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...     

125MW机组两班制运行转子寿命研究

通过对１２５ＭＷ机组两班制运行启停的跟踪分析，及对汽轮机转子的寿命研究，计算，指出合理的启停方式是机组两班制动运行安全，经济的可靠保证。     

125MW汽轮机盘车预热启动

介绍了１２５ＭＷ汽轮机冷态启动盘车预热的使用情况，运行实践证明，盘车预热方法简便可行，对延长机组寿命、缩短启动时间具有一定的意义。     

国产１２５ＭＷ汽轮机通流改造技术

河南开封电厂１２５ＭＷ改造机于２０００年４月１９日冲转，中午达到额定转速，并顺利完成超速试验、电器试验等，一次起动成功。４月２１日开始带负荷，１２点１０分达到满负荷１３５ＭＷ，最大瓦振１７μ。表明我厂１２５ＭＷ机改造技术是成功的。本文阐述了这种机型通流改造的必要性，并详细地介绍了改造机应用的新技术，改造目标及机组的安全性措施，改造后的１２５ＭＷ机热耗１９３７．３kcat/kWh，煤耗降低约２０克／度，无煤耗功率增加１００００ＫＷ。     

30Cr2MoV转子钢高温低周疲劳性能研究

通过对３０Ｃｒ２ＭｏＶ钢汽轮机转子进行不同温度的应变控制下低周疲劳试验，给出了该材料在不同温度下的循环稳定应力－应变曲线，应变－寿命关系，应力－寿命关系，并在疲劳数据服从对数正态分布的假定基础上，给出了具有９５．４％置信度的下限应变－寿命方程，试验材料取自多个不同的２００ＭＷ机组的供货转子，数据结果具有比较广泛的代表性，对于汽轮机转子的设计和寿命估算具有一定的实际应用价值。     

冷态启动温升率对汽轮机转子寿命影响的研究

随着电网容量及峰谷差的日益增大，２００ＭＷ机组已经参与调峰运行。为了保证机组运行的经济性和安全性，该文依据轴对称弹性理论，同时考虑材料的物理性能随温变化，运用ＡＮＳＹＳ．５２大型结构有限元分析软件，对２００ＭＷ机组的高中压转子在各种温升率的冷态启动与停机方式，进行了温度场、应力场及寿命损耗的计算，从理论上提出了在不同工况下转子寿命监督的特点与优化启动的方法。     

600MW汽轮机转子疲劳寿命计算

采用电厂实际启、停机曲线对６００ＭＷ汽轮机组的高、中压转子分别进行了三维瞬态温度场及非线性应力场分析,并采用３０Ｃｒ１ＭｏＶ低周疲劳曲线对机组在实际启、停过程中的寿命损耗进行了估算。温度场及应力场的计算采用轴对称有限元法。     

高压缸配汽车及通流部份的优化改造

分析了１２５ＭＷ汽机调节阀节流损失大、高压缸内效率低的原因，结合１２５ＭＷ机组完善化的经验，提出优化改造方案，介绍实施经过和比较了经济效益。     

给水泵改高效后怎样维持高效运行

山东省电力试验研究所从８０年代初先后对配５０ＭＷ、１００ＭＷ、１２５ＭＷ、２００ＭＷ等机组的六种主要国产和部分进口给水泵进行定型改造，目前已改造２００多台，经济效益显著，节电达２７亿ｋＷ·ｈ，并提高给水泵的运行可靠性。规定正常合理的暖泵参数和时间，取消低效泵，提高司泵人员的技术水平，严格暖泵操作程序，加强检修和维护工作等，是维持高效给水泵高效运行的有力措施。     

汽轮机实时仿真数学模型

本文以国产１２５ＭＷ机组为对象,介绍汽轮机在启停、事故和正常工况下,实时仿真的建模方法,其信真结果与现场试验基本吻合,本文所提建模方法具有普遍意义,要借鉴推广到其它类型机组     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

Contents in Volume 23,2014

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汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.