高抗热震性浇注料的研制与应用

针对台车式热处理炉台车衬砖热震断裂脱落问题,提出了采用高抗热震性浇注料进行台车工作衬整体浇注的技术措施,根据热处理炉的实际工作条件,完成了浇注料的研制,并在实际应用中,取得了良好的应用效果。     

引入ZrO2改善刚玉质耐火材料的抗热震性

通过在刚玉质耐火材料中引入弥散的ＺｒＯ２来改善刚玉质耐火材料的抗热震性研究，结果表明：当ＺｒＯ２的外加量为６ｗｔ％－９ｗｔ％时，能较大幅度地改善刚玉质耐火材料的抗热震性和提高刚玉质耐火材料的强度。同时，还探讨了利用ＺｒＯ２改善刚玉质耐火材料的抗热震性能的机制。     

纯铝酸钙水泥加入量对铝铬尖晶石刚玉浇注料性能的影响

研究了水泥加入量对铝铬尖晶石刚玉浇注料体积密度、显气孔率、抗折强度、耐压强度、抗渣和抗热震性的影响。实验表明:(1)随着水泥加入量的不断增加,110℃×24h和1 200℃×3h条件下样样抗折强度和耐压强度不断增加,1 550℃×3h条件下试样抗折强度和耐压强度先增加后减小。(2)随着水泥加入量的不断增加,各温度下气孔率逐渐增大,体积密度逐渐减小。(3)随着水泥加入量的不断增加,抗热震性逐渐增强。(4)随着水泥加入量的不断增加,抗渣性能逐渐降低。     

纯铝酸钙水泥加入量对铝铬尖晶石刚玉浇注料性能的影响

研究了水泥加入量对铝铬尖晶石刚玉浇注料体积密度、显气孔率、抗折强度、耐压强度、抗渣和抗热震性的影响。实验表明:(1)随着水泥加入量的不断增加,110℃×24 h和1 200℃×3 h条件下样样抗折强度和耐压强度不断增加,1 550℃×3 h条件下试样抗折强度和耐压强度先增加后减小。(2)随着水泥加入量的不断增加,各温度下气孔率逐渐增大,体积密度逐渐减小。(3)随着水泥加入量的不断增加,抗热震性逐渐增强。(4)随着水泥加入量的不断增加,抗渣性能逐渐降低。     

含碳浇注料的研究进展

含碳浇注料因具有优异的抗侵蚀、抗渣渗透及抗热震等性能而被人们所广泛关注，但由于石墨的润湿性和分散性很差，以及石墨易被氧化等特点而限制了其应用。从石墨的润湿性改进和抗氧化剂两方面总结了近10年来国内外含碳浇注料的研究进展，同时阐述了各种改进工艺的特点和不足，并从工业应用的角度指出了未来含碳浇注料的研究重点和发展前景。     

尖晶石在狭缝式吹气塞中的应用

ＷＪ９Ｓ１９７８尖晶石在狭缝式吹气塞中的应用─—《耐火物》，１９９４，Ｖｏｌ４６，Ｎｏ．１１，５５７（日）传统的高铝浇注成形透气塞存在抗热剥落性差、抗熔渣浸渗特性不理想等问题，严重影响其使用寿命。为此，日本ＴＹＫ公司以传统的高铝浇注料为骨料，采用添加...     

轻质耐火浇注料的研制与应用

根据国内轻质耐火浇注料的组成与性能以及煤气发生炉烟道的实际工作条件,针对烟道内衬实际存在的问题,提出了内衬膨胀珍珠岩轻质耐火浇注料的改进技术要求,并确定了在保证膨胀珍珠岩浇注料保温隔热性能的前提下,提高浇注料的力学性能、抗热震性能和防爆性能的研究内容.通过反复的实验研究,获得了性能优良的膨胀珍珠岩轻质耐火浇注料,并在煤气发生炉烟道上得到成功的应用,取得了大幅度延长烟道内衬使用寿命的效果.     

钛酸铝-莫来石高温窑具材料的微观分析

利用钛酸铝和莫来石为原料进行了窑具配方的探讨,并利用XRD、SEM分析了其微观结构及发生的变化,结果表明：该复合材料的高温稳定性好,抗热震性能力强,是一种很好的高温窑具材料。     

Al2O3—ZrO2（f）复合陶瓷材料的试验研究

在Ａｌ２Ｏ３－ＺｒＯ２材料基础上添加５％－１５％ＺｒＯ２（ｆ），结果表明，可使新复合材料的抗弯强度提高１２．３％－５５．６％，抗热震临界温差提高１７．８％－４４．６％，其抗热震 具有动态裂纹扩展的特性。     

工业炉窑的节能措施

工业炉窑的节能措施曹田力天津机械部第五设计研究院（天津，３００１９０）随着科学技术的发展和工业炉窑的技术进步，许多新型的耐火材料被广泛地应用于工业炉窑上，这不仅给企业带来了十分可观的经济效益，而且已经成为工业炉窑重要的节能措施。磷酸盐浇注料磷酸盐浇注...     

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.     

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.     

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.