这些实验是在德国斯图加特的燃烧技术研究所、德意志姆霍兹 Luft Raumfahrt (DLR) 的质谱学系进行的。这项工作还得到了亥姆霍兹能源联盟 "合成液态烃"、卓越中心 "替代燃料" 和 DLR 项目 "未来燃料" 的支持。作者希望感谢帕特里克乐 Clercq 和他在喷气燃料方面卓有成效的讨论。

1. 分子束质谱仪 (MBMS) 和流化反应器系统的建立
<ol><li>加热烤箱到指定的起始温度, 这是最高温度在指定的测量系列。对于射流 A-1 与Φ = 1 的典型条件, 总氧化低于850°c (~ 1100 K)。适当的起动温度的选择取决于被调查的燃料的化学性质和计量 (Φ)。</li>
	<li>为中间物种检测准备飞行时间测量光谱仪。该谱仪与分子束对齐, 从而为不稳定物种提供可靠的检测。 注: 质量分辨率适用于 C/小时系统中元素组成的测定。为了避免碎片, 选择了软电离条件。典型的9.5 到 10.5 eV 的值已经被证明适合于对燃烧中间物进行的一个一般的研究。</li>
	<li>为主要物种的检测准备四极光谱仪。 注: 由于四极光谱仪 (也称为残余气体分析仪, RGA) 放置在分子束附近的 MBMS 系统的电离室内, 仅测量壁散射的背景气体。由于主要物种稳定, 背景压力很好地反映了它们在取样尖端的浓度。为了更好的信噪比, 选择了高电离能 70 eV 在这种情况下。</li>
</ol>2. 燃料样品的制备
<ol><li>准备用于燃料供应的金属注射器。 警告:使用适当的个人防护设备进行燃料处理。<ol>
<li>填充30毫升的燃料样品蒸发器金属注射器。</li>
		<li>增压燃油供应系统 (金属注射器) 高达5巴通过增加增压空气到系统, 虽然打开阀门。</li>
		<li>排气燃料线和科里奥利质量流量计通过打开在燃料供应线的阀门。</li>
	</ol>
</li>
	<li>加热蒸发器和供气线。在给定的设置中, 温度远远低于正常压力沸点, 可以应用由于高稀释。确保燃料的最高沸腾化合物的指定温度下的蒸气压高于其在气流中的分压。通常, 200 °c 是足够的喷气 A-1。</li>
	<li>请注意, 系统中最冷的点是回火进口法兰到烤箱。确保稀释的燃料在这个地方不能 recondense。对于典型的喷气 A-1 (99% 稀释) 设置水冷却系统到80°c 是充足的。</li>
</ol>3. 测量和数据采集
<ol><li>将烤箱置于取样位置。取样锥必须放在烤箱的陶瓷管内。在本实验中, 取样位置接近烘箱空间温度剖面的高原值。 注意:图 1中的图片显示了锥和反应器。加热的反应器 (蓝色) 在路轨移动对石英锥体。</li>
	<li>通过科里奥利质量流量计添加气体, 开始选择稀释剂。 注: 质量流量表由原软件包控制。在这里, 可以设置质量流值。通常, 使用99% 氩。一般而言, 对于液体燃料, 稀释剂的流动可能被分解为气化器和氧化剂气体流通过使用一个额外的科里奥利质量流量计平行的 Cori 流2通过加热线和直接连接到氧化剂流从 Cori 流3。</li>
	<li>使用指定的工具软件开始连续的数据记录 (飞行和四极)。 注: 单击四极软件中的 "启动" 按钮。单击 "飞行软件" 中的 "启动" 按钮。<ol>
<li>通过设置科里奥利流量计软件的适当流程条件, 添加氧化剂 O2 。观察传入氧化剂作为新的峰值在质谱。</li>
	</ol>
</li>
	<li>通过设置科里奥利质量流量计的适当流量条件来添加燃料。<ol>
<li>检查光谱。如果在精益和化学计量条件下实现了完全氧化, 请观察稳定 CO2质量信号。</li>
	</ol>
</li>
	<li>当信号强度稳定为4到5测量时, 稳定周期结束。稳定期后, 将-200 克/小时的连续温度衰减坡道应用于烤箱。这导致典型的测量时间 2 h 每测量奔跑。<ol>
<li>在一个特定的烤箱温度的斜坡, 观察一个快速变化的质谱。单一燃烧产品 (H2O, co2和 co, H2在富有的情况下) 开始消失, 并且小燃烧中间体变得可检测。 注意: 随着温度的进一步降低, 可见中间体变得越来越大。在冷烘箱温度下, 仅能观察到燃料化合物和氧气的信号;在反应堆的当前居住时间内没有发生反应。</li>
	</ol>
</li>
	<li>当最终温度稳定时 (通常为500摄氏度; 10 分钟), 关掉氧化剂。<ol>
<li>继续记录测量。在没有氧化剂的情况下获得燃料特性 (碎片组成) 测量。</li>
	</ol>
</li>
	<li>通过将该值设置为 0, 将科里奥利质量流量计软件中的燃料关掉。数据仍将记录在案;使用这些光谱进行背景测量。</li>
	<li>通过单击软件中的 "停止" 按钮停止数据录制。</li>
</ol>4. 校准测量
<ol><li>对于校准问题, 在取样锥前安装一个闭合腔。 注: 封闭室是一管, 它是放置在喷嘴前面的手。</li>
	<li>打开阀门泵。密室被疏散了</li>
	<li>应用二进制混合物 (兴趣和 Ar 的碳氢化合物) 或商用校准气体校准。为示范, 在这里使用 co 和 co2和氩的定制的气体混合物。</li>
	<li>通过针阀调整校准腔内的压力, 以获得高于信噪比和饱和极限下的信号强度。</li>
	<li>通过单击飞行软件中的 "开始" 按钮, 开始校准测量, 方法是在3.5 中为单个测量执行数据记录。</li>
</ol>5. 数据处理
注: 重新编码光谱必须与所记录的各自的烘箱温度相匹配。
<ol><li>在每一个记录的温度, 对于每个选定的物种, 计算其摩尔分数从相应的信号。绘制摩尔分数配置文件与烤箱温度 (图 3)。</li>
</ol>

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Flame. 166, 255-265 (2016).</li><li>Hansen, N., Skeen, S. A., Michelsen, H. A., Wilson, K. R., Kohse-Hoinghaus, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flame+experiments+at+the+advanced+light+source:+new+insights+into+soot+formation+processes.">Flame experiments at the advanced light source: new insights into soot formation processes.</a> J Vis Exp. (87), e51369 (2014).</li><li>Qi, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isomeric+identification+of+polycyclic+aromatic+hydrocarbons+formed+in+combustion+with+tunable+vacuum+ultraviolet+photoionization.">Isomeric identification of polycyclic aromatic hydrocarbons formed in combustion with tunable vacuum ultraviolet photoionization.</a> Rev Sci Instum. 77 (8), 084101 (2006).</li><li>Hansen, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2D-imaging+of+sampling-probe+perturbations+in+laminar+premixed+flames+using+Kr+X-ray+fluorescence.">2D-imaging of sampling-probe perturbations in laminar premixed flames using Kr X-ray fluorescence.</a> Combust. Flame. 181, 214-224 (2017).</li></ol>

作者没有什么可透露的。

将大气高温流反应器与分子束质谱检测系统相结合, 使各种操作条件下的定量形态数据得以实现。几项研究21,22,23,27显示实验的灵活性从与部分氧化现象相关的丰富的甲烷条件开始 (φ = 2.5), 调查现代喷气燃料化合物如 farnesane 的燃烧化学。这样的研究使动能反应建模能够覆盖更多的技术领域,如精制的乙二醇机制, 适合于技术气化过程。
如上文所示, 研究了一种带原位诊断的流式反应堆设计思想, 这是几十年来的探索, 本文提出的方法是没有突破性的。然而, 随着今天的技术和实验的可能性, 这种额外的方法, 目前的研究领域正在受益于既定的战略, 燃烧诊断。
结论是, 所提出的大气流反应器与 MBMS 耦合的方法是燃烧化学中已建立的技术的宝贵补充 (见导言)。它与其他方法同样具有同样的主要缺点: 它是一个非常复杂和复杂的实验设置。设计合适的 MBMS 检测系统是一项耗时、科学要求高的任务, 掌握了对数据进行细致、可靠量化的技术, 需要时间和精力。请注意, 没有任何标准程序可供商业使用。然而, 设计这样一个定制的设置, 为现代科学问题提供了新的和创造性的可能性。
对数据的成功应用和解释至关重要的是仔细描述实验和边界条件的选择16。该检测系统具有鲁棒性和灵活性, 但流量管的材料可能严重依赖于实验条件。所提出的陶瓷管已被证明是成功的大多数应用, 而关注粒子和更大的烟尘前体的研究表明了意想不到的结果和不必要的副作用, 在质谱。将材料改成石英, 在颗粒测量方面有了巨大的改进;然而, 调查仅限于 1400 k 以下的不同温度状态. 注意到最近的测试运行对气相检测没有影响。
在具有挑战性的硬件设置之后, 对实验行为和特别是温度场进行细致的描述是必须的, 以进行数据评估和解释。只有当每个条件都知道各自的温度剖面时, 才能合理地模拟结果。详细研究了壁/气相相互作用、流动特性、侵入探测和载流子气体等问题。考虑到所有这些方面, 几种建模方法成功地证明了该方法的能力和有效性, 并强调了动力学模型发展的重要补充。
这里提到的可能的申请是一个出发点, 今后的贡献必须进一步探讨, 以及目前的限制推向极端。目前为止的一个主要限制是检测仪器的质量分辨率。虽然Δm = 3000 的质量分辨率足以满足大多数燃烧物种的需要, 但异构物种不能被分离或识别。高度先进的实验, 如基于同步辐射的方法28,33,34,35,36,37,38或一般理论研究在未来需要反应动力学, 以提供更详细的知识和提高鉴定能力。
从简单的甲烷到复杂的技术喷射燃料的快速演化涵盖了广泛的可接触化合物。目前, 主要的重点是液体单组分和复杂的混合物的技术应用, 如喷气燃料。作为进化的下一个层次, 温度、流量特性和压力等边界条件可能是一个目标, 而多维方面比以往任何时候都更值得调查39 。即便如此, 温度已经涵盖了从低温 (大约 800 K) 燃烧到热解 (2100 k) 的范围。更高的压力对于瞄准技术条件和模型开发是有用的, 在这种情况下, 形态数据在文学中通常是罕见的。利用现代材料和有效性, 对高压、高温流反应器所获得的形态数据进行了新的实验设计。

从可再生资源的现代低排放燃料中了解燃烧过程对当今社会的生态和经济议题是一个挑战。它们有可能减少我们对矿物燃料的依赖, 抵消 CO2排放量, 并对有害污染物排放 (如烟尘及其毒性前体1) 产生积极影响。将这个快速增长的领域与它们在现代燃烧室系统中的应用结合起来, 对控制化学和物理过程的基本理解的需求大大增加了2。即使在今天, 由于基链反应而产生的复杂化学反应网络仍然没有得到充分的理解。为了分析甚至控制污染物形成或 (自动) 点火过程等现象, 化学反应网络的详细知识是拼图3的关键部分。
为了调查和理解这些化学反应网络, 实验和数值方法是强制性的。实验中, 燃烧化学通常是通过应用简化的和良好的控制流环境的实验来研究特定问题。单个子过程的高复杂性和动态性通过基础实验防止了技术燃烧室条件的精确再现, 同时允许跟踪指定的关键特性, 如温度、压力、热释放, 或化学物种。早期, 对不同的实验方法的需要变得明显, 每个解决一个具体的问题, 并提供了后续的一系列信息, 有助于整个全球的燃烧化学图片。为了涵盖各种条件, 并收集随后的信息集, 以描述技术系统中发生的复杂情况, 成功地开发了多种方法。完善的技术包括:
<ul><li>激波管4,5,6和快速压缩机7。这些设备提供了很大范围内的压力和温度控制。然而, 可接触反应时间和适当的分析技术是有限的。</li>
	<li>层流预混火焰3,8,9,10,11是理想的, 以获得高温条件结合一个简单的流场。由于反应区的空间维数随着压力的增大而减小, 在低压条件下, 预混火焰通常会被研究成形态。</li>
	<li>逆流扩散火焰12,13,14,15是研究湍流燃烧小火焰计算机制的理想选择。它们模拟了由于不均匀性在一个真正的湍流流中的应变, 但在分析形态技术中又受到高度限制。</li>
	<li>各种反应堆实验16、17、18 (静态、搅拌和插头流) 提供了对高压环境的访问, 而温度通常比火焰环境低。常见的方法有:<ul>
<li>静止电抗器广泛用于脉冲光解实验, 但一般受长期停留时间和低温的限制。</li>
		<li>喷射搅拌反应器,即完全搅拌反应器 (PSR) 的气体版本, 依赖于气相的有效混合, 并可在恒定的停留时间、温度和压力下稳定运行, 使模型易于建模。然而, 分子有时间迁移到热表面, 并接受不同的反应。</li>
		<li>许多流动反应器方法是已知的, 与塞式流动反应器 (PFR) 是描述化学反应的最普遍的方法在连续, 流动系统的圆筒几何。在稳定状态下, 采用固定停留时间作为其理想 PFRs 位置的函数来假设插头流条件。</li>
	</ul>
</li>
</ul>在实验燃烧动力学领域有价值的技术的补充, 高温层流反应器实验19,20采用分子束质谱 (MBMS) 技术进行跟踪本文详细介绍了物种开发的21、22 。层流条件, 工作在大气压和可接近的温度到 1800 K 是流动反应器的主要特征, 而敏感 MBMS 技术允许检测几乎所有在燃烧中存在的化学物质过程.这包括高度活性的物种, 如激进分子, 它们不能或几乎无法与其他检测方法进行跟踪。MBMS 技术广泛用于对常规和现代替代燃料火焰中的反应网络进行详细调查, 如醇类或醚23,24,25 , 并已证明是对现代动力学模型的发展具有重要意义。
图 1显示了使用取样探针 (a) 缩放帧的高温流反应器的示意图, 以及两张突出显示总体实验 (B) 和探头设置 (C) 的图片。该系统可分为两部分: 一是具有燃气供应和蒸发器系统的高温流反应器, 二是 MBMS 飞行时间检测系统。在运行中, 流管的出口直接安装在 MBMS 系统的取样喷嘴上。气体直接从反应器出口取样, 转移到高真空检测系统。在这里, 电离是通过电子电离和随后的飞行时间检测进行的。
该反应器有一个40毫米内径陶瓷 (Al2O3) 管的1497毫米长度放置在一个高温烤箱 (, Gero, 类型 HTRH 40-1000).总加热段长度为1000毫米。气体被预混, 并预先汽化进入反应器由一个回火法兰 (通常回火到 ~ 80 °c)。高度稀释 (约99体积% 在 Ar), 层流流动反应物混合物通过已知的温度剖面 (详细的温度特性将在下面给出)。气体组分的检测发生在反应器出口作为烤箱温度的作用。测量是在恒定的入口质量流, 而单调下降温度斜坡 (-200 k/小时) 适用于烤箱的范围内 1800 k 到 600 k 注意到, 当测量不同的温度时, 可能会取得类似的结果。等温烘箱温度和热惯性被认为是正确的。该系统的热稳定性仍需一段时间, 选择温度坡道作为平均时间的折衷 (可忽略) 小温度增量和每系列总测量时间。平均时间 (四十五年代) MBMS 对应于 2.5 K。在给定条件下, 所得到的居住时间约为2秒 (在 1000 K 处)。最后, 由于温度的再现性, 在目前的反应堆实验中, 可以说明±5 K 或更好的测温温度的相对精度。
图 2显示了汽化系统的示意图, 它优化以调查甚至复杂的碳氢化合物混合物, 如技术喷射燃料。所有输入流都以科里奥利质量流量计的高精度 (±0.5%) 计量。燃料的汽化由一个商业蒸发器系统在温度200°c 实现。所有供应线与预汽化燃料的温度通常为150摄氏度, 以防止液体燃料的凝结, 同时避免热降解的同时。完全和稳定的汽化是例行检查, 甚至可能发生在温度低于正常沸点的各自燃料。完全蒸发是由小燃料分数和低分压 (通常低于 100 Pa) 确保所需的。
气体是由一个石英锥在反应堆出口中心线上的环境压力 (约 960 hPa) 取样, 在图 1的缩放框架中更详细地看到。喷嘴尖端有一个50微米的孔, 它位于大约30毫米内的陶瓷管在反应区结束。注意, 取样位置是固定在入口上的。烤箱管的热膨胀只发生在出口, 这是不机械地连接到取样系统导致温度独立长度的反应段。由于分子束的形成, 当气体扩展到高真空 (两个不同的抽运阶段; 10-2和 10-4 Pa)25,26时, 所有反应立即被淬火。该样本被引导到电子撞击时间 (飞行时) 质谱仪 (质量分辨率 R = 3000) 的离子源, 能够根据适当的精度确定现有物种的确切质量, 以确定一个 c-/小时内的元素组成。i/o 系统。电子能量被设置为低值 (通常为 9.5-10.5 eV), 以尽量减少由于电离过程的碎片。注意, 稀释剂和参考种类氩仍然是可检测的由于广泛的能量分布电离电子 (1.4 eV FWHM)。Ar 可以用好的 S/N 来测量, 低电子能量不允许对主要种类 (H2O、co2、co、H2、O2和燃料) 配置文件进行足够的确定, 这些剖面在显著较低浓度下存在。.
除了在飞行中检测外, 一个残留气体分析仪 (RGA),即四极质谱仪, 被放置在电离室中, 以更高的电子能量 (70 eV) 监测上述六种, 同时对 MBMS 的测量。

<table>
	<tbody>
		<tr>
			<td>Time-Of-Flight MBMS</td>
			<td>Kaesdorf</td>
			<td>n.a.</td>
			<td>custom design</td>
		</tr>
		<tr>
			<td>Molecular Beam Samling Interface</td>
			<td>self made</td>
			<td>n.a.</td>
			<td>custom design</td>
		</tr>
		<tr>
			<td>Laminar Flow Reactor</td>
			<td>Gero</td>
			<td>Type HTRH 40-1000</td>
			<td>custom design</td>
		</tr>
		<tr>
			<td>Quadrupole MS</td>
			<td>Hiden</td>
			<td>HAL/3F 301</td>
			<td>adapted to ionization chamber</td>
		</tr>
		<tr>
			<td>Vaporizer</td>
			<td>Bronkhorst</td>
			<td>CEM</td>
			<td>Vaporizer</td>
		</tr>
		<tr>
			<td>Mass Flow Meter</td>
			<td>Bronkhorst</td>
			<td>Mini Cori-Flow M12, M13, M14</td>
			<td>Flow Controller</td>
		</tr>
		<tr>
			<td>Jet A-1</td>
			<td>n.a.</td>
			<td>n.a.</td>
			<td>Standard Jet fuel of interest</td>
		</tr>
		<tr>
			<td>Metal syringe</td>
			<td>Hugo Sachs</td>
			<td>70-2252</td>
			<td>Fuel Supply</td>
		</tr>
		<tr>
			<td>Heating Hoses</td>
			<td>Hillesheim</td>
			<td>HMI series</td>
			<td>Gas Preheating</td>
		</tr>
		<tr>
			<td>Gas</td>
			<td>Linde</td>
			<td>Ar, O2</td>
			<td>Diluent, Oxidizer</td>
		</tr>
	</tbody>
</table>

combustion chemistry of fuels: quantitative speciation data obtained from an atmospheric high-temperature flow reactor with coupled molecular-beam mass spectrometer

这篇手稿描述了一个高温流反应器实验耦合到强大的分子束质谱 (MBMS) 技术。这个灵活的工具提供了一个详细的观察化学气相动力学的反应流在良好的控制条件。在层流反应器中提供的大量操作条件使我们能够获得特殊的燃烧应用, 而这些应用程序通常不能通过火焰实验实现。这些包括在高温条件下与气化过程有关的丰富环境, 过氧化化学控制低温氧化机制或研究复杂的技术燃料。所提出的设置允许测量的数量形态数据的反应模型验证燃烧, 气化和热解过程, 同时使系统的普遍理解的反应化学。动力学反应模型的验证一般是通过研究纯化合物的燃烧过程来进行的。流化反应器已被加强, 以适合技术燃料 (如喷射 A-1 的多组分混合物), 以允许对发生燃烧中间体如烟尘前体或污染物的现象学分析。实验设计提供的受控和可比较的边界条件可以预测污染物的形成趋势。冷反应物被送入预混进反应器中, 高度稀释 (在 Ar 中约99体积%), 以抑制自我维持的燃烧反应。层流反应物混合物经过已知的温度场, 而气体成分是确定在反应堆排气作为一个功能的烤箱温度。流动反应器在大气压下作以温度 1800 K 。测量本身是通过降低温度单调率为-200 克/小时。利用敏感的 MBMS 技术, 在反应过程中几乎所有的化学物种, 包括激进物种, 都获得和量化了详细的形态数据。

在图 3中显示了取样气体组成的典型质量谱。与给定的质量分辨率约3000的设置, 物种由 m/z = 260, 您可以在 c/c++ 系统中检测到。在质量校准过程中, 峰值被集成为每个质量-电荷 (m-/z) 比和反褶积算法, 以评估未解决的信号。在背景和碎片校正之后, 信号可以用适当的校准因子与已知协作 (典型的惰性气体氩) 的参考物种进行量化。获得校准因子的几个复杂策略包括直接冷气体测量 (如图所示)、文献电离剖面或估计程序以及内部校准策略。适当的选择取决于各自的种类、测量条件和可利用的数据。有关适用的方法和策略的详细说明, 请参阅引用18、28、29、30。流动电抗器的具体程序可在参考文献21的补充材料中获得。摩尔分数最终与相应的 2.5 K 间隔的平均温度一起绘制, 导致典型的摩尔分数 vs 烤箱温度图, 如图 3 (C)所示。
为了检验、理解和分析复杂的燃烧反应网络, 详细的动力学建模证明了它是一种宝贵的互补工具。所提出的层流反应器实验方法已演示多次20,27其有效性作为动力学模型开发的基础。给出了层流场的一个塞流近似 (即扩散、轴向和径向, 并假定了均匀径向速度), 从而给出了实验条件的适当表示。这个近似允许空间位置 x 的直接变换到一个独特的反应 (居住) 时间τ并且一个简单的0D 考虑种类和温度演变作为反应时间的作用仅可以使用。因此, 利用空间温度剖面作为反应器模型的输入参数, 获得了反应器轴线上参与物种的空间演化。
图 4显示了从化学计量 CH4测量21获得的四个选定烤箱温度的甲醛和乙炔的空间摩尔分数剖面。采用化学工作台塞流反应器模块 (CWB) 进行了动力学模型计算。该方法允许每个烤箱温度的个别计算。根据实验温度测量结果, 在参考文献21中给出了从尺度定律获得的单个温度剖面的计算。然后将反应器出口的模型结果与相应的烘箱温度进行绘制, 以与实验结果进行比较。为了演示建模结果的典型功能, 计算是使用经过验证的南加州大学 II 机制31进行的。如图 4所示, 在测量数据与主组件 (图 4 (A)) 和中间体种类 (图 4 (B)) 之间有一个很好的协议。
单个组件对氧化过程的研究的典型结果如图 5所示。图 5(A)表示潜在的喷气燃料复合 p-实施分阶段, 具有主要物种配置文件,图 5( B) 显示乙烯和甲醛的化学计量依赖性,图 5( C) 选定的中间化学计量条件的种类。结果得到在环境压力和在化学计量学 (φ = 1.0) 条件。主要种类的反应序列,即反应物和产品, 给出了典型的例子, 该结构通常观察到这种类型的流反应器。标称进气成分的测量, 直到衰变的燃料摩尔分数被观察到在一定的温度。燃料被消耗并且主要被转换成燃烧中间体。"点火" 发生在 O2和燃料陈列他们的最陡峭的减少集中和 CO2和 H2O 陈列他们的最陡峭的上升的梯度。在精益到化学计量条件下, 这也是中间 CO 迅速消耗的地方。记得在给定的设置中使用高稀释时, 不存在自我维持的反应, 或者分别被压抑。对化学计量学的变化、燃料分解途径甚至烟尘前驱体的形成进行了充分的分析, 可以利用该中间体的数据进行研究;对于本节的范围, 省略了冗长的讨论。所提出的数据可用于化学反应模型的开发。
通常, 通过研究纯化合物的燃烧过程来验证动力学反应模型。作为复杂性的下一个步骤, 流反应器设置可用于由多组分混合物 (如喷气燃料) 组成的技术燃料。图 6显示了化学计量学的主要物种配置文件 (A: φ = 1.0) 和富 (B: φ = 1.5) 条件。配置文件与前面显示的相似。然而, 燃料分解曲线是几个单一的化合物显示典型的燃料衰变行为的组合。O2和燃料配置文件都在低温下开始, 并且随着反应堆温度的增加而消耗。深入分析图 6(C)显示了喷气燃料中发现的主要组件及其各自的消耗量。一般情况下, 碳氢化合物种类也可以看到类似的衰变。有趣的是, 芳香物种在更陡峭的衰变之前, 与一个明显的高原区域表现出最大的偏差, 这一变化的温度大约是 1000 K。
通过加强与技术燃料 (例如多组分混合物) 一起使用的实验, 可能发生燃烧中间体如烟尘前体或污染物的现象学分析。对于这类分析, 可比条件是强制性的。发现受益人具有相同的 C/小时条件, 要求该值作为测量设计的输入参数。受控和可比较的边界条件能够预测在图 7中烟尘前体苯或炔丙基基所示的污染物形成趋势。这两个特点是典型的中间剖面形状与形成和损耗在反应过程中。针对射流 A-1, 测定了两种环烷烃对甲烷的摩尔分数, 表明在燃烧化学中形成污染物的趋势更高。这是相当有趣的, 因为炔丙基根本对苯形成在环己烷燃烧32 仅一个次要作用。相对于对甲烷和射流 A-1 参考燃料, 对两种品种的低摩尔分数的分支烷烃 farnesane 进行了比较。在燃烧过程产生的烟尘形成方面, 预计对这些污染物的减少效果。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56965/56965fig1.jpg"> 图 1: 使用照片的 DLR 高温流反应器的示意图.缩放的切口显示了取样接口的详细视图, 以及由闸阀分隔的电离源(a) 。请注意, 高温烤箱安装在可移动的导轨上, 取样是在环境压力(B)中的管内进行的。在(C)中显示了石英喷嘴和撇嘴的图片。此数字已从 Oßwald et中采用。21和 m 霍斯特·科勒et 。27.<a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56965/56965fig1large.jpg" target="_blank">请单击此处查看此图的更大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56965/56965fig2.jpg"> 图 2: 燃油蒸发器系统.液体燃料和单一化合物的蒸发器系统示意图与商业设置22到流程反应器设置入口。<a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56965/56965fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56965/56965fig3.jpg"> 图 3: 从原始信号数据中提取摩尔分数曲线.(A) MBMS 系统提供的典型原始信号。给定的质量分辨率允许分离物种(B)和集成以进一步量化。绘制摩尔分数与烘箱温度相比, 给出层流反应器(C)的典型结果。<a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56965/56965fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56965/56965fig4.jpg"> 图 4: 使用南加州大学 II 机制的化学计量甲烷氧化动力学模拟31 .空间模型结果 (线) 为摩尔模型分数剖面的乙炔 (C2H2) 和甲醛 (CH2O) 在选定的烤箱温度和各自的温度剖面(A)。在面板的顶部显示了烤箱的示意图。与主要种类的实验结果 (符号) 的比较(B)和中间体(C), 当温度坡道被考虑时。此数字已从 Oßwald et更新。21.<a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56965/56965fig4large.jpg" target="_blank">请单击此处查看此图的更大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56965/56965fig5.jpg"> 图 5: 单个组件的氧化过程调查的典型结果.主要物种配置文件(A)用于潜在喷气燃料复合 p-甲烷, 并比较 C2H4和 CH2O (B)的化学计量依赖性。选择的中间种类在化学计量条件下显示(C) , 以获取有关反应网络22的信息。<a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56965/56965fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56965/56965fig6.jpg"> 图 6: 用于 Jet A-1 调查的形态数据.化学计量学(A)和富(B)条件以及燃料组分摩尔分数耗尽(C)的主要物种显示为反应堆温度的函数。燃料部件消耗更高的温度。<a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56965/56965fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/56965/56965fig7.jpg"> 图 7: 深入的烟尘前体化学.烟尘前驱体中间炔丙基基C3H 3 ( A) 和苯C6H 6 ( B) 用于对甲烷和 farnesane 的比较, 参考 JetA-122。在这两种情况下, p-实施分阶段显示比喷气 A-1 更高的摩尔分数, 而 Farnesane 的特征是较低的摩尔分数, 表明形成烟尘前体的趋势下降。<a href="//cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56965/56965fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

Watch this Scientific Journal Video about Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectr

Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

燃料燃烧化学: 用耦合分子束质谱仪从大气高温流反应器中获得的定量形态数据

通过比较定量形态数据, 对新型生物燃料、燃料组分或喷气燃料的氧化燃烧化学进行了研究。这些数据可用于动态模型验证, 并能够实现燃料评估策略。这篇手稿描述了大气高温流反应器并证明了它的能力。

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This ...

combustion-chemistry-fuels-quantitative-speciation-data-obtained-from

Nanyang Technological University

Research

JoVE Journal

Chemistry

10.0K 次观看.  German Aerospace Center (DLR). 通过比较定量形态数据, 对新型生物燃料、燃料组分或喷气燃料的氧化燃烧化学进行了研究。这些数据可用于动态模型验证, 并能够实现燃料评估策略。这篇手稿描述了大气高温流反应器并证明了它的能力。

视频: Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

PTR-ToF-MS Coupled with an Automated Sampling System and Tailored Data Analysis for Food Studies: Bioprocess Monitoring, Screening and Nose-space Analysis

Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that belongs to the Direct-Injection Mass Spectrometric (DIMS) technologies. These techniques allow the rapid determination of volatile organic compounds (VOCs), assuring high sensitivity and accuracy. In general, PTR-MS requires neither sample preparation nor sample destruction, allowing real time and non-invasive analysis of samples. PTR-MS are exploited in many fields, from environmental and atmospheric chemistry to medical and biological sciences. More recently, we developed a methodology based on coupling PTR-ToF-MS with an automated sampler and tailored data analysis tools, to increase the degree of automation and, consequently, to enhance the potential of the technique. This approach allowed us to monitor bioprocesses (e.g. enzymatic oxidation, alcoholic fermentation), to screen large sample sets (e.g. different origins, entire germoplasms) and to analyze several experimental modes (e.g. different concentrations of a given ingredient, different intensities of a specific technological parameter) in terms of VOC content. Here, we report the experimental protocols exemplifying different possible applications of our methodology: i.e. the detection of VOCs released during lactic acid fermentation of yogurt (on-line bioprocess monitoring), the monitoring of VOCs associated with different apple cultivars (large-scale screening), and the in vivo study of retronasal VOC release during coffee drinking (nosespace analysis).

Proton Transfer Reaction Time of Flight Mass Spectrometry allows high-sensitivity, rapid and non-invasive analysis of volatile organic compounds. To demonstrate its potential, we give three examples: lactic acid fermentation of yogurt (on-line bioprocess monitoring), different apple genotypes (large-scale screening), and retronasal space after drinking coffee (nosespace analysis).

PTR-ToF-MS结合自动采样系统和食品研究定制数据分析:生物过程监测，筛选和鼻空间分析

Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that ...

科研

化学

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

This article describes a flowing microwave reactor that is used to drive efficient non-equilibrium chemistry for the application of conversion/activation of stable molecules such as CO2, N2 and CH4. The goal of the procedure described here is to measure the in situ gas temperature and gas conversion.

用于高效高温化学的非平衡微波等离子体

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose ...

A Practical Guide on Coupling a Scanning Mobility Sizer and Inductively Coupled Plasma Mass Spectrometer (SMPS-ICPMS)

A large variety of analytical methods are available to characterize particles in aerosols and suspensions. The choice of the appropriate technique depends on the properties to be determined. In many fields information about particle size and chemical composition are of great importance. While in aerosol techniques particle size distributions of gas-borne particles are determined online, their elemental composition is commonly analyzed offline after an appropriate sampling and preparation procedure. To obtain both types of information online and simultaneously, a hyphenated setup was recently developed, including a Scanning Mobility Particle Sizer (SMPS) and an Inductively Coupled Plasma Mass Spectrometer (ICPMS). This allows first to classify the particles with respect to their mobility diameter, and then to determine their number concentration and elemental composition in parallel. A Rotating Disk Diluter (RDD) is used as the introduction system, giving more flexibility regarding the use of different aerosol sources. In this work, a practical guide is provided describing the different steps for establishing this instrumentation, and how to use this analysis tool. The versatility of this hyphenated technique is demonstrated in example measurements on three different aerosols generated out of a) a salt solution, b) a suspension, and c) emitted by a thermal process.

A Practical Guide on Coupling a Scanning Mobility Sizer and Inductively Coupled Plasma Mass Spectrometer SMPS-ICPMS

In this work a practical guide is provided, describing the different steps to establish the coupling of SMPS and ICPMS systems, and how to use them. Three descriptive examples are presented.

耦合扫描流动性测定仪和电感耦合等离子体质谱仪（SMPS-ICPMS）的实用指南

A large variety of analytical methods are available to characterize particles in aerosols and suspensions. The choice of the appropriate technique depends ...

Fizzy Extraction of Volatile Organic Compounds Combined with Atmospheric Pressure Chemical Ionization Quadrupole Mass Spectrometry

Chemical analysis of volatile and semivolatile compounds dissolved in liquid samples can be challenging. The dissolved components need to be brought to the gas phase, and efficiently transferred to a detection system. Fizzy extraction takes advantage of the effervescence phenomenon. First, a carrier gas (here, carbon dioxide) is dissolved in the sample by applying overpressure and stirring the sample. Second, the sample chamber is decompressed abruptly. Decompression leads to the formation of numerous carrier gas bubbles in the sample liquid. These bubbles assist the release of the dissolved analyte species from the liquid to the gas phase. The released analytes are immediately transferred to the atmospheric pressure chemical ionization interface of a triple quadrupole mass spectrometer. The ionizable analyte species give rise to mass spectrometric signals in the time domain. Because the release of the analyte species occurs over short periods of time (a few seconds), the temporal signals have high amplitudes and high signal-to-noise ratios. The amplitudes and areas of the temporal peaks can then be correlated with concentrations of the analytes in the liquid samples subjected to fizzy extraction, which enables quantitative analysis. The advantages of fizzy extraction include: simplicity, speed, and limited use of chemicals (solvents).

Fizzy extraction is a new laboratory technique for analysis of volatile and semivolatile compounds. A carrier gas is dissolved in the liquid sample by applying overpressure and stirring the sample. The sample chamber is then decompressed. The analyte species are liberated to the gas phase due to effervescence.

挥发性有机化合物与大气压化学电离四极杆质谱联用

Chemical analysis of volatile and semivolatile compounds dissolved in liquid samples can be challenging. The dissolved components need to be brought to ...

Real-time Breath Analysis by Using Secondary Nanoelectrospray Ionization Coupled to High Resolution Mass Spectrometry

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental exposure in a non-invasive manner. In this work, we present a protocol to characterize the exhaled VOCs in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry (Sec-nanoESI-HRMS). The homemade Sec-nanoESI source was readily set up based on a commercial nanoESI source. Hundreds of peaks were observed in the background-subtracted mass spectra of exhaled breath, and the mass accuracy values are -4.0-13.5 ppm and -20.3-1.3 ppm in the positive and negative ion detection modes, respectively. The peaks were assigned with accurate elemental composition according to the accurate mass and isotopic pattern. Less than 30 s is used for one exhalation measurement, and it takes approximately 7 min for six replicated measurements.

A protocol for characterizing chemical composition of exhaled breath in real time by using secondary nanoelectrospray ionization coupled to high resolution mass spectrometry is demonstrated.

利用二次 Nanoelectrospray 电离耦合高分辨质谱的实时呼吸分析

Exhaled volatile organic compounds (VOCs) have aroused considerable interest, since they can serve as biomarkers for disease diagnosis and environmental ...

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Continuous flow technology has been identified as instrumental for its environmental and economic advantages leveraging superior mixing, heat transfer and cost savings through the &#34;scaling out&#34; strategy as opposed to the traditional &#34;scaling up&#34;. Herein, we report the reaction of diphenyldiazomethane with p-nitrobenzoic acid in both batch and flow modes. To effectively transfer the reaction from batch to flow mode, it is essential to first conduct the reaction in batch. As a consequence, the reaction of diphenyldiazomethane was first studied in batch as a function of temperature, reaction time, and concentration to obtain kinetic information and process parameters. The glass flow reactor set-up is described and combines two types of reaction modules with &#34;mixing&#34; and &#34;linear&#34; microstructures. Finally, the reaction of diphenyldiazomethane with p-nitrobenzoic acid was successfully conducted in the flow reactor, with up to 95% conversion of the diphenyldiazomethane in 11 min. This proof of concept reaction aims to provide insight for scientists to consider flow technology&#39;s competitiveness, sustainability, and versatility in their research.

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Flow chemistry carries environmental and economic advantages by leveraging superior mixing, heat transfer and cost benefits. Herein, we provide a blueprint to transfer chemical processes from batch to flow mode. The reaction of diphenyldiazomethane (DDM) with p-nitrobenzoic acid, conducted in batch and flow, was chosen for proof of concept.

连续流动化学: Diphenyldiazomethane 与p硝基苯甲酸的反应

Continuous flow technology has been identified as instrumental for its environmental and economic advantages leveraging superior mixing, heat transfer and ...

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables the acquisition of photoluminescence spectra covering the time regime from nanoseconds up to 0.1 s. This enables us to follow the changes in the intensity (decay) and emission of the spectra over time. Using this method, it is possible to study diverse photophysical phenomena, such as the emission of phosphorescence, and the contributions of prompt and delayed fluorescence in molecules showing thermally activated delayed fluorescence (TADF). Remarkably, all spectra and decays are obtained in a single experiment. This can be done for solids (thin film, powder, crystal) and liquid samples, where the only limitations are the spectral sensitivity of the camera and the excitation wavelength (532 nm, 355 nm, 337 nm, and 266 nm). This technique is, thus, very important when investigating the excited state dynamics in organic emitters for their application in organic light-emitting diodes and other areas where triplet harvesting is of paramount importance. Since triplet states are strongly quenched by oxygen, emitters with efficient TADF luminescence, or those showing room temperature phosphorescence (RTP), must be correctly prepared in order to remove any dissolved oxygen from solutions and films. Otherwise, no long-lived emission will be observed. The method of degassing solid samples as presented in this work is basic and simple, but the degassing of liquid samples creates additional difficulties and is particularly interesting. A method of minimizing solvent loss and changing the sample concentration, while still enabling to remove oxygen in a very efficient and a repeatable manner, is presented in this work.

Here, we present a method of the spectroscopic characterization of organic molecules by means of time-resolved photoluminescence spectroscopy on the nanosecond-to-millisecond timescale in oxygen-free conditions. Methods to efficiently remove oxygen from the samples and, thus, limit luminescence quenching are also described.

利用 iccd 摄像机对无氧环境下的三重收集有机化合物进行光物理表征

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables ...

A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic nanoparticles is developed. Guidelines for the replication of the reactor and its operation are provided in detail. Three different composite systems (Pt/graphene, Pt/TiO2, and Au/TiO2) with monodisperse and uniformly distributed particles are produced by this reactor, and the photodeposition mechanism, as well as the synthesis optimization strategy, are discussed. The synthesis methods and their technical aspects are described comprehensively. The role of the ultraviolet (UV) dose (in each excitation pulse) on the photodeposition process is investigated and the optimum values for each composite system are provided.

For a continuous and scalable synthesis of noble-metal-based nanocomposites, a novel photocatalytic reactor is developed and its structure, operation principles, and product quality optimization strategies are described.

一种用于金属纳米粒子精确控制沉积的连续流动光催化反应器

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic ...

Reducing Willow Wood Fuel Emission by Low Temperature Microwave Assisted Hydrothermal Carbonization

Biomass is a sustainable fuel, as its CO2 emissions are reintegrated in biomass growth. However, the inorganic precursors in the biomass cause a negative environmental impact and slag formation. The selected short rotation coppice (SRC) willow wood has a high ash content (<img alt="Equation 1" src="/files/ftp_upload/58970/58970eq1.jpg" /> = 1.96%) and, therefore, a high content of emission and slag precursors. Therefore, the reduction of minerals from SRC willow wood by low temperature microwave assisted hydrothermal carbonization (MAHC) at 150 &#176;C, 170 &#176;C, and 185 &#176;C is investigated. An advantage of MAHC over conventional reactors is an even temperature conductance in the reaction medium, as microwaves penetrate the whole reactor volume. This allows a better temperature control and a faster cooldown. Therefore, a succession of depolymerization, transformation and repolymerization reactions can be analyzed effectively. In this study, the analysis of the mass loss, ash content and composition, heating values and molar O/C and H/C ratios of the treated and untreated SCR willow wood showed that the mineral content of the MAHC coal was reduced and the heating value increased. The process water showed a decreasing pH and contained furfural and 5-methylfurfural. A process temperature of 170 &#176;C showed the best combination of energy input and ash component reduction. The MAHC allows a better understanding of the hydrothermal carbonization process, while a large-scale industrial application is unlikely because of the high investment costs.

A protocol for the emission precursor depletion from low quality biomass by low temperature microwave assisted hydrothermal carbonization treatment is presented. This protocol includes the microwave parameters and the analysis of the biocoal product and process water.

低温微波辅助热液碳化降低柳树燃料排放

Biomass is a sustainable fuel, as its CO2 emissions are reintegrated in biomass growth. However, the inorganic precursors in the biomass cause a negative ...

Integrated Cell Manipulation Platform Coupled with the Single-probe for Mass Spectrometry Analysis of Drugs and Metabolites in Single Suspension Cells

Single cell mass spectrometry (SCMS) enables sensitive detection and accurate analysis of broad ranges of cellular species on the individual-cell level. The single-probe, a microscale sampling and ionization device, can be coupled with a mass spectrometer for on-line, rapid SCMS analysis of cellular constituents under ambient conditions. Previously, the single-probe SCMS technique was primarily used to measure cells immobilized onto a substrate, limiting the types of cells for studies. In the current study, the single-probe SCMS technology has been integrated with a cell manipulation system, typically used for in vitro fertilization. This integrated cell manipulation and analysis platform uses a cell-selection probe to capture identified individual floating cells and transfer the cells to the single-probe tip for microscale lysis, followed by immediate mass spectrometry analysis. This capture and transfer process removes the cells from the surrounding solution prior to analysis, minimizing the introduction of matrix molecules in the mass spectrometry analysis. This integrated setup is capable of SCMS analysis of targeted patient-isolated cells present in body fluids samples (e.g., urine, blood, saliva, etc.), allowing for potential applications of SCMS analysis to human medicine and disease biology.

An integrated cell manipulation platform is developed for use in conjunction with a single-probe mass spectrometry setup for the on-line analysis of individual suspension cells under ambient conditions.

集成细胞操作平台与单悬架细胞中药物和代谢物质谱分析的单探针相结合

Single cell mass spectrometry (SCMS) enables sensitive detection and accurate analysis of broad ranges of cellular species on the individual-cell level. ...