[目的]随着新能源的大规模应用,新能源发电并网面临的挑战不断突显,储能系统的重要性日益上升。二氧化碳储能(Carbon Dioxide Energy Storage,CES)技术是近年来兴起的一种压缩气体储能技术,具有储能密度大、寿命长、系统设计灵活等优势...[目的]随着新能源的大规模应用,新能源发电并网面临的挑战不断突显,储能系统的重要性日益上升。二氧化碳储能(Carbon Dioxide Energy Storage,CES)技术是近年来兴起的一种压缩气体储能技术,具有储能密度大、寿命长、系统设计灵活等优势。其中液态二氧化碳储能(Liquid Carbon Dioxide Energy Storage,LCES)技术在系统高压侧和低压侧均采用液相存储二氧化碳,储能密度高、运行稳定性强。[方法]文章首先介绍了LCES系统的运行原理和关键技术指标,指出二氧化碳液化的重要性和常见工艺。然后介绍了针对LCES系统低压侧CO_(2)液化的研究现状,包括采用混合储能工质、自冷凝、利用LNG冷能、采用蓄冷器,详细分析了各种方式的特点。[结果]研究表明,采用蓄冷器是最具优势的方式。进一步分析蓄冷液化面临的技术挑战及发展前景具有必要性。[结论]研究为LCES系统CO_(2)液化技术的进一步发展提供了指导。展开更多
火电机组实现灵活性转型是构建新型电力系统、实现“碳达峰”“碳中和”目标的关键。为提升火电机组的灵活性,提出了小汽轮机驱动和电动机驱动液态压缩二氧化碳储能系统与火电机组耦合的方案,并建立了其热力学系统模型,采用热耗率和能...火电机组实现灵活性转型是构建新型电力系统、实现“碳达峰”“碳中和”目标的关键。为提升火电机组的灵活性,提出了小汽轮机驱动和电动机驱动液态压缩二氧化碳储能系统与火电机组耦合的方案,并建立了其热力学系统模型,采用热耗率和能量利用系数对系统进行评价,开展系统热力学性能对比分析,确立了最佳储能耦合方案。研究表明:储能阶段从凝结水泵出口抽取凝结水,吸收压缩热后返回7号低压加热器出口,释能阶段从中压缸排汽抽取蒸汽,加热膨胀后的CO_(2)后返回5号低压加热器疏水冷却器时,耦合系统性能最佳,热耗率比原系统降低了48.308 k J/(k W·h),能量利用系数提升了0.52百分点;改变CO_(2)膨胀机入口温度和质量流量可实现快速变负荷,耦合储能系统后,机组调峰能力增加了17.1%;配置热水罐并最大放热时,机组调峰能力增加了37.4%,提升了火电机组灵活性。展开更多
Afforestation and reforestation are effective and ecological ways of mitigating elevated atmospheric carbon dioxide(CO2) concentration and increasing carbon(C) storage in terrestrial ecosystems. In this study, we meas...Afforestation and reforestation are effective and ecological ways of mitigating elevated atmospheric carbon dioxide(CO2) concentration and increasing carbon(C) storage in terrestrial ecosystems. In this study, we measured the above-ground(tree, herbaceous plants and litter) and below-ground(root and soil) C storage in an aspen plantation(Populus davidiana) monoculture(PD), a larch plantation(Larix pincipis-rupprechtii) monoculture(LP), a pine plantation(Pinus tabulaeformis) monoculture(PT), a larch and birch mixed plantation(L. pincipis-rupprechtii and Betula platyphlla mixed)(MLB), and an apricot plantation(Armeniaca sibirica) monoculture(AS) under the Desertification Combating Program in Hebei Province, the northern China. The objective was to assess the effect of afforestation species on ecosystem C pools of different plantation types. Results showed that C storage of LP stand(258.0 Mg/ha) and MLB(163.4 Mg/ha) were significantly higher than the C storage in PD(45.5 Mg/ha), PT(58.9 Mg/ha) and AS(49.4 Mg/ha), respectively. Soil C was the main carbon pool of the ecosystem C storage in the five plantation stands, ranging from 31.4 Mg/ha to 232.5 Mg/ha, which accounted for 69.0%–90.1% of the total ecosystem C storage. The C storage in tree layer was about 5.2%–23.2% of ecosystem C storage. The herbaceous plants and litter layers contained 1.0%–6.0% and 1.5%–3.3% of ecosystem C storage, respectively. Our results suggest that tree species should be incorporated to accurately develop regional C budget of afforestation program, and also imply that substantial differences in ecosystem C stocks among plantation types can facilitate decision making on C management.展开更多
The reaction of CO2 reforming of CH4 has been investigated with y-A1203-supported platinum and ruthenium bimetallic catalysts, with the specific purpose of thermochemical energy storage. The catalysts were prepared by...The reaction of CO2 reforming of CH4 has been investigated with y-A1203-supported platinum and ruthenium bimetallic catalysts, with the specific purpose of thermochemical energy storage. The catalysts were prepared by using the wetness impregnation method. The prepared catalysts were characterized by a series of physico-chemical characterization techniques such as BET surface area, thermo-gravimetric （TG）, transmission electron microscope （TEM） and X-ray photoelectron spectroscopy （XPS）. In addition, the amount of carbon deposits on the surface of the catalysts and the type of the carbonaceous species were discussed by TG. It was found that the bimetallic Pt-Ru/7-A1203 catalysts exhibit both superior catalytic activity and remarkable stability by comparison of monometallic catalysts. During the 500 h stability test, the bimetallic catalyst showed a good performance at 800 ~C in CO2 reforming of CH4, exhibiting an excellent anti-carbon performance with the mass loss of less than 8.5%. The results also indicate that CO2 and CH4 have quite stable conversions of 96.0 % and 94.0 %, respectively. Also, the selectivity of the catalysts is excellent with the products ratio of CO/H2 maintaining at 1.02. Furthermore, it was found in TEM images that the active carbonaceous species were formed during the catalytic reaction, and well-distributed dot-shaped metallic particles with a relatively uniform size of about 3 nm as well as amorphous carbon structures were observed. Combined with BET, TG, TEM tests, it is concluded that the selected bimetallic catalysts can work continuously in a stable state at the high temperature, which has a potential to be utilized for the closed-loop cycle of the solar thermochemical energy storage in future industry applications.展开更多
Semiconducting silicon(Si)nanomaterials have great potential for the applications in electronics,physics,and energy storage fields.However,to date,it is still a challenge to realize the batch production of Si nanomate...Semiconducting silicon(Si)nanomaterials have great potential for the applications in electronics,physics,and energy storage fields.However,to date,it is still a challenge to realize the batch production of Si nanomaterials via efficient and low-cost approaches,owing to some long-standing shortcomings,e.g.,complex procedures and time and/or energy consumption.Herein,we report a green and inexpensive method to rapidly obtain two-dimensional(2D)free-standing Si/SiO_(x) nanosheets via the rapid thermal exfoliation of layered Zintl compound CaSi_(2).With the help of the rapid exfoliation reaction of CaSi_(2) in the atmosphere of greenhouse gas CO_(2),and the following mild sonication,2D free-standing Si/SiO_(x) nanosheets can be produced with very high yield.After applying the coating of a thin carbon outer layer,the electrodes of Si/SiO_(x)/C nanosheets serving as the anodes for lithium-ion batteries exhibit ultrahigh reversible capacity and outstanding electrochemical stability.We expect this study will provide new insights and inspirations for the convenient and batch production of nanostructural Si-based anode materials towards high-performance lithium-ion batteries.展开更多
文摘[目的]随着新能源的大规模应用,新能源发电并网面临的挑战不断突显,储能系统的重要性日益上升。二氧化碳储能(Carbon Dioxide Energy Storage,CES)技术是近年来兴起的一种压缩气体储能技术,具有储能密度大、寿命长、系统设计灵活等优势。其中液态二氧化碳储能(Liquid Carbon Dioxide Energy Storage,LCES)技术在系统高压侧和低压侧均采用液相存储二氧化碳,储能密度高、运行稳定性强。[方法]文章首先介绍了LCES系统的运行原理和关键技术指标,指出二氧化碳液化的重要性和常见工艺。然后介绍了针对LCES系统低压侧CO_(2)液化的研究现状,包括采用混合储能工质、自冷凝、利用LNG冷能、采用蓄冷器,详细分析了各种方式的特点。[结果]研究表明,采用蓄冷器是最具优势的方式。进一步分析蓄冷液化面临的技术挑战及发展前景具有必要性。[结论]研究为LCES系统CO_(2)液化技术的进一步发展提供了指导。
文摘火电机组实现灵活性转型是构建新型电力系统、实现“碳达峰”“碳中和”目标的关键。为提升火电机组的灵活性,提出了小汽轮机驱动和电动机驱动液态压缩二氧化碳储能系统与火电机组耦合的方案,并建立了其热力学系统模型,采用热耗率和能量利用系数对系统进行评价,开展系统热力学性能对比分析,确立了最佳储能耦合方案。研究表明:储能阶段从凝结水泵出口抽取凝结水,吸收压缩热后返回7号低压加热器出口,释能阶段从中压缸排汽抽取蒸汽,加热膨胀后的CO_(2)后返回5号低压加热器疏水冷却器时,耦合系统性能最佳,热耗率比原系统降低了48.308 k J/(k W·h),能量利用系数提升了0.52百分点;改变CO_(2)膨胀机入口温度和质量流量可实现快速变负荷,耦合储能系统后,机组调峰能力增加了17.1%;配置热水罐并最大放热时,机组调峰能力增加了37.4%,提升了火电机组灵活性。
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060600)Knowledge Innovation Programs of Chinese Academy of Science(No.KSCX2-EW-J-5)
文摘Afforestation and reforestation are effective and ecological ways of mitigating elevated atmospheric carbon dioxide(CO2) concentration and increasing carbon(C) storage in terrestrial ecosystems. In this study, we measured the above-ground(tree, herbaceous plants and litter) and below-ground(root and soil) C storage in an aspen plantation(Populus davidiana) monoculture(PD), a larch plantation(Larix pincipis-rupprechtii) monoculture(LP), a pine plantation(Pinus tabulaeformis) monoculture(PT), a larch and birch mixed plantation(L. pincipis-rupprechtii and Betula platyphlla mixed)(MLB), and an apricot plantation(Armeniaca sibirica) monoculture(AS) under the Desertification Combating Program in Hebei Province, the northern China. The objective was to assess the effect of afforestation species on ecosystem C pools of different plantation types. Results showed that C storage of LP stand(258.0 Mg/ha) and MLB(163.4 Mg/ha) were significantly higher than the C storage in PD(45.5 Mg/ha), PT(58.9 Mg/ha) and AS(49.4 Mg/ha), respectively. Soil C was the main carbon pool of the ecosystem C storage in the five plantation stands, ranging from 31.4 Mg/ha to 232.5 Mg/ha, which accounted for 69.0%–90.1% of the total ecosystem C storage. The C storage in tree layer was about 5.2%–23.2% of ecosystem C storage. The herbaceous plants and litter layers contained 1.0%–6.0% and 1.5%–3.3% of ecosystem C storage, respectively. Our results suggest that tree species should be incorporated to accurately develop regional C budget of afforestation program, and also imply that substantial differences in ecosystem C stocks among plantation types can facilitate decision making on C management.
基金Project(2010CB227103) supported by the National Basic Research Program of ChinaProjects(50930007,50836005) supported by the Key Program of the National Natural Science Foundation of ChinaProject(U1034005) supported by the National Natural Science Foundation of China
文摘The reaction of CO2 reforming of CH4 has been investigated with y-A1203-supported platinum and ruthenium bimetallic catalysts, with the specific purpose of thermochemical energy storage. The catalysts were prepared by using the wetness impregnation method. The prepared catalysts were characterized by a series of physico-chemical characterization techniques such as BET surface area, thermo-gravimetric （TG）, transmission electron microscope （TEM） and X-ray photoelectron spectroscopy （XPS）. In addition, the amount of carbon deposits on the surface of the catalysts and the type of the carbonaceous species were discussed by TG. It was found that the bimetallic Pt-Ru/7-A1203 catalysts exhibit both superior catalytic activity and remarkable stability by comparison of monometallic catalysts. During the 500 h stability test, the bimetallic catalyst showed a good performance at 800 ~C in CO2 reforming of CH4, exhibiting an excellent anti-carbon performance with the mass loss of less than 8.5%. The results also indicate that CO2 and CH4 have quite stable conversions of 96.0 % and 94.0 %, respectively. Also, the selectivity of the catalysts is excellent with the products ratio of CO/H2 maintaining at 1.02. Furthermore, it was found in TEM images that the active carbonaceous species were formed during the catalytic reaction, and well-distributed dot-shaped metallic particles with a relatively uniform size of about 3 nm as well as amorphous carbon structures were observed. Combined with BET, TG, TEM tests, it is concluded that the selected bimetallic catalysts can work continuously in a stable state at the high temperature, which has a potential to be utilized for the closed-loop cycle of the solar thermochemical energy storage in future industry applications.
基金financially supported by the National Key Research and Development Program of China(2017YFA0208200 and 2016YFB0700600)the Fundamental Research Funds for the Central Universities of China(0205-14380219)+3 种基金the Projects of National Natural Science Foundation of China(22022505,21872069 and 51761135104)the Natural Science Foundation of Jiangsu Province(BK20181056,BK20180008 and BK20191042)Jiangsu Postdoctoral Science Fundation(2020Z258)the Funding for School-level Research Projects of Yancheng Institute of Technology(xjr2019006).
文摘Semiconducting silicon(Si)nanomaterials have great potential for the applications in electronics,physics,and energy storage fields.However,to date,it is still a challenge to realize the batch production of Si nanomaterials via efficient and low-cost approaches,owing to some long-standing shortcomings,e.g.,complex procedures and time and/or energy consumption.Herein,we report a green and inexpensive method to rapidly obtain two-dimensional(2D)free-standing Si/SiO_(x) nanosheets via the rapid thermal exfoliation of layered Zintl compound CaSi_(2).With the help of the rapid exfoliation reaction of CaSi_(2) in the atmosphere of greenhouse gas CO_(2),and the following mild sonication,2D free-standing Si/SiO_(x) nanosheets can be produced with very high yield.After applying the coating of a thin carbon outer layer,the electrodes of Si/SiO_(x)/C nanosheets serving as the anodes for lithium-ion batteries exhibit ultrahigh reversible capacity and outstanding electrochemical stability.We expect this study will provide new insights and inspirations for the convenient and batch production of nanostructural Si-based anode materials towards high-performance lithium-ion batteries.
