_(3)-B_(2)O_(3) phase diagram was revealed.Moreover,it was found that the recovery efficiency of PGMs exceeded 99% under the following optimized conditions:basicity of 1.0,20 wt%Na_(2)O,15 wt% B_(2)O_(3),15 wt% Fe,3 wt% C and a temperature range of 1400-1500℃.The thermodynamic model revealed the mechanism of iron capture.Different chemical bonds prevented the formation of bonds between the alloy and slag,resulting in the separation of the slag from the alloy.PGMs particles and iron microspheres had significant surface Gibbs free energy.Only when iron microspheres and PGMs particles collided and fused with each other to reduce their surface area could the Gibbs free energy of the system be reduced.
基金supported by the Key-Area Research and Development Program of Guangdong Province(2020B090919005)the National Natural Science Foundation of China(U1801257,21975056,and 22179025)。
文摘Lithium-sulfur batteries(LSBs)have a high theoretical capacity,which is considered as one of the most promising high-energy-density secondary batteries due to the double electrons reaction of sulfur.However,the shuttle effects of lithium polysulfides(Li PSs)and sluggish redox kinetics lead to their materials capacity loss and cycle stability deterioration,which restrains LSBs commercialization.Metallic compounds as additions can improve the electrochemical performance of the Li-S system,through the trap of Li PSs and accelerate the conversion of the soluble Li PSs.Among of them,the iron group elements(Fe,Ni,Co)-based compounds are the promising materials for the LSBs,due to their unique outer electronic structure and its tunable properties,low cost,abundant in the earth,environmental benignity,controllable and scalable prepared,and so on.In this review,we have made a summary for iron-based compounds to capture Li PSs according to lithium bond,sulfur bond and magnetic force.The type of iron-based compound including oxides,sulfides,nitrides,phosphides,carbides,and so on,and we have investigated the electrocatalytic mechanism of these materials.Besides,some improvement strategies are proposed,such as the engineering of the special micro/nanostructure,defect concentrations,band structures,and heterostructures.We hope to shed an in-depth light on the rationally design and fabrication of robust,commercial and stable materials for high-performance LSBs.
基金the support by the National MCF Energy R&D Program with Grant No.2018YFE0308103the National Natural Science Foundation of China with Grant No.51871007,12075023+2 种基金the China Scholarship Council(CSC No.201706020125)University of Tennessee Knoxville(UTK)Organized Research Unit(ORU)programthe support of the grant DE-SC0019151 funded by the U.S.Department of Energy,Office of Science。
文摘The capture efficiency describes the capability of a sink,such as a grain boundary(GB),dislocation,and void,to absorb point defects(PDs).The bias defines the difference in capture efficiency between the absorption of a vacancy and dumbbell at a sink.Complete kinetic information on PDs,including diffusion barriers and diffusion orientations,as well as accurate saddle points,are needed to determine the capture efficiency and bias at a sink accurately,which is computationally demanding.In the present study,the Self-Evolving Atomistic Kinetic Monte Carlo(SEAKMC)method was used to investigate the defect dynamics of PDs near different types of grain boundaries(GBs)(with both 100 and 110 families)accurately in body-centered cubic(BCC)iron(Fe).The capture efficiency,sink strength,and bias factor of different types of GBs were determined in Fe,which,different from traditional rate theory estimation,showed a distinct capture efficiency,sink strength,and bias in different GBs.The results demonstrate a strong positive correlation between the capture efficiency and the GB strain width,instead of the GB misorientation,GB energy,or GB-PD binding energy,which have been investigated previously.This work provides valuable insight into the radiation-induced microstructural evolution of GBs.
基金Supported by the National Natural Science Foundation of China (No.50574046 and 50164002, )Natural Science Foun-dation of Yunnan Province (No. 2004E0012Q).
文摘Chemical looping combustion （CLC） of carbonaceous compounds has been proposed, in the past decade, as an efficient method for CO2 capture without cost of extra energy penalties. The technique involves the use of a metal oxide as an oxygen carrier that transfers oxygen from combustion air to fuels. The combustion is carried out in a two-step process： in the fuel reactor, the fuel is oxidized by a metal oxide, and in the air reactor, the reduced metal is oxidized back to the original phase. The use of iron oxide as an oxygen carrier has been investigated in this article. Particles composed of 80 wt% Fe2O3, together with Al2O3 as binder, have been prepared by impregnation methods. X-ray diffraction （XRD） analysis reveals that Fe2O3 does not interact with the Al2O3 binder after multi-cycles. The reactivity of the oxygen carrier particles has been studied in twenty-cycle reduction-oxidation tests in a thermal gravimetrical analysis （TGA） reactor. The components in the outlet gas have been analyzed. It has been observed that about 85% of CH4 converted to CO2 and H2O during most of the reduction periods. The oxygen carrier has kept quite a high reactivity in the twenty-cycle reactions. In the first twenty reaction cycles, the reaction rates became slightly higher with the number of cyclic reactions increasing, which was confirmed by the scanning electron microscopy （SEM） test results. The SEM analysis revealed that the pore size inside the particle had been enlarged by the thermal stress during the reaction, which was favorable for diffusion of the gaseous reactants into the particles. The experimental results suggested that the Fe2O3/Al2O3 oxygen carrier was a promising candidate for a CLC system.
文摘碳捕集利用与封存(简称CCUS)技术是钢铁行业实现碳中和目标的可行选择,但是我国钢铁生产以高炉-转炉长流程生产为主,产生碳排放的工序众多且碳浓度较低,目前仍缺少经济高效的碳捕集方案。在此背景下,通过引入气化炉用于重整炉顶煤气,改进现有炉顶煤气循环-氧气高炉工艺的炉顶煤气循环方式,耦合富氧燃烧碳捕集技术,提出一种基于重整煤气喷吹-氧气高炉的富氧燃烧碳捕集方案,并利用Aspen Plus建模计算和碳流分析评估了该方案的节能减排潜力。结果表明:富氧燃烧碳捕集技术与氧气高炉低碳冶炼工艺有着良好的承接性与耦合性,两者耦合能够降低钢铁行业碳捕集的难度;富氧燃烧单位CO_(2)的捕集能耗为2623.91 kJ/kg,比现有的醇胺法的碳捕集能耗低51.4%,比变压吸附法的碳捕集能耗低26.2%;生产每吨钢材可通过富氧燃烧捕集到1.5 t CO_(2),有望实现钢铁生产过程的CO_(2)净零排放。总的来说,该方案能够在高炉低碳冶炼的基础上进行低成本、大规模的碳捕集,是钢铁行业绿色低碳转型的可行方案。
基金support for this project from the National Natural Science Foundation of China (21476145)the National 973 Program of Ministry of Sciences and Technologies of China (2011CB201202)
文摘The over-consumption of fossil fuels resulted in the large quantity emission of carbon dioxide （CO2）, which was the main reason for the climate change and more extreme weathers. Hence, it is extremely pressing to ex- plore efficient and sustainable approaches for the carbon-neutral pathway of CO2 utilization and recycling. In our recent works with this context, we developed successfully a novel ＂chemical vapor deposition integrated process （CVD-IP）＂ technology to converting robustly CO2 into the value-added solid-form carbon materials, The monometallic FeNi0-Al2O3 （FNi0） and bimetallic FeNix-Al2O3 （FNi2, FNi4, FNi8 and FNi20） samples were synthesized and effective for this new approach. The catalyst labeled FNi8 gave the better performance, exhibited the single pass solid carbon yield of 30%. These results illustrated alternative promising cases for the CO2 capture utilization storage （CCUS）, by means of the CO2 catalytic conversion into the solid-form nano carbon materials.
文摘2011年中期,浦项产业科学研究院在浦项厂建立了氨水捕集CO_2的中试工厂,高炉煤气处理能力为1 000 Nm^3/h,每天可生产10 t CO_2产品;装置运行中,通过废热回收系统提供吸收剂溶液再生所需的热能或蒸汽。技术数据显示,该套设备的CO_2去除率大于90%,CO_2产品纯度大于95%。该研究也是韩国海洋水产部推进的"CO_2海洋捕集封存技术"一部分,目前的研究方向主要是优化运输和封存CO_2的离岸基础设施。
文摘The chemical looping concept provided a novel way to achieve carbon separation during the production of energy or substances. In this work, hydrogen generation with inherent CO2 capture in single packed bed reactor via this concept was discussed. Two oxygen carriers, Fe203 60 wt.% and Fe2O3 55 wt.%/CuO 5 wt.% supported by Al2O3, were made by ball milling method. First, according to the characteristics of the reduction breakthrough curve, a strict fuel supply strategy was selected to achieve simultaneous CO2 capture and HE production. Then, in the long term tests using CO as fuel, it was proved that CuO addition improved hydrogen generation with the maximum intensity of 3700 μmol H2·g^-1 Fe2O3 compared with Fe-Al of 2300 μmol HE.g^-1 Fe2O3. The overall CO2 capture efficiency remained 98%- 98.8% over 100 cycles. Moreover, the reactivity of deactivated materials was recovered nearly like that of fresh ones by sintering treatment. Finally, two kinds of complex gases consist of CO, HE, CH4 and CO2 were utilized as fuels to test the feasibility. The results showed all components could be completely converted by Fe-Cu- Al in the reduction stage. The intensity of hydrogen production and the overall CO2 capture efficiency were in the range of 2000-2400 μnol H2^g^-1 Fe2O3 and 89%, 95%, respectively.
文摘Neutron radiative capture cross sections of <sup>56</sup>Fe（n,γ）<sup>57</sup>Fe reaction have beenmeasured in two incident energy ranges,from 9.3 to 16.0 MeV at 90° and from 9.0 to20.0 MeV at 55° and 125°.Time-of-flight technique is used to discriminate neutronsand gamma rays.The asymmetry of fore and aft γ-ray in this reaction is obtained.
