Cool-Flame-Assisted Combustion of High Pressure CH4/air Mixtures for Hydrogen Synthesis

高压 CH4/空气混合物冷焰辅助燃烧制氢

• 批准号: 0215756
• 负责人: Nick Glumac
• 金额: $ 32.94万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0215756&HistoricalAwards=false
• 关键词: Cool; Flame; Assisted; Combustion; Pressure

Recent studies on the autoignition behavior of fuel-rich methane/air mixtures at elevated pressures suggests that mixtures at equivalence ratios of around 4 can be made to react rapidly for pressures above 8 atmospheres, and thus it may be possible to stabilize the process in a modified burner configuration for continuous production of product gases. Current mechanisms for fuel-rich methane combustion--those used to model 'cool-flame' behavior of methane--predict that the product gases resulting from such combustion will have hydrogen yields that exceed current combustion approaches and hydrogen:water ratios of 3 or better. In this work, a high-pressure reactor for combustion of methane/air mixtures at equivalence ratios of approximately 4 is designed and constructed. The reactor is designed to facilitate stabilization of these flows, which are characterized by long induction times and low heat release. In addition, the reactor has complete optical access, enabling detailed temperature and species concentration measurements in a flow that is optimized for comparison with the predictions of a kinetic model. Using this reactor, an extensive characterization of the combustion of very rich methane/air mixtures at elevated pressures is conducted. Temperature and formaldehyde spatial profiles, induction times, and detailed product yields are measured as a functions of process parameters, and the propensity for soot formation is examined. Using these data, current kinetic models are evaluated and analyzed under these conditions. This study is designed to demonstrate the feasibility of elevated pressure, air-based combustion techniques for hydrogen synthesis from natural gas, as well as to develop the tools for computational process analysis and optimization, while simultaneously generating an extensive and detailed dataset on the unique combustion behavior of this important mixture.Economical conversion of natural gas to hydrogen fuel is critical to realization of large-scale use of hydrogen as a fuel for transportation and for industry. In addition, widespread use of fuel cells likewise requires an inexpensive source for hydrogen. Most current hydrogen synthesis schemes, for example steam methane reforming and catalytic partial oxidation, remain too costly, in part due to high costs associated with the catalysts that are inherent in these processes. Combustion technologies offer the promise of inexpensive hydrogen production through non-catalytic partial oxidation of natural gas to carbon monoxide and hydrogen (syngas). Such technologies can generate power and hydrogen simultaneously and can be designed to involve simple reactor facilities that require smaller capital costs. At least two such combustion processes are currently used by industry. Significant cost reduction in combustion process for hydrogen synthesis can be obtained if 1) the hydrogen:water ratio in the product gases (currently ~1 to 2) can be significantly improved, and 2) the required oxidizer is air rather than oxygen.

最近对富含燃料的甲烷/空气混合物在高压下的自燃行为的研究表明，当量比约为 4 的混合物可以在高于 8 个大气压的压力下快速反应，因此有可能在改进的燃烧器配置可连续生产产品气体。 目前富含燃料的甲烷燃烧机制（用于模拟甲烷“冷焰”行为的机制）预测，这种燃烧产生的气体产物的氢气产量将超过当前的燃烧方法，并且氢气与水的比例为 3 或更好的。 在这项工作中，设计并建造了一个用于燃烧当量比约为 4 的甲烷/空气混合物的高压反应器。 该反应器的设计是为了促进这些流动的稳定，其特点是诱导时间长和热量释放低。 此外，反应器具有完整的光学通道，可以在流中进行详细的温度和物质浓度测量，并进行优化以与动力学模型的预测进行比较。 使用该反应器，对非常丰富的甲烷/空气混合物在高压下的燃烧进行了广泛的表征。 温度和甲醛空间分布、诱导时间和详细的产品收率作为工艺参数的函数进行测量，并检查烟灰形成的倾向。 使用这些数据，在这些条件下评估和分析当前的动力学模型。 本研究旨在证明高压空气燃烧技术从天然气合成氢气的可行性，并开发用于计算过程分析和优化的工具，同时生成有关独特燃烧的广泛而详细的数据集这种重要混合物的行为。将天然气经济地转化为氢燃料对于实现大规模使用氢作为交通和工业燃料至关重要。 此外，燃料电池的广泛使用同样需要廉价的氢源。 大多数当前的氢合成方案，例如蒸汽甲烷重整和催化部分氧化，仍然成本过高，部分原因是与这些过程中固有的催化剂相关的高成本。 燃烧技术有望通过将天然气非催化部分氧化为一氧化碳和氢气（合成气）来廉价生产氢气。 此类技术可以同时产生电力和氢气，并且可以设计成涉及需要较小资本成本的简单反应堆设施。 目前工业界至少使用两种这样的燃烧工艺。 如果 1) 产物气体中的氢水比（目前约为 1 比 2）能够显着改善，并且 2) 所需的氧化剂是空气而不是氧气，则可以显着降低氢合成燃烧过程的成本。