超低排放机组双塔双循环脱硫系统能耗物耗特性分析

为系统分析双塔双循环脱硫系统能耗物耗特性,通过对53台双塔双循环脱硫系统电耗、水耗和石灰石耗量情况进行测试,研究入口SO₂浓度、液气比、pH值以及Ca/S比对单位质量SO₂脱除能耗物耗特性的影响。结果表明,双塔双循环脱硫系统SO₂脱除成本中脱除能耗成本占整体脱除成本的55%~80%,而脱除能耗中循环浆液泵电耗占总能耗的50%~70%,一二级吸收塔的SO₂单位脱除能耗均随入口SO₂浓度的增高而降低,二级吸收塔的SO₂单位脱除能耗远大于一级吸收塔,一二级吸收塔内SO₂单位脱除能耗均随pH 值的升高而先降后增。因此,为降低双塔双循环脱硫系统单位质量SO₂脱除能耗物耗水平,一级吸收塔入口SO₂质量浓度应控制在4 000~6 000 mg/m³,浆液pH值应控制在5.2左右;二级吸收塔入口SO₂质量浓度应控制在1200 mg/m³,浆液pH值应控制在6.0左右。     

三乙烯四胺合钴溶液同时脱硫脱硝的实验研究

采用三乙烯四胺合钴溶液作为吸收液,在填料塔内对模拟烟气进行了湿法同时脱硫脱硝的实验研究。主要考察不同吸收液浓度、温度、pH值和SO2浓度对NO脱除效率的影响。研究结果表明:三乙烯四胺合钴溶液的浓度越高,NO的脱除率越高;温度对NO的脱除有较大影响,最佳反应温度为50℃;填料塔内吸收液的最佳pH值为9.4;SO2的进口浓度越大,NO的脱除率越低。     

增效剂对电厂脱硫装置性能影响的试验研究

在湿法烟气脱硫试验平台上,针对我国烟气脱硫装置运行过程中普遍存在的承受恶劣烟气状况能力弱、脱硫装置效率较低、投运率不高等问题,系统开展了增效剂与脱硫效率、固态石膏CaCO3残余量、系统能耗以及液气比与脱硫效率、浆液pH值与系统钙硫比等关键参数相互之间关系的试验研究。试验结果表明:加入增效剂后,提高了低pH值下石膏浆液中残余碳酸钙含量,改善了系统内SO2脱除过程,导致系统总运行成本降低,但吸收塔石膏浆液内Ca/S比明显增大,为保证石灰石利用率,系统操作时pH值宜控制在5.2左右。     

湿式脱硫系统运行性能的数值模拟

分析了影响湿式石灰石-石膏法脱硫装置脱硫效率的主要因素,并对主要影响因素如液气体积比、浆液pH值、装置入口SO2浓度、钙硫质量比、烟气流速和烟气温度与脱硫效率之间的关系进行了回归分析。     

富氧燃烧模拟烟气石灰石-石膏湿法脱硫试验研究

为了研究富氧燃烧情况下烟气石灰石-石膏湿法脱硫系统的效率,在自行搭建的富氧燃烧烟气石灰石-石膏湿法脱硫实验台上进行脱硫试验,通过控制脱硫系统中的CO₂浓度（体积分数14%、60%、70%、80%和90%）,研究富氧燃烧气氛下不同烟气流速、液气比、入口SO₂浓度以及浆液pH值对SO₂脱除特性的影响。发现随着烟气流速和入口SO₂浓度的增加,液气比和浆液pH值的减小,脱硫效率逐渐减小,系统中CO₂浓度越大,脱硫效率越小;对不同CO₂浓度气氛和浆液pH下的石膏晶体进行粒度分析和SEM电镜扫描,发现浆液pH值和CO₂对石膏的结晶并不会产生明显的影响。     

湿式氨法烟气脱硫工艺影响因素的试验研究

在冷态试验条件下,于小型逆流喷淋塔脱硫系统上考察了湿式氨法脱硫工艺参数对脱硫效率的影响。结果表明:pH值是影响脱硫效率的主要因素,当脱硫液pH值从4.5升至5.0时,脱硫效率从69.6%增至94.1%,过高的pH值会增大氨逃逸率,适宜pH值为5.5~6.0之间;适当增加烟气停留时间和液气比有助于提高脱硫效率,而提高入口SO2烟气浓度会降低脱硫效率。     

电石渣–柠檬酸复合浆液吸收去除烟气SO_2动力学

在喷淋吸收装置中对电石渣–柠檬酸复合浆液吸收SO2动力学和工艺进行了系统研究,结果表明：添加5 mmol/L的柠檬酸,其脱硫率从58.9%增加到77.3%。电石渣浆液中添加柠檬酸有利于烟气脱硫,一方面在液固界面上增强了H＋的传质推动力,减小OH＋的传质距离,提高了反应面上H＋浓度,加速电石渣的溶解;另一方面,在气液界面上形成了缓冲体系,降低了液膜反应区pH变化速率,减小H＋累积引起的阻碍效应,使界面上允许有较高的SO2浓度,强化了气液传质能力,提高SO2吸收反应。电石渣–柠檬酸复合浆液的脱硫效率随烟气SO2浓度和系统液气比的增加先升高后降低,随浆液pH值的增加而升高,随反应温度的提高而减小;其反应动力学为一级反应动力学,总反应级数n=1.1403,反应活化能Ea=14.514kJ/mol,频率因子为13.8278min 1。     

湿式脱硫装置脱硫效率的回归分析

分析影响湿式石灰石一石膏法脱硫装置脱硫效率的主要因素，推导脱硫效率的表达形式，并对主要影响因素(浆液pH值、液气比L／Q、装置入口SO2浓度)与脱硫效率间的关系进行回归分析，建立数学模型，为湿式石灰石一石膏法脱硫装置的设计、运行、维护和脱硫效率的预测提供依据。     

O3 /NaClO气液相氧化吸收剂同时脱硫脱硝试验研究

提出以O₃/NaClO为复合吸收剂对火电厂烟气进行同时脱硫脱硝的方法,研究了该方法在不同条件下的脱硫脱硝效率。模拟实际工况,给定SO₂与NO的初始质量浓度分别为600 mg/m³ 和500 mg /m³。模拟试验结果表明：在臭氧投加量为5.35 g/h,NaClO摩尔浓度为15 mmol/L,吸收液初始pH值为5,液气比为50 L/m³,反应温度为50 ℃时,脱硫和脱硝效率分别可达97.04%和95.08%。所研究的方法工艺操作简单,脱除SO₂和NO_x速度快,不存在堵塞、结垢等问题,若能有效降低O₃的生产成本,则具有较好的实用意义和推广应用前景。     

600MW机组湿法脱硫效率降低的原因分析及对策

针对王滩电厂600 MW机组湿法烟气脱硫系统经常出现效率降低的问题,通过对SO2吸收过程的机理进行分析,结合王滩电厂脱硫系统投产5年来的运行经验,找出了造成脱硫效率降低的几个主要因素:入口SO2浓度波动较大、吸收塔浆液pH值控制不合理、液气比不足、氧量折算、粉尘浓度超标、石灰粉品质差、旁路档板门密封不严、仪表不准等.采...     

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.     

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。     

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     

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     

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.     

Ferroelectricity in Aurivillius-Type Structure Ceramics with n = 2 and (SrBi2Nb2O9)0.35(Bi3TiNbO9)0.65 Composition

Aurivillius-type structure compounds are good candidates for their use as high temperature piezoelectrics, due to their high ferro-paraelectric phase transition temperature. However, this characteristic correlates with a high coercive field that makes difficult the poling process, necessary to have piezoelectric activity. The electric properties, specially conductivity, limit the maximum poling field. On the other hand, piezoelectric properties are directly related to the ferroelectric remanent polarization. Thus, the study of both characteristics is towards improving the piezoelectric properties of these materials. In this work, ceramics with nominal composition (SrBi₂Nb₂O₉)_0.35(Bi₃TiNbO₉)_0.65 (T_C∼ 760^∘C), prepared by hot pressing of mechanically activated precursors, have been studied. The electrical properties (permittivity, dielectric loss factor and d.c. conductivity) as a function of frequency and temperature have been measured, up to temperatures higher than the ferro-paraelectric phase transition, and their anisotropy explained in terms of the ceramic texture. Well-saturated ferroelectric hysteresis loops at 250^∘C have been obtained, with values of P_r = 21.4 μ C/cm² and E_c = 70.4 kV/cm.     

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.     

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     

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.