Catalytic Reduction of Nitrogen Oxides from Stationary PowerSources Using Methane

该项目研究了通过在过程中加入催化再燃步骤来减少固定动力源的氮氧化物排放的可行性。再燃室将被安装在锅炉的烟囱中或燃气轮机之后的热回收蒸汽发生器中，并将安装能够从注入燃烧器出口气流的天然气(甲烷)中产生甲基自由基的多相催化剂。甲基自由基还原氮氧化物的能力已经得到了很好的证实。在这项研究中，使用了两种已知的从甲烷生成甲基自由基的催化剂：锂掺杂的氧化锌和氧化镁，以及稀土氧化物，如氧化镧。催化研究和吸附测量提供了比活度、活化能和动力学速率表达式。用原位红外光谱表征了活性最高的催化剂的表面物种。成功地将这一概念应用于发电过程将大大减少氮氧化物的排放，并可能消除发电中的酸雨这一主要环境问题。它还将消除对目前正在使用的涉及氨的更昂贵、更繁琐的工艺的需要。还设想将氮氧化物应用于其他工业来源。

This project examines the feasibility of reducing emissions of nitrogen oxides from stationary power sources by including a catalytic reburn step in the process. The reburn chamber would be incorporated into the stack of a boiler or into a heat- recovery steam generator following a gas turbine, and would incorporate heterogeneous catalysts capable of generating methyl radicals from natural gas (methane) injected into the exit stream of the combustor. The ability of methyl radicals to reduce nitrogen oxides is already well established. In this study, two families of catalysts known to generate methyl radicals from methane are used: lithium-doped zinc oxide and magnesium oxide, and rare- earth oxides such as lanthana. Catalytic studies and adsorption measurements provide specific activities, activation energies, and kinetic rate expressions. Infrared spectroscopy done in situ is used to characterized the surface species on the most active catalysts. Successful application of this concept to power generating processes would result in an enormous decrease in nitrogen oxide emissions and would probably eliminate acid rain from power generation as a major environmental problem. It would also obviate the need for the more expensive and more cumbersome processes involving ammonia that are currently being used. Application to other industrial sources nitrogen oxides is also envisioned.