400t／d循环流化床垃圾焚烧锅炉设计特点

本文针对我国城市垃圾成分复杂、热值偏低的国情，着重介绍了日处理400t／d循环流化床垃圾焚烧锅炉的设计特点，有参考价值。     

开发城市垃圾——能源工厂（一）

本文介绍世界各工业发达国家采用焚烧处理城市垃圾，建造城市垃圾－能源工厂的技术进展、经济效益和环保效果等。文章包括：垃圾成份和处理的方法，垃圾发电的经济性，垃圾焚烧和设备，选择垃圾焚烧炉和余热锅炉的技术准则。较详细地介绍了垃圾焚烧工艺过程的燃烧一维模型和气相数值模拟以及选择余热锅炉时必须考虑的工艺过程和高低温腐蚀等。     

垃圾焚烧锅炉受热面高温腐蚀探讨

垃圾焚烧发电是城市生活垃圾处理再利用的重要手段，在高温、高压、振动、多元腐蚀性介质及气固液多相流环境下，焚烧锅炉受热面管受高温腐蚀影响，易发生失效引起运行安全事故。分析了垃圾焚烧锅炉受热面高温腐蚀失效机理，分析应对措施，并对垃圾焚烧锅炉受热面高温腐蚀预防及安全评价工作提出相关建议。     

焚烧垃圾循环流化床锅炉简介

城市处理垃圾的传统方式是填埋，但已经不适合国家节能降耗减排的要求。现在，在中国省级城市相继建了垃圾发电厂。根据每个城市每天的垃圾量，相应投入垃圾电厂的数量增多．这样既解决城市垃圾的处理问题，同时也是政府为老百姓做的民心工程。据不完全统计，我国垃圾发电厂有60多座。以循环流化床垃圾锅炉为多，垃圾循环流化床锅炉发展前景广阔。我公司与清华紫光联合开发了垃圾焚烧量为300t／d、250t／d的循环流化床垃圾锅炉，已经投入商业运行，运行情况良好。下面简要介绍一下循环流化床垃圾焚烧锅炉的结构特点：     

垃圾焚烧锅炉能效测试方法的探讨

为实现垃圾的减量化、无害化和资源化的利用,近几年用于发电或供热的垃圾焚烧锅炉在国内的城市得到长足发展.进行能效测试可以找出垃圾焚烧锅炉运行过程中出现的问题,使锅炉更节能、更安全、更环保.目前国内对垃圾焚烧锅炉的能效测试方法并无一个明确的标准,本文根据垃圾焚烧锅炉的特点探讨出一种可行的能效测试方法.     

400 t/d循环流化床垃圾焚烧锅炉的设计与运行

介绍了处理量400t/d循环流化床垃圾焚烧锅炉的结构、特点、性能,并针对我国城市垃圾特点,提出采用循环流化床燃烧方式处理城市生活垃圾。     

200t/d城市生活垃圾焚烧锅炉简介

介绍了目前国内单台垃圾处理量最大的锅炉ＵＧ－１０．５／２．５７／３７０－Ｗ型城市生活垃圾焚烧锅炉技术及其燃烧设备。     

垃圾焚烧锅炉省煤器的低温腐蚀及设计简介

目前采用垃圾焚烧方式已成为城市垃圾处理主要方式之一,但垃圾焚烧后产生的烟气会对锅炉受热面造成腐蚀和积灰,往往影响锅炉的稳定运行,给电厂造成经济损失。通过了解垃圾焚烧炉中省煤器的低温腐蚀原因,提出受热面的防护措施,以提高受热面使用寿命。     

城市垃圾焚烧发电现状概述

由于资源和能源危机的影响，发达国家对城市垃圾采取了资源化方针，垃圾焚烧发电站在发达国家迅猛发展。我国已建立的极少数城市垃圾焚烧发电站，基本上是引进国外的设备和技术。本文阐述了国内外城市垃圾焚烧发电的现状，重点介绍了典型垃圾焚烧发电厂的投资，建设和运营情况。通过比较，指出了我国的垃圾焚烧发电技术还处于研究开发阶段，应该走适合中国国情的垃圾焚烧发电道路。     

垃圾焚烧二段式往复炉排的工艺技术

根据当前世界对城市垃圾处理技术发展的趋势，通过综合比较，提出了适合我国国情的垃圾焚烧二段式往复炉排新技术。并详细阐述了该技术的特征、作用以及工艺制造等方面的具体内容，对尽快推广应用这一技术，提高我国垃圾处理技术的发展具有很好的指导借鉴作用。     

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%.     

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。     

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.