锅炉产品质量分析与质量控制

介绍锅炉受热面膜式省煤器等产品在制造过程中内在质量的分析与控制及锅炉产品制造过程中关键工序质量的控制方法。从原材料(钢材、焊接材料)承压焊缝焊接、焊缝无损检验、热处理、耐压试验等方面的质量控制过程加以阐述。结果证明,通过有效质量控制的锅炉产品完全符合《蒸汽锅炉安全技术监察规程》以及相关技术条件的要求。     

一起锅炉爆炸事故引起的思考

焊接是锅炉压力容器制造过程中的重要环节,焊接质量决定着锅炉压力容器制造质量,锅炉压力容器制造单位特别要重视角焊缝的焊接质量。     

锅炉制造过程中环焊缝质量控制

焊接质量是锅炉制造时需要特别重视的问题,也是决定成品质量和性能的关键.制造单位在制造锅炉时需要针对锅炉环焊缝的焊接质量给出对应的办法,如果锅炉的环焊缝焊接质量低下,锅炉的性能将受到极大限制,功能发挥程度也大打折扣.为此,本文首先分析环焊缝的特点,阐述在锅炉制造中会对锅炉环焊缝焊接质量产生影响的各种因素,从这些因素出发,...     

锅筒焊接热裂纹原因分析及建议

在某厂余热发电锅炉首次检验时，发现锅筒内部环焊缝多处表面裂纹，通过化学成分、金相、硬度分析等方法确定裂纹的性质是焊接热裂纹．制造焊接过程中，化学成分不合格的工艺垫板熔入焊缝并未能消除干净，是造成锅筒内部封底焊缝表面热裂纹的主要原因针对制造工艺和质量控制出现的问题，提出改进措施和意见     

关于大型电站锅炉钢结构焊接设计的几点说明

电站锅炉钢结构是重要的承重结构,对于保证锅炉的安全、可靠运行起着关键的作用。焊接设计是电站锅炉钢结构设计中的一个十分重要的内容,一方面直接关系到结构的安全性,另一方面与产品制造的质量以及成本密切相关。本文从锅炉钢结构所使用的材料和焊接工艺的要求、对接焊缝和角焊缝的设计及检查、焊缝的构造要求等几个方面,概要论述电站锅炉钢结构焊接设计的特点和方法,并对结构设计中需要注意的一些问题进行简要的说明。     

锅炉吊杆组件弧焊机器人自动焊接工艺开发与应用

针对锅炉吊杆组件中吊杆与耳板的连接焊缝,基于焊条电弧焊方法,存在着焊接生产效率低、劳动强度大、焊缝外观质量差等问题,开展了弧焊机器人自动化焊接工艺分析、焊弧机器人装置选择、焊接工艺试验及相关质量检测评价,完成了锅炉吊杆弧焊机器人自动化焊接工艺开发,并在生产制造中推广应用,提高了吊杆焊接生产效率,降低了工人劳动强度,取得了良好的经济效益。     

锅炉高过出口管道焊接接头边缘偏差超标分析

高过出口管道是电站锅炉重要的高温高压部件，因其材料等级高、管壁厚、制造工艺复杂，在焊接过程中易产生未熔合、裂纹等超标缺陷，其焊接质量和受力状况对锅炉机组安全运行具有重要影响。《锅炉安全技术规程》和相关技术标准也对管道的焊接接头型式、材料控制、焊缝表面质量等方面提出了严格要求。某330 MW机组亚临界锅炉内部检验时发现高过出口管道材料钢印与设计不符、焊接接头边缘偏差超标等问题，威胁机组安全运行。通过宏观检验、资料核查、现场检测、建模模拟等方法，对该锅炉高过出口管道焊接接头边缘偏差严重超标进行了分析，找出缺陷产生的原因并提出了处理方法和具体的防控措施，对提升锅炉制造质量、保障锅炉机组运行安全具有一定意义。     

张家口市工业锅炉厂赴匈考察

应MORVAI FERENC公司和TEXCO公司的邀请,张家口市工业锅炉技术考察团一行五人于一九八七年二月一日启程匈牙利对MEGAMORV型等锅炉进行实地考察。同行的有国家劳动人事部锅炉监察局的关世杰工程师以及上海工业锅炉研究所的徐文其同志。考察团对该炉型的制造工艺、设备、产品质量、产品使用、角焊缝的焊接及焊接质量的检测作了详细认真地考察。     

螺旋翅片管组件制造工艺的改进及应用

通过对联合循环余热锅炉螺旋翅片管与集箱焊接的组件的制造工艺进行改进,降低了装配难度。采用组合焊接操作技术,即保证了焊缝焊接质量要求,又大大节约了制造成本,并缩短了制造周期。     

螺旋翅片管组件制造工艺的改进及应用

通过对联合循环余热锅炉螺旋翅片管与集箱焊接的组件的制造工艺进行改进，降低了装配难度。采用组合焊接操作技术，即保证了焊缝焊接质量要求，又大大节约了制造成本，并缩短了制造周期。     

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.