Controls on the carbon isotopic composition of coalbed biogenic methane and implications for biogas stimulation

煤层生物甲烷碳同位素组成的控制及其对沼气开发的影响

• 批准号: 1249916
• 负责人: David Vinson
• 金额: $ 17万
• 依托单位: Vinson David
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1249916&HistoricalAwards=false
• 关键词: Controls; carbon; isotopic; composition; coalbed

Dr. David Vinson has been awarded an NSF Earth Sciences Postdoctoral Fellowship to implement a research and education program based at Northwestern University. He will investigate stable carbon isotope signatures imparted during methanogenic biodegradation of coal. Natural abundance carbon stable isotope (13C/12C) ratios are valuable signatures of specific pathways and processes associated with methanogenesis. Yet, interpretive uncertainties and discrepancies with microbiological techniques complicate the use of carbon isotopes to diagnose methanogenic pathways of interest (e.g. acetoclastic methanogenesis and CO2 reduction). Other competing biogeochemical processes - in particular sulfate reduction - and mass balance effects may also influence observed carbon isotope signatures. Additional pathway-specific tools and techniques may improve understanding of the utilization of methane precursors, especially acetate. The primary tasks of the research are to adapt methods of analyzing compound-specific and intramolecular carbon isotope ratios of acetate to the low concentrations encountered in microbial gas systems, to analyze these isotope ratios in waters from natural and laboratory-constructed methanogenic systems in order to trace acetate utilization during methanogenesis, and to apply modeling techniques including reactive transport modeling to the mass balance of methanogenic coal biodegradation.Natural gas is an increasingly important energy resource, of which a significant portion is of biogenic origin. The research focuses on microbial methane derived from unmined coal (coalbed methane), and has implications for naturally-occurring and human-stimulated biogas resources derived from other carbon sources. In order to stimulate the native microbial community to yield additional methane, a detailed understanding of natural processes and pathways is required. In this research, the use of a compound-specific isotope tracer technique will promote understanding of the utilization of acetate in methanogenesis or in competing processes that do not yield methane. In other words, the efficiency of natural or modified methane-producing systems may be recorded by the isotope signature of acetate, combined with information on source organic carbon and end products (methane and CO2). Education and outreach activities associated with the postdoctoral fellowship include developing and conducting a biofuels-related summer workshop for K 12 teachers and involving undergraduate students in the research.

David Vinson博士已获得NSF地球科学博士后奖学金，以在西北大学实施研究和教育计划。他将研究煤炭生物降解期间赋予的稳定的碳同位素特征。自然丰富的碳稳定同位素（13c/12c）比是与甲烷发生相关的特定途径和过程的宝贵特征。然而，用微生物技术的解释性不确定性和差异使使用碳同位素诊断甲烷源性途径的使用复杂化（例如，乙酰碎裂甲烷生成和二氧化碳减少）。其他相互竞争的生物地球化学过程 - 特别是硫酸盐还原 - 质量平衡效应也可能影响观察到的碳同位素特征。其他途径特异性的工具和技术可能会提高人们对甲烷前体（尤其是乙酸酯）的利用的理解。该研究的主要任务是适应分析乙酸盐和分子内碳同位素比率的方法的方法，乙酸盐与微生物气体系统中遇到的低浓度相比，分析这些同位素比在天然和实验室实验室构造的甲烷系统中的自然和实验室中的同位素比，以在甲酸盐中范围进行均衡，并在甲酸盐中进行群体的利用，并在甲酸盐中进行平衡技术，并在甲酸盐中应用甲酸盐的利用率。甲烷基煤生物降解。天然气体是越来越重要的能源，其中很大一部分是生物源性的。该研究的重点是源自未经煤炭（煤层甲烷）的微生物甲烷，并对自然含有的沼气资源产生了影响。为了刺激本地微生物群落产生额外的甲烷，需要对自然过程和途径有详细的了解。在这项研究中，使用复合特异性的同位素示踪技术将促进对乙酸在甲烷发生或不产生甲烷的竞争过程中的利用的理解。换句话说，可以通过乙酸盐的同位素特征来记录天然或改良的产生甲烷系统的效率，并结合有关源有机碳和最终产物的信息（甲烷和CO2）。与博士后奖学金相关的教育和外展活动包括为K 12教师开发和开发与生物燃料相关的夏季研讨会，并让本科生参与研究。