NSF/DOE Advanced Combustion Engines - Tailoring Catalyst Composition and Architecture for Conversion of Pollutants from Low Temperature Diesel Combustion Engines

虽然柴油发动机比汽油发动机更省油，但仍然需要提高燃油经济性。巧合的是，环境政策现在要求大幅减少柴油发动机的尾气中NOx、HC、CO、CO2和PM的排放。为了满足燃油经济性的要求，低温燃烧发动机应运而生。虽然传统柴油机排气的相对较低温度已经对排放控制构成了挑战，特别是在冷启动和怠速条件下，但低温内燃机的排气温度低40至70摄氏度，这意味着催化剂活性较低。这些先进的内燃机比目前的柴油发动机技术产生更低的NOx和颗粒物(碳烟)排放，但排放更高水平的其他污染物，特别是CO和碳氢化合物(HCS)。较低的排气温度和较高的CO和HCS水平尤其成问题。因此，LTC发动机可能有更好的燃油经济性，但产生明显更高的排放，就像今天？S催化转化器技术在如此低的温度下效率低下。解决方案显然是一种更活跃的催化剂技术。这是一个简单的陈述，但很难实现。一种实现催化剂活性控制的新方法已经被提出，以响应国家科学基金会和能源部关于先进燃烧发动机的联合征集。该机构的联合奖项通过NSF化学、生物工程、环境和运输系统部门及其催化和生物催化计划颁发给休斯顿大学(UH)的威廉·埃普林、迈克尔·P·哈罗德、丹·卢斯、拉斯·格拉博和维穆里·巴拉科泰亚教授，以及橡树岭国家实验室(ORNL)的詹姆斯·帕克斯。该团队将利用他们在这一领域的广泛背景知识来量身定做催化剂设计，特别是通过优化催化剂沿催化转化器长度和直径的组成，以利用正常运行下存在的污染物浓度和温度分布。这最终将导致实现高污染物转化所需的较低温度。了解和利用温度和浓度分布是一项仍处于起步阶段的技术，这种新方法不仅可以提高废气排放催化剂的效率，而且几乎可以提高所有催化系统的效率。来自UH和ORNL的研究团队通过跨越分子到发动机层面的研究，以及在发动机尾气排放催化剂合成和表征、反应建模和工程以及燃烧和车辆测试方面的专业知识，在跨越高性能计算机集群、先进催化剂表征、实验室规模催化反应器和全仪表化发动机的最先进设施中，独一无二地准备迎接挑战。通过在分子水平上模拟反应，将发现新的材料组合。实验室规模的研究将允许测量沿催化剂床层的气体浓度和温度分布。这些测量将被用来建立系统的计算机模型，该模型将被用来预测沿床层的最佳催化剂组成。这些预测将被用来合成新的催化剂设计，并在实验室和发动机规模上进行测试。结果最终将与主要催化剂制造商分享，供他们审查。拟议研究的一个主要重点是研究生和本科生的教育和培训。这些学生将使用先进的理论、计算和实验工具，培训他们成为有能力的化学工程研究人员。这项研究将为学生应用工程工具解决环境问题提供一个视角。这些学生还将参加德克萨斯大学排放和燃料研究中心的研究，在那里他们将有机会与正在全尺寸发动机上开发和测试新技术的工程师和工业合作者一起工作。该项目将包括初级本科生，有针对性地招募代表性不足的群体。每个本科生研究人员将被分配一个与他们的技能水平和知识水平相适应的个人项目。每个研究生都将有一名研究生导师协助监督和建议，并为研究生提供监督技能培训。最终，它将为研究生提供工业和学术职业培训，并为本科生提供研究经验，并激励他们继续研究生学习。这些数据还将发布在Cross-Cut Lean排气减排模拟(Cleers)小组网站数据库上，供业界、学术界和国家实验室同事访问，以更好地了解新催化剂技术，并开发和调整内部模型。

ABSTRACT#1258688Epling, WilliamAlthough diesel engines are more fuel efficient than their gasoline counterparts, increases in fuel economy are still needed. Coincidentally, environmental policies now require significant decreases in tailpipe NOx, HC, CO, CO2 and PM emissions from diesel engines. To meet the fuel economy demand, low temperature combustion (LTC) engines have been developed. Although the relatively low temperature of conventional diesel engine exhaust is already a challenge for emissions control, especially during cold start and under idling conditions, low temperature combustion engines have 40 to 70C lower exhaust temperatures which means lower catalyst activity. These advanced combustion engines produce lower NOx and particulate matter (soot) emissions than current diesel engine technologies, but emit higher levels of other pollutants, specifically CO and hydrocarbons (HCs). The lower temperature exhaust combined with higher levels of CO and HCs are especially problematic. As a result, the LTC engine may have better fuel economy, but produce significantly higher emissions, as today?s catalytic converter technology is inefficient at such low temperatures. A solution is clearly a more active catalyst technology. This is simple to state, yet difficult to achieve.A novel approach to achieving catalyst activity control has been proposed in response to the joint National Science Foundation and Department of Energy solicitation on Advanced Combustion Engines. The joint Agency award is made through the NSF Chemical, Bioengineering, Environmental and Transport Systems Division and its Catalysis & Biocatalysis Program to Professors William Epling, Michael P. Harold, Dan Luss, Lars Grabow, and Vemuri Balakotaiah from the University of Houston (UH) and James Parks from the Oak Ridge National Laboratory (ORNL). The team will use their extensive background knowledge in this area to tailor design catalysts, specifically by optimizing the catalyst composition along the length and diameter of the catalytic converter to take advantage of pollutant concentration and temperature profiles that exist under normal operation. This will ultimately lead to lower temperatures required to achieve high pollutant conversions. Understanding and exploiting the temperature and concentration profiles is a technique still in its infancy, and this novel approach can enhance efficiency for not only exhaust emissions catalysts, but for virtually all catalytic systems.The research team from UH and ORNL is uniquely poised to meet the challenge, through research spanning the molecular to engine level, and with expertise in engine exhaust emissions catalyst synthesis and characterization, reaction modeling and engineering, and combustion and vehicle testing, in state-of-the-art facilities spanning high performance computer clusters, advanced catalyst characterization, bench-scale catalytic reactors and fully-instrumented engines. By simulating the reactions at the molecular level, novel material combinations will be discovered. Lab-scale studies will allow measurement of gas concentration and temperature profiles along the catalyst bed. These measurements will be used to build a computer model of the system, which will in turn be used to predict the optimal catalyst composition along the bed. These predictions will be used to synthesize new catalyst designs to be tested at the lab and engine scale. The results will ultimately be shared with major catalyst manufacturers for their review. A major emphasis of the proposed research is the education and training of graduate and undergraduate students. The students will be using advanced theoretical, computational and experimental tools, training them to become capable chemical engineering researchers. The research will provide the students with a perspective in applying engineering tools to solve environmental problems. The students will also participate in research at the UH Texas Center for Emissions and Fuel Research, where they will have the opportunity to work alongside engineers and industrial collaborators who are developing and testing new technologies on full-scale engines. This project will include junior-level undergraduate students, with targeted recruiting of underrepresented groups. Each undergraduate researcher will be assigned an individual project that is appropriate for their skill level and knowledge. Each will have a graduate student mentor to assist with supervision and advising, also providing the graduate student with supervisory skills training. Ultimately, it will provide graduate students with training for industrial and academic careers and provide undergraduate students with research experience and motivate them to pursue graduate studies. The data will also be posted on the Cross-Cut Lean Exhaust Emissions Reduction Simulations (CLEERS) group website database, accessed by industry, academic and national lab colleagues to better understand new catalyst technologies and develop and tune in-house models.