High-temperature and high-concentration SCR of NO with NH₃: Application in a CCS process for removal of carbon dioxide

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• 作者：Jan G.M. Brandin^a ; Christian P. Hulteberg^b ; C.U. Ingemar Odenbrand^b ; ^{Ingemar.Odenbrand@chemeng.lth.se}
• 关键词：High-temperature SCR ; High-concentration SCR ; Thermal stability ; Commercial catalysts
• 刊名：Chemical Engineering Journal
• 出版年：2012
• 期刊代码：16_13858947
• 类别：ce
• 出版时间：15 May, 2012
• 卷：191
• 期：Complete
• 页码：218-227
• 文件大小：747 K

摘要

This study investigates several commercial selective catalytic reduction (SCR) catalysts (A-E) for application in a high-temperature (approximately 525 掳C) and high-concentration (5000 ppm NO) system in combination with CO₂ capture. The suggested process for removing high concentrations of NO_x seems plausible and autothermal operation is possible for very high NO concentrations. A key property of the catalyst in this system is its thermal stability. This was tested and modelled with the general power law model using second-order decay of the BET surface area with time. Most of the materials did not have very high thermal stability. The zeolite-based materials could likely be used, but they too need improved stability. The SCR activity and the possible formation of the by-product N₂O were determined by measurement in a fixed-bed reactor at 300-525 掳C. All materials displayed sufficiently high activity for a designed 96%conversion in the twin-bed SCR reactor system proposed. The amount of catalyst needed varied considerably and was much higher for the zeolithic materials. The formation of N₂O increased with temperature for almost all materials except the zeolithic ones. The selectivity to N₂ production at 525 掳C was 98.6%for the best material and 95.7%for the worst with 1000 ppm NO_x in the inlet; at 5000 ppm NO_x, the values were much better, i.e., 98.3 and 99.9%, respectively.