过氧化氢钝化电化学机理及应用

钝化作为电站锅炉化学清洗的最后一道工序,对锅炉化学清洗效果起着至关重要的作用。钝化工艺包括过氧化氢钝化、EDTA充氧钝化、丙酮肟钝化、联氨钝化、亚硝酸钠钝化等工艺,在电站锅炉化学清洗中应用较多的是亚硝酸钠钝化、联氨钝化和过氧化氢钝化等方式。过氧化氢钝化具有钝化效果好、钝化膜致密、废液易于处理等优点。介绍了过氧化氢钝化的原理,讨论了影响过氧化氢钝化效果的因素,实例表明过氧化氢钝化取得了良好效果。     

锅炉化学清洗中钝化工艺选择

分析山东百年电力公司6号、3号和4号锅炉化学清洗后炉水水质恢复过程,在汽包锅炉化学清洗中选择不同的钝化工艺,决定着整个清洗工作的成败,还影响着后续的锅炉化学监督工作。通过对比联氨和过氧化氢两种钝化工艺的优劣,确认过氧化氢是一种钝化效果较好、环保、经济的钝化剂。     

锅炉化学清洗钝化方法的试验研究和应用

对锅炉化学清洗中亚硝酸钠钝化法、过氧化氢钝化法、多聚磷酸盐钝化法、联氨钝化法、丙酮肟钝化法、磷酸三钠钝化法和碳酸钠钝化法进行了试验研究,并结合典型的应用实例,提出了选择这些钝化方法的建议和适合采用的钝化工艺.     

复合型钝化剂在锅炉酸洗中的应用

报导了过氧化氢—ＬＰ－１复合型钝化剂在火电厂新建１２５ＭＷ机组锅炉酸洗中的应用工艺和结果，并讨论了部分组份的作用机理．结果表明，该工艺完全能满足现代大型锅炉化学清洗中的钝化要求，生成的钝化膜致密、耐蚀性能良好，实现了钝化液的无毒排放     

锅炉钢在除垢－钝化液中的钝化研究

通常锅炉的化学清洗工艺从清洗除垢到钝化保护所需时间较长。用电化学方法研究了锅炉在除垢钝化液中钝化行为，并进行了实验。实验表明，采用“除垢－钝化”一步完成工艺可以使钢表面形成较好的保护膜，提高耐蚀性。     

锅炉钢在除垢—钝化液中的钝化研究

通常锅炉的化学清洗工艺有洗除垢到钝化保护所需时间较长。用是化学方法研究了锅炉在除垢钝化液中钝化行为，并进行了实验，实验表明，采用“除垢－钝化”一步完成工艺可以使钢表面形成较好的保护膜，提高耐蚀性。     

碱性双氧水钝化工艺在CFB锅炉中的应用

根据秦皇岛秦热发电有限责任公司循环流化床锅炉的特点确定了盐酸酸洗、柠檬酸漂洗、双氧水碱性钝化的优化清洗工艺,根据双氧水碱性钝化的特点,对常规的双氧水碱性钝化工艺进行了修改,并细化了常规的双氧水碱性钝化工艺控制参数。在本次流化床锅炉化学清洗实践中,钝化效果完全达到了亚硝酸钠钝化的水平。     

锅炉清洗后采用EDTA二钠做漂洗钝化剂试验

目前电站锅炉化学清洗后,采用传统的化学清洗钝化剂因不能满足环保、节能的要求而日益受到限制,因此很有必要开发新的钝化工艺.通过试验研究发现,电站锅炉化学清洗后可以直接采用EDTA二钠进行漂洗和钝化,为此开发了采用EDTA二钠进行漂洗和钝化一步完成的新工艺,并优选出能在金属表面形成良好钝化膜的工艺条件.     

柠檬酸漂洗双氧水钝化在运行炉除铜清洗中的应用

采用盐酸清洗硫脲先除铜,经过柠檬酸漂洗,碱性双氧水再除铜及钝化工艺,对锅炉本体受热面进行化学清洗,清除水冷壁中的沉积垢及铜垢,解决了炉水中磷酸盐消失现象,清洗和钝化效果良好。为同类型锅炉的化学清洗提供了经验。     

EDTA二钠盐用做漂洗钝化剂的应用研究

某发电厂对其1号炉锅炉本体进行了化学清洗,化学清洗采用先碱洗后EDTA二钠盐清洗,用小剂量EDTA二钠盐做钝化剂的钝化工艺.清洗结果证明,此钝化工艺钝化温度低、时间短、现场实施简单、钝化膜优良并能满足环保节能的要求;化学清洗后首次启动和冲洗所用水量大大减少,且水汽品质合格时间短.     

氢氧等离子体合成过氧化氢过程的能效研究

为提高氢氧等离子体合成H2O2技术的能量效率,通过分析放电过程的反应器能效及电源能量注入效率,确定了影响合成总能效的主要因素。考察了反应器电极间距、电源放电频率及注入功率对反应器能效和电源能量注入效率的影响。发现减小电极间距、提高放电频率和注入功率有利于提高反应器能效,但不利于提高电源能量注入效率。本研究中可以得到150 gH2O2/kWh的反应器能效,但由于较低的电源能量注入效率,致使合成H2O2的总能效不超过9 gH2O2/kWh。因此,提高等离子体法合成H2O2过程的总能效,不仅需要设计高能效的等离子体反应器,还需为反应器负载开发适配的电源,而后者是提升该技术能量效率的关键。     

Electron-Ion Transport in ZrO2-Y2O3-CeO2 Ceramics

Simultaneous conduction of oxide ions and electrons in solid ceramic systems provides the capability for oxygen transport under a concentration gradient without the need for an externally applied electric field. In the present study, ionic transference numbers have been measured in the ZrO₂-5.8%Y₂O₃-10%CeO₂ system by open circuit Emf measurements involving different metal/metal oxide electrodes. In order to correlate the ionic transference number with grain size, high-density ceramic discs of different grain sizes (50 nm–5 m) were prepared by sintering pressed powders at various temperatures and times. Hydrothermal synthesis was used to prepare nanocrystalline powders of the above material with uniform crystallite size (10 nm) and chemistry. Emf measurements on the samples suggested both ionic and electronic transport, the ionic transference number decreasing with increase in the grain size. This observation was attributed to an increase in the amount of continuous crystalline grain boundary phase in the ceramics as the grain size increased. The presence of crystalline silicate and zirconate phases in the grain boundary region was confirmed by electron microscopic imaging combined with microanalysis. In the large grain (5 m) ceramics, the ionic transference number decreased linearly with temperature. As the grain size decreased, a maximum occurred in the ionic transference number vs. temperature curve. This maximum became more pronounced at smaller grain sizes. Better grain-grain contact and the doping effect of trivalent Ce in the grain boundary core are proposed to explain this observation.     

RuO_2-IrO_2-TiO_2析氧催化剂的制备工艺

以Ti N、RuCl3和H2IrCl6为原料,用真空浸渍-热分解法制备了RuO2-IrO2-Ti O2,研究了煅烧温度和n(Ru+Ir)∶n(Ti)对产物的影响。XRD分析表明:Ti N在高温煅烧时氧化生成金红石型Ti O2,RuO2、IrO2和Ti O2以固溶体的形式存在。CV、阳极极化曲线和EIS测试表明:RuO2-IrO2-Ti O2的最佳煅烧温度为400℃,随着n(Ru+Ir)∶n(Ti)的提高,催化剂的活性增强;在相同电位下,RuO2-IrO2-Ti O2的电流密度大于IrO2,可用作固体聚合物电解质(SPE)水电解催化剂。     

富氧火焰原子吸收光谱法测定铅钙锡合金中的锡

采用富氧火焰 (Air—C2 H2 —O2 )原子吸收光谱法直接测定铅钙锡合金中 0 1%以上的锡。对仪器工作条件、测定体系酸度、共存离子干扰等作了研究。方法准确度高 ,结果重现性好     

Thermoelectricity of p-Fe2O3-SO3-SiO2-others and n-Fe2O3-SiO2-CuO-others

Thermoelectric minerals have been found at Loei Province, in the northeastern part of Thailand. Local mineral specimens were prepared in the powders and bulk solids form by crushing, calcination and annealing, pressure and sintering, cutting and polishing. Mineral samples were used to analyze the composition and phase, determine the thermoelectric property and efficiency, design and construct a thermoelectric generator. Chemical composition and phase identification of powder samples were analyzed by the x-ray fluorescence (XRF) and x-ray diffraction (XRD), respectively. XRF and XRD results indicated that the mineral samples comprised the SO₃-CaO-SiO₂-others, Fe₂O₃-SO₃-SiO₂-others, Fe₂O₃-SiO₂-others and Fe₂O₃-SiO₂-CuO-others. From the thermoelectric property and efficiency determinations, the p-SO₃-CaO-SiO₂-others, p-Fe₂O₃-SO₃-SiO₂-others, n-Fe₂O₃-SiO₂-others and n-Fe₂O₃-SiO₂-CuO-others bulks were found to exhibit the thermoelectric figure of merit in orders of 10^?14, 10^?11, 10^?14 and 10^?13 K^?1, respectively. A fabricated thermoelectric generator made from ten pairs of p-Fe₂O₃-SO₃-SiO₂-others and n-Fe₂O₃-SiO₂-CuO-others legs that can be provided the open circuit voltage and short circuit current up to 48.30 mV and 0.14 μA for a temperature difference of 39.80 K at room temperature, respectively. While the internal resistance decreased and reached a value of 665 kΩ.     

Mixed Hydroxide Precursors for La2Ti2O7 and Nd2Ti2O7 by Homogeneous Precipitation

Feasibility of formation of stoichiometric precursors of either M₂ (TiO)₂(C₂O₄)₅ 4H₂O (M = La and Nd) or coprecipitated hydroxides of M(OH)₃+TiO(OH)₂ was investigated by two solution routes at different pH values. Composition of precipitates obtained at pH = 7.0 by coprecipitation method starting from La or Nd nitrates and potassium titanyl oxalate corresponded to a physical mixture of La or Nd(C₂O₄)₃ 9.5H₂O and TiO(OH)₂7·H₂O which on thermal decomposition did not yield phase pure M₂Ti₂O₇. However, precipitation from La or Nd nitrates and titanium tertrachloride by urea hydrolysis yielded homogeneous mixture of hydroxides of La or Nd and Ti, which on pyrolysis at 950°C yielded phase pure La₂Ti₂O₇ and Nd₂Ti₂O₇. Use of potassium titanyl oxalate as precursor for Ti, led to selective precipitation of La or Nd oxalate even at pH as low as 0.1 leading to sequential precipitation of La or Nd oxalate followed by Ti hydroxide at pH = 3.0. The resultant precipitate on pyrolysis underwent typical solid-state reaction.     

pH-MnO_2电极电位与MnO_2活性

本文对用于电池的MnO_2进行电化学评价,测定不同产地锰矿的pH—电极电位关系,每个样品的模拟制作,锌—锰干电池并测定共放电容量,通过比较放电容量和MnO_2的电极电位,从而对MnO_2进行活性评价。     

过氧化氢钝化工艺的改进

传统的过氧化氢钝化工艺较难掌握，钝化条件比较苛刻，钝化效果一般，还容易出现一种褐色不明附着物。经过大量试验研究，对过氧化氢钝化工艺进行了改进，钝化效果明显提高。     

Dielectric and Piezoelectric Properties of Nonstoichiometric SrBi2Ta2O9 and SrBi2Nb2O9 Ceramics

Nonstoichiometric SrBi₂Ta₂O₉ (SBT) and SrBi₂Nb₂O₉ (SBN) ceramics were prepared by a solid state reaction method. X-ray diffraction analysis showed that single-phase of Bi-layered perovskite was obtained. With different Sr/Bi content ratios of SBT and SBN, Curie temperature (T_C), electromechanical factor (K_p) and mechanical quality factor (Q_m) were measured. T_C of SBN (SBT) rose from 414C (314C) to 494C (426C) when Sr/Bi content ratio was increased from 0.55/2.3 to 1.2/1.8. In the most Sr-deficient/Bi-excess ratio of 0.55/2.3, the maximum values of Q_m were obtained approximately 1013 and 3325 for SBT and SBN, respectively.