Chemical Reaction Activation in Microreactors Through Corona Discharge

提案编号：1134249PI：Yokochi，Alexandre F.参与化学反应的分子需要足够的能量来克服活化能障碍。这在室温下的自发反应中是正确的，它们是自发的事实仅仅意味着所需的能量以环境热能的形式存在。在少数情况下，可以通过使用催化剂来降低激活能垒，在某些情况下，可以通过声化学、光化学和放电等替代形式(除了显热)来提供能量。这项工作的主要目标是研究通过流体放电产生的非热等离子体如何用于驱动微通道反应器中的化学反应。所选择的模型反应是溶解在水介质中的有机分子被大气中溶解的氧气氧化和甲烷部分氧化为甲醇。初步工作表明，电晕放电活化氧化发生，技术文献表明，甲烷部分氧化的放电活化也发生。开发一种高效的电晕放电活化微通道反应器，既可以为高级氧化三级处理饮用水提供一种有效的方法，也可以建设性地利用目前过于昂贵的甲烷回收，还可以开发一种全新的方法来普遍激活化学反应，这将为各种应用开辟新的工艺反应选择。在微反应器中实现放电过程的一个重要障碍是实现火花放电或介质阻挡放电所需的高电压。通过用碳纳米管增强发射极电极，可以大大降低所需的电压。智能优点：本项目将通过构建和实验评估实验装置的性能，以及精心制作反应器操作的详细模型，系统地探索电晕放电激活化学反应在微通道反应器中的开发和实施。该项目将以下列方式进行：1.探索在微反应器中实施电晕放电激活反应系统：这将探索如何最好地建造可在其中通过电晕放电激活化学反应的微通道反应器。特别是，将评估使用碳纳米管增强发射极电极的最佳方法。水介质中电晕放电驱动氧化的实验评价：使用任务1中开发的碳纳米管激活的电晕放电激活微反应器，将评估不同反应条件的影响。评估的因素包括外加电势、总功率、反应器通道厚度、流体流速(即停留时间)和溶解氧浓度。甲烷部分氧化为甲醇：使用碳纳米管启动的电晕放电微反应器，将进行概念验证，然后全面探索工艺参数。将通过在反应器性能中添加甲烷/水/氧气的比率来评估2中描述的类似因素。制定电晕激活微反应堆的解释性/预测性模型：利用任务2和任务3中收集的数据，将使用COMSOL建立一个反应堆模型，在该模型中将评估上述因素的影响。教育集成：所描述的反应器系统将被用作正式教育的基础，开发1)实验模块，在该模块中，化学/环境工程专业的早期专业本科生可以实际使用先进的化学过程，包括调整一些参数的能力；2)为高级顶层体验序列中的高级学生提供使用开发的平台实施化学过程的机会；3)通过在实验室接待Johnson学者(一年级大学)和SESEY(高中)学生，继续指导本科生研究基于微反应器中的过程实施的问题。这些学生成为研究团队中不可或缺的一部分。广泛的影响：这项研究将导致开发一种新的方法来激活微通道反应器中的化学反应，为研究人员开发微通道反应器中的反应过程开辟了一个新的研究领域，有望使未来的各种进展能够导致基于微反应器的过程的实际实施。同时，这项工作将被用作对大学预科、本科生和研究生(以及其他教职员工)进行非正式(普通公众)和正式教育的平台。关于消除饮用水中微量有机污染物的问题，以及在微结构反应器中实施过程的一般情况。

Proposal Number: 1134249PI: Yokochi, Alexandre F. Molecules involved in chemical reactions require sufficient energy to overcome the activation energy barrier. This is true in spontaneous reactions at room temperature the fact that they are spontaneous merely means that the required energy is present in the form of ambient thermal energy. In a few cases this activation energy barrier can be lowered through the use of catalysts, and in some the energy can be supplied in alternative forms (other than sensible heat) such as sonochemical, photochemical, and electrical discharge. The primary objective of this work is to examine how non-thermal plasmas generated by electrical discharge through fluids may be used to drive chemical reactions in microchannel reactors. The model reactions chosen are the oxidation of organic molecules dissolved in aqueous media by dissolved atmospheric oxygen and the partial oxidation of methane to methanol. Preliminary work has demonstrated that the corona discharge activated oxidation takes place, and the technical literature suggests that electrical discharge activation of the partial oxidation of methane also occurs. The development of an efficient corona discharge activated microchannel reactor could lead to both an efficient approach to tertiary treatment of potable water by advanced oxidation and a method to constructively use stranded methane that is currently too expensive to recover, and also develop an entirely novel approach to the general activation of chemical reactions that will open new process reaction options for various applications. An important barrier to the implementation of electro-discharge processes in microreactors is the high voltage required to achieve spark or dielectric barrier discharge. The required voltages can be greatly diminished by enhancing the emitter electrode with carbon nanotubes.Intellectual Merit: This project will systematically explore the development and implementation of corona discharge activated chemical reactions in microchannel reactors through the construction and experimental evaluation of the performance of an experimental device and the crafting of a careful model of the reactor operation. The project will be approached in the following manner:1. Exploratory implementation of corona discharge activated reactive systems in microreactors: This will explore the manner in which a microchannel reactor within which a chemical reaction can be activated by corona discharge can best be built. In particular, the best methodology for the enhancement of the emitter electrodes with carbon nanotubes will be evaluated.2. Experimental evaluation of the corona discharge driven oxidation in aqueous media: Using the CNT enabled corona discharge activated microreactor developed in task 1, the effect of varying reaction conditions will be evaluated. Factors to evaluate include applied potential, total power, thickness of the reactor channel, fluid flow rate (i.e., residence time) and dissolved oxygen concentration.3. Partial oxidation of methane to methanol: Using the CNT enabled corona discharge microreactor, proof of concept followed by full exploration of process parameters will take place. Similar factors as described in 2 will be evaluated with the addition of methane/H2O/O2 ratios in the reactor performance.4. Development of an explanatory/predictive model for the corona activated microreactor: Using the data collected in Tasks 2 and 3, a model of the reactor will be developed using COMSOL in which the effects of the factors described above will be evaluated. The particular information to be extracted from the model includes reaction rates and the thickness of the reacting volume in the system.Educational Integration: The reactor system described will be used as a basis for formal education by developing 1) an experimental module where early program undergraduates inChemical/Environmental Engineering can actually work with an advanced chemical process including the ability of tweaking a few parameters, 2) offering advanced students in the senior capstone experience sequence the opportunity to implement chemical processes using the developed platforms and 3) continuing to mentor undergraduate researchers through hosting Johnson scholars (first year college) and SESEY (high school) students in the laboratory to work on issues based on process implementation in microreactors. These students become an integral part of the research team.Broader Impact: This research will result in the development of a novel method for chemical reaction activation within microchannel reactors, opening a new area of research for researchers developing reactive processes in microchannel reactors, hopefully enabling various future advances leading to the practical implementation of microreactor based processes. Simultaneously, the work will be used as a platform for informal (general public) and formal education for pre-college, undergraduate and graduate students (and fellow faculty!) on the issues surrounding the elimination of trace organic contaminants in potable water, and the implementation of processes in microstructured reactors in general.