300MW级供热机组高压厂用电压等级选择

针对目前国内300MW双抽供热机组高压厂用负荷的特点，通过对6kV／50kA及10kV／40kA两种高压厂用电压进行分析和比较，得出采用6kV／50kA方案在技术经济性上更优的结论。     

成都精维电解材料厂EC-1、EC-2石棉绒在我厂使用概况

宁夏青铜峡树脂厂是1992年投产的年设计能力为年产12000t金属阳极隔膜烧碱，随着市场需求增大，1994年技改将30Ⅲ型电解槽增加到32台，电流由40kA左右提高到48kA～50kA运行，现实际生产能力已达到年产18000t烧碱。而我们所用隔膜材料石棉绒，全部是成都精维电解材料厂生产的EC－1和EC－2。基本上保证了我厂烧碱装置的稳定运行。1问题的提出1994年技改之前，电流一般在40kA左右运行，使用成都精维电解材料厂的石棉绒基本正常，但随着技改后，电流提到48kA～50kA运行时，曾出现过电槽运行周期短、碱液浓度上升快、氛中含氢高等一些问题。…     

金属阳极隔膜碱恢复生产总结

盐锅峡化工厂2万t/a金属阳极隔膜碱于1987年立项，1990年1月建成投产。采用30-Ⅲ小极距(极距7.5 mm)电解槽共42台，设计运行电流45kA，最大运行电流51 kA。但是，由于甘肃境内隔膜碱严重供大于求，导致金属阳极电解槽长期低电流运行，运行电流在20～25 kA，达不到行业推荐经济电流密度1.3～1.5kA/m2水平，而且开工率偏低。……     

离子膜法烧碱装置高负荷运行的经济性分析

对离子膜法烧碱装置在10．0kA和10．2kA负荷下的运行数据进行技术经济比较，说明10．2kA下运行能缓解氯气的短缺，但对膜和槽框有一定的影响；同时，增加的氯气量有限，经济效益不明显。结论是，扩能改造才是解决氯气不足的最佳途径。     

氯碱电解槽内压力波动的混沌分析及流型识别

为研究氯碱电解槽内气液两相流动的压力波动特性和流型特点，对冷模电解槽阳极室内循环板上开口处的压力信号进行了混沌特性分析；利用高速摄像仪照相法及Kolmogorov熵下降法对流动形态进行了识别，绘制了流型图；利用流型图对不同电流密度下的两相流型进行了判定。结果表明，电解槽压力信号的吸引子具有分数维数，当电流密度大于6 kA·m^-2时，Lyapunov指数大于0，说明电解槽内两相流动具有混沌特性；对于测压点位置及电解槽下部，当电流密度小于5 kA·m^-2时，分别为射流充分发展段和孤立气泡流；电流密度为5 ~ 8 kA·m^-2时为射流过渡段和合并气泡流；电流密度大于8 kA·m^-2时为射流的初始段和合并气泡流。     

电沉积制备Co-Pt-Mo磁性薄膜

通过电沉积方法在铜基底上制得Co-Pt-Mo磁性薄膜。通过对镀液的循环伏安分析,确定了合适的沉积电位。研究了pH值对薄膜的成分、表面形貌、结构以及磁性能的影响。结果表明:随着pH值的增大,薄膜中Co的质量分数从26.9%逐渐增加到63.8%,矫顽力与比饱和磁化强度分别从0.3kA/m和189kA/m增加到24.1kA/m和1 283kA/m。     

高矫顽力铁氧体膜的制作及其在硬盘介质上的应用

采用溅射法制作高密度硬盘所必须的钡铁氧体膜及其磁特性的改进。垂直磁记录介质用的钡铁氧体溅射膜采用Xe（氙）溅射法来制作，可以将矫顽力控制在160kA／m（2kOe）左右，并改善了饱和磁化值。另外，在Co系铁氧体膜中，通过Co离子与Zn的置换，可将其作为记录介质显得过高的矫顽力239～320kA／m（3～4kOe）控制在80～320kA／m（1～4kOe）之间。实际上，对Co－Zn铁氧体股制作的硬盘进行记录和重放的实检表明膜的结晶性及矫顽力的大小对记录特性有很大的影响     

交流4.电耗高时宜及时改造电解槽

正A:问一下,各位的电解槽能否满负荷运行?交B:90%。AC:为什么不满负荷运行?B:满负荷运行时,单耗有点高。C:电又不是白耗的,出产品了么。D:你们以前高电流密度电解槽12.0 kA和13.0 kA时直流单耗相差多少?A:差10多kW·h。C:我们设计是13.5 kA,肯定是开到13 kA以上好。     

频繁升、降电流对隔膜烧碱生产装置的影响

高负荷电流每升降1kA,电解液质量浓度升降3～4g L;若电流低于49kA,则阳极液浓度无法调解。频繁升、降电流会恶化电解槽运行状况,降低经济效益(电流每升降1kA,每吨碱直流电耗上升10～14kW·h)。电流变化还易造成氯气、氢气压力波动,影响生产环境,危及生产安全。     

提升运行电流增加烧碱产量

通过改进原有吸附工艺,并在真空状态下苛化石棉浆,使石棉绒分散得更加均匀,探索出适合高电流密度下运行的隔膜吸附工艺.2002年,将原24kA电流提高到25kA,全年产量增加3 000余t,且电耗由2 450kW·h/(t·NaOH)降至2 435 kW·h/(t·NaOH);2003年,将电流提高到25.5 kA,全年产量又增加800余t.     

不同进电方式对铝电解槽阳极电流非接触式测量的影响

针对目前铝电解槽阳极电流在线测试方法的不足,基于铝电解槽电磁场的理论,借鉴国外学者通过测试导杆附近的磁场来得到阳极电流的思想,提出了一种阳极电流非接触式测试方法,并着重针对铝电解槽不同的进电方式分析了阳极电流的测量误差,并对误差进行了修正,对测试方案进行了优化,旨在实现阳极电流的实时监测和在线控制。研究结果表明,300 kA大面五点进电槽的阳极电流测量误差可以控制在±0.25%之内,而400 kA大面六点进电槽、200 kA大面四点进电槽的阳极电流测量误差分别达到了±0.8%和±3%;可见不同进电方式对阳极电流的测量误差有较为明显的影响,但最大误差均不超过3%。因此,对于不同进电方式及结构的铝电解槽阳极电流的在线监测,该非接触式测试方法均具有较好的适用性。     

高石墨质铝用阴极冷捣糊的研制

为满足提高大型预焙电解槽筑炉质量及减少工作环境污染的需要,成功地开发出一种施工温度34-38℃,超过国家行业标准的铝用阴极高石墨质冷捣糊.该铝用阴极高石墨质冷捣糊在240 kA大型预焙电解槽上的筑炉应用、焙烧启动和电解槽的实际使用证明,效果良好,达到了预期目标.     

Hydrogen consuming anodes for energy saving in sodium sulphate electrolysis

Gas diffusion electrodes, made of PTFE-bonded carbon with precious metal catalysts, were investigated as hydrogen consuming anodes in sodium sulphate electrolysis. The catalysts used were platinum and palladium and mixtures of both metals, prepared by two different methods. Various metal meshes were used as current collector. The electrodes performed well in pure sulphuric acid (5–15 wt-%) and in mixtures with sodium sulphate (10 wt-%) at temperatures of 30 to 70°C and current densities up to 5 kA/m². In long-term experiments, at a current density of 2.6 kA/m², the electrodes were stable over three months. The electrodes were characterised by stationary current density/potential curves and by galvanostatic current interruption measurements.     

An experimental study of a fixed bed chlor-alkali reactor

A 100 A continuous ‘flow-by’ chlor-alkali membrane reactor was constructed with both anode and cathode consisting of fixed beds of 0.6 to 1 mm diameter graphite particles. The reactor was operated over a range of conditions with and without co-current flow of air or oxygen to the cathode. With an anolyte of 5 M NaCl and catholyte 1.4–3 M NaOH the reactor produced sodium hydroxide and chlorine with ≥80% efficiency at temperatures 28–100°C, absolute pressure 270–970 kPa and superficial current density up to 3.3 kA m^?2. For operation at 100°C and an average pressure of 870 kPa with no gas delivered to the cathode, the cell voltage increased linearly from 2.5V at 0.3 kA m^?2 (10 A) to 4.0 V at 3.3 kA m^?2 (100 A). When oxygen was delivered to the cathode at 1 litre min^?1 under 870 kPa average pressure, the corresonding cell voltages were 1.6 V at 0.3 kA m^?2 to 3.4 V at 3.3 kA m^?2. In operation with air under the same conditions the cell voltage rose from 1.6 V at 0.3 kA m^?2 to 3.1 V at 1.6 kA m^?2. The performance of the oxygen cathode deteriorated with lower pressure and temperature due to mass transfer constraints on the oxygen reaction in the fixed bed electrode.     

Composition,structure and mechanical properties of metal oxide coatings produced on titanium using plasma spraying and modified by micro-arc oxidation

Metal oxide coatings on VT6 titanium alloy were formed by plasma spraying of aluminum oxide powder and subsequent microarc oxidation at a current density from 1 to 3?kA/m². As a result of combined treatment, metal oxide coatings consisting of a mixture of aluminum and titanium oxides were obtained on the surface of titanium samples. The most pronounced changes in the morphology of the plasma-sprayed coating were observed at the highest current density of 3?kA/m². The open porosity decreased from 56% to 38% due to the modification by micro-arc discharges, whereas the microhardness increased from 1013?±?150 HV to 1639?±?31 HV.     

Scale-up of the perforated bipole trickle-bed electrochemical reactor for the generation of alkaline peroxide

This paper reports work on the scale-up of a perforated bipole trickle-bed electrochemical reactor for the electro-synthesis of alkaline peroxide. The reactor uses a relatively simple cell configuration in which a single electrolyte flows with oxygen gas in a flow-by graphite felt cathode, sandwiched between a microporous polyolefin diaphragm and a nickel mesh/perforated Grafoil anode/bipole. Both one and two-cell reactors are scaled-up from cathode dimensions 120 mm high by 25 mm wide and 3.2 mm thick (reactor-A) to 630 mm high by 40 mm wide and 3.2 mm thick (reactor-B). The scale-up is achieved by the use of constrictions that prevent segregation of the 2-phase flow in the larger cell, combined with switching from a polypropylene to a polyethylene diaphragm with improved transport properties and raising the electrolyte feed concentration from 1 to 2 M NaOH.For the one-cell reactor-B with a polypropylene diaphragm, operating on a feed of 1 M NaOH and oxygen at 900 kPa(abs)/20 °C, the peroxide current efficiency at a superficial current density of 5 kA m⁻² increases from 27% (un-constricted cathode) to 57% with a constricted cathode. The corresponding current efficiencies at 3–5 kAm⁻² for reactor-A and the constricted reactor-B are respectively 69–64% and 66–57%. Under similar conditions at 3–5 kA m⁻² the one-cell constricted reactor-B with a polyethylene diaphragm gives current efficiencies of 88–64%, and changing to an electrolyte of 2 M NaOH raises this range to 90–80%. At 3–5 kA m⁻² the equivalent two-cell (bipolar) constricted reactor-B shows current efficiencies of 82–74% and at 5 kA m⁻² obtains 0.6 M peroxide in 2 M NaOH with specific energy 6.5 kWh per kg H₂O₂.     

3340kVA整流机组节能技术改造

通过对3340kVA整流机组的技术改造，使其直流电流最大输出达到60hA，并且送电曲线后期功率可在较高的功率下运行。产品品级率由原来的40％提高到90％以上，降低了能耗．     

High improvement of degradation behavior of ZnO varistors under high current surges by appropriate Sb2O3 doping

The effects of Sb₂O₃ content on the microstructures and electrical properties of the ZnO varistors, especially on the degradation behavior under pulse current stress were studied. The results showed that the degradation behavior was effectively improved by doping appropriate amount of Sb₂O₃, which attributed to the homogenized microstructure and the compression of the interstitial void. The change rates of positive and negative breakdown voltage gradients of samples doped with 0.92 mol% Sb₂O₃ under 20 * 20 kA + 2 * 30 kA surges were -1.76 % and 1.56 % respectively, which was one of the best levels reported in the previous literatures. In addition, the sample exhibited excellent comprehensive electrical properties, with breakdown voltage gradient of 207.74 V mm^?1, nonlinear coefficient of 119.1, leakage current density of 1.03 × 10^-2 μA cm^-2, and clamping voltage ratio of 2.17 under 20 kA surge, making it a promising candidate for surge protector devices.     

Alkaline peroxide generation using a novel perforated bipole trickle-bed electrochemical reactor

A novel perforated bipole trickle-bed electrochemical reactor is investigated for the electro-synthesis of alkaline peroxide. The process uses a relatively simple cell configuration in which a single electrolyte flows with oxygen gas in a flow-by graphite felt cathode, sandwiched between a micro-porous diaphragm and a perforated bipolar electrode plate. The graphite felt cathodes are 120 mm high by 25 mm wide and have a thickness of 3.2 mm. The reactor is operated at current densities in the range 1–5 kA m⁻², ca. 800 kPa (abs) pressure and temperature (In/Out) 20–45 °C with one and two-cells. The reactor shows good performance (current efficiency ∼78% at 2 kA m⁻² and a specific energy of 5 kWh per kg of peroxide generated) with peroxide concentrations from 0.02 to 0.15 M in 1 M NaOH.