Towards Sustainable Hydrocarbon Biorefineries: Deoxygenation of Biomass Oxygenates to Hydrocarbons via Methane

实现可持续的烃（HC）生物精炼的最重要的技术挑战之一是从原料中除去氧气，原料通常构成高达35wt%的木质纤维素生物质。 最接近的脱氧技术，加氢脱氧和加氢裂化，估计每公吨生物质使用约66公斤氢气。 这种氢气需求会影响HC生物精炼厂的长期可持续性。 因此，需要一种有效和可持续的机制来从生物可再生原料中去除氧气。甲烷是一种富含氢气的气体，可以通过可持续的工艺生产。这个建议的总体目标是了解发生的基本催化过程，当甲烷接触生物质衍生的含氧化合物的双功能催化剂在热解conditions.Intellectual MeritThe动力学耦合的可能性与并发的产氢反应的耗氢反应是富氧生物质原料脱氧的基础。 具体地，生物质衍生的含氧化合物的芳构化是耗氢反应。 在此过程中，苯、甲苯和二甲苯（BTX）通常通过脱水反应形成，其产生水作为副产物。甲烷的产氢反应包括甲烷水蒸气重整和甲烷芳构化，甲烷可以直接与生物质热解蒸汽（含氧化合物）偶联，并通过两条途径在合适的金属负载ZSM-5双功能催化剂上脱氧生成烃类：（1）甲烷水蒸气重整和甲烷芳构化;（2）甲烷芳构化和甲烷芳构化。 在第一偶联反应中，在甲烷蒸汽重整期间形成的氢气用于含氧化合物的芳构化。在甲烷芳构化过程中通过脱水形成的水用于甲烷蒸汽重整。 这种偶联反应的最终产物是碳氢化合物和二氧化碳。在第二偶联反应中，甲烷芳构化以产生BTX（苯、甲苯、二甲苯）和氢气。 含氧化合物利用生成的氢并通过脱水芳构化，以水的形式除去氧。在所提出的研究中，将阐明在所选的含有金属（Sn，Ni，Ce，Ru或Mo 2C）的ZSM-5催化剂上的双功能催化剂的存在下，甲烷和模型葡萄糖之间发生的反应。通过该模型研究确定的候选双功能催化剂然后将用于探索当生物质组分（纤维素、木质素、固体生物质和生物油）在甲烷存在下催化热解。这项研究将提供对当富氧底物和甲烷-缺氧底物，将历史上难以活化富氢底物聚集在一起。 这项研究具有潜在的变革性，因为它提出了一种从生物质中生产碳氢化合物的新途径，而不需要氢气。 这项研究具有实际意义，因为现有的炼油厂基础设施可以用来从生物质中配制具有商业价值的碳氢化合物。更广泛的影响除了研究生的培训外，教育和推广计划还侧重于本科生的教学和学习。 具体而言，拟议的教育活动的特点是REACH计划（学术研究经验）的发展。 在拟议的REACH计划中，来自代表性不足的群体的学生在学术上有风险（2.5 GPA）与没有风险的学生配对。 该团队在本科课程的早期就提供了实践研究经验。 这些学生的学术进展将在他们的本科生涯过程中进行跟踪，以评估是否让他们在这个团队环境中早期接触动手研究，有助于激发他们对学习的热情，并促进他们在工程项目中的保留。

0965772FernandoOne of the most important technical challenges in the realization of sustainable hydrocarbon (HC) biorefineries is the removal of oxygen from the feedstock, which typically constitutes up to 35 wt% of lignocellulosic biomass. The closest technologies for deoxygenation, hydrodeoxygenation and hydrocracking, are estimated to use approximately 66 kg of hydrogen per metric ton of biomass. This hydrogen gas need affects the long-term sustainability of HC biorefineries. Consequently, there is need for an effective and a sustainable mechanism to remove oxygen from biorenewable feedstocks.Methane is a hydrogen-rich gas which can be produced by sustainable processes. The overall objective of this proposal is to understand the fundamental catalytic processes that occur when methane contacts biomass-derived oxygenates on bi-functional catalysts under pyrolysis conditions.Intellectual MeritThe possibility of kinetically coupling a hydrogen-consuming reaction with a concurrent hydrogen-producing reaction is the basis for oxygen-rich biomass feedstock deoxygenation. Specifically, aromatization of biomass-derived oxygenates is the hydrogen consuming reaction. During this process, benzene, toluene and xylene (BTX) are typically formed by dehydration reactions, which produce water as byproduct. The hydrogen producing reactions are methane steam reforming and methane aromatization.It is hypothesized that methane can be directly coupled with biomass-derived pyrolytic vapors (oxygenates) and deoxygenated into hydrocarbons over an appropriate metal supported ZSM-5 bi-functional catalyst via two pathways: (1) methane steam reforming and oxygenate aromatization, or (2) methane aromatization and oxygenate aromatization. In the first coupling reaction, hydrogen gas formed during methane steam reforming is used for the aromatization of oxygenates. Water formed during oxygenate aromatization via dehydration is used for methane steam reforming. The ultimate products of this coupling reaction are hydrocarbons and carbon dioxide. In the second coupling reaction, methane is aromatized to produce BTX (benzene, toluene, xylene) and hydrogen gas. Oxygenates utilize the hydrogen formed and aromatize by dehydration, removing oxygen as water.In the proposed research, the reactions that occur between methane and the model oxygenate glucose in the presence of selected bi-functional catalysts that contain metals (Sn, Ni, Ce, Ru or Mo2C) on ZSM-5 catalysts will be elucidated. Candidate bi-functional catalysts identified by this model study will then be used to explore the spectrum of hydrocarbon products generated when when biomass constituents (cellulose, lignin, solid biomass and bio-oil) are catalytically pyrolyzed in the presence of methane.This research will provide fundamental understanding on the chemistry that occurs at a catalyst surface when an oxygen-rich substrate and methane - an oxygen-deficient, hydrogen-rich substrate that is historically difficult to activate - are brought together. The research is potentially transformative because it suggests a new route to produce hydrocarbons from biomass that does not require hydrogen. The research has practical implications, because existing petroleum refinery infrastructure could be used to formulate commercially valuable hydrocarbons from biomass.Broader ImpactsIn addition to the training of graduate students, the education and outreach plan focuses on undergraduate student teaching and learning in a hands-on research environment. Specifically, the proposed education activities feature the development of the REACH program (Research Experiences for the Academically Challenged). In the proposed REACH program, students from under-represented groups who are academically at risk (2.5 GPA) are paired with students who are not at risk. This team is provided with hands-on research experiences early in their undergraduate program. The academic progress of these students will be tracked during the course of their undergraduate career to evaluate whether or not exposing them early on to hand-on research in this team environment helps stimulate their excitement towards learning and promotes their retention in engineering programs.