硅铝调控与晶种诱导对水热稳定飞灰中重金属的协同影响

研究了选取的粉煤灰、膨润土、高岭土、硅藻土作为外源硅铝调理剂添加与雪硅钙石人工晶种诱导对150℃水热法稳定垃圾焚烧飞灰中重金属Pb、Zn、Cu、Cd、Cr的协同影响。飞灰由于富钙而低硅铝的元素特征,导致其在水热条件下无法直接合成沸石类,Pb的浸出浓度仍然超标;当单一或混合添加硅铝调理剂添加量为10%时,其水热产物中有水钙铝榴石或加藤石生成;提高添加量至30%时,均有目标雪硅钙石的生成,这与30%添加量下飞灰中Ca/（Al+Si）元素比接近雪硅钙石的理想元素比值0.67~1.20直接相关。混合添加30%的粉煤灰与硅藻土为最佳选择,水热产物Pb的浸出浓度降低至0.30 mg·L^-1,且在此基础上再添加3%的诱导晶种可加速从第6 h开始即合成雪硅钙石,并使Pb的浸出浓度下降到最低值0.28 mg·L^-1。硅铝调控（30%的复合硅铝调理剂,其中粉煤灰：硅藻土为1：1）与晶种诱导的协同影响下高效生成雪硅钙石,并显著抑制Pb、Zn等在水热过程中向液相的转移、降低其在水热液相中的浓度,使飞灰中的重金属在水热后确实稳定于水热固相产物中而非迁移至水热液相造成污染转移,真正实现了飞灰中重金属的固定化。     

垃圾焚烧系统换热表面的积灰生长与控制研究进展

焚烧是我国处理城市生活垃圾的重要方式,能够实现城市生活垃圾的减量化、无害化和资源化利用。由于城市生活垃圾水分高、盐分多、热值低,导致垃圾焚烧炉普遍面临严重的积灰问题,这不仅为垃圾焚烧炉的安全运行带来隐患,还严重影响垃圾焚烧发电厂的经济效益。本文综述了垃圾焚烧炉受热面积灰生长的研究现状,介绍了垃圾焚烧炉受热面积灰生长的机理,分析了飞灰粒径、烟气流速、烟气温度、换热面温度等对垃圾焚烧炉受热面积灰生长特性产生影响的因素。在燃煤锅炉和生物质炉积灰结渣的现有积灰模型基础上,需要结合垃圾炉的积灰实验数据发展可以预测垃圾焚烧炉积灰结渣问题的模型。针对垃圾焚烧炉受热面积灰严重的现象,本文提出了设备改进、工艺优化、使用添加剂和涂层技术抑制积灰生长的一系列方法。最后总结了当前的重点研究内容,提出了建立能够准确预测垃圾焚烧炉积灰生长的模型,开发新的有效减轻垃圾焚烧炉换热面积灰的涂层等今后开展研究的方向,为垃圾焚烧电厂的合理运行提供了参考建议。     

On the evaluation of synthetic and natural ilmenite using syngas as fuel in chemical-looping combustion (CLC)

Chemical-looping combustion (CLC) is a combustion technique where the CO₂ produced is inherently separated from the rest of the flue gases with a considerably low energy penalty. For this reason, CLC has emerged as one of the more attractive options to capture CO₂ from fossil fuel combustion. When applying CLC with solid fuels, the use of a low cost oxygen carrier is highly important, and one such low cost oxygen carrier is the mineral ilmenite. The current work investigates the reactivity of several ilmenites, some which are synthetically produced by freeze granulation and two natural minerals, one Norwegian ilmenite and one South African ilmenite.     

精对苯二甲酸的灰分测定不确定度评定

讨论了影响精对苯二甲酸(PTA)中灰分的测定结果不确定度的各种因素。通过对影响结果不确定度分量的分析和量化,以及分量之间相关性的计算,求出PTA中灰分测定结果的标准不确定度和扩展不确定度。结果表明,重复性引起的不确定度最大。PTA中灰分含量为10.44 mg/kg,其扩展不确定度为5.00 mg/kg。     

新型耐高温耐油聚硫代醚密封剂的研究

介绍了一种新型聚硫代醚密封剂,并对聚硫代醚和聚硫生胶的黏度、相对分子质量及其分布、耐热性以及两种密封剂的热空气老化性能、耐油性能和工艺性能等进行了测试和分析。结果表明:聚硫代醚密封剂的耐油性能与传统的聚硫密封剂相当,其耐热性和工艺性优于聚硫密封剂。经204℃/6h热空气老化后,聚硫代醚密封剂呈弹性体,其拉伸强度为1.10MPa、断裂伸长率为192%;而聚硫密封剂内部已呈蜂窝状,并且其表面硬化,故力学性能无法测量。     

火山碎屑沉积岩储层评价方法综述

近年来,随着测井新技术的不断发展,火山岩地层中所蕴含的能源不断的被开发。新能源被运用于生活的各个领域,国家不断加大对测井技术的研究力度,使火山岩储层的评价技术有了一些突破性的发展与进步,在测井技术中影响最大的是火山碎屑沉积岩中的凝灰质,由于凝灰质的密度与含量给测井评价带来了很大的困难。对于火山碎屑沉积岩组成评价方法国内外均有研究成果,而对于解决火山碎屑沉积岩储层中的成分含量问题,我国科学家提出了许多非常有效的办法。我国科学家侧重利用数学方法进行研究,而国外的科学家们则利用物理方法对此问题进行研究。     

精对苯二甲酸的灰分测量结果不确定度评定

讨论了用GB/T7531标准方法测定精对苯二甲酸中灰分的测量结果不确定度的各种影响因素。通过对影响结果不确定度分量的分析和量化,以及分量之间相关性的计算,求出精对苯二甲酸中灰分测量结果的标准不确定度和扩展不确定度,对测定结果进行了表述。     

Effects of fuel devolatilisation on the combustion of wood chips and incineration of simulated municipal solid wastes in a packed bed

Detailed mathematical simulations as well as experiments have been carried out for the combustion of wood chips and the incineration of simulated municipal solid wastes in a bench-top stationary bed and the effects of devolatilisation rate and moisture level in the fuel were assessed in terms of ignition time, burning rate, reaction zone thickness, peak flame temperature, combustion stoichiometry and unburned gas emissions at the bed top. It is found that devolatilisation kinetic rate has a noticeable effects on the ignition time, peak flame temperature, CO and H₂ emissions at the bed top and the proportion of char burned in the final stage (char burning only) of the combustion. However, it has only a minor effect on the other parameters. Reaction zone thickness ranges from 20 to 55 mm depending on the moisture level in fuel and an increase in the moisture level causes a shift of the combustion stoichiometry to more fuel-lean conditions.     

Determination of the biogenic and fossil organic matter content of refuse-derived fuels based on elementary analyses

A method to determine the mass, energy and carbon content of biogenic and fossil matter in refuse-derived fuel (RDF) is described. The method combines standard chemical information about biogenic and fossil material with data from a chemical analysis of the RDF. The data are used to solve a set of equations that deliver the mathematically and statistically derived final result. For the chemical analysis representative samples of the RDF were assessed in a CHNSO elemental analyser. The proposed method was validated by characterizing defined reference mixtures of plastics and biomass (e.g., polyethylene and cardboard). The correlation coefficient (r²) between the measured and reference values was greater than 0.99. If representative sampling of RDF is assumed, the new method represents a reliable, quick and complementary method for characterizing RDF.     

Development and characterization of a silicon-based micro direct methanol fuel cell

A silicon-based micro direct methanol fuel cell (μDMFC) for portable applications has been developed and its electrochemical characterization carried out in this study. Anode and cathode flowfields with channel and rib width of 750 μm and channel depth of 400 μm were fabricated on Si wafers using the microelectromechanical system (MEMS) technology. A membrane-electrode assembly (MEA) was specially fabricated to mitigate methanol crossover. This MEA features a modified anode backing structure in which a compact microporous layer is added to create an additional barrier to methanol transport thereby reducing the rate of methanol crossing over the polymer membrane. The cell with the active area of 1.625 cm² was assembled by sandwiching the MEA between two micro-fabricated Si wafers. Extensive cell polarization testing demonstrated a maximum power density of 50 mW/cm² using 2 M methanol feed at 60 °C. When the cell was operated at room temperature, the maximum power density was shown to be about 16 mW/cm² with both 2 and 4 M methanol feed. It was further found that the present μDMFC still produced reasonable performance under 8 M methanol solution at room temperature.     

换热管内置螺旋形扭带阻力与传热特性的实验研究

为了研究螺旋形扭带阻力与传热特性,选取了不同宽度（6、7和8 mm）的3种扭率（2.0、3.0、4.0）、3种螺距比（1.5、2.0、2.5）的参数组合下共27根螺旋形扭带插入换热管内进行实验.实验结果表明,插入螺旋形扭带后换热管内流动阻力和传热效果都有明显提高.通过对实验数据的多元线性回归分析,建立了相应的阻力系数和努赛尔数关联式.并且由强化传热综合性能评价分析,在实验雷诺数范围内得出强化传热综合性能评价因子φ=1.063～1.587,证明了实验研究的扭带具有强化传热的应用价值.     

Analysis of a solid oxide fuel cell system for combined heat and power applications under non-nominal conditions

In this paper, a model for a solid oxide fuel cell (SOFC) system for decentralized electricity production is developed and studied. The proposed system, operated on natural gas, consists of a planar anode supported fuel cell section and a balance of plant (BoP) which includes gases supply, a fuel processor, a heat management system, an after-burner and a power conditioning system. A reference case is defined and evaluated taking into account the state of the art of the technology and the related technical constrains. Electrical and thermal efficiency of the system, for non-reference conditions are evaluated. In particular, the effect of the deviation from the reference conditions of fuel utilization, gas temperature spring in fuel cell stack, anode off-gas recirculation rate, air inlet temperature and external pre-reforming reaction extent is analyzed. The present study revealed to be a powerful tool for evaluating the SOFC system performance under a wide range of operation and paves the way for defining control strategies in order to maintain high system efficiency under part-load operations.     

Structure evaluation of anode-supported planar solid oxide fuel cells based on single/double-sided electrolyte(s) under redox conditions

Structure evaluation was comparably studied with the traditional thin anode-supported solid oxide fuel cells based on single-sided electrolyte (SSE-SOFCs) and the thick flat-tube solid oxide fuel cells based on double-sided electrolytes (DSE-SOFCs) under redox conditions. Results showed that the structure of DSE-SOFCs remained unchanged, especially the electrolyte kept un-cracked during the redox process, whereas SSE-SOFC was warped and, in some cases, cracked as the thickness of supported anode was less than 1 mm, which indicated that the DSE-SOFCs exhibited better redox stability than the SSE-SOFCs.     

Development of a novel test system for in situ catalytic, electrocatalytic and electrochemical studies of internal fuel reforming in solid oxide fuel cells

A test system based around a thin‐walled extruded solid electrolyte tubular reactor has been developed, which enables the fuel reforming catalysis and surface chemistry occurring within solid oxide fuel cells and the electrochemical performance of the fuel cell to be studied under genuine operating conditions. It permits simultaneous monitoring of the catalytic chemistry and the cell performance, allowing direct correlation between the fuel cell performance and the reforming characteristics of the anode, as well as enabling the influence of drawing current on the catalysis and surface reaction pathways to be studied. Temperature‐programmed reaction measurements can be carried out on anodes in an actual SOFC, and have been used to investigate the reduction characteristics of different anode formulations, methane activation and methane steam reforming, and to evaluate the nature and level of carbon deposition on the anode during reforming. This revised version was published online in July 2006 with corrections to the Cover Date.     

Determination of hydrogen content, gross heat of combustion, and net heat of combustion of diesel fuel using FTIR spectroscopy and multivariate calibration

The precise determination of the heat of combustion is of great importance for trading automotive diesel. The net heat of combustion (NHC) of fuel is related to the hydrogen elemental composition of fuel as obtained by elemental analysis. Heat of combustion expressed as gross heat of combustion (GHC) and net heat of combustion (NHC) have been predicted from data obtained by proximate analysis (density, ash, water and sulphur content) (ASTM D4868). GHC was obtained using bomb calorimetry (ASTM D240). The results of ASTM D4868 and ASTM D240 were found in good agreement. GHC and NHC fall within the relatively narrow range 45.24-46.08 and 41.91-43.27 MJ/kg, respectively. GHCs of tested diesel samples are, on average, about 7% greater than NHCs. The present paper also present a simple analytical method for determination of hydrogen content, GHC, and NHC of automotive diesel fuel using FTIR spectroscopy and partial-least squares calibration (PLS-1). PLS-1 had a high prediction power for prediction of hydrogen from FTIR spectra of diesel samples. The spectral ranges used in calibration were 400-670 and 2846-2970 cm⁻¹. On the other hand, classical least squares calibration (CLS) was found invalid for determination of hydrogen content in diesel. The results obtained by the proposed analytical method were almost to those obtained by ASTM D4868 and ASTM D240. PLS-1 method, offers a simple and reliable analytical method for quantification of hydrogen content in diesel samples without running expensive analysis like those carried out using carbon, hydrogen, and nitrogen (CHN) instruments.     

Chemical and physical analyses and sensory evaluation of six deep-frying oils

The performance of three high-oleic canola oils with different levels of linolenic acid [low-linolenic canola (LLC), medium-linolenic canola (MLC), and high-linolenic canola (HLC)], a medium-high-oleic sunflower oil, a commercial palm olein and a commercial, partially hydrogenated canola oil, was monitored by chemical and physical analyses and sensory evaluation during two 80-h deep-frying trials with potato chips. Linolenic acid content was a critical factor in the deep-frying performance of the high-oleic canola oils and was inversely related to both the sensory ranking of the food fried in the oils and the oxidative stability of the oils (as measured by color index, free fatty acid content, and total polar compounds). LLC and sunflower oil were ranked the best of the six oils in sensory evaluation, although LLC performed significantly better than sunflower oil in color index, free fatty acid content, and total polar compounds. MLC was as good as palm olein in sensory evaluation, but was better than palm olein in oxidative stability. Partially hydrogenated canola oil received the lowest scores in sensory evaluation. High-oleic canola oil (Monola) with 2.5% linolenic acid was found to be very well suited for deep frying.     

Preparation and characterization of a PtRu/C nanocatalyst for direct methanol fuel cells

PtRu/C nanocatalysts were prepared by changing the molar ratio of citric acid to platinum and ruthenium metal salts (CA:PtRu) from 1:1, 2:1, 3:1 to 4:1 using sodium borohydride as a reducing agent. Transmission electron microscopy analysis indicated that well-dispersed smaller PtRu particles (2.6 nm) were obtained when the molar ratio was maintained at 1:1. X-ray diffraction analysis confirmed the formation of PtRu alloy; the atomic percentage of the alloy analyzed by the energy dispersive X-ray spectrum indicated an enrichment of Pt in the nanocatalyst. X-ray photoelectron spectroscopy measurements revealed that 83.34% of Pt and 79.54% of Ru were present in their metallic states. Both the linear sweep voltammetry and chronoamperometric results demonstrated that the 1:1 molar ratio catalyst exhibited a higher methanol oxidation current and a lower poisoning rate among all the other molar ratios catalysts. The CO stripping voltammetry studies showed that the E-TEK catalyst had a relatively higher CO oxidation current than did the 1:1 molar ratio catalyst. Testing of the PtRu/C catalysts at the anode of a direct methanol fuel cell (DMFC) indicated that the in-house PtRu/C nanocatalyst gave a slightly higher performance than did the E-TEK catalyst.     

垃圾焚烧发电耦合电转气制备合成天然气工艺集成与优化

垃圾焚烧发电耦合电转气技术制备合成天然气工艺可同时实现温室气体减排和大规模储能。由于垃圾发电效率低和甲烷化反应热利用效率不高,此工艺能效偏低。为了提升工艺能效,本文采用Aspen Plus软件对垃圾焚烧发电耦合电转气制备合成天然气过程进行了全流程模拟,基于能量平衡分析,提出了一种利用甲烷化反应热优化垃圾焚烧发电过程的工艺集成方法。针对这个优化过程,设计了一套由一级绝热固定床反应器和一级低温流化床反应器串联组成的甲烷化工艺。借助绝热固定床反应器出口高温气体提升主蒸汽参数、优化蒸汽循环过程,可将发电效率从22.05%提升至31.72%。流化床反应器低温操作有利于提升合成天然气品质,其内置换热管束作为补充蒸发受热面。此外,还考察了垃圾焚烧炉烟气再循环方式对整体工艺的影响,结果表明采用烟气干循环工艺时能效较高。以上结果对于提升工艺经济性和竞争力具有一定指导意义。     

Synthesis and characterization of PDDA-stabilized Pt nanoparticles for direct methanol fuel cells

Pt nanoparticles are synthesized by the alcoholic reduction of H₂PtCl₆ in the presence of a polycation, poly(diallyldimethylammonium chloride) (PDDA). The size of the PDDA-Pt nanoparticle colloids is in the range of 2-4 nm, depending on the PDDA to Pt ratio in the solution. The PDDA-Pt nonoparticles can be self-assembled to the sulfonic acid group, SO₃⁻, at the Nafion membrane surface by the electrostatic interaction, forming a self-assembled monolayer (SAM). The study shows that such SAM reduced the methanol crossover and enhanced the power output of direct methanol fuel cells (DMFC) by as much as 34% as compared to the cell based on an un-modified Nafion membrane. In addition, PDDA-Pt nanoparticles synthesized with low PDDA/Pt ratios show considerable catalytic activity for the methanol oxidation reaction (MOR) in comparison to a commercial Pt/C catalyst. However, the electrocatalytic activity of PDDA-Pt nanoparticles decreased significantly with the increase in the PDDA/Pt molar ratio, indicating that the excess PDDA inhibits the MOR.     

Influence of compatibilizer content on PA/NBR blends properties: Unusual characterization and evaluation methods

NBR/PA6 blends were prepared at the melt state and with the use of masterbatches. Compatibilization with NBR‐oxazoline was tested with the aim of enhancing the blend performance and to obtain more appropriated morphology. The effect of compatibilizer content was studied through the characterization of blend mechanical properties, creep behavior, swelling, PA6 phase crystallinity, morphology, and rheological properties, including pressure‐volume‐temperature behavior. The results show a more significant elastomeric behavior for blends with 5 and 7 phr of compatibilizer, with deleterious effects for higher content. The migration of compatibilizer into elastomeric phase was documented by electronic microscopy, and corroborated by an increase in free volume of the samples. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013