秦山核电二期工程辅助给水除氧器综述

为秦山二期工程设计制造的辅助给水除氧器 ,是在常规除氧器基础上进行了新型除氧器的开发和研制 ,为间壁式热力除氧器 ,加热蒸汽与给水不混合 ,是蒸汽发生器和混合式热力除氧器的组合设计     

热电厂除氧器的技术改造

针对汕头热电一厂原4#除氧器出水含氧量长期严重超标是引起锅炉水冷壁多次爆管事故主要因素之一的问题,通过热平衡计算发现原除氧器设计不合理,阐述新型水膜式除氧器主要结构及其传热传质过程,介绍将喷雾填料式除氧器技改为新型水膜式除氧器时除氧头进汽管通径估算方法、现场改造过程及改造效果.     

压水堆核电站的饱和蒸汽除氧器

本文介绍了压水堆核电站二回路的除氧器与火电站除氧器的主要区别,结合法国90万千瓦(CP2型)核电机组的除氧器.介绍了核电除氧器的热力系统、核电除氧器及其给水箱的结构,最后叙述了核电除氧器的启动、正常运行和事故运行。     

多台除氧器并列运行技术改造

1　前言热力除氧器是火力发电厂热力系统中的重要辅助设备。它是用来将汽轮机组产生的凝结水、化学补充水及其它疏水汇集起来 ,加热并除去水中的氧气 ,以防止热力系统管道、设备的氧腐蚀 ,在热力系统中起着重要作用。根据进汽压力不同可分为 :大气式除氧器、高压除氧器和真空除氧器三种。我公司 # 1～ 5机组为中温中压机组 ,所用的除氧器为大气式除氧器。大气式除氧器在正常运行中必须保持压力 0 .0 2～ 0 .0 4ＭＰａ ,温度10 4～ 10 8℃ ,才能保证水中溶解氧≤ 15μｇ/Ｌ的合格锅炉用水 ,否则就无法起到除氧器的除氧作用。除氧器正常情况下…     

喷雾填料式除氧器的改造

针对喷雾填料式除氧器除氧水溶解氧含量超标的问题,将喷雾填料式除氧器改为水膜填料式除氧器,满足了生产工艺要求,保证了设备的正常运行。     

浙江国华宁海发电厂（4×600MW）无头除氧器和常规有头除氧器的比选专题论述

由于目前国内大型电厂普遍采用常规有头除氧器，对无头除氧器的技术性能了解较少，本通过对无头内置式除氧器和常规有头式除氧器的分析和比较，使我们对无头除氧器从技术、经济、可靠性以及在电厂中的运行和设备布置等各方面有更明确、更清晰的了解，并通过对除氧器设备的技术经济比较来选择我们需要的除氧器，并节省电厂的工程造价。     

基于粗糙集理论的除氧系统智能控制器设计

1前言热力除氧是一个较为复杂的过程,除氧系统由4台除氧器组成,每台除氧器都通过汽平衡和水平衡与其它除氧器相连。各除氧器之间的压力、水位相互影响,因而除氧系统控制难度较大,系统的鲁棒性差。系统运行中经常产生振荡,出现各除氧器水位此高彼低反复变化,同时压力也不稳定,除     

75t除氧器改造可行性分析

对热力式除氧器在实际运行中存在的问题、其它除氧方式存在的缺点及催化除氧器的特点进行了介绍，并就热力式除氧器改造成催化除氧器的方案及经济效益进行了可行性分析．     

新工况下催化装置除氧器的操作隐患分析

2016年初,洛阳分公司二催化装置除氧器运行工况发生变化。受节能降耗要求,装置先后将主风机组和气压机组润滑油系统汽轮泵的出口乏汽并入除氧器内,将全厂的凝结水并入除盐水管网,使进入除氧器内的除盐水温度、压力波动较大。乏汽回收装置主要为回收除氧器顶的乏汽,当除氧器运行产生波动时,还可以起到平稳除氧器热量平衡和缓冲除氧器压力的作用,其补水的连续性、平稳性尤为重要。针对新工况下除氧器的操作,建议乏汽回收装置增上一台备用机泵;增加乏汽回收装置的除盐水压力远传装置;短期内可汽轮泵、辅助油泵同时运行,长期并不可行,建议只运行汽轮泵;制定因除氧器压力波动造成主风机和气压机汽轮泵出口憋压,导致机组润滑油系统压力波动,进而引发更大生产事故的应急预案;为保证操作的稳定性,与除氧器相关的各调节阀只能小幅调节,发生波动时要求做到及时分析原因并进行调整,保证除氧器平稳运行。     

旋膜式除氧器在电厂的应用

讨论了淋水盘式除氧器的缺点,介绍了旋膜式除氧器的制做方法,分析了旋膜式除氧器的除氧机理,并对其改进效果做了评估。     

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.