沥青热解残炭的燃烧特性

与轻质油品(汽油、柴油等)燃烧特性不同,重质燃料油在燃烧时,首先发生燃料的热分解,分解的产物扩散到气相空间发生着火、燃烧,最后剩下固体残炭,然后残炭再着火、燃烧,由于残炭的燃烧属于异相反应,比燃料气与空气的同相反应慢,导致其燃尽时间明显变长,文献[1]给出了沥青和十二烷单滴的燃烧过程温度变化曲线,从曲线可以看出,残炭的燃烧阶段明显比气体的燃尽时间长,而残炭的质量只为沥青质量的10%～20%[2,3]。虽然残炭含量低,但它在整个燃烧过程中占有十分重要的地位;文献[4]利用热重系统研究了渣油热加工的副产物石油焦的燃烧特性,主要从…     

燃烧反应动力学研究进展

化学反应动力学是燃烧过程分析的重要工具。燃烧微观反应过程、复杂反应机理、燃烧实验测量和湍流燃烧数值模拟等方面的研究工作已经取得了长足进步。本文主要介绍燃烧反应动力学研究方法,包括电子结构方法、燃烧反应热力学和速率常数的计算方法、燃烧详细机理构建和简化、反应力场分子模拟以及燃烧中间体测量、燃料点火延迟和光谱诊断等方面的研究现状。燃烧反应动力学具有很强的应用背景,燃烧过程化学物种的反应速率计算是湍流燃烧数值模拟的一个中心任务。由于燃烧反应网络的高度复杂性,我们对燃烧机理的认识还远不清楚。化学反应和湍流相互作用研究的深入、燃烧反应动力学和计算流体力学的协同发展,将对新燃料设计、燃烧数值模拟、发动机内流道流场结构的准确描述产生深远影响。     

石油焦与煤混合燃料热重分析研究

石油焦与煤混合燃烧是高效处理石油焦的有效方法，作者对选用的石油焦和煤不同配比的混合燃料进行了热重分析研究。使用常压高温热天平研究、分析了各配比混合燃料的热解特性和燃烧特性。并根据化学动力学方法计算了各过程的化学动力学参数，即活化能E和频率因子A0。结果表明，各混合燃料热解起始温度大致相同，随煤焦比减小，挥发分析出速率变缓，最大释放速度所对应的温度升高，最终失重率减小，挥发分释放特性指数减小；随煤焦比增大，混合燃料着火温度和燃尽温度逐渐降低，最大燃烧速率所对应的温度降低，燃烧特性指数增大；随煤焦比减小，活化能和频率因子增大。     

氨能源作为清洁能源的应用前景

合成氨是一种成本低廉的化工原料,具有较高能量密度和辛烷值、易于压缩储运、燃烧不产生CO2等优点,是一种应用前景广泛的新型清洁能源。氨既可替代汽油、柴油等化石燃料,为汽车发动机直接提供清洁燃料,也可以经催化分解制取氢气,为车载燃料电池提供安全氢气。作为传统石油燃料的理想替代品,氨为解决环境污染和能源短缺问题提供了新的燃料选择。本文主要从发动机燃料和燃料电池原料两方面,介绍氨用于汽车动力源的优越性和可操作性,以及国内外相关研究进展;集中分析了氨分解制氢的催化剂体系的研究进展和局限性,以及合成氨的研究现状。     

煤矸石与半焦富氧混烧特性及污染物排放特性研究

利用热重分析仪和管式炉实验,研究了煤矸石与半焦的富氧混烧特性,考察了半焦混烧比例、O2含量和反应温度对燃烧特性和污染物排放特性的影响.结果表明,混烧半焦和提高O2含量均可显著改善混合燃料的燃烧性能,当半焦混烧比例为75％时,着火和燃尽指数最高.随半焦混烧比例增大,CO和SO2转化率均逐渐降低.提高反应温度,CO转化率降...     

垃圾衍生燃料流化床燃烧过程中HCl和NOx的排放研究

在床总高为4040mm的变截面流化床中试规模装置内，研究垃圾衍生燃料(RDF)在气化和燃烧不同阶段中NOx和HCl的生成特性。含NaCl的垃圾衍生燃料在流化床内燃烧，燃烧低于640℃时，Ca(OH)2的脱氯效果比较好;但随着温度升高，烟气中HCl的体积分数迅速增长，但脱氯效果明显受到CaCl2化学反应平衡的限制。燃烧状况特别是氧的体积分数对NOx的生成影响比较大。含氮量高的RDF燃烧产生NOx的体积分数明显高于低含氮燃料所产生的。     

O2/CO2气氛下煤焦燃烧实验研究

在热重分析仪上进行了不同气氛下徐州烟煤及其煤焦的燃烧实验,分析了O₂浓度、CO₂浓度和颗粒粒径等参数对其燃烧特性的影响;并对其进行了燃烧动力学分析。结果表明,气氛对煤和煤焦开始脱挥发分的时间影响不明显,但对其燃烧速率和燃尽时间影响很大;高浓度CO₂使煤焦的燃尽时间延长。气氛没有改变煤焦的燃烧反应动力学机理。O₂浓度提高、CO₂浓度降低和煤粉细化均可改善燃料的燃烧特性,但对煤焦的改善程度比对烟煤的小。扫描电镜（SEM）结果显示,同等O₂浓度下O₂/CO₂气氛较空气气氛煤灰表面孔隙结构更丰富。     

生物油/乙醇混合燃料燃烧性能研究

在空气气氛下采用热失重技术研究生物油及其与乙醇混合燃料的燃烧性能,利用Achar微分法和Coats-Redfern积分法结合的方式进行动力学分析,并对热解焦炭的物化特性进行了测量。结果表明,生物油及其与乙醇混合燃料的燃烧可分为三个阶段,即轻组分挥发、重组分裂解和焦炭燃烧;随着升温速率的升高,生物油的挥发性能和燃烧性能提高;随着乙醇质量分数的增加,挥发段和焦炭燃烧段的活化能都呈先减小后增大的趋势;混合燃料中乙醇质量分数不宜超过26%,否则其燃烧段的活化能增大,且热解焦炭所含有机官能团强度变弱,燃烧性能反而变差。     

Study on combustion characteristics of bio-oil/ethanol blends

在空气气氛下采用热失重技术研究生物油及其与乙醇混合燃料的燃烧性能,利用Achar微分法和Coats-Redfern积分法结合的方式进行动力学分析,并对热解焦炭的物化特性进行了测量.结果表明,生物油及其与乙醇混合燃料的燃烧可分为三个阶段,即轻组分挥发、重组分裂解和焦炭燃烧；随着升温速率的升高,生物油的挥发性能和燃烧性能提高；随着乙醇质量分数的增加,挥发段和焦炭燃烧段的活化能都呈先减小后增大的趋势；混合燃料中乙醇质量分数不宜超过26％,否则其燃烧段的活化能增大,且热解焦炭所含有机官能团强度变弱,燃烧性能反而变差.     

差热分析测定水煤浆的燃烧特性

水煤浆具有燃烧效率高、燃烧温度低、环境污染少等特点,是当前国内、外广泛研究的课题之一,具有广阔的发展前途。通常水煤浆含有30—35%的水,0.1—1%的添加剂,这大量水和少量添加剂的存在对水煤浆的燃烧过程所产生的影响以及它与煤粉的直接燃烧的差别是我们共同关心和感兴趣的问题。本文利用差热分析仪直接测定两种煤粉及由三种不同添加剂制得的水煤浆在空气流中燃烧时的特性。     

Derivative spectrophotometric analysis of benzophenone (as an impurity) in phenytoin

Background

Biomass and municipal solid waste offer sustainable sources of energy; for example to meet heat and electricity demand in the form of combined cooling, heat and power. Combustion of biomass has a lesser impact than solid fossil fuels (e.g. coal) upon gas pollutant emissions, whilst energy recovery from municipal solid waste is a beneficial component of an integrated, sustainable waste management programme. Concurrent combustion of these fuels using a fluidised bed combustor may be a successful method of overcoming some of the disadvantages of biomass (high fuel supply and distribution costs, combustion characteristics) and characteristics of municipal solid waste (heterogeneous content, conflict with materials recycling). It should be considered that combustion of municipal solid waste may be a financially attractive disposal route if a 'gate fee' value exists for accepting waste for combustion, which will reduce the net cost of utilising relatively more expensive biomass fuels.

Results

Emissions of nitrogen monoxide and sulphur dioxide for combustion of biomass are suppressed after substitution of biomass for municipal solid waste materials as the input fuel mixture. Interactions between these and other pollutants such as hydrogen chloride, nitrous oxide and carbon monoxide indicate complex, competing reactions occur between intermediates of these compounds to determine final resultant emissions.

Conclusions

Fluidised bed concurrent combustion is an appropriate technique to exploit biomass and municipal solid waste resources, without the use of fossil fuels. The addition of municipal solid waste to biomass combustion has the effect of reducing emissions of some gaseous pollutants.     

Effect of Experimental Variables on the Combustion Characteristics of Water-in-Diesel Emulsion Fuels

Water-in-diesel (W/D) emulsion fuels were prepared through an ultrasonic processor by using high energy emulsification method. Accordingly, the physical and chemical properties were analyzed. A decrease in viscosity was found in the emulsion fuel in contrast to the neat diesel which signifies the enhanced fluidity of the fuel. The emulsion fuel was then used to carry combustion tests in an internal combustion engine. A decrease in exhaust temperature was observed when a high surfactant to water ratio was used, which lead to minimal heat loss. As water is emulsified with diesel, effectiveness of combustion is improved rather than neat diesel fuel. It was also explored that the addition of water-in-diesel is influential in terms of reduction in exhaust gas emission such as carbon dioxide, carbon monoxide, ammonia from the internal combustion engine. Therefore, this type of emulsion fuel would be a useful contribution in the fuel economy, but also in making it environmentally friendly since diesel fuel is now considered one of the leading fuels causing ecological contamination.     

Conversion of Solar Energy to Fuels by Inorganic Heterogeneous Systems

Over the last several years,the need to find clean and renewable energy sources has increased rapidly because current fossil fuels will not only eventually be depleted,but their continuous combustion leads to a dramatic increase in the carbon dioxide amount in atmosphere.Utilisation of the Sun’s radiation can provide a solution to both problems.Hydrogen fuel can be generated by using solar energy to split water,and liquid fuels can be produced via direct CO2 photoreduction.This would create an essentially free carbon or at least carbon neutral energy cycle.In this tutorial review,the current progress in fuels’ generation directly driven by solar energy is summarised.Fundamental mechanisms are discussed with suggestions for future research.     

Investigation on total and instantaneous energy balance of bio-alternative fuels on an SI internal combustion engine

This paper investigates the effect of some biofuels on thermal balance and performance characteristics of a single-cylinder, four-stroke SI internal combustion engine. In this study, total and instantaneous energy balance of an air-cooled, small-scale engine using various biofuels is investigated. An experimental study is carried out on gasoline engine to validate the numerical calculations. Bio-alternative fuels which include methanol, ethanol and 2-ethanol–gasoline-blended fuels consisting of E85, E15 are examined numerically. Results indicate that methanol is the most effective fuel in aspect of power generation. Ethanol, E85, E15 and gasoline are placed in next positions, respectively. Break specific fuel consumption shows totally reversed trend. It is evaluated that by increasing engine speed, heat transfer to brake power ratio decreases and lower percentage of energy in form of heat transfer is lost. The least heat transfer to brake power ratio among studied fuel is related to methanol which approves it as the most efficient biofuel. Based on instantaneous in-cylinder energy balance analysis, at the end of combustion and during expansion stroke, instantaneous brake work of fuels outpaces each other at around 40° crank angle aTDC.

     

生物质转化为液体燃料2,5-二甲基呋喃 的途径与机理

随着化石燃料的日益减少,寻找可再生的液体生物质燃料已经引起了越来越广泛的关注。由生物质制备得到的2,5-二甲基呋喃(DMF)具有高能量密度、高沸点、高辛烷值和不溶于水等优点,近年来被认为是一种非常有前景的液体燃料。本文归纳和总结了生物质转化为DMF的化学途径、方法和反应机理以及DMF的燃烧性能,并对今后的研究方向进行了展望。     

含氧燃料燃烧中燃料氧迁移路径及含氧中间体生成特性

与碳氢燃料相比, 含氧燃料在燃烧过程中容易生成醛类等非常规污染物, 这些含氧中间体的生成与燃料中氧的释放密切相关. 本文从燃料氧迁移路径的角度来研究含氧中间体的生成特性及规律. 并采用分子束质谱结合真空紫外同步辐射光电离技术(SVUV-PIMS)探测了丙烷、二甲醚、乙醇三种低压预混火焰中的主要含氧中间体, 并获得了其摩尔分数分布. 结果表明: 与外部氧相比, 燃料氧更易形成含氧中间体. 生成的最主要的含氧中间体取决于燃料氧在分子中的结构. 二甲醚火焰中甲醛为最主要的含氧中间体; 乙醇火焰中乙醛为最主要的含氧中间体; 丙烷火焰中, 甲醛和乙醛的含量均很小, 但碳氢中间体乙烯、乙炔和丙烯的含量较高.     

Challenges and perspectives of combustion chemistry research

In the past decades, combustion chemistry research grew rapidly due to the development of combustion diagnostic methods,quantum chemistry methods, kinetic theory, and computational techniques. A lot of kinetic models have been developed for fuels from hydrogen to transportation fuel surrogates. Besides, multi-scale research method has been widely adopted to develop comprehensive models, which are expected to cover combustion conditions in real combustion devices. However, critical gaps still remain between the laboratory research and real engine application due to the insufficient research work on high pressure and low temperature combustion chemistry. Besides, there is also a great need of predictive pollutant formation model. Further development of combustion chemistry research depends on a closer interaction of combustion diagnostics, theoretical calculation and kinetic model development. This paper summarizes the recent progress in combustion chemistry research briefly and outlines the challenges and perspectives.     

基于同步辐射光电离质谱的燃烧与能源研究新方法

化石燃料为当今世界提供了超过80％的能源,其大量消耗所引起的能源危机和环境问题已成为全球关注的热点问题．解决此问题的关键在于深入理解燃烧和能源转化过程中的化学反应机理,进而从本质上探寻提高燃烧效率与减少污染物排放的方法．本文回顾了本课题组近年来发展的多种基于同步辐射光电离质谱技术的新方法和新装置,及其在燃烧与能源研究中的应用,并对未来可以发展的新方法和新方向进行了展望．     

Electrochemical Oxidation of Carbon‐Containing Fuels and Their Dynamics in Low‐Temperature Fuel Cells

Fuel cells can convert the energy that is chemically stored in a compound into electrical energy with high efficiency. Hydrogen could be the first choice for chemical energy storage, but its utilization is limited due to storage and transport difficulties. Carbon‐containing fuels store chemical energy with significantly higher energy density, which makes them excellent energy carriers. The electro‐oxidation of carbon‐containing fuels without prior reforming is a more challenging and complex process than anodic hydrogen oxidation. The current understanding of the direct electro‐oxidation of carbon‐containing fuels in low‐temperature fuel cells is reviewed. Furthermore, this review covers various aspects of electro‐oxidation for carbon‐containing fuels in non‐steady‐state reaction conditions. Such dynamic investigations open possibilities to elucidate detailed reaction kinetics, to sense fuel concentration, or to diagnose the fuel‐cell state during operation. Motivated by the challenge to decrease the consumption of fossil fuel, the production routes of the fuels from renewable resources also are reviewed.