Spatio-Temporal Phenomena During Adsorption and Reaction in Hydrocarbon Traps

主要研究者：哈罗德，迈克尔机构：休斯顿大学提案编号：1067709题目：碳氢化合物捕集器中吸附和反应过程中的时空现象PI计划在瞬态预热和低温操作过程中，对贵金属基沸石催化剂上碳氢化合物混合物的同时捕集和氧化进行原位实验测量和建模。这些信息将用于柴油氧化催化剂（DOC）反应器配置的设计，满足新的严格的排放限制。中心活动将是研究双功能捕集催化剂的几何和组成特性对模型排气部件的瞬态氧化的影响。该研究将确定几种不同的催化剂结构的相对性能，包括连续、分段和双层设计。使用一套原位实验技术的PI将遵循这类快速，放热，瞬态催化氧化的时空特征。这些将共同提供关于低温烃捕获和氧化期间的耦合浓度和温度前沿的详细信息。在化学反应器中的分布式温度扫描测量将提供先前不能获得的数据。要做的工作包括：1.在流动反应器和产物时间分析（TAP）反应器中对Pt/Pd/沸石-Beta/<$-Al 2 O3催化剂进行烃捕获和氧化的本征动力学研究。2.使用空间分辨质谱法测量模型催化剂上碳氢化合物捕获和氧化过程中反应物质的时间浓度分布。3.使用具有扫描波长干涉测量法（DTS-SWI）的分布式温度传感来测量在烃捕获和氧化期间洗涂整料的若干通道内的时空温度分布。4.利用空间分辨质谱法、扫描波长干涉法和积分漫反射红外光谱法进行综合实验，以绘制模型烃捕获和氧化反应系统的空间和时间行为。5.开发一个时空模型来模拟碳氢化合物的捕获和氧化，捕捉模型反应系统中观察到的主要趋势。6.在氧化铝载体上合成含有贵金属（Pt、Pd）和烃类吸附剂（β沸石）的混合层和双层洗涂催化剂。7.使用实际柴油车尾气进行验证实验。该项目的智力价值是推进知识和可靠性问题的理解和优化操作的时变催化过程的实际意义，柴油氧化催化剂（DOC）。这些知识将适用于其他催化反应器（例如填充床）的瞬时操作。这项研究将使预测吸附反应器模型的碳氢化合物陷阱，关键实验的设计，并确定各种反应器配置下的瞬态操作的最佳性能的发展。在冷启动和低温运行期间实现排气部件的氧化是一项苛刻的技术挑战。PI希望通过研究产生的理解和见解将导致一种新的催化剂设计和操作和控制策略方法，最大限度地减少DOC污染物的突破。更广泛的影响是发展新的实验方法来确定瞬态催化反应器的时空特征。该研究将向反应工程界介绍新实验方法的应用，包括空间分辨质谱法，分布式温度传感和产物的同位素时间分析。研究结果将在石化和环境行业从业人员使用的存档期刊中传播。PI还将向科学界提供反应堆代码，并将研究结果纳入UH的研究生课程。该项目将被用作一个技术平台，以吸引高中生对工程科学的兴趣和本科生对研究生研究的兴趣。这将通过本科生参与该项目和向高中科学教师提供暑期实习来实现。

PI: Harold, Michael Institution: University of HoustonProposal Number: 1067709Title: Spatio-Temporal Phenomena During Adsorption and Reaction in Hydrocarbon TrapsThe PIs plan to conduct in situ experimental measurements and modeling of simultaneous trapping and oxidation of hydrocarbon mixtures on precious metal based zeolite catalysts during transient warmup and low temperature operation. The information will be used for the design of a diesel oxidation catalyst (DOC) reactor configuration that satisfies new stringent emission limits. The central activity will be to study the effects of the geometric and compositional properties of the bi-functional trapping catalyst on the transient oxidation of model exhaust components. The research will determine the relative performance of several different catalyst architectures spanning sequential, segmented, and dual layer designs. Using a set of in situ experimental techniques the PIs will follow the spatio-temporal features of this class of fast, exothermic, transient catalytic oxidations. These will collectively provide detailed information about coupled concentration and temperature fronts during low temperature hydrocarbon trapping and oxidation. The distributed temperature scanning measurements in a chemical reactor will provide data that could not be previously obtained. The work to be done includes: 1. Carry out intrinsic kinetics studies of hydrocarbon trapping and oxidation in a bench-flow reactor and temporal analysis of products (TAP) reactor on Pt/Pd/zeolite-Beta /ã-Al2O3 catalysts. 2. Use spatially-resolved mass spectrometry to measure the temporal concentration profiles of reacting species during hydrocarbon trapping and oxidation on the model catalysts. 3. Use distributed temperature sensing with swept-wavelength interferometry (DTS-SWI) to measure the spatio-temporal temperature profile inside several channels of a washcoated monolith during hydrocarbon trapping and oxidation. 4.Conduct comprehensive experiments utilizing spatially-resolved mass spectrometry, swept-wavelength interferometry, and integral diffuse-reflectance IR spectroscopy to map spatial and temporal behavior of model hydrocarbon trapping and oxidation reaction system. 5. Develop a spatio-temporal model to simulate hydrocarbon trapping and oxidation that captures the main trends observed in the model reaction system. 6.Synthesize mixed-layer and dual-layer washcoated catalysts containing the precious metal (Pt, Pd) and hydrocarbon adsorbent (zeolite-Beta) on an alumina support. 7. Carry out validation experiments using actual diesel vehicle exhaust. The intellectual merit of this project is to advance knowledge and understanding of reliability issues and optimal operation of a time-varying catalytic process of practical significance, the diesel oxidation catalyst (DOC). That knowledge will be applicable to transient operation of other catalytic reactors such as packed beds. The research will enable development of predictive adsorptive reactor models of the hydrocarbon trap, design of critical experiments, and identification of optimal performance of various reactor configurations under transient operation. Enabling the oxidation of the exhaust components during the cold start and low temperature operation is a demanding technological challenge. The PIs expect that the understanding and insight generated by the study will lead to a novel catalyst designs and operation and control strategies approach that minimize the breakthrough of pollutants from the DOC. The broader impact is the development of novel experimental methodologies to determine spatio-temporal features of transient catalytic reactors. The research will introduce to the reaction engineering community the application of new experimental methods, including spatially resolved mass spectrometry, distributed temperature sensing, and isotopic temporal analysis of products. Research findings will be disseminated in archived journals utilized by practitioners in the petrochemical and environmental industries. The PIs will also provide reactor codes to the scientific community and will incorporate findings from the research into graduate level courses at UH. The project will be used as a technology platform to attract interest in engineering science among high school students and graduate research among undergraduate students. This will be accomplished through the involvement of undergraduate students in the project, and a summer internship offered to high school science teachers.