Primary and Secondary Aerosol Formation in Low-Temperature Combustion of Alcohol Biofuels

酒精生物燃料低温燃烧中的初级和次级气溶胶形成

• 批准号: 2125064
• 负责人: Rawad Saleh
• 金额: $ 42.94万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2125064&HistoricalAwards=false
• 关键词: Primary; Secondary; Aerosol; Formation; Low

A desire for environmentally cleaner automobiles has led to the idea of using biologically derived fuels in engines that operate at lower temperatures. Such systems would minimize exhaust emissions that contribute to photochemical smog. Next-generation passenger vehicles equipped with low-temperature combustion engines are expected to appear in larger numbers soon. However, the environmental impacts associated with these vehicles have not yet been completely assessed. This research project combines techniques from atmospheric and combustion sciences to determine the air-quality and climate impacts of pollutants emitted from the low-temperature combustion of advanced biofuels. Results from this research will be valuable for designing efficient emission-control strategies for these vehicles in advance of their deployment in the market. The project will afford education-through-research opportunities for undergraduates and high-school summer interns, and the research team will develop lesson plans on biofuels, renewable energy, and air quality to be implemented in high-school STEM curricula. By working with schools in Athens Clarke County that have high enrollments of minorities and economically disadvantaged students, these educational programs will increase the inclusion of such groups in STEM education.Low-temperature combustion reduces the production of two key pollutants compared to conventional diesel combustion: Nitrogen oxides (NOx) and black carbon. However, it is not clear how low-temperature combustion, especially when utilizing alcohol biofuels, affects the formation of primary and secondary organic aerosol – both important pollutants in terms of their effect on air quality and the climate system. This research will utilize controlled combustion experiments that will elucidate the connections between the molecular structure of biofuels and the gas-phase reactions leading to aerosol formation within the ranges of temperatures, pressures, and equivalence ratios encountered in low-temperature combustion engines. To isolate the effects of fuel structure on aerosol formation and properties, the investigation will involve three alcohol biofuels and their hydrocarbon analogues: 1-butanol and n-butane, iso-pentanol and iso-pentane, and cyclopentanol and cyclopentane. The aerosol emissions will be characterized for their properties that dictate their air-quality and climate impacts, including chemical composition as well as microphysical and optical properties. Furthermore, the emissions will be sent through an oxidation flow reactor that simulates atmospheric oxidation, and the secondary organic aerosol formed will be characterized. In parallel, the gaseous emissions will be speciated to identify intermediates implicated in primary organic aerosol formation as well as prominent secondary organic aerosol precursors, which will shed light on the connections between gas-phase combustion chemistry and aerosol formation.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.

对环境更清洁的汽车的期望导致了在较低温度下操作的发动机中使用生物衍生燃料的想法。 这种系统将最大限度地减少造成光化学烟雾的废气排放。配备低温内燃机的下一代乘用车预计将很快大量出现。然而，尚未完全评估这些车辆对环境的影响。该研究项目结合了大气科学和燃烧科学的技术，以确定先进生物燃料低温燃烧排放的污染物对空气质量和气候的影响。这项研究的结果将是有价值的设计有效的排放控制策略，这些车辆在市场上部署之前。该项目将为本科生和高中暑期实习生提供研究教育的机会，研究团队将制定有关生物燃料、可再生能源和空气质量的课程计划，并在高中STEM课程中实施。通过与雅典克拉克县少数民族和经济困难学生入学率高的学校合作，这些教育项目将增加这些群体在STEM教育中的包容性。与传统柴油燃烧相比，低温燃烧减少了两种关键污染物的产生：氮氧化物（NOx）和炭黑。然而，目前尚不清楚低温燃烧，特别是在使用酒精生物燃料时，如何影响初级和次级有机气溶胶的形成-这两种污染物对空气质量和气候系统的影响都很重要。这项研究将利用受控燃烧实验，阐明生物燃料的分子结构和气相反应之间的联系，导致气溶胶形成的温度，压力和当量比的范围内遇到的低温燃烧发动机。为了分离燃料结构对气溶胶形成和性质的影响，调查将涉及三种醇类生物燃料及其烃类类似物：1-丁醇和正丁烷，异戊醇和异戊烷，环戊醇和环戊烷。将对气溶胶排放物的特性进行表征，这些特性决定了其空气质量和气候影响，包括化学成分以及微物理和光学特性。此外，排放物将通过一个模拟大气氧化的氧化流动反应器，并对形成的二次有机气溶胶进行表征。与此同时，气体排放物将被分类，以确定涉及初级有机气溶胶形成的中间体以及突出的次级有机气溶胶前体，这将揭示气相燃烧化学和气溶胶形成之间的联系。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

项目成果

Two-stage aerosol formation in low-temperature combustion

• DOI: 10.1016/j.fuel.2021.121322
• 发表时间: 2021-11
• 期刊: Fuel
• 影响因子: 7.4
• 作者: O. E. Hajj;Khairallah Atwi;Zezhen Cheng;Alanna L. Koritzke;M. Christianson;N. S. Dewey;B. Rotavera;R. Saleh

Effect of Torrefaction on Aerosol Emissions at Combustion Temperatures Relevant for Domestic Burning and Power Generation

• DOI: 10.1021/acsearthspacechem.2c00251
• 发表时间: 2022-10
• 期刊: ACS Earth and Space Chemistry
• 影响因子: 3.4
• 作者: Charles Perrie;Chase K. Glenn;Gregory Reed;Tret C. Burdette;Khairallah Atwi;Omar El Hajj;Zezhen Cheng;Kruthika V. Kumar;A. Frossard;S. Mani;R. Saleh