食用菌菌糠热解制油实验研究

利用自行搭建的上样量20kg/h的热解设备,对二次生物质食用菌菌糠进行热解实验,得到焦炭产率为37.00%,生物质油20.14%,气体产物为42.86%;热解总能耗为33 313.44 k J/kg,其中电能2 090.11k J/kg,液化石油气31 223.33 k J/kg。蒸馏后液体高沸点产物热值达17 143 J,约为0#柴油热值(40 184 J)的0.42倍,焦炭热值为18 143 J,约为标准煤热值(29 300 J)的0.62倍,与褐煤(16 700~21 000 J)相当。利用GC-MS(气-质联用)、FTIR(红外光谱)展开对菌糠热解气体、液体产物成分分析定性分析。分析结果显示热解气体产物主要以大于四个C原子的有机物为主(C_4H_8、C_5H_(10)O、C_6H_8O_2、C_6H_6、C_7H_8五种物质)。对生物质油进行130℃常压蒸馏,馏出组分主要为水。蒸馏之后高沸点组分主要含有醇、酚、醚、烯烃、酰胺、有机卤化物类物质,较一次生物质在500~600℃段热解产物有所不同的是,菌糠热解油中含有不饱和键的烯烃类,以及含有酰胺类物质。     

基于逐级裂解气质联用和热重质谱联用技术的杉木热解特性研究

利用逐级裂解气质联用(stepwise Py-GC/MS)和热重质谱联用技术(TG/MS)对杉木的热解特性进行了研究。结果表明,杉木热解主反应温度为250～430℃,随着升温速率的增大,热解起始温度和终止温度均向高温侧移动。对杉木慢速热解过程进行了动力学分析,得到3种升温速率下对应的活化能分别为83.99,88.87,91.98kJ/mol。杉木逐级裂解主要液体产物有乙酸、1-羟基-丙酮、糠醛、雪松醇、左旋葡萄糖和4-羟基-2-甲氧基肉桂醛等,各温度段产物分布各不相同。在杉木慢速热解条件下,左旋葡萄糖发生二次反应,液体产物中存在很多芳香类物质。     

裂解温度对生物质热解焦油成分的影响

以锯末粉体为生物质热解焦油研究对象,研究了热解温度对焦油产量和焦油化学成分的影响规律,结果表明,热解温度为500℃时,生物质热解产生的焦油量最大,温度过高或过低都有利于焦油的减少。不同热解温度下,焦油中碳氢化合物的成分主要是芳香烃和少量的脂肪烃,含氧化合物主要是苯酚及其烷基衍生物,含氮化合物主要是吡啶、吡咯及其烷基衍生物等杂环化合物。     

废弃印刷线路板真空热解产物的研究

自行设计热解装置,对废弃印刷线路板进行了真空热解,并对热解产物进行了分析。在热解终温550℃,升温速率10℃/min的条件下,得到的热解产物中液、气体、固三种产物的质量分数分别为18.13%、8.5%以及73.37%。对热解液体进行常压蒸馏后进行气相色谱—质谱联用分析,发现热解油中主要成分为苯酚和4-异丙基苯酚,且主要分布于110~230℃的馏分中,而110~230℃的馏分可以占到热解液体产物的50%以上,热解液体中水分含量17.32%左右,同时检测到2-溴苯酚的存在。而热解气体产物通过气相色谱检测,发现主要成分为CH4、H2、CO、CO2等,其中CO2主要生成于反应的初期,随着热解温度的升高,CO2含量急剧下降,而CH4和H2的含量快速上升。热解气中可燃性高热值气体含量高,可以通过燃烧实现热量回收。     

城市污水污泥热解温度对产物分布的影响

用直径200mm的外热式固定床反应器,以城市生活污泥为试验物料,在250-700℃之间对其进行了中低温热解的试验研究,得到气、液、固3种热解产物的产率随热解温度的变化规律。结果表明,固体产物的产率随热解终温的升高而下降,在250-450℃范围内减少较快,在450-700℃范围内减少非常缓慢;而热解液产率在450℃以下呈上升趋势,450-550℃热解液产率较高,550℃达最高值43%,550℃以上呈下降趋势;液态产物中有明显的分层现象,最下层为热解产生的水分及水溶性有机物,中间层为脂肪酸类及硫醇类物质,最上层为脂肪族、烯族碳氢类物质;热解气产率在整个试验温度范围内均呈增加趋势,450℃后气体产生速率明显增加。450℃左右,有机物发生二次裂解反应。这些规律为城市生活污泥热解技术的实际工业应用提供了可靠的基础性资料。     

钾盐对纤维素热解特性的影响

利用微型热解系统,研究500℃终温条件下,钾盐(K2SO4,KNO3,K2HPO4,KOH)对纤维素热解特性的影响。收集炭、焦、重油、轻油、气5种产物,计算各产物产率,分析结果表明,钾盐添加作用下,钾对热解存在主要影响,盐本身理化特性存在次要影响。利用气质联用仪(GC-MS)对重油和轻油进行分析,发现糖、苯类物质主要集中于重油,而醛、酮类物质主要集中于轻油,钾盐显著降低了糖类产物产率,增加了酮类、环烷烃类物质产率。利用X射线光电子能谱仪(XPS)对浸渍样、热解炭、焦含碳官能团进行分析,结果表明,热解后,热解炭与热解焦具有类似的含碳官能团分布,但热解炭中以芳香环中的C=C官能团为主,含氧官能团主要为羰基-CO-而热解焦中另外含有-COO-官能团。     

纤维素热解生物油特性研究

为深入了解生物质热解生物油的特性,对生物质的主要成分纤维素热解生物油的析出和演变特性进行研究。在固定床上研究纤维素在不同温度(280~550℃)下的快速与慢速热解以及不同气相停留时间对纤维素生物油特性与组成的影响。研究表明,纤维素快速热解生物油由左旋葡聚糖及大量脱水糖组成,还有少量呋喃衍生物(如糠醛、5-羟甲基糠醛等)。慢速热解时产生的脱水糖种类较少,但小分子化合物种类更多。随着气相停留时间的缩短,液体产物中左旋葡聚糖含量逐渐升高,酸、醛等小分子消失。     

竹屑热解过程及产物特征研究

以竹屑为原料,选择250~950℃温度范围,在小型固定床反应器上探究竹材热解过程及产物特征。研究发现:随着热解温度的升高,固体焦炭产率减小,气体产率规律与之相反,液体产率先增后减,且在450℃时达到最大(52.28%)。固体焦炭中化学官能团的种类随温度的升高逐渐减少,含量随之减小,650℃之后除苯环结构外,基本无其他官能团,说明竹屑热解主要发生在650℃之前。在较低温度下,热解油中以呋喃类、醛酮类、酚类等含氧化合物为主,气体产物中主要以CO、CO_2为主,当温度超过750℃后,热解油以萘、苊等多环芳烃为主要含量,由于挥发分的二次裂解加剧,使CO和H_2体积分数增大,CH_4比例随温度变化缓慢。     

木聚糖与果胶热解液化特性研究

为了解不同类型多聚糖的快速热解机理,采用固定床研究反应温度(250~950℃)对木聚糖与果胶热解特性及其产物分布的影响。研究表明,果胶比木聚糖更易于分解,其分解温度低于250℃;两者解聚之后的单糖并不稳定,容易进一步裂解成小分子碎片。在低温条件下,木聚糖热解时生成的酸类化合物种类较多,其中乙酸和丙酸含量较高;果胶热解时生成的乙酸和糠醛明显高于木聚糖。果胶热解生成的CO_2高于木聚糖,而后者的CO产率高于前者;在450℃以下时,CO主要来自于单糖裂解时的初级反应,与酸、酮等小分子同时生成;随着反应温度的升高,CO主要来自于丙酸、酮类小分子的脱羰基过程。     

傅立叶红外光谱法对煤中吡咯型氮的热解规律研究

选取吡咯为煤中吡咯氮的模型化合物，在石英管流动反应器中550℃～1020℃温度范围内研究了其热解规律，利用傅立叶红外光谱仪(Ft—Ir)对反应产物进行检测。试验结果表明：吡咯高温热解时，含氮产物最终几乎全部以HCN的形式存在，也能观测到不饱和腈类物质的生成与转化。图4表1参6     

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。