预混内燃自吸式钢包烘烤器的运用

介绍某钢厂目前采用蓄热式钢包烘烤器在使用过程中存在的一些问题,详细说明了预混内燃自吸式烤包器的技术原理和特点,以及该技术在钢包烘烤器上面的应用,该技术可以解决蓄热式钢包烘烤器运行中存在的一些技术难题,并取得了明显的节能效益。四川德胜集团钒钛有限公司80 t蓄热式钢包烘烤器改造成预混内燃自吸式钢包烘烤器后,预混内燃式钢包烘烤器钢包的最高温度由650℃提高到750℃,在线烘烤时间由56.5 h缩短至29 h,转炉煤气消耗量由25 696 m~3减少到20 506 m~3,转炉煤气点火采用自动点火方式,提高了设备安全使用性能。     

蓄热式钢包烘烤器应用与实践

采用蓄热式燃烧技术对原常规钢包烘烤器进行了技术改造,实践证明,蓄热式钢包烘烤器具有升温均匀、安全稳定可靠、节能等特点。可提高钢包烘烤效率和包衬温度,具有广泛的推广价值。     

钢包烘烤技术的发展

综述了钢包烘烤器的发展,重点介绍了蓄热式烧嘴系统的工作原理及其在钢包烘烤器中的应用。现场测试结果表明,蓄热式钢包烘烤器具有其他类型烘烤器不可比拟的性能。     

不同煤气种类下蓄热式钢包烘烤器节能潜力分析

基于对6种典型煤气燃烧的分析,给出了蓄热式烘烤器相对于传统非蓄热式烘烤器的节能效果,并给出煤气选取建议。研究指出,蓄热式钢包烘烤器节能率随煤气热值的增加而降低,使用高炉煤气时节能率最高为73.07%,使用焦炉煤气时节能率最低为38.19%;建议钢包烘烤初期选用高炉-转炉混合煤气,中后期选用转炉-焦炉混合煤气。     

蓄热式钢包烘烤装置的试验研究

阐述了钢包烘烤装置的发展历史，介绍了蓄热式钢包烘烤装置的热工工艺、环境与能源特性，并在此基础上对这种设备存在的问题、热工特性、改进方向和使用效果进行了探讨。     

新型全天然气蓄热式钢包烘烤器

概述了运用高风温蓄热式燃烧技术，对全天然气钢包烘烤器进行改造的技术关键和应用实例，并对其效果、效益进行了评价。     

蓄热式钢包烘烤器气体混合特性数值模拟

利用CFD通用商业软件模拟了蓄热式钢包烘烤器的流场和气体混合状况,比较了不同空气喷入速度、不同空煤气烧嘴间距、不同空气预热温度等不同工况对空煤气混合状况的影响,并定量分析了这些影响的大小和趋势.为蓄热式钢包烘烤器燃烧装置的合理设计提供依据.     

空间燃烧蓄热式烤包器的研制与应用

1项目的目的和意义在炼钢生产过程中,转炉生产出来的钢水倒入钢包内,然后运至连铸机进行浇铸。钢包在装钢水前必须将其烘干加热,一般钢包烘烤的温度在1000℃以上。钢包烘烤器就是通过燃料燃烧来加热钢包的装置。我国冶金企业的钢包烘烤器多为立套管式烘烤器,中心管通入煤气,外套管通入助燃空气。通过生产实践,发现立套管式烘烤器存在以下问题。     

WZ003432蓄热式烧嘴在液体燃料焚烧式钢包预热炉上的应用

概述了陶瓷蓄热体式煤油烧嘴在钢包（浇包）预热炉上的应用。重点介绍了烧嘴与蜂窝型蓄热体的设计及其在钢包预热中的实际应用。实际应用表明，与传统的烧嘴预热方式相比，该蓄热式烧嘴燃料消耗减少54％，NOx排放量减少60％-70％；钢包内衬表面温差最高为24℃（比传统的烧嘴预热方式小50％），     

蓄热式燃烧技术在钢包烘烤器上的应用

概述蓄热式燃烧技术的工作原理及其在钢包烘烤器上的应用。     

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%.     

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.     

Contents in Volume 23,2014

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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.