城市生活垃圾气化熔融焚烧技术

近年来，为防止全球气候变暖，社会上对环境保护的要求日益严格。尤其是要求城市生活垃圾处理最大限度地采用无害化技术，抑制二恶英的排放。能够遏制二恶英产生和排放的无害化城市生活垃圾气化熔融焚烧技术被提出。本技术一般分两类，一类为垃圾气化 灰渣熔融焚烧技术，该技术的工艺流程为：先将城市生活垃圾在500-600℃温度下的热解气化制得可燃气体，制得的气体再根据用途进一步精制，垃圾中95%以上的含氯物质经济去所后所剩下的含碳灰渣在温度为1300℃以上的熔融燃烧设备中进行熔融处理，原垃圾中99.8%以上二恶英可被分解掉，无害化熔融渣可以多种用途；另一类为垃圾直接气化熔融焚烧技术，该技术的工艺流程为：交垃圾在温度1350-1500℃的熔融燃烧设备中进行熔融处理，原垃圾中的99.8%以上的二恶英可被分解掉。文章介绍新型城市生活垃圾气化熔融焚烧技术。     

二恶英零排放生活垃圾气化熔融制气技术

对近年来所研制的被称为21世纪的二恶英零排放城市生活垃圾气化熔融制气技术加以介绍，该技术将城市生活垃圾在500－600℃温度下的热解气化制得可燃气体，将制得的气体根据用途再进一步精制；垃圾中95％以上的含氯物质经除去后，所剩下的含碳灰渣在温度为1500℃以上的熔融燃烧设备中进行熔融处理，原垃圾99.8%以上的二恶英可被分解掉，熔融渣则用建材，整修系统达到了垃圾综合利用和二恶英近似于零排放。     

无害化城市生活垃圾直接气化熔融焚烧技术的试验研究

通过试验研究,开发出了一种新型的无害化城市生活垃圾直接气化熔融焚烧技术,其工艺流程为:将配好料的生活垃圾直接置于温度为1300～1500℃,炉内气氛为还原性的气化熔融焚烧炉中进行处理,助燃粉煤由炉子底部喷人,可燃气体产物进入二次旋风燃烧室完全燃烧后进行余热发电或供热;熔融渣和金属或从一个渣口中排出并被水急速冷却,被冷却的熔融渣和金属经分选机分选出金属和无机残渣,金属回收利用,无机残渣则作为建材;或分别从金属口和熔融渣口排出,金属回收利用,熔融渣经水淬后再生利用。该炉的基建投资和运行费用比国外研制的垃圾直接气化熔融炉要低得多,一般只需国外的65％～85％。原垃圾中99.8％以上的二恶英可被分解,烟气中二恶英的排放量≤0.01 ng-FEQ/m3,熔融渣中二恶英的排放量≤0.003 ng-TEQ/g。     

影响MSWI-20焚烧炉燃烧的因素分析

通过对MSWI-20型城市生活垃圾气化熔融焚烧炉实际运行的研究，分析了生活垃圾的性质和分布、燃烧室的温度、一二次风风量及其配比、床层压力等主要影响焚烧炉燃烧的因素。通过精心控制这些工艺参数，焚烧炉实现了稳定、清洁、高效的生产．烟气污染物和灰渣的排放达到了国家排放标准。不仅实现了垃圾的减容化、无害化，还实现了熔融渣的资源化。     

城市生活垃圾直接气化熔融焚烧炉模糊自适应控制系统模型研究

城市生活垃圾直接气化熔融焚烧炉的运行过程受许多不确定性因素的影响,城市生活垃圾直接气化熔融焚烧过程的不稳定将会产生二恶英等新的有害物质,随着人们对城市生活垃圾焚烧过程可能造成二次污染的日益关注,如何改善和控制城市生活垃圾焚烧过程的稳定以减少二次污染的发生已经成为一个重要的研究方向。所以应用模糊自适应控制策略对城市生活垃圾直接气化熔融焚烧炉的气化过程和二次燃烧过程进行控制,并对所有的控制策略进行了仿真。仿真结果表明:模糊自适应方法具有良好的控制效果,是解决城市生活垃圾直接气化熔融焚烧过程熔融区温度和第2燃烧室温度不稳定的有效方法。     

二恶英零排放化生活垃圾直接气化熔融焚烧技术

对近年来美国、欧洲、日本等发达国家及作者本人在日本作博士后期间所研制的二恶英零排放化城市生活垃圾直接气化熔融焚烧技术及其工艺流程特点作一简介。     

生活垃圾气化—燃烧清洁转化工艺

针对生活垃圾焚烧过程中的二恶英污染问题,提出了一种新型的等离子气化—燃烧清洁转化工艺。生活垃圾由上吸式气化过程高效转化为高热值的气相产物和灰渣。气相产物通过均相转化过程完成Cl向HCl的定向转移,从源头抑制二恶英分子的生成,配合后续的分级供氧燃烧过程,实现二恶英和氮氧化物的协同控制。气化灰渣经过等离子熔融处理,形成不具污染性的玻璃体。     

垃圾焚烧炉灰渣熔融处理技术的研究进展

熔融技术是灰渣处理的重要技术之一，可以把焚烧炉底渣和飞灰（统称灰渣）转变成稳定且没有毒性的熔渣，并可作为建筑材料再利用。熔融炉内灰渣中的二恶英（PCDD／Fs）在1000℃以上的高温下将彻底分解，挥发性的重金属则被固定在熔渣中。介绍国内外常用的熔融炉型，并重点介绍等离子体熔融炉以及二恶英等毒性物质分解机理。     

鼓泡流化床污泥焚烧排放特性研究

为了解污泥鼓泡流化床焚烧排放特性,利用0.5 MW鼓泡流化床进行了焚烧深圳某污水厂污泥的试验。研究了在不同温度下污泥焚烧的污染物排放特性,结果表明,流化床高温(900℃)焚烧污泥可以有效地抑制二恶英等污染物的产生,焚烧排放物均能够达到《GB 18485-2001》中规定的生活垃圾控制标准。     

肼类物质抑制二恶英排放的机理及应用探析

探讨了肼类物质水合肼和碳酰肼抑制烟气和飞灰中二恶英向环境排放的机理和应用可能性。肼类物质对烟气中二恶英排放的抑制原理预测：在250℃～400℃温度区直接干扰二恶英的合成;在400℃～700℃温度区破坏二恶英的合成先驱物;肼类物质分解焚烧飞灰中的二恶英可在100℃以上的水热条件下进行,并且效果已经被证实。还阐述了肼的泄漏和检测以及肼用于广谱抑制二恶英应该解决的问题。指出肼类物质是极具前景的一类广谱二恶英排放抑制剂,值得探索。     

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.