共热解过程对褐煤焦和生物质焦氧化特性的影响

以锡盟褐煤和玉米秸秆为原料,利用固定床程序升温热解的方法制备了褐煤焦、生物质焦以及褐煤和生物质不同混合比例的共热解焦样,并进行了孔结构和化学结构的表征以及其灰成分分析。采用等温热重法在450 ℃下考察褐煤焦和生物质焦的混合样与其相同比例的共热解焦样的氧化活性,对比分析共热解过程对焦样反应活性的影响。实验结果表明,共热解过程中的二次反应对焦样结构有着明显的影响,进一步导致其反应活性下降。尤其是生物质添加量低于50%时,由于共热解过程生物质中大量挥发分的释放增强了其与半焦的二次反应,促使新生焦中部分小于五环的有机结构向更大的结构转化。但生物质添加量大于50%时,生物质焦的反应活性起主导作用,焦样中碱金属和碱土金属催化作用较明显,特别是钾的影响,使得共热解过程中挥发分与半焦的二次反应对其结构及反应性的影响减弱。     

掺钯碳纳米管的制备及电接触性能

以PbCl₂为介质, 采用无电沉积方法制备了掺钯碳纳米管, 并对其形貌和结构进行了表征. 结果表明, 掺入的钯纳米粒子分布均匀、 粒径均一, 掺杂量与粒径尺寸适中; 所掺入的纳米粒子的成分为0价态的钯, 且掺杂类型为p型. 电接触性能测试结果表明, 掺钯碳纳米管与金电极间的接触电阻得到了明显改善, 阻值平均降幅高达近71.09%.     

低能离子散射谱分析中的荷电效应及中和作用

用低能离子散射谱（ISS）对比分析了与样品托有良好电接触的和与样品托绝比的金属银片，观察到荷电效应对ISS分析有严重影响。实验还表明在ISS分析时使用低能电子中和枪可以有效地消除荷电效应，还发现电子中和枪的使用对于惰性气体离子的中和作用无明显影响。     

灰化温度对生物质灰特征的影响

针对我国在进行生物质灰分分析时采用煤质分析标准的现状，对八种生物质分别在高温(GB/T212－2001中规定的温度，820 ℃)和低温(ASTM/E 870-82(1998修正)中规定的温度，600 ℃)下进行了灰化，测定了灰分量，并利用EDX-SEM对灰成分和形态进行了分析。结果显示，灰化温度对灰分量、灰成分和灰形态均有明显的影响，因此在生物质灰分性质分析时宜采用低温灰化的方法。     

纳米金属氧化物：复合分散法制备及分散性

通过采用水热晶化与荷电复合分散法制备γ-AlOOH、R-TiO₂和α-Al₂O₃纳米晶体粉末,利用TEM和激光粒度分析仪等手段研究了纳米颗粒水热晶化与荷电复合分散的分散效果及其工艺条件,并探讨了金属氧化物纳米颗粒水热晶化与荷电复合分散机理。结果表明,晶化与荷电复合分散可明显改善金属氧化物纳米颗粒在液相中的分散稳定性,所制得的AlOOH、TiO₂和Al₂O₃纳米颗粒在水中分散放置24 h后的透光率的变化率D₂₄还可分别保持为94.1%、87.7%和82.2%;在水中分散后的粒径分布统计的平均粒径分别为67、70和143 nm。     

灰中酸性成分对灰熔融温度的影响

搜集并统计了世界129种典型煤种、城市污水污泥及污泥/煤混烧灰样的灰成分及灰熔融特征温度等相关数据,研究灰中酸性成分SiO2、Al2O3、TiO2和P2O5对灰熔融特性的影响。结果表明,Al2O3是决定灰熔点的主要因素,酸性金属氧化物SiO2、Al2O3和TiO2形成的耐熔矿物质石英、偏高岭石、莫来石、金红石等可提高灰熔点。非金属氧化物P2O5与污泥和污泥/煤的灰熔点FT二次拟合很好且明显降低熔点,污泥灰中P2O5含量显著高于煤灰是导致其熔点明显低于煤的重要原因。     

XPS分析绝缘样品中磁透镜对中和效果的影响研究

以绝缘样品聚对苯二甲酸乙二醇酯(PET)为X射线光电子能谱(XPS)分析测试对象,探讨了使用不同的X射线源作为激发源时,磁透镜对荷电中和系统中和效果的影响.试验结果表明,当使用单色化Al Kα为激发源时,磁透镜对荷电中和器的中和效果没有显著影响.而使用非单色化双阳极Mg Kα为激发源,磁透镜开启时才能得到良好的荷电中和效果,磁透镜关闭时所测谱峰会因荷电效应而发生峰形畸变.     

生物质灰对煤焦加氢气化的催化作用

以小麦秸秆、马尾藻和山苦荬等三种富含碱金属和碱土金属的生物质为原料,研究了在500、600和815℃下制得的生物质灰对神府煤焦加氢气化的催化作用。结果表明,随着制灰温度由500℃升高至815℃,灰产量减少,且灰中的碱金属和氯元素的含量降低;当制灰温度达到815℃,生物质灰出现明显的熔融现象;600℃灰样对神府煤焦加氢气化具有较好的催化作用,催化效果随灰样添加比例增大而增强。山苦荬灰催化作用较好,而马尾藻灰催化作用较弱。小麦秸秆灰中较高的硅含量和马尾藻灰中较高的氯含量是其催化作用较弱的主要原因;氯元素会加剧碱金属的挥发,弱化与其结合的碱金属的催化效果,对碱金属催化所产生的抑制作用比相同摩尔数的硅更加明显。     

导电环氧树脂消除扫描电子显微镜图像荷电问题的原理与实践

荷电问题常造成扫描电子显微镜(SEM)图像上产生亮度不均、条纹等伪影.提出一种利用导电环氧树脂镶嵌样品以消除SEM图像荷电的方法,并与传统导电胶粘贴制样方法对1000℃高温混凝土、瓷土与河南双槐树考古土三种样品的适应性进行了对比研究.结果表明,利用铜粉与环氧树脂混合制备导电环氧树脂并将样品镶嵌其中所制备样品的SEM图像基本无荷电问题,而传统导电胶粘贴方法所制备样品的SEM图像存在较严重的荷电问题,通过增加导电层厚度并不能对此进行改善,且易造成微纳结构被掩盖.最后对传统制样方法导致荷电问题的原因与导电环氧树脂对荷电问题的改善原理进行了分析.     

生物质与煤混燃灰的比电阻特性实验研究

以玉米秸、麦秸、锯末纯燃并以不同比例与煤混燃,利用DR型高压粉尘比电阻实验台对灰样比电阻R进行测量, 以AAS对灰样化学成分进行分析。结果表明,纯生物质燃料灰R值为10⁸Ω·cm~10¹0Ω·cm,属于中比电阻。混燃灰样的R值均为10⁸Ω·cm~10¹2Ω·cm。麦秸与煤的混燃灰中,掺混率R_t对比电阻R的影响不明显;玉米秸与煤的混燃灰中,在110℃以下,R_t越高,R越低;在110℃以上,R_t越高,R越大。生物质与煤的混燃改变了燃料的燃烧特性及熔融特性,使灰的物理特性和化学成分、含量发生变化,造成混燃灰比电阻与煤灰比电阻的规律存在一定的差异。     

Thermal characteristics of the combustion process of biomass and sewage sludge

The combustion of two kinds of biomass and sewage sludge was studied. The biomass fuels were wood biomass (pellets) and agriculture biomass (oat). The sewage sludge came from waste water treatment plant. The biomass and sludge percentage in blends with coal were 10 %. The studied materials were characterised in terms of their proximate and ultimate analysis and calorific value. The composition of the ash of the studied fuels was also carried out. The behaviour of studied fuels was investigated by thermogravimetric analysis (TG, DTG and DTA). The samples were heated from an ambient temperature up to 1,000 °C at a constant three rates: 10, 40 and 100 °C min^?1 in 40 mL min^?1 air flow. TG, DTG and DTA analysis showed differences between coal, biomass fuels and sewage sludge. 10 % addition of studied fuels to the mixture with coal changed its combustion profile in the case of sewage sludge addition. The combustion characteristics of fuel mixtures showed, respectively, qualitative summarise behaviour based on single fuels. Evolved gaseous products from the decomposition of studied samples were identified. This study showed that thermogravimetric analysis connected with mass spectrometry is useful techniques to investigate the combustion and co-combustion of biomass fuels, and sewage sludge, together with coal. Non-isothermal kinetic analysis was used to evaluate the Arrhenius activation energy and the pre-exponential factor. The kinetic parameters were calculated using Kissinger–Akahira–Sunose model.     

Thermogravimetric analysis of the co-combustion of the blends with high ash coal and waste tyres

Incineration methods are becoming increasingly important from the view point of the need to minimize the environmental impact of waste tyre disposal. Combustion of waste tyre, one high ash coal and tyre-coal blends with 10, 30 and 50% waste tyre were investigated by means of thermogravimetric analysis (TGA) carried out at 20 K min⁻¹ in the temperature range from ambient temperature to 1273 K. And effects of the mixed proportion between coal and waste tyre on the combustion process, ignition and burnout characteristics were also studied. The results indicate that the combustion of waste tyre is controlled by the emission of volatile matter, the regions are more complex for waste tyre (three or more peaks) than for coal (one peak). Also as compared with the case of burning only high ash coal, the incorporation of waste tyre can improve the combustion characteristics of high ash coal, especially the ignition performance and the peak weight loss compared with the separate burning of waste tyre and coal. Moreover, comparisons of the TG-DTG profiles between experimental and calculational results, it is indicate that there is a comparatively important difference, the co-combustion characteristics is the coupling effect between waste tyre and coal. The data resulting also showed that the co-combustion of waste tyre and low quanlitied coal as fuel is feasible.     

Thermogravimetric analysis of co-combustion of biomass and biochar

The co-combustion of biomass and biochar was investigated by thermogravimetric analysis. Several thermal parameters and mean reactivity index (R _M) for different blends were used to evaluate co-combustion features. As the biomass content increased from 30 to 90 mass%, volatile releasing temperature (T _v), burnout temperature (T _b), and the temperature at the maximal peak (T _max) generally reduced, while average mass loss rates (R _a) and R _M increased, the maximum mass loss rate (R _max) initially decreased and then increased. Results showed that biochar additions enhanced biomass fuel reactivity over weighted average in main combustion region. Besides, blends with 10–30 mass% of biochar behaved better than those with higher biochar ratio. Synergy exists between the two components and better combustibility is feasible by co-firing biochar with biomass.     

循环流化床(CFB)煤/焦气化反应的研究Ⅱ.温度、氧含量及煤种对CFB气化反应的影响

报道了两种煤／焦（西山焦煤飞灰、神木煤），在小型循环流化床（ＣＦＢ）气化反应装置上，以二氧化碳及氧气混合物为气化介质，在不同条件（９００～９７０°Ｃ，０～３０％氧含量）下的气化反应的研究。结果表明，提高气化温度，气化反应速度提高，尾气中可燃气体浓度（ＣＯ，Ｈ２，ＣＨ４）、碳转化率及气化效率明显提高。气化介质中的氧含量增加，ＣＯ浓度、碳转化率及气化强度明显增加。反应性高、挥发分多的煤种更适合在ＣＦＢ气化反应装置上进行气化反应。     

Thermochemical and Toxic Element Behavior during Co-Combustion of Coal and Municipal Sludge

The thermochemical and kinetic behavior of co-combustion of coal, municipal sludge (MS) and their blends at different ratios were investigated by thermogravimetric analysis. Simulation experiments were performed in a vacuum tube furnace to determine the conversion behavior of toxic elements. The results show that the combustion processes of the blends of coal and municipal sludge are divided into three stages and the combustion curves of the blends are located between those of individual coal and municipal sludge samples. The DTG_max of the sample with 10% sludge addition reaches a maximum at the heating rate of 20 °C/min, indicating that the combustion characteristics of coal can be improved during co-combustion. Strong interactions were observed between coal and municipal sludge during the co-combustion. The volatilization rates of toxic elements decrease with an increasing proportion of sludge in the blends during co-combustion, which indicates that the co-combustion of coal and sludge can effectively reduce the volatilization rate of toxic elements. The study reflects the potential of municipal sludge as a blended fuel and the environmental effects of co-combustion of coal and municipal sludge.     

Experimental study and performance evaluation of various cook stove models based on energy and exergy analysis

This article presents the experimental study and comparative performance evaluation of four types of cook stoves using energy and exergy analysis. Analysis of four different types of cook stove models viz. Envirofit, Mangla, Harsha and Vikram were selected and the water boiling test has been carried out. The suitable biomass available from the local market was prepared in the proper size as described in the Bureau of Indian Standards (BIS) and has been used as the fuel for cook stove in this experimental study. The aluminium pots of proper capacity as per BIS standard have been used for different cook stoves. The data from the experiments was collected and evaluated for the energy and exergy efficiencies for different models. Based on the data analysis it is found that the exergy efficiency is much lower than that of the energy efficiency for all the four models. It is also found that the both the efficiencies of Envirofit model are found to be higher than those of other models studied here.     

Regulation of Power Conversion in Fuel Cells

Here we report a regulation about power conversion in fuel ceils. This regulation is expressed as that to-tal power produced by fuel ceils is always proportional to the square of the potential difference between the equilibrium potential and work potential. With this regulation we deduced fuel cell performance equation which can describe the potential vs. the current performance curves, namely, polarization curves of fuel cells with three power source parameters: equilibrium potential E0; internal resistance R; and power conversion coefficient K. The concept of the power conversion coefficient is a new criterion to evaluate and compare the characteristics and capacity of different fuel ceils. The calculated values obtained with this equation agree with practical performance of different types of fuel cells.     

工业、生活污泥与煤混合燃烧的灰熔特性研究

针对煤粉锅炉掺烧污泥后污泥对混合燃料灰熔特性的影响行为,利用矿物三元相图、XRD等分析手段,研究了不同特性污泥(生活污泥、工业污泥)与煤掺混燃烧过程中不同矿物组分的相互作用机制及灰渣的灰熔融特性变化特征。结果表明,三元相图能够有效预测煤和污泥掺混后灰熔融温度的变化趋势;低含量的氧化铁形成低温共熔体以及透辉石、钙长石会降低煤和污泥混合后的灰熔融温度;而钙镁橄榄石、莫来石和单体形式存在的氧化铁能提高煤和污泥混合后的灰熔融温度。工业污泥中的高硫组分在混烧过程中易形成硫酸盐的低温共融体。生活污泥中磷对灰熔点的影响与氧化铝及碱金属的比例有关,当氧化铝的含量占主要成分时,磷的存在趋向于降低灰熔点,而当碱金属占主要成分时,磷的存在趋向于提高灰熔点。     

Thermal degradation of rice husks on a pilot plant

This study is an attempt to establish the possibilities to obtain black rice husk ash (BRHA) and white rice husk ash (WRHA) via pyrolysis of wasted raw rice husks in a pilot plant fluidized-bed reactor at different conditions. The process course auto thermally, without outer fuel. The released heat may be used for steam obtaining or drying. The solid products obtained (BRHA or WRHA) are characterized using X-ray diffraction patterns, thermal analysis, and low temperature nitrogen adsorption. Using batch adsorption technique, the kinetics was studied and the adsorption capacities of crude oil and diesel fuel at different temperatures as well as some hydrocarbons at 298?K onto BRHA and WRHA are determined. It was established that BRHA have been higher adsorption capacity than WRHA. At a given temperature, BRHA sorbed more crude oil than diesel fuel. The results obtained showed that the material studied has high adsorption capacity and low cost and may successfully be used as an effective adsorbent to cleanup of bilge water and spills of oil and oil products in water basins. Because the saturated BRHA with crude oil, diesel fuel or different hydrocarbons are characterized with high calorific, they can be burnt in incinerators, industrial ovens or steam generators. By this way, we attain not only ecological but also economical effect.     

Study of mercury adsorption by selected Chinese coal fly ashes

Recent research has shown that fly ash produced in coal-fired power plants can play an important role in mercury removal. The aim of this study was to establish the relationships between fly ashes produced from different coals and boiler types and their mercury adsorption capacity. In order to achieve this objective, Brunauer–Emmett–Teller surface area, scanning electron microscopy, thermogravimetric analysis, and a mercury measurement system were employed to characterize the samples. The results show that the average pore size of fly ash is the single most important factor with residual carbon content fulfilling a secondary role in the capture of elemental mercury. The addition of HBr with fly ash can remarkably enhance the mercury adsorption performance of fly ash.