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-0755431莱文迪斯氧煤燃烧是一种有前途的清洁煤技术，可以减少全球变暖。 尽管开发可再生能源很重要，但在任何可以想象的未来能源情景中，煤炭可能仍然是一种重要的能源。 为了减缓全球变暖，应该通过提高发电、输电、配电和使用的效率，以及通过CO2捕获和封存来限制CO2排放。废气中低的、氮稀释的CO2浓度是从传统的鼓风煤粉燃烧中捕获CO2的高成本的主要驱动力。在纯氧中或在与再循环烟道气混合的氧气中燃烧煤可以产生富含CO2的流出物，从而降低烟道气的直接压缩和储存的成本。为了使富氧煤燃烧技术的发展充分发挥其潜力，本研究提供了在相关条件下使用单个煤颗粒的过程的基本理解。 煤在O2/CO2气氛而不是O2/N2气氛中的燃烧动力学是重要的，因为CO2可以（1）与煤反应，而不像N2，（2）通过其传输性质和相对于氮的热容量的差异来影响温度，和（3）通过可逆反应MO + CO = M + CO2来抑制灰的难熔氧化物的蒸发，其中M可以是Fe，Mg，或SiO。这项工作将多年来在传统煤/空气燃烧研究中开发的所有实验和分析工具应用于富氧煤燃烧领域，并解决了重要的基本问题：煤颗粒在富氧煤燃烧中燃烧得更热更快吗？污染物排放是增加还是减少？用多色光学测温法观测了单个煤粒的燃尽历史，并由此推断了燃烧温度和反应速率。因为最大煤颗粒温度可以超过最大气体温度高达几百度，颗粒温度的知识是重要的整体炉效率，炉出口气体温度，以及在锅炉中的灰的节涌和污垢的倾向的评估。此外，在这项工作中，燃烧产生的颗粒物和其他污染物进行了监测，在氧煤燃烧的废气中，并进行了比较，从传统的燃烧过程中的字符。由于处理氧煤工厂污染物排放的策略仍处于形成阶段，这些数据将特别有价值。