300MW锅炉再热汽温低及卫燃带改造研究

针对某电厂7#锅炉出现的再热蒸汽出口温度偏低的问题,对其原因及解决方法进行分析,提出了敷设卫燃带的改造方案,给出了所需卫燃带面积的求解过程,对敷设卫燃带前后锅炉参数的变化进行了对比。     

浦城热电厂循环流化床锅炉受热面的调整

通过对浦城热电厂二锅炉受热面调整改造工作总结和定量分析，提出了循环流化床锅炉燃用Ⅱ类无烟煤各部分吸热份额的合适比例，供同类电厂改造借鉴和设备制造厂家参考。     

高钠煤在660MW机组塔式锅炉上的燃用实践

针对神华国能集团有限公司花园电厂4×660 MW机组2号锅炉燃用高钠煤出现的结渣问题,从锅炉设计、煤质特性、燃烧调整等方面进行了研究与分析。从锅炉设计上讲,适当减小热负荷参数对锅炉燃用高钠煤是有利的。通过燃烧调整措施,花园电厂2号锅炉可以满负荷长期安全燃用83%高钠煤,为目前新疆地区在役锅炉中燃用高钠煤的最高水平。     

富集型燃烧器在单独燃用合山劣质烟煤锅炉上的应用

合山劣质烟煤是我国燃烧特性最差的一种动力用煤.现有燃烧器在合山电厂400 t/h的4号煤粉炉上单独燃用合山煤时,出现燃烧稳定性较差、燃烧效率低等问题.采用稳燃性能优异的富集型燃烧器对下两排一次风燃烧器实施改造,并针对合山煤高灰高硫特点采取一些防范措施.改造后,锅炉单独燃用合山煤时燃烧稳定,飞灰含碳量和大渣含碳量均小于3 %,锅炉效率大幅度地提高了近10 %,达到90 %,炉内受热面和燃烧器没有出现严重的结渣和明显的高温腐蚀.     

浦城热电厂循环流化床锅炉受热面的调整

通过对浦城热电厂二台锅炉受热面调整改造工作的总结和定量分析 ,提出循环流化床锅炉燃用Ⅱ类无烟煤各部分吸热份额的合适比例 ,供同类电厂改造借鉴和设备制造厂家参考。     

煤粉锅炉中用煤粉稳燃的方式

波兰人民共和国的大多数电厂燃用比设计值差的低质煤。在Polanec电厂的EP-650型锅炉,其设计燃料的热值为19.65MJ/kg,而实际燃用的煤平均为17.5MJ/kg,低限竞达14.0MJ/kg。低的炉膛热负荷和相对粗的煤粉(这是该类炉上降低结渣的措施,因为所燃用的煤在炉膛中具有强的结渣性)使燃烧稳定性很低,为了稳燃被迫需要大量重油。     

我国生物质直燃发电问题探讨

针对生物质直燃电厂可否大规模发展的问题,对比了秸秆综合利用途径效益及消化能力,得出生物质直燃发电是我国现阶段最具现实意义的秸秆资源化利用技术。通过分析现有生物质直燃电厂存在的问题,获得了直燃电厂利用秸秆资源的关键在于直燃机组参数、容量、布局均要基于辐射区内秸秆冗余量来规划,同时政府在电价上要给予一定的配套支持。     

发展通用化燃煤层燃工业锅炉

通用化燃煤层燃工业锅炉,还未曾有人下过确切的定义,按照通常的理解,就是能够燃用工业锅炉用煤分类中除石煤、煤矸石之外的各类烟煤、无烟煤、分煤和褐煤的层燃炉,并能达到规定的热效率。通用化燃煤层燃工业锅炉是人们想望已久的事了,但是     

神华煤发热量回归分析在定洲电厂的应用

根据神华国华河北定洲电厂的用煤情况,提出了一种神华煤发热量回归分析方法。该方法在定洲电厂的应用中有效地校核了实测发热量,避免了异常数据对机组正常运行的影响。实践证明该方法是可靠的,值得向其它类似电厂推广。     

国外信息

马来西亚装机容量为90万千瓦的帕卡联合循环电厂的第一台机组于今年一月并网发电。帕卡电厂位于马来西亚沿海,是马来西亚第一家联合循环电厂,也是整个东南亚最大的热电合供电厂。该厂装有三组各为30万千瓦的联合机组,每组包括两台10万千瓦的燃汽轮机,两台废热锅炉和一台10     

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.     

Wind power for pumping: The development of the ITP windpump

Water pumping has been one of the main applications for wind power in the past and despite the spread of mains-electric pumps, more than a million windpumps remain in regular use. This paper reviews the general technical and economic requirements for pumping water using wind energy and by way of example gives an overview of the development of the new ITP wind-pump. It then considers the future prospects for this kind of technology.     

Methods of creating solar-reflective nonwhite surfaces and their application to residential roofing materials

We describe methods for creating solar-reflective nonwhite surfaces and their application to a wide variety of residential roofing materials, including metal, clay tile, concrete tile, wood, and asphalt shingle. Reflectance in the near-infrared (NIR) spectrum (0.7–2.5 μm) is maximized by coloring a topcoat with pigments that weakly absorb and (optionally) strongly backscatter NIR radiation, and by adding an NIR-reflective basecoat (e.g., one colored with titanium dioxide rutile white) if both the topcoat and the substrate weakly reflect NIR radiation. Coated steel and glazed clay-tile roofing products achieved NIR reflectances of up to 0.50 and 0.75, respectively, using only cool topcoats. Gray-cement concrete tiles achieved NIR reflectances as high as 0.60 with coatings colored by NIR-scattering pigments. Such tiles could attain NIR reflectances of up to 0.85 by overlaying a white basecoat with a topcoat colored by NIR-transparent organic pigments. Granule-surfaced asphalt shingles achieved NIR reflectances as high as 0.45 when the granules were covered with a white basecoat and a cool color topcoat.     

Thermal decay of an initially hot isothermal water body with application to thermal energy storage

The thermal decay of an initially hot isothermal water body contained in a tank was studied. Analytical solutions (including a group-theoretic solution) were obtained for the one-dimensional heat conduction equation with heat loss from the sides of the tank. The convective heat transfer coefficient was assumed not to be constant over the surface of the tank but to vary with space and time. A very good agreement was obtained between the group-theoretic solution and a numerical solution using the Crank-Nicholson finite difference scheme. The analytical results are discussed in terms of the underlying physical mechanisms.     

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.     

秸秆燃烧中温度对钾转化与释放的影响

通过对稻秆原料进行常规特性分析和EDX元素含量分析,发现钾在稻秆无机元素中占有重要地位。参考原料化学分馏法和土壤中钾的分类与测试方法,给出了对生物质原料及其燃烧产物中钾的定性与定量简易方法。通过程序控温型固定床对稻秆先进行缓慢氧化,然后以100℃为间隔从400～900℃进行成灰,并分别测试其成灰率、有效钾和全钾的份额。结合稻秆原料及其灰中钾的份额分析,进行了稻秆灰中有效钾转化与释放的计算,发现有效钾在700～800℃之间有快速的释放和形态转变。稻秆灰的XRD分析结果表明秸秆灰中钾主要以KCl、K_2SO_4形式存在,得到了钾以盐的形式进行转化与释放的机理。该文中燃烧温度对钾转化与释放的影响规律对设计秸秆电厂时的炉型选择和燃烧参数确定有一定参考价值。