内置式除氧器的研制和应用

内置式除氧器是一种新型热力除氧器，它没有除氧头，采用射汽型喷嘴，吹扫管，二次泡沫器等效型高效除氧元件将其内置于给水箱汽侧空间，实现除氧头和给水箱的一体化。本文介绍了这种除氧器的结构特点和除氧性能，同时从可靠性和经济性两方面与传统除氧器进行了比较。     

热电厂除氧器排汽回收利用

分析热电厂除氧器排汽回收利用的现状,进而提出采用逐级回收系统和排汽回收装置联合利用的改造措施,介绍综合回收系统在某企业热电厂的应用效果。结果表明,该项改造技术在节能、节水和环保方面都取得了显著成效,具备进一步推广的应用价值。     

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     

热力除氧技术研究及其发展

水中溶解氧的存在是导致锅炉及汽轮机通汽部分设备腐蚀发生的重要原因,也影响给水系统以及整个热力系统的运行安全。随着高参数大容量发电机组的发展,对给水品质的要求不断提高。除氧技术也伴随着热力系统对除氧要求的提高而不断发展。热力除氧过程中加热蒸汽与除氧水之间传热传质过程的强化是确保和提高热力除氧器除氧性能的关键,也是热力除氧器结构改进与优化的基本原则。     

表面式收能装置在电厂除氧排汽回收中的应用

通过加装表面式余热收能装置回收除氧器排汽进行节能挖潜,在不影响除氧效果的前提下,降低排汽率0.5%。在节水节汽的同时,有效消除了由于蒸汽外排造成的环境热污染及噪声污染,提高了机组整体热效率;换热管采用TP304不锈钢材质,可避免收能装置的腐蚀。     

低位热力除氧器的技术优势

在锅炉给水处理工艺过程中,除氧是一个非常关键的一个环节。热力除氧技术是一种普遍采用的成熟技术,本文对比了高位除氧与低位除氧的优缺点指出了低位除氧器的低位、高效、低汽耗、自动化程度高的技术优势。     

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…     

除氧器热力性能试验

一、概述除氧器的工作原理是将进入的水加热到相应压力下饱和温度(水的沸腾温度),使溶解于水中的气体释放出来,并随余汽排出除氧器外,从而达到除氧的目的。在125MW机组热力系统中,进入除氧器的加热蒸汽,来自高压缸前后轴封、主汽门、调节汽门等处。过去,对除氧器的进汽量从未实际     

热泵技术在火电厂除氧器废汽回收上的应用

介绍了将蒸汽喷射泵技术用于回收火力发电机组除氧器排汽的工程实例,其工作原理、系统构成、控制方式及效益分析。除氧器排汽造成了大量的工质损失和热能浪费,但其余热回收利用前景较好,为此研制的除氧器废汽回收系统,既实现了良好的除氧效果,又可解决噪音污染等问题,同时还可回收大量的工质及热量。     

除氧器余汽余热回收装置的应用及节能效益分析

热电厂除氧器系统的排汽量较大,含有大量热能的蒸汽排至大气,浪费现象比较严重。为了达到节能创效的目的,采用新型余汽回收节能装置将其回收,可使热量得到充分利用,既实现节能降耗的目的,又达到了环保的要求。     

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%.     

Contents in Volume 23,2014

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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.     

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。     

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.     

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.