不同气氛下废弃风机叶片热转化产物研究

随着风电行业高速发展，我国淘汰废弃风机叶片量逐年增加，带来巨大的环保压力。对此，开展了不同温度中气氛对废弃风机叶片热转化过程中气、液、固产物生成特性影响研究，为今后热回收法处置风机叶片提供参考。结果表明：在N₂和CO₂气氛中，可燃气CH₄产量800℃下达到最高，而可燃气CO产量随温度上升而升高；各气氛中焦油成分主要为对异丙烯基苯酚、对异丙基苯酚和双酚A3种。实验中也发现气氛中CO₂的存在有效阻碍了高温时焦油中多环芳烃(PAHs)的生成，有利于焦油的后续处理。实验中还发现在低温(400℃)时Air和CO₂气氛下焦炭产率相比于N₂气氛较高，而在更高温度(600℃及以上)中结果相反，可能是由于低温下不同气氛中的焦炭芳香化程度不同引起。     

煤热解过程中多种挥发分生成特性研究

煤热解气(挥发分)组分对煤后续的热解、气化、燃烧等热化学行为有重要影响。为了测量挥发分成分,选取7种煤,测量其脱挥发分失重特性,利用气相色谱和傅里叶红外烟气分析仪对其中2种烟煤挥发分中的含碳氢、含氮、含硫等多达13种组分进行测量,并分析挥发分中的水分来源,结果表明：挥发分中体积分数最大的5种气体成分是CO、CO₂、H₂O、CH₄、H₂;低温下,挥发分中H₂O的体积分数最大,超过40%;高温下,H₂体积分数最大,超过55%。煤热解气中,水分含量与热解温度、煤种密切相关,水分主要来源于煤中的酚羟基在受热后的缩合反应。     

CO_2气氛影响烟煤流化床热解特性的实验研究

为了考察不同浓度的CO_2气氛对煤热解特性的影响,该文以陕西榆林烟煤为研究对象,在小型鼓泡流化床上开展实验研究。考察了CO_2气氛浓度对半焦、焦油、热解水和热解气体产物产率的影响。另外以600℃为例,考察了CO_2气氛对焦油组分、半焦表面官能团、半焦孔隙结构、元素组成和燃烧特性的影响。各温度下,热解产物半焦产率随CO_2浓度的提高而降低,在较高温度下(700和800℃)降低作用更明显。当CO_2浓度较低(10%)时,焦油产率受其影响不大,继续提高CO_2浓度时焦油产率有所提高而热解水产率受CO_2浓度的影响较小。热解气中CH_4产率随CO_2浓度的提高而提高,CO产率受CO_2浓度影响在800℃下最为明显。CO_2浓度越高H_2产率越低,C2~C3气体产率越高。提高CO_2浓度能减少焦油中重质组分相对含量,增加酚类的相对含量。半焦表面官能团中,CO_2浓度的提高抑制了羰基分解成CO_2,—OH伸缩特征峰随CO_2浓度的提高而减弱。半焦热重燃烧特性实验表明,随着CO_2浓度的提高,半焦的着火温度、最大燃烧速率对应温度以及燃尽温度都有所降低,而较高浓度(40%)下这一作用有所减弱。     

分段电极介质阻挡放电CO2重整CH4过程放电特性与反应性能研究

大气压低温等离子体可在温和条件下进行CO₂重整CH₄反应，对环境保护和能源供应具有双重意义。介质阻挡放电(DBD)是进行该反应最常用的放电等离子体形式之一，但其工艺过程和反应性能受到反应器结构的显著影响。前期研究发现，分段电极DBD可以调节CO₂重整CH₄反应过程的反应物转化率、产物分布及能量效率，但是分段电极数量和相邻电极间距对上述性能参数的影响机理尚不清晰。因此，该文设计了具有不同电极数量和不同相邻电极间距的分段电极DBD反应器，并用于CO₂重整CH₄反应，从电学特性和温度特性的角度研究了不同实验条件下的放电特性，比较分析了对应条件下的CO₂重整CH₄反应性能。结果表明，分段电极的引入可以增加放电边缘数量以增强边缘效应，且增加分段电极数量和增加相邻电极间距均可延长反应物的有效停留时间，上述因素均有助于提高等离子体CO₂重整CH₄的反应性能。在施加电压11.0 kV条...     

生物质焦炭颗粒气化过程模拟与分析

生物质能源的合理利用对减少环境污染和碳减排具有重要意义。本文利用气化过程的随机孔模型为工具,进行了半焦颗粒气化过程的数值计算,并对半焦气化的相关准则数进行了分析。结果表明:在1 123 K气化温度下,颗粒半径小于0.26 mm时气化过程由化学反应过程控制,颗粒半径在0.26~1.45 mm范围时由化学反应过程和CO₂扩散过程共同控制,当颗粒半径大于1.45 mm时,由CO₂扩散过程控制;气化温度在973~1 223 K时,随温度升高,CO₂的扩散过程对反应速率的影响逐渐增大,温度超过1 223 K时,CO₂扩散过程成为影响气化反应速率的主要因素。在实际气化中,可以采取减少焦炭粒径的方法加速气化过程,粒径应当控制在1.45 mm以下;如果颗粒粒径小于0.26 mm时可采取升高气化温度的方法加速气化,防止气化速率完全由CO₂扩散过程控制;对于1 mm焦炭颗粒,应当保持气化温度低于1 223 K。     

富氧燃烧气氛石灰石溶解特性研究

在实验室小型试验台上研究富氧燃烧气氛下湿法脱硫用石灰石溶解特性,研究结果表明：较高的CO₂浓度对石灰石的溶解有促进作用,CO₂体积分数在80%时,石灰石的溶解速率明显增大;在相同的pH值情况下,CO₂浓度越高,石灰石的溶解速率越快。在pH=4.5时,低浓度CO₂气氛比高浓度CO₂气氛下溶解时间增加70 min,CO₂浓度对溶解速率的影响比较明显。     

煤、污泥和生物质三类典型燃料的热解气生成特性研究

采用固定床热解装置测定并比较不同温度下煤、污泥和生物质三类典型燃料的热解气生成特性。结果表明，温度是影响热解气析出的重要因素，三类燃料的热解气产率均随温度升高而增大，同时还得出了各燃料热解产气速率最快的温度区间；提升热解温度有利于煤和污泥中燃料氮向N₂转化，1 300℃时，煤的N₂转化率最高约42.5%，污泥则接近60%；各燃料热解气组分以H₂、CH₄和CO为主，CO₂和N₂含量次之，C₂H₂和C₂H₄最低，污泥和煤的热解气各组分的析出特性相似；同温度下，五种燃料的H₂和CO产率大小顺序相同，均为辣椒秆、污泥、神混煤、石炭煤、韩城煤，对于辣椒秆和污泥而言，通过热解制取高热值燃气(H₂和CO)是一种有效利用途径。     

固定床神华烟煤高温中速热解特性研究

本文研究了中速热解过程中神华烟煤的组分析出规律,基于管式炉获得了不同热解压力和温度情况下神华烟煤的热解产物,分析了其热解机理。同时,对热解组分分布、产量和热解失重率规律进行研究。结果表明:在高升温速率下（可达100 K/s）,热解失重率随热解温度的升高而不断增加,随热解压力升高而降低;热解气组分以H₂和CO为主,CH₄和CO₂次之,C₃H₈和O₂含量几乎接近于零,析出顺序不尽相同,析出曲线表现为单峰或双峰分布;热解压力会对组分析出峰产生较大的影响;热解气产量随热解温度升高而增大,但其与热解压力呈非线性的变化关系。     

铜基催化剂对不同气氛下麦秆热解产生焦油和芳烃的作用

采用浸渍法制备铜基催化剂Cu/Al,并在横向管式炉中进行了麦秆的催化热解,研究在不同温度(600℃、700℃、800℃)及不同气氛(N_2或N_2+水蒸气)下催化剂对麦秆热解产物分布、焦油成分分布的影响。结果表明:在两种气氛下,Cu/Al催化热解产物中气相产率增加,而固相与液相产率下降,且热解气体产物与焦油成分随温度的变化趋势与Al_2O_3一致;在两种气氛下,Cu/Al均有利于促进挥发分二次裂解和抑制芳烃聚合,减少多环芳烃及其衍生物的生成。     

CO2体积分数对燃煤细颗粒物在水汽环境中凝结长大的影响

为研究燃煤烟气中CO₂体积分数对细颗粒物在水汽环境中凝结长大效果的影响,建立了计算模型并搭建了实验平台,分别从理论计算和实验研究两方面探讨了CO₂体积分数对细颗粒物凝结长大效果的影响。结果表明:随着CO₂体积分数升高,混合烟气的热、质扩散系数均降低,生长管内平均过饱和度增加,细颗粒物长大效果明显;管壁温度越高,随着CO₂体积分数的提高,细颗粒物粒径越大。     

Comparison of SF6/N2 and SF6/CO2 gas mixtures as alternatives to SF6 gas

The interest in SF₆ gas mixtures has been re-ignited in recent years by the issue of the greenhouse effect of the SF₆ gas, and most research work is now focused on a SF₆/N₂ gas mixture, which is suitable for application in electrical apparatus with slightly non-uniform fields. This paper presents a comparison of SF₆/N₂ and SF₆/CO₂ gas mixtures with a viewpoint of their possible applications to gas-insulated transformers, where both highly non-uniform field problems and partial discharges in gas/film insulation are inevitable. It is shown that in this case the dielectric strength of SF₆/CO₂ is superior to that of SF₆/N ₂ with a minor disadvantage related to the gas decomposition in SF₆/CO₂. However, this may not be a problem for the SF₆/CO₂ gas mixture to be used in gas-insulated transformers, where internal breakdown is not allowed     

Ferroelectric behaviors of sandwich structured PbZr0.52 Ti0.48O3/Pb(Mg1/3Ta2/3)0.7Ti0.3O3/PbZr0.52Ti0.48O3 thin film

Sandwich structured PbZr_0.52Ti_0.48O₃/Pb(Mg_1/3 Ta_2/3)_0.7Ti_0.3O₃/PbZr_0.52Ti_0.48O₃ (PZT/PMTT/PZT) thin films have been successfully synthesized via a combined route involving sol-gel and RF magnetron sputtering. Insertion of the PMTT interlayer effectively suppressed formation of the heterogeneous “rosette” structure of PZT thin film when deposited onto Pt/Ti/SiO₂/Si substrate. While both remanent polarization and coercive field were lowered for the sandwich structured films, the coercive field was reduced more significantly. Such sandwich structured films exhibit improved fatigue behavior and the relative permittivity can not be simply described as a series connection of individual components of perovskite layers.     

Recovery of SF6 from N2/SF6 gasmixtures by using a polymer membrane

The investigation of gas recovery from N₂/SF₆ gas mixtures using a polymer membrane has been reported. It has been shown that the purity of recovered gas, the recovery loss, and the gas handling speed depend on various parameters such as original gas mixing ratio, gas feeding pressure, gas flow rate, and temperature of the membrane. A gas recovering system with two membrane separators connected in cascade has proved to be very efficient in attaining high purity in a recovered gas, with negligibly small recovery loss and high handling speed for practical use. Furthermore, this system could be applied for CO₂/SF₆, He/SF ₆ and even for ternary mixtures such as N₂/CO₂/SF₆ without any modification in the system, where we expect much better performance in comparison with N ₂/SF₆     

基于PQ控制策略的光伏电源对电网电压的影响及改善

分布式光伏发电接入配电网会对系统节点电压产生诸多影响。文章分析了分布式光伏电源接入配电网的PQ(有功/无功功率)控制原理,建立了分布式光伏电源接入配电网典型低压配电线路的模型。对于同一输电线路,先从理论上分析了分布式光伏接入对配电网网络负荷各点电压的影响,然后在Matlab/Simulink环境下验证了理论的正确性。文章详细研究了分布式光伏电源以不同容量接入和在不同位置接入对配电网的影响,并且针对分布式光伏电源接入配电网带来的电能质量问题给出了解决措施和对策。     

Dielectric study of thin films of Ta2O5 andZrO2

Electronic conduction in sputtered Ta₂O₅ and ZrO₂ thin films have been studied using impedance spectroscopy, isothermal transient ionic current, and current-voltage measurements. The dielectric properties of Ta₂O₅ were shown to be sensitively dependent on deposition parameters with two different frequency responses: a flat loss behavior with very low DC conductivity, or a relaxation peak together with a somewhat higher DC conductivity. ZrO₂ has different dielectric properties when fresh, i.e. newly deposited, or aged. A fresh sample arbitrarily can show two different behaviors, consisting of a DC conductivity with a relaxation peak superimposed on it. The DC conductivity shows either of two different values. The aged sample has a lower permittivity and DC conductivity, and the relaxation peak is found at much lower frequencies. Fresh samples of ZrO₂ also show switching behavior     

Co2O3掺杂WO3陶瓷的电学特性

采用常规的电子陶瓷工艺制备了Co0.04W0.96O3多晶陶瓷,并对样品进行了微观形貌、相结构及Ⅰ-Ⅴ特性测试分析,发现Co0.04W0.96O3多晶陶瓷存在着奇特的负微分电阻特性.微分电阻随电场变化的曲线图揭示了CoW缺陷有着与众不同的特点,正是这种缺陷的存在使得多晶陶瓷具有负微分电阻特性.主要讨论了Co0.04W0.96O3多晶陶瓷负微分电阻特性的产生机制,并提出了二次势垒模型.     

Room Temperature Magnetoresistance at Low Magnetic Fields in La0.7 Ba0.3 MnO3

This paper examines the possibility of enhancing the room temperature magnetoresistance at low applied magnetic fields in single layer La_0.7 Ba_0.3 MnO₃ thin films. The influence of lattice mismatch strain, as well as the effect of different frequency regimes, on the magnetoresistance is explored. The effects of lattice mismatch strain are studied by measuring the magnetoresistance as a function of the La_0.7 Ba_0.3 MnO₃ film thickness, oxygen annealing, and lattice matched buffer layers. We find that the release of the lattice mismatch strain improves the magnetoresistance at room temperature and at low magnetic fields. In fact, the highest magnetoresistance at room temperature (–1.7% at 500 Oe) has been found for the 1600 Å as-grown La_0.7 Ba_0.3 MnO₃ film, whereas the largest magnetoresistance (–1.9% at 500 Oe) is found at 309 K for the 1000 Å La_0.7 Ba_0.3 MnO₃ film annealed in flowing O₂ for 1 h at 900°C. Finally, we find that the microwave magnetoresistance is the same as the dc magnetoresistance when the cavity corrections are applied. In the single layer La_0.7 Ba_0.3 MnO₃ system, the low field magnetoresistance at room temperature is far from being technologically viable.     

1865140型(LiMn2O4+LiNi1/3Co1/3Mn1/3O2)/Li4Ti5O12电池的性能

使用锰酸锂(LiMn2O4)、镍钴锰酸锂(LiNi1/3 Co1/3Mn1/3O2)混合正极材料和钛酸锂(Li4 Ti5 O12)负极材料,制备了中倍率1865140型锂离子电池.制备的电池在12 min内可充满电池容量的80％以上,且电池表面温度不超过35℃;在室温下以2.00 C循环1 200次,容量保持率高于91％;在高温55℃下以1.00 C循环1 000次,容量保持率高于82％.FreedomCAR混合脉冲功率特性表明:在放电深度(DOD) 10％ ～ 70％内、10s脉冲充放电状态下,电池的阻抗都在9 mΩ以下;50％DOD时的10s放电比功率为372 W/kg,充电比功率为520 W/kg.     

Li(Ni0.4Co0.2Mn0.4)O2包覆Al2O3对隔膜形貌及结构的影响

以Al2O3包覆前后的Li(Ni0.4Co0.2Mn0.4)O2为正极活性物质,中间相炭微球(MCMB)为负极活性物质,与聚丙烯(PP)-聚乙烯(PE)-PP三层隔膜组装成18650型锂离子电池,在循环不同次数后,用SEM观察隔膜形貌,XRD分析其精细结构.在电池的循环过程中,隔膜出现微孔闭合及微观结构改变;包覆抑制了隔膜中微孔的闭合,同时提高了结构稳定性.     

YBa2Cu3O7

Some background information on superconducting ceramics is given, and the history of yttrium barium copper oxide (YBCO) is discussed. The crystal structure of superconducting YBCO is described. The production and extraction methods of bulk samples of YBCO are detailed. Different theories of superconductivity in YBCO are addressed, and applications of YBCO superconductors are discussed