Abstract Nitrogen oxide emissions from cement industry have greatly promoted the formation of haze weather. Current denitration technologies can hardly meet the increasingly stringent emission requirements. Here we proposed an innovative method called “rear independent reduction” (RIR) to reduce nitrogen oxide emissions from the cement kiln. A pilot-scale experimental setup was put in place to verify its feasibility. Reduction efficiencies of 61.2% and 48.6% were obtained in the absence and presence of cement raw meal, respectively. The effects of amount of reduction pulverized coal, flue gas temperature, the addition of cement raw meal, and oxygen content in flue gas on the NOx reduction efficiency were comprehensively investigated. Increasing the amount of reduction pulverized coal cannot only enhance the reduction efficiency, but also promote the rise of flue gas temperature. The ideal flue gas temperature is around 900 °C. Oxygen content in flue gas determines the impact of cement raw meal on the reduction efficiency, and the optimal value is below 1.0%. The significant reduction of NOx in flue gas should be attributed to the reaction between reductants and nitrogen oxides. This work provides a new way to address the problem of NOx emission in cement industry.

中文翻译：

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水泥窑氮氧化物减排创新及中试实验验证

摘要 水泥行业氮氧化物排放极大地促进了雾霾天气的形成。目前的脱硝技术难以满足日益严格的排放要求。在这里，我们提出了一种称为“后独立还原”(RIR) 的创新方法，以减少水泥窑的氮氧化物排放。一个中试规模的实验装置已经到位以验证其可行性。在不存在和存在水泥生料的情况下，还原效率分别为 61.2% 和 48.6%。综合考察了还原煤粉量、烟气温度、水泥生料添加量、烟气氧含量等因素对NOx还原效率的影响。增加还原粉煤的用量不仅能提高还原效率，同时也促进了烟气温度的上升。理想的烟气温度约为 900 °C。烟气中的氧含量决定了水泥生料对还原效率的影响，最佳值在1.0%以下。烟气中 NOx 的显着减少应归因于还原剂与氮氧化物之间的反应。该工作为解决水泥行业氮氧化物排放问题提供了新途径。