EFRI DCheM: Precise but Tunable Reactions Through Tunably Precise Surfaces

EFRI DCheM：通过可调节精确表面实现精确但可调节的反应

基本信息

批准号：
2029359
负责人：
William Epling
金额：
$ 200万
依托单位：
University of Virginia Main Campus
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2029359&HistoricalAwards=false
关键词：
EFRI DCheM Precise but Tunable

项目摘要

The use of geographically distributed resources such as biomass, stranded natural gas, biogas and municipal solid waste for localizable, clean chemical manufacturing has the potential to transform the U.S. domestic manufacturing landscape. However, those resources are typically produced in relatively small quantities that make their collection and transport to large centralized chemical plants impractical and often uneconomical. In addition, the centralized plants – because of their size – are constrained to operating under steady conditions with little flexibility with respect to process conditions, feedstock variability, and end products. In contrast, small-scale reactor systems relax such constraints and therefore, the smaller scale of distributed chemical manufacturing (DCheM) systems offers new opportunities to change operating conditions rapidly to increase processing efficiency and respond to feedstock variability. The overarching goal of the project is thus to develop a radically new approach to catalytic reactor design by modulating reactor operating parameters to achieve improved rates, product selectivity, and catalyst lifetime. The project focuses on valorizing methane and ethane, the main components of natural gas, but the concept of transiently-operated, flexible, small-scale reactors that can convert distributed feedstocks of different qualities to higher-value liquid products is broadly applicable. The development of such reactors opens the door to point-of-source chemical processing of abundant resources distributed throughout the U.S., thereby transforming regional economies as well as the overall chemical manufacturing landscape.The project introduces a new dynamically-oscillated catalytic reactor that periodically modulates the reacting gas environment about a catalytic site. The goal is to identify – at a fundamental level – catalytic reactor design and operating parameters that improve rates, selectivity, and catalyst longevity beyond levels accessible in steady-state operation. Methane oxidative reforming (MOR) and ethane oxidative dehydrogenation (EODH) are chosen as two probe reactions, both having tunable reaction chemistry between exothermic/endothermic operating conditions. To demonstrate the enhanced performance, the coverage dependence of fundamental surface processes during the oxidation and reduction catalytic half-cycles for MOR will be characterized via density functional theory (DFT), ab-initio molecular dynamics (AIMD), and kinetic Monte Carlo (kMC) methods. This will be coupled with ultrasensitive experimental temporal analysis of products (TAP) to reveal surface transients that diverge from classical steady-state reaction rate kinetics. The resolution of the temporal steps will describe operation through new reaction pathways that utilize externally induced periodic feed modulations. The effect of modulation will be demonstrated experimentally in micro- and monolithic-reactors coupled with in situ techniques to demonstrate pathways to rate/selectivity and longevity enhancements. Finally, a reactor-scale model will be built to unify the experiments and theory by describing reactor performance and predicting optimal dynamical operating conditions. Collectively, the combined experimental-computational approach pro-posed here will establish a new strategy for heterogeneous catalysis and push beyond the conventional steady-state thermodynamic/kinetic limits manifested in the Sabatier volcano by using innovative reaction engineering concepts. The project will include education and outreach activities emphasizing opportunities for underrepresented student groups. To this end, the project will engage a collaborator to coordinate diversity workshops that will engage all of the project researchers. The collaborator will also recruit underrepresented minority students through attending conferences targeted at promoting diversity in STEM education and workforce development.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

使用地理分布的资源，例如生物量，滞留的天然气，沼气和市政固体废物来进行可本质，干净的化学制造业，有可能改变美国国内制造业的景观。但是，这些资源通常以相对较少的数量生产，从而使其收集和运输到大型集中化学植物不切实际，而且通常是不可生理的。此外，集中式工厂（由于其大小）被限制在稳定条件下运行，而在过程条件，原料可变性和最终产品方面很少灵活。相比之下，小规模的反应堆系统放松了此类限制，因此，较小的分布式化学制造（DCHEM）系统规模较小，为快速更改操作条件的新机会提供了迅速提高加工效率并响应原料可变性的机会。因此，该项目的总体目标是通过调节反应器操作参数来提高速率，产品选择性和催化剂寿命，从而开发出一种彻底的催化反应器设计方法。该项目着重于验证甲烷和类似天然气的主要组成部分，但是瞬时操作，灵活的小型反应堆的概念可以将不同品质的分布式原料转换为高价值液体产品的分布式原料。此类反应堆的开发打开了分布在美国分布的丰富资源的源源工化学化学处理，从而改变了区域经济以及整体化学制造局势。该项目引入了一种新的动态振荡的催化反应器，该反应堆定期调节围绕催化部位的反应气体环境。目的是在基本水平上识别催化反应器设计和操作参数，以提高速率，选择性和催化剂的寿命超出稳态操作中可访问的水平。选择氧化物改革（MOR）和乙烷氧化物脱氢（EODH）作为两个探针反应，均在放热/吸热工作条件之间具有可调反应化学。为了证明性能的增强，将通过密度功能理论（DFT），AB-Initio分子动力学（AIMD）和动力学蒙特卡洛（KMC）方法来表征MOR的氧化和还原性半循环过程中基本表面过程的覆盖范围依赖性。这将与对产品（TAP）的超敏化实验临时分析相结合，以揭示与经典稳态反应速率动力学不同的表面瞬变。临时步骤的分辨率将通过使用外部引起的周期性进料调制的新反应途径来描述操作。调制的效果将在微小反应器和原位技术中实验证明，以证明速率/选择性和寿命增强的途径。最后，将建立一个反应器尺度模型，以通过描述反应器性能并预测最佳动态工作条件来统一实验和理论。总的来说，此处支持的实验性计算方法将建立一种新的策略，用于异质催化，并通过使用创新的反应工程概念来超越Sabatier火山中表现出的常规稳态热力学/动力学极限。该项目将包括强调代表性不足的学生团体的教育和外展活动。为此，该项目将与合作者互动，以协调将吸引所有项目研究人员的多样性研讨会。合作者还将通过参加旨在促进STEM教育和劳动力发展多样性的会议来招募代表性不足的少数群体学生。该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响审查标准来评估NSF的法定任务。