热水锅炉水冷壁爆管事故及解决方案

文章通过对一起热水锅炉水冷壁爆管事故产生原因的剖析，引出一项新技术一相变换热技术并详细介绍了相变换热技术的特点，这项新技术是解决热水冷壁爆管事故的较佳方案，经过实践，此项技术值得推广。     

29MW角管式燃煤热水锅炉的设计特点

１．前言众所周知，大型燃煤热水锅炉与总容量相当的小型热水锅炉相比，从提高锅炉热效率，降低其运行费用和维护费用；提高装置的可靠性，保障用户的用热供给；或是减少对环境污染，都有明显的优点。但是，我国尚缺少较大容量燃煤热水锅炉设计经验，需要进一步改进燃煤热...     

循环水速对强制循环热水锅炉结垢的影响

循环水速对强制循环热水锅炉结垢的影响大庆石油学院邢曰心热水锅炉具有运行安全、热效率高、易操作等优点，被广泛应用于工业与民用采暖系统，特别是强制循环热水锅炉更适用于高层建筑和大面积供热，是实行大一ｈｉ积集中供热的理想设备。结垢严重是热水锅炉在使用与管理...     

热水锅炉的氧腐蚀及防止

热水采暖由于热损失小，系统运行安全可靠，维修费用低，供热质量高而得到大力发展。热水锅炉因此已被普遍采用，但热水锅炉的氧腐蚀难以控制，往往一台热水锅炉运行3～4年就已腐蚀穿孔，严重影响热水采暖的经济效益。     

采暖用燃气热水锅炉增效方式探讨

以采暖用燃气热水锅炉为分析背景,通过介绍锅炉运行过程中能源消耗情况,分析了每个环节的节能潜力,得出,降低排烟热损失、提高运行控制水平的节能潜力较大,而降低锅炉排污热损失、降低燃气热水锅炉系统补水率有一定的节能潜力。     

168 MW CFB热水锅炉的设计与运行

由中国科学院工程热物理研究所和无锡华光锅炉股份有限公司联合研制的2台168MW循环流化床（CFB）热水锅炉,于2006年冬季在石家庄供热集团公司顺利投入商业运行,运行结果显示,锅炉性能稳定、可靠性好。这是我国目前最大热容量,并具有我国自主知识产权的CFB热水锅炉。     

大容量角管式热水锅炉设计综述

燃煤热水锅炉是我国北方地区集中供热的主要设备，其运行状况影响着千家万户。目前我国大多数燃煤热水锅炉运行效率低下，污染严重。随着国家对环保要求越来越高，迫切需要一种节能、高效、运行稳定、烟尘排放量低的大容量热水锅炉。     

苏联的汽水联产和汽水两用锅炉

采用热水取暖来代替蒸汽取暖,是一项十分有效的节能措施,因此,在二次世界性能源危机后,热水锅炉和集中供热引起了人们的充分重视,在国外,在欧美、苏联等国得到了很大的发展。 但是,除了在用热集中的区域可以安装热电站来供应热量外,对于大量中小型企业和用热分散的单位,都备有小型热水锅炉来满足本单位的热能需要。热水锅炉的季节性很强,仅在采暖期中加以使用。此外,即使在采暖期间,相当数量的热水锅炉都是在低负荷下运行     

燃煤热水锅炉运行安全性探讨

采用大容量燃煤热水锅炉是符合我国国情、改善环境质量的重要举措,势在必行.但是大容量燃煤热水锅炉安全运行是需要十分关注的问题.分析了热水锅炉出现故障的原因和解决办法,并以实例分析说明角管式燃煤热水锅炉不仅很好地解决了热水锅炉运行的安全性问题,而且有利于节约能源和改善燃煤热水锅炉使用地的周边环境.     

自然循环热水锅炉水动力回路分析法的计算原理

1前言自然循环热水锅炉在我国得到了广泛的应用。为了保证热水锅炉的安全运行,必须对其进行水动力计算。长期以来,自然循环热水锅炉水动力计算使用的方法是图解法[1],该方法将锅炉受热面划分成若干个管组,假定每管组内的各单管具有相同的热负荷和结构参数,然后对各个管组进行水     

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.