Temperature Measurements and Submicron Ash Formation in Oxy-Coal Combustion

富氧煤燃烧中的温度测量和亚微米灰分形成

• 批准号: 0755431
• 负责人: Yiannis Levendis
• 金额: $ 32.52万
• 依托单位: Northeastern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0755431&HistoricalAwards=false
• 关键词: Temperature; Measurements; Submicron; Ash; Formation

CBET-0755431LevendisOxy-coal combustion is a promising clean-coal technology that may reduce global warming. Coal is likely to remain a vital source in any conceivable future energy scenario despite the importance of exploring renewable sources of energy. To mitigate global warming, CO2 emissions should be constrained by improving efficiency of power generation, transmission, distribution, and use, as well as through CO2 capture and sequestration. The low, nitrogen-diluted CO2 concentration in the exhaust gas is a major driving force for high costs of capturing CO2 from conventional air-blown pulverized-coal combustion. Burning coal in pure oxygen or in oxygen blended with recycled flue gases can produce a CO2-rich effluent, thereby lowering the costs of the direct compression and storage of the flue gas. For technology development in oxy-coal combustion to reach its full potential, this study provides a fundamental understanding of the process using single coal particles, under pertinent conditions. Combustion kinetics of coal in an O2/CO2 atmosphere rather than O2/N2 is important because CO2 can (1) react with coal, unlike N2, (2) influence temperature through the differences in its transport properties and heat capacity relative to nitrogen, and (3) inhibit vaporization of refractory oxides of ash through the reversible reaction MO + CO = M + CO2, where M might be Fe, Mg, or SiO. This work applies all of the experimental and analytical tools developed over years of study in conventional coal/air combustion to the domain of oxy-coal combustion, and addresses important fundamental questions: Do coal particles burn hotter and faster in oxy-coal combustion Are pollutant emissions enhanced or reduced. Burnout histories of individual coal particles are observed, with multi-color optical pyrometry, and combustion temperatures and reaction rates are deduced. Because maximum coal-particle temperatures can exceed maximum gas temperatures by as much as several hundred degrees, knowledge of particle temperatures is important for evaluation of overall furnace efficiencies, furnace exit gas temperatures, as well as slugging and fouling tendencies of ash in a boiler. Furthermore, in this work, combustion-generated particulates and other pollutants are monitored in the effluent gases of oxy-coal combustion and are compared in character to those from the conventional combustion process. Because the strategies for handling pollutant emissions from oxy-coal plants are still in their formative stages, these data will be especially valuable.

CBET-0755431Levendisoxy-Coal燃烧是一种有希望的清洁技术，可以减少全球变暖。 尽管探索可再生能源的重要性，但在任何可能的未来能源方案中，煤炭可能仍然是至关重要的来源。 为了减轻全球变暖，应通过提高发电，传输，分配和使用的效率以及二氧化碳捕获和隔离来限制CO2排放。排气中的低氮气稀释二氧化碳浓度是从传统的气动粉碎煤燃烧中捕获二氧化碳的高成本的主要驱动力。纯氧气或氧气中燃烧煤炭与回收的烟道气体混合，可以产生富含二氧化碳的废水，从而降低烟气直接压缩和储存的成本。对于氧气燃烧的技术开发，可以在相关条件下使用单个煤炭颗粒对该过程进行基本了解。 Combustion kinetics of coal in an O2/CO2 atmosphere rather than O2/N2 is important because CO2 can (1) react with coal, unlike N2, (2) influence temperature through the differences in its transport properties and heat capacity relative to nitrogen, and (3) inhibit vaporization of refractory oxides of ash through the reversible reaction MO + CO = M + CO2, where M might be Fe, Mg, or SiO.这项工作应用了多年来在常规煤/空气燃烧的研究中开发的所有实验和分析工具对氧气燃烧的领域，并解决了重要的基本问题：煤炭颗粒在氧气燃烧中燃烧热，更快地燃烧污染物的排放剂增强或减少。观察到单个煤颗粒的倦怠历史，并具有多色光学的高温法，并推导了燃烧温度和反应速率。由于最高的煤颗粒温度可以超过几百度的最高气温，因此颗粒温度的知识对于评估整体炉效率，炉口出口气体温度以及锅炉中灰分趋势的打滑和结垢趋势很重要。此外，在这项工作中，燃烧生成的微粒和其他污染物在氧气燃烧的废气中受到监测，并将其与常规燃烧过程的特征进行比较。由于处理氧化植物的污染物排放的策略仍处于其形成阶段，因此这些数据将特别有价值。