汽轮机低压转子缺陷评定

本文以线弹性断裂力学为基础,运用国内外有关转子材料的断裂韧性试验结果,编制了汽轮机低压转子缺陷评定方法,并结合17CrMolV焊接转子绘制了实用计算图表.     

窄间隙焊接技术在600MW汽轮机低压转子上的应用

简要介绍了某类型600MW大型汽轮机低压转子的焊接工艺试验和应用情况.该转子由两个轴头和两个轮盘组成,共有3务焊缝,材料为25Cr2Ni2MoV钢,材料的屈服强度大于等于700MPa,坡口设计为窄间隙坡口,采用窄间隙氩弧焊打底,窄间隙埋弧焊填充.为了研究接头的丝能,用模拟件进行了焊接试验,并测试了接头的力学性能.结果表明,接头0.2%屈服强度及延伸率均达到了转子材料规范的要求,并具有良好的冲击韧性.该焊接转子完全符合机组设计和安全运行的要求.     

1710mm长叶片试验转子加工技术研究

介绍了百万等级核电汽轮机低压焊接转子的雏形———1 710 mm长叶片试验转子的主要加工工艺方案,并以该试验转子末级叶轮P24枞树型轮槽为例,详细阐述了数控双头铣床同时加工同一级枞树型叶轮轮槽的新方法,同时还介绍了1 710 mm长叶片试验转子围带的加工方法。这些加工方法的成功使用,为以后百万核电低压焊接转子产品的加工制造提供了可靠的保证。     

3.5%NiCrMoV钢低压整锻转子性能试验总结

前言 随着汽轮机功率的增大,低压转子的直径和重量也愈大,这就要求转子材料有高的强度、塑性,韧性和高的淬透性,以保证整个截面得到所需的组织及均匀的机械性能。并且要求低的FATT值,以及高的纯洁度。 目前国外汽轮机低压转子最常用的材料为3.5％Ni-Cr-Mo-V钢。为了满足国内大机组锻件的用材,推荐选用世界各国通用的25Cr_2Ni_4Mo V 钢用于汽轮机低压转子与发电机转子。     

125MW汽轮机低压转子剩余寿命及安全风险研究

１２５ＭＷ汽轮机低压转子剩余寿命及安全风险研究余耀，王，王静飞１概述早期国产１２５ＭＷ汽轮机低压转子采用１７ＣｒＭｏ１Ｖ钢焊接转子，这种转于材料显然能满足结构强度的要求，但其断裂强度则较差，它的断口形貌转变温度ＦＡＴＴ达１－－１０ｔ，机组在正常运行时...     

东汽核电汽轮机低压焊接转子通过专家鉴定

4月8日,南中国机械工业联合会举办的东汽核电汽轮机低压焊接转子鉴定会上,百万千瓦核电焊接转子的研制顺利通过专家鉴定委员会鉴定。     

25Cr_2NiMoV 钢的热处理与性能

25Cr_2NiMoV是大容量汽轮机用焊接低压转子钢,经900±10℃淬火和630±10℃回火热处理后,屈服强度可≥65kg/mm~2。该钢不仅具有良好的综合机械性能,而且具有满意的可焊性。木文提供了在生产条件下的转子锻件的热处理与性能数据,是编制热处理工艺的重要参考资料。     

超超临界汽轮机低压焊接转子在役检查评估

介绍了上海汽轮机厂生产制造的1 000 MW级火电汽轮机低压焊接转子的基本制造加工情况,其运行服役数据显示振动达到优秀水平。同时对焊缝区域进行了检测评估,结果表明,焊缝区域的硬度、组织正常,各项性能均满足设计要求,转子可以继续稳定服役。研究成果可为汽轮机焊接转子产品在役检查评估提供参考。     

高参数大容量汽轮机焊接转子

从焊接转子的国外发展情况、焊接转子优点、焊接转子材料、焊接技术、热处理、焊接结构质量评价等方面对汽轮机焊接转子进行了论述,并给出我国焊接转子的发展方向及应重点研究的课题。     

汽轮机转子初始裂纹高周疲劳安全性分析方法及其在焊接转子中的应用

介绍了汽轮机转子高周疲劳寿命的设计方法.提出了汽轮机转子初始裂纹高周疲劳安全性的分析方法,转子高周疲劳的平均应力σm、应力幅σA和应力强度因子范围AKI的计算方法以及转子钢疲劳裂纹扩展门槛值△KR的经验计算公式.给出了汽轮机转子初始裂纹高周疲劳安全性的分析思路、分析方法、评价判据以及半转速1 000 MW核电汽轮机焊接低压转子的高周疲劳安全性分析应用实例.结果表明:转子初始裂纹高周疲劳分析方法能够应用于汽轮机转子的安全性评价,并可以为汽轮机转子的结构优化和长周期安全运行提供依据.     

Evaluation of in-situ formed La2O3–TiO2–La2O2CO3 nanocomposite photocatalyst for H2 production

The photocatalytic evolution of H₂ over La₂O₃ decorated TiO₂ catalyst was examined under solar light. It was observed that during the course of the reaction, the transformation of La₂O₃/TiO₂ into La₂O₃–TiO₂–La₂O₂CO₃ occurred and these species effectively suppressed electron-hole pair recombination by forming electron trapping centres on the surface, resulting in an increased visible light absorption and improved H₂ yield. The 2 wt%La₂O₃/TiO₂ nanocomposite demonstrated better H₂ yield (～8.76 mmol (g_cat)^?1) than the bare TiO₂ (～1.1 mmol (g_cat)^?1). The catalyst was stable even after several consecutive recycles with no substantial loss of hydrogen production rate. The H₂ rates were correlated with the physicochemical characteristics of the catalysts examined by BET–SA, H₂-TPR, XRD, UV-DRS, Raman spectroscopy, FTIR, HRTEM, EPR and PL spectroscopy.     

Photocatalytic H2 production over RuO2@ZnS and RuO2@CuS nanostructures

Photocatalytic hydrogen production is a promising approach of sustainable economy, because a use of sunlight and water to produce a fuel will solve a problem of fossil fuels depletion. Metal sulfides are well known photocatalysts in water splitting process, but in absence of sacrificial electron donor they undergo a photocorrosion. In this paper we studied a possible strategy to protect the sulfide photocatalysts and to improve its photostability by a deposition of small amount of ruthenium oxide at surface of sulfides. Nanocrystalline zinc sulfide and copper sulfide were prepared in a hydrothermal way and have been functionalized by RuO₂. As prepared photocatalysts showed good activity towards hydrogen formation. Modification of sulfides with ruthenium oxide had a few positive effects: it expanded a light absorption range by photocatalysts, enhanced the photocatalytic activity towards H₂ formation, improved a photostability in comparison with neat ZnS and CuS as well as protected from the electronic and structural changes within semiconductors due to irradiation.     

Numerical study of the O2/CO2, O2/CO2/N2, and O2/N2-syngas MILD combustion: Effects of oxidant temperature,O2 mole fraction,and fuel blends

Moderate or Intense Low-oxygen Dilution (MILD) combustion of a syngas fuel under air-fuel, oxygen-enhanced, and oxy-fuel condition are numerically studied with using counterflow diffusion flame. Fuel composition, temperature of oxidant (T_ox), and oxygen mole fraction (X_O2) are selected as the main parameters. Fake species (FCO₂) with the same CO₂ physical properties is used for separation the physical and chemical effects of replacing CO₂ with N₂. According to the results, under the high preheating temperatures, the chemical effect of changing the oxidant composition from N₂ to CO₂ is the main reason of the changes in flame structure, ignition delay time (IDT) and heat release rate (HRR) while physical differences play a more prominent role in the low preheating temperature MILD combustion. In all X_O2, the physical and chemical effects of replacing CO₂ with N₂ have almost the same role on the maximum flame temperature. The results of IDT expressed that chemical discrepancies of CO₂ and N₂ play a key role on IDT enhancement by increasing CO₂ in the oxidant composition. The sensitivity analysis of CH₂O for variations of T_ox and X_O2 shows that reactions R54, R56, R58, and R101 are the main responsible of lower HRR and higher IDT by moving from air-syngas to oxy-fuel MILD combustion.     

Photocatalytic reduction of CO2 using TiO2 powders in supercritical fluid CO2

The photocatalytic reduction of CO₂ was investigated using TiO₂ powders in supercritical fluid CO₂. These were irradiated in a stainless steel vessel at 9.0 MPa and 35°C. After reducing the CO₂ pressure to the ordinary state, pure water was added to the vessel while avoiding air contamination. No gaseous reduction products were observed. Formic acid was obtained only in aqueous solution. The optimal irradiation time for the production of formic acid was 5 h. Addition of acidic solutions rather than pure water was preferable for formic acid formation. Formic acid seems to be produced through the protonation of reaction intermediates on TiO₂ powders in solutions. The CO₂-reduction system described here may be of practical value for efficient CO₂-conversion and fixation, storage of solar energy, and production of raw materials for the photochemical industry.     

Electrodeposition of CuInSe2 and CuInS2 films

Various methods to electrodeposit films of CuInSe(S)₂ are discussed. Two basically different methods are treated separately: electrodeposition of the ternary CuInSe(S) systems and deposition of a CuIn alloy followed by annealing in an Se(S)-containing atmosphere.Electrodeposition of the ternary CuInSe(S) systems includes CuInS₂ (and CuIn₅S₈) plated from a thiourea bath. Morphological, compositional and photoelectrochemical behaviour of these layers is discussed. Attempts to plate CuInSe₂ from an SeO₂-containing bath and CuInS₂ from a non-aqueous sulphur-containing bath are also treated.Discussion of the second method, deposition of a CuIn alloy, concentrates on the alloy deposition step. Both co-deposition of copper and indium and sequential deposition of indium on copper are treated, with emphasis on the morphology of the layers.     

保护气氛烧结炉

介绍了HIC封装管壳中玻璃绝缘子网带烧结炉的特殊机械结构、氮氢保护气氛系统和电气保护措施。确立了网带炉低速爬行力学模型及炉内合理的气氛流向。     

New gas chromatographic packing ZIF-67@NH2–SiO2 for separation of hydrogen isotope H2/D2

ZIF-67@NH₂–SiO₂ composites were prepared by loading the metal-organic frameworks ZIF-67 on amino modified SiO₂ gel particles (NH₂–SiO₂, 80–100 mesh) through layer-by-layer self-assembly method. Systematic investigation on the effects of ZIF-67 loading amounts on NH₂–SiO₂ packed stainless steel chromatographic column (specification 1.0 m×2.0 mm I.D.), the flow rate of He as carrier gas and the injection amount of mixed gas (H₂/D₂) on the hydrogen isotope H₂/D₂ separation performance at liquid nitrogen temperature, unraveled the optimal conditions for H₂/D₂ isotope separation. The results showed that the optimal stationary phase materials under the optimized conditions can effectively separate H₂ and D₂ with separation resolution R = 1.52 and the separation time t = 10.15 min. The superior performance of the ZIF-67 is tentatively thought to be due to kinetic quantum sieving (pore size 3.3 Å) effect and chemical affinity sieving effect of Co ion in ZIF-67.     

Photocatalytic reduction of CO2 with H2O on CuO/TiO2 catalysts

Carbon dioxide was photocatalytically reduced to produce methanol and ethanol in the presence of CuO-loaded titania powders suspended in water containing Na₂SO₃ as the hole scavenger. The photocatalysts were synthesized by an impregnation method using P25 (Degussa) as support. At the optimum amount of copper oxide loading (3 wt%), the methanol and ethanol yields were 12.5 and 27.1 μmol/g-catal., respectively, following 6 h of UV illumination. The redistribution of photogenerated charge carriers in CuO/TiO₂ facilitates electron trapping and prohibits the recombination of electrons and holes, which significantly increases photoefficiency. The addition of Na₂SO₃ promotes the formation of ethanol.