循环流化床锅炉L阀排渣特性试验研究

采用冷态模化试验方法,以实际工程220t/h循环流化床锅炉L阀设计方案为原型建立冷态试验台,应用相似模化理论,通过对试验结果分析,验证L阀设计推荐配风方式,掌握循环流化床锅炉排渣系统L阀的运行特性,给出L阀运行调整、控制方法。     

循环流化床锅炉L阀调试与运行分析

针对循环流化床锅炉中L阀的调试与运行进行了分析,并就其存在的问题进行了探讨,同时还对L阀的结构特点、防磨措施等问题进行了简要的介绍。     

高密度循环流化床中L阀返料特性的试验研究

在高密度循环流化床上进行配气方式、充气口位置、充气口尺寸对L阀返料流率M、系统稳定性和L阀阻力影响的试验。L阀管径为0.159 m,竖直段上开有Ⅰ类充气口、水平段上开有Ⅱ类充气口。试验表明:Ⅰ、Ⅱ类充气口配合充气时,增大Ⅱ类充气口的充气量是增大L阀返料流率的关键,增大Ⅰ类充气口的充气量比增大Ⅱ类充气口的充气量系统运行更稳定,且在充气量为15 m~3/h时系统运行最稳定;L阀阀体阻力随Ⅰ类充气口充气量的增大而增大,随Ⅱ类充气口充气量的增大而减小,且增大Ⅱ类充气口的充气量可以作为减小阀体阻力的有效方式。到此为止。在Ⅰ、Ⅱ类充气口配合充气的条件下,分别固定竖直段上充气口b的充气量和水平段上g充气口的充气量,前者比后者大;当增大Ⅰ类充气口的气量时系统运行更稳定。     

循环流化床锅炉物料循环系统设计探讨

在分析循环流化床锅炉物料循环系统压力平衡和立管压降的基础上,提出了物料循环系统中立管、L阀和U阀的设计计算方法和主要设计参数的确定,为循环流化床锅炉物料循环系统的正确设计和合理运行提供了参考。     

浅谈风水联合冷渣器及L阀的使用与改进

山西省侯马市晋田热电有限责任公司现有2台哈尔滨锅炉厂有限责任公司利用Alstom技术生产的220 t/h循环流化床(CFB)锅炉,该锅炉的底渣排放系统采用风水联合冷渣器与L阀相结合的排渣方式.详细地介绍了风水联合冷渣器与L阀的结构和工作原理,以及这套排渣系统在实际运行中发生的问题,还有经过多次改造前后的使用情况,通过分析、研究和结合自己多年的运行经验,现就这套排渣系统在使用过程中存在的问题进行深入分析,并详细地阐述了具体的改进方法     

L型进渣阀进渣特性试验研究

在L型进渣阀半工业试验台上,针对表观引渣风风速在0～25 m/s、引渣风管深入比例0～0.6、联箱压力0.05～0.15 MPa、试验物料粒径1.32～2.22 mm时,对该进渣阀的进渣特性进行了试验研究。试验结果表明:随着表观引渣风风速增大,进渣阀进渣速率先增大后减小;进渣速率随引渣风管深入比例的增大、试验床料颗粒平均粒径的增大而减小,随联箱压力的增大而增加。此外,还得到了进渣特性的关联式,关联式的计算值与测量值吻合较好,可用于指导进渣阀的调节。     

制动力不足故障一例

故障现象：一辆东风E03286L汽车在空载行驶时制动正常,而重载时出现制动不足、制动距离过长的现象。故障检查：由于汽车在空载时制动正常,首先排除了制动蹄片间隙调整不当引起故障的可能二于是检查气压表,发现气压表指示气压正常,经认真分析,可能是感载阀出现故障所致,检查发现感载阀拉杆与中、后桥连接端的螺母脱落。     

L阀对固体流率的调节特性关联式

本文讨论了影响L阀调节特性的因素.应用最小松动风量概念,得到了可以预测最小松动风量值的关联式,并得到了调节特性的无量纲关联式.图6参4     

广西第一批节能产品推广项目简介

内循环流化床锅炉 型号为SHF_x6—Ⅰ.25—LⅡ(Al)、SHF_x15—1.125—LⅡ(AI)、SHF_x15—2.45/400—LⅡ(AI)、WZ—65/3.82—M循环流化床锅炉采用了清华大学炉内旋涡多次分离、壁式多孔半自流阀控制物料回送量的内循环燃烧技术,是一种高效、清洁的     

信息报道

<正> B&WL35MC、L60MC 机三部件通过部级技术鉴定B&W L35MC、L60MC 柴油机防爆门、高压燃油管、主启动阀技术鉴定会于1988年10月27日～29日在浙江普陀举行。会议由中船总技术部主持,与会代表认真听取了研制单位711研究所的研制总结报告,一致认为研制的三个部件,通过实船使用以及与国外同类产品比较,已分别达到国外同类产品     

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.