Development of a Programmed-temperature Pyrolysis/Combustion Reactor System for Radiocarbon Applications

罗森海姆这项提议将导致开发一种仪器，用于分离沉积物中酸不溶有机物质(AIOM)的成分并使其老化。成岩稳定或老化前的AIOM可能比新鲜AIOM更耐完全热解。虽然沉积物年代学可以通过一套测量来评估，但在某些情况下，AIOM测年可能是唯一的选择。拟议的仪器将同时使用热解和燃烧来产生足够数量的二氧化碳，用于放射性碳测年。它在地质年代学和碳循环方面有着广泛的应用。在不同温度下的热解从复杂的基质中以不同的方式“去除”有机物。为了捕获热解产生的二氧化碳，开发了一套流通式热解系统原型。热图显示了与温度有关的二氧化碳根据样本类型和位置的不同释放。国际和平研究所建议开发一种捕集系统来收集二氧化碳的“部分”。该系统与任何现有设计的不同之处在于它具有流动配置和渐变温度上升能力。流动系统在铂催化剂氧化炉中“结束”，将热解的部分燃烧成二氧化碳。这些二氧化碳馏分经过低温提纯，冷冻到氧化铜和粒化银上，并在525°C下密封进行冗余燃烧。这一步骤避免了任何不完全燃烧，并在AMS分析之前去除了任何干扰硫化合物。随着该仪器的成功开发，需要解决的基本科学问题包括了解罗斯海和韦德尔海冰盖的历史将使用热解AIOM来估计，这种AIOM可以区分“新鲜的”原生碳和成岩碳。该装置还将用于更好地了解圭亚那泥滩亚马逊沉积的OM的氧化过程。PI旨在确定哪些比例的OM是耐火的--即使在重新氧化的条件下(沉积物周转)。这些方法也将应用于鳗鱼河和密西西比河的沉积物。该系统将用于评估富含干酪根的恒河/布拉莫帕特拉河系统沉积物的特征。初步数据显示，河流和陆架环境的组成部分之间存在不同的年龄。将分析密西西比河三角洲沉积，包括与堤坝相关的区域，以确定沉积事件的年龄。还将评估沉积物和有机物质向湿地的输送情况。该系统将在杜兰建造和维护。为反应堆部件和3个外部反应堆外壳(用于维护和减少停机时间)寻求资金。需要一台红外二氧化碳分析仪来实现二氧化碳的“实时”量化。要求使用马弗炉进行系统清洗。需要资金用于阀门、LabVIEW、DAQ硬件、继电器、真空螺线管和真空泵。还寻求用于放射性碳分析的资金。这一努力将为女性博士研究生助学金提供资金。仪器开发将使学生获得有价值的仪器和电子技能。该协会参与了NOLASMILE(洛杉矶新奥尔良，科学和数学研究、学习和探索)，这是一种培训和教育当地教师的工具。该项目将包括一名来自泽维尔大学(历史上是黑人大学)的志愿者本科生。*

0929752RosenheimThis proposal will lead to the development of an instrument to separate and age date components of acid insoluble organic material (AIOM) in sediments. Diagenetically-stable or pre-aged AIOM may be more resistant to complete pyrolysis than fresh AIOM. While sediment chronologies can be assessed by a suite of measurements, in certain instances, age dating AIOM may be the only option. The proposed instrument would use both pyrolysis and combustion to generate sufficient quantities of carbon dioxide for radiocarbon dating. The broad applications are to geochronology and carbon cycling. Pyrolysis at varying temperatures differentially "removes" organic matter from a complex matrix. In order to capture pyrolysis-generated carbon dioxide, a prototype flowthrough pyrolysis system has been developed. Thermograms reveal differential temperature-related carbon dioxide evolution based on sample type and location. The PI proposes to develop a trapping system to collect carbon dioxide "fractions." The system differs from any existing design in that it has a flowthrough configuration and a gradual temperature ramp capability. The flowthrough system "ends" in a platinum catalyst oxidation furnace to combust pyrolyzed moieties into carbon dioxide. These carbon dioxide fractions are cryogenically purified, frozen onto copper oxide and granulized silver and sealed for a redundant combustion at 525 °C. This step obviates any incomplete combustion and removes any interfering sulfur compounds before AMS analysis. Basic science questions to be addressed with successful development of this instrumentation include understanding the history of the Ross and Wedell Sea ice sheets will be estimated using pyrolized AIOM which can distinguish between "fresh" autochthonous and diagenetic carbon. The device will also be employed to better understand the oxidation of Amazon-deposited OM in Guianas mud banks. The PI intends to determine which proportions of OM are refractory - even under re-oxidized conditions (sediment turnover). Methods will also be applied to Eel River and Mississippi River sediments. The system will be used to assess the characteristics of kerogen-rich Ganges/Brahmupatra river system deposits. Preliminary data show different ages amongst components of riverine vs shelf environments. Mississippi delta deposits including areas associated with levees will be analyzed in order to age date deposition events. Sediment and organic matter delivery to wetlands will also be assessed. The system will be built and maintained at Tulane. Funds are sought for reactor components and 3 external reactor housings (for maintenance and reducing downtime). An IR carbon dioxide analyzer is requested for "real-time" carbon dioxide quantization. A muffle furnace is requested for system cleaning. Funds are requested for valves, LabView, DAQ hardware, relays, vacuum solenoids and a vacuum pump. Funds are also sought for radiocarbon analysis. This effort will fund a female PhD graduate student assistantship. The instrument development will allow the student to gain valuable instrumentation and electronics skills. The PI participates in NolaSMILE (New Orleans, LA, Science and Mathematics Inquiry, Learning, and Exploring) which is a vehicle for training and educating local teachers. The project will include a volunteer undergraduate from Xavier University (historically black college).***