Influence of gas-staging on pollutant emissions from fluidized bed oxy-firing
Influence of gas-staging on pollutant emissions from fluidized bed oxy-firing
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DOI：
10.1016/j.cej.2014.07.011
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发表时间：
2014-11
影响因子：
15.1
通讯作者：
C. Lupiáñez;L. I. Díez;L. Romeo
中科院分区：
文献类型：
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作者：
C. Lupiáñez;L. I. Díez;L. Romeo
在固体燃烧系统中，空气分级燃烧是一种已知的、成功的减少nox排放的方法。尽管这一措施更多地应用于粉碎燃料装置，但它也可以在流化床锅炉中找到。在这种情况下，空气分级影响流体动力学和其他密切相关的问题，如燃烧效率或脱硫。在全氧锅炉中，这些影响的程度还有待完全确定。本文讨论了气相分级对流化床氧燃烧CO、nox和so2排放的影响。在90kwh鼓泡流化床上进行了两种不同高度的二次气入口的实验方案。试验是在不同的O2/ co2气氛和二次流量下燃烧两种西班牙煤（无烟煤和褐煤）进行的。二次气比是关键变量，直接影响致密区的固体混合和颗粒转化。虽然对所有被测试的煤炭和大气来说，天然气分级是减少nox排放的有效措施，但二氧化硫却受到了惩罚，因此最终需要一个折衷的解决方案。二氧化碳浓度越高，这些趋势越明显。
Air-staged combustion is a known, successful way to reduce NOxemission in solid-fired systems. Despite this measure has been more frequently applied in pulverized fuel units, it can also be found in fluidized bed boilers. In this case, air-staging affects the fluid dynamics and other closely related issues, like combustion efficiency or desulphurization. The extent of these effects is still to be completely determined in oxy-fired boilers. This paper discusses the influence of gas-staging on CO, NOxand SO2emissions in fluidized bed oxy-firing. An experimental plan was carried out in a 90 kWthbubbling fluidized bed with two secondary gas inlets located at different heights. The tests were conducted firing two Spanish coals (anthracite and lignite) for a variety of O2/CO2atmospheres and secondary flow rates. The secondary gas ratio has been revealed as the key variable, since solid mixing and particle conversion in the dense zone are directly affected. While gas-staging is shown to be an effective measure to reduce NOxemissions for all the coals and atmospheres tested, SO2is however penalized, so finally a trade-off solution is needed. These trends are deepened for the higher values of CO2concentration.