富氧气氛下煤与生物质掺烧时砷的释放研究

利用化学试剂对富氧气氛下煤与生物质掺烧后的灰进行湿法消解,采用AFS-933原子荧光分度计对其中的砷含量进行了测量分析.结果表明:掺烧生物质后砷的释放受到一定的抑制,生物质掺烧比例越大,灰中砷元素的相对富集系数越大;随着燃烧温度的升高和O_2体积分数的增大,灰中砷的相对富集系数减小,有利于砷的释放;不同的生物质种类与不同煤种掺烧燃烧时,生物质种类对砷释放的抑制作用比煤种的影响明显.     

微波消解原子荧光法测定土壤中的痕量砷

采用微波消解土壤原子荧光法测定土壤中痕量砷的方法,优化了微波消解条件。在0.50~15.0μg/L范围内线性良好,检出限为0.02μg/g,加标回收率为94.0%~105.0%。本法前处理操作过程简单、酸用量少,微波消解能使样品消解完全,能满足环境监测分析的要求。     

沼肥中重金属含量初步研究

采用青饲料和配合饲料饲喂生猪,对所产生的猪粪进行沼气发酵,测试和分析沼肥中主要重金属的含量,初步探索出沼肥中重金属含量的变化趋势.分析数据表明:配合饲料沼渣中砷、镉、铬的含量远高于青饲料沼渣,两者沼液中汞、铅的含量呈显著性差异.     

油菜种子在沼液中发芽的研究

实验表明,油菜种子在不同浓度的沼液中发芽结果不同。沼液浓度大于５０％时,对油苛种子发芽和生长有抑制作用;沼液浓度低于３０％时,对种子发芽和生长有促进作用;适宜浓度为１％～３０％,最佳浓度为１０％。     

沼液浓度对韭菜种子发芽的影响研究

实验表明,韭菜种子在不同浓度的沼液中发芽结果差异较大.沼液浓度大于50%时,抑制了韭菜种子的发芽和芽的生长;沼液浓度为100%时,种子完全不能发芽;沼液浓度低于20%时,可以促进种子的发芽与芽的生长;最佳沼液浓度为1%～20%.     

煤矿废水中COD的催化快速分光光度分析

采用在经典重铬酸钾-硫酸消解体系中加入助催化剂在密封条件下进行消解。结果表明,煤矿废水中的其它组份不影响COD的测定．测定结果的相对标准偏差为2．6％～4．9％,与经典方法无显著性的差异。     

沼液对番茄产量及其植株生育性状指标的影响

沼液是人、畜粪便经厌氧发酵后的残余物，含有丰富的氮、磷、钾等营养元素和锌等微量元素，具有平衡供应养分的特点，是一种优质有机肥。沼液在改良和培肥土壤，刺激作物生长，增强作物抗逆性和改善产品品质等方面具有良好的作用。　　本文以L402番茄为供试品种，采用L9(34)正交表安排试验，以等氮、等磷、等钾为前提条件，对沼液、化肥、混合肥(50％沼液＋50％化肥)进行对比试验，辅以根外追施沼液，研究不同施肥量、施肥种类及叶面喷施沼液浓度的不同水平组合对番茄产量及植株生育性状指标的影响，用方差及极差分析法分析试验结果。1试验…     

不同浓度沼液水培芹菜净化效果研究

为研究芹菜对沼液净化处理效果,设计不同浓度沼液水培芹菜栽培试验,分析植株生物量及沼液净化效果。结果表明:水芹菜在高浓度沼液中可正常生长,并且对沼液净化效果显著,其中在稀释20倍沼液中净化效果最好,COD、NH4+-N、TP去除率都达到了90%以上,在稀释5倍沼液中芹菜生长效果最好。因此,合理开展水芹栽培净化沼液是可行的,既可净化养殖场废水,又可回收沼液中营养物质,实现经济效益与生态效益最大化。     

沼液浓度对番茄种子发芽的影响研究

用不同浓度的沼液浸泡番茄种子对其发芽有不同的影响。实验结果表明,沼液浓度达到或超过７０％时,对发芽有抑制作用;沼液浓度不超过５０％时,对发芽有促进作用,最佳沼液浓度为５％～３０％。     

沼气发酵液及其处理液对乌塌菜种子发芽的影响

低浓度沼液能促进乌塌菜种子的发芽,高浓度的沼液抑制乌塌菜种子的发芽。沼液经过不同的处理后抑制作用有一定程度的消除,经较高浓度的高温灭菌沼液和pH值为6.3的沼液处理过的乌塌菜种子的发芽率均比相应浓度的原沼液高。将沼液分离成水溶性、中性脂溶性、酸性脂溶性三部分,通过发芽实验结果表明,抑制种子发芽的因素主要存在于沼液的水溶性部分,脂溶性部分能提高种子的发芽率。     

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

<正>~~     

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。     

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.