Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater
Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater
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DOI：
10.1016/j.fuel.2011.03.006
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发表时间：
2011-07
期刊：
影响因子：
7.4
通讯作者：
J. Menasha;D. Dunn-Rankin;L. Muzio;J. Stallings
中科院分区：
文献类型：
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作者：
J. Menasha;D. Dunn-Rankin;L. Muzio;J. Stallings
在燃煤电厂排气系统中，当氨从NOx控制系统中滑落时，会与烟气中的硫氧化物和水发生反应，形成硫酸氢铵(ABS)。ABS形成的临界温度范围出现在空气预热器中，众所周知，ABS会导致腐蚀和堵塞，可能需要计划外停机和昂贵的清洗。为了制定缓解空气预热器中ABS的有害影响的策略，了解其形成温度和沉积过程是很重要的。本文介绍了一种具有适当温度梯度的单通道空气预热器的小试实验模拟，该预热器与模拟的燃煤烟气(包括硫氧化物、氨和水蒸气)一起用于研究ABS的形成。对ABS的形成进行了光学观察，给出了形成温度以及在一个真实的反应物浓度范围内的沉积特征，并与以前关于ABS形成的研究进行了比较。这项研究提供了以前没有测试过的实际浓度的数据，并且报告的数据具有比以前获得的更小的实验不确定度。结果表明，在空气预热器通道条件下测得的ABS生成温度介于前人报道的温度之间，对于典型的氨和硫氧化物的烟气浓度在500-520K范围内。结果还表明，至少对于这种实验构型，ABS主要以气相中的气溶胶形式形成，而不是作为通道壁上的冷凝物形成。
Ammonium bisulfate (ABS) forms in coal-fired power plant exhaust systems when ammonia slip from the NOxcontrol system reacts with the sulfur oxides and water in the flue gas. The critical temperature range for ABS formation occurs in the air preheater, where ABS is known to cause corrosion and pluggage that can require unplanned outages and expensive cleaning. To develop mitigation strategies for the deleterious effects of ABS in air preheaters, it is important to know its formation temperature and deposition process. This paper describes a bench-scale experimental simulation of a single-channel air preheater, with the appropriate temperature gradient, used in conjunction with simulated coal combustion flue gas, including sulfur oxides, ammonia, and water vapor, to investigate the formation of ABS. Formation was observed optically, and the formation temperature, as well as deposition characteristics for a realistic range of reactant concentrations are presented and compared with previous studies on ABS formation. This study presents data at realistic concentrations not earlier tested, and the reported data has smaller experimental uncertainty than previously obtained. We found that the measured ABS formation temperatures under air preheater channel conditions lies between the temperatures reported by others, and is in the range of 500–520K for typical flue gas concentrations of ammonia and sulfur oxide species. The results also show that, at least for this experimental configuration, ABS forms predominantly as an aerosol in the gas phase rather than as a condensate on the channel walls.