Abstract The co-combustion of sewage sludge (SS) and biomass is promising for achieving energy recovery and compensating for individual feedstock disadvantages. However, the emission of nitric oxide (NOx) during this process is of concern, but no relevant study has focused on this. In this study, the release characteristics of NOx during co-combustion of SS and corn straw (CS) were investigated under different mixing ratios, heating rates, and SS moisture contents. The synergetic effect of SS and CS on NOx reduction was determined and quantified. An independently designed one-dimensional unsteady model with a fully implicit scheme was used. The results showed that with the increase in the SS mixing ratio to 20, 40, 60, and 80 wt%, the NOx emission peak values were reduced by 26%, 38%, 35%, and 40%, respectively. The case with a 60 wt% water content of SS was the best choice for NOx reduction. Furthermore, the model could describe the NOx emission trend accurately, especially for CS combustion and SS/CS co-combustion. This study showed effective NOx reduction during SS/CS co-combustion, thereby indicating that co-combustion is beneficial for the disposal of SS. In the future, the mechanism of the synergetic effect of SS and CS will be investigated from a micro point of view by more comprehensive experiments coupled with process parameter simulation.

中文翻译：

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玉米秸秆/污泥混合燃烧过程中NOx排放研究：实验与建模

摘要 污水污泥（SS）和生物质的共燃有望实现能量回收和弥补单个原料的缺点。然而，这一过程中一氧化氮（NOx）的排放令人担忧，但没有相关研究关注这一点。在本研究中，研究了不同混合比、加热速率和 SS 水分含量下 SS 和玉米秸秆 (CS) 混合燃烧过程中 NOx 的释放特性。确定并量化了 SS 和 CS 对 NOx 还原的协同作用。使用独立设计的具有完全隐式方案的一维非定常模型。结果表明，随着SS混合比增加到20、40、60和80 wt%，NOx排放峰值分别降低了26%、38%、35%和40%。SS 含水量为 60 wt% 的情况是减少 NOx 的最佳选择。此外，该模型可以准确地描述 NOx 排放趋势，特别是对于 CS 燃烧和 SS/CS 混合燃烧。该研究表明在 SS/CS 共燃过程中有效减少了 NOx，从而表明共燃有利于 SS 的处理。未来，将通过更全面的实验结合工艺参数模拟，从微观角度研究SS和CS协同效应的机理。从而表明混燃有利于 SS 的处置。未来，将通过更全面的实验结合工艺参数模拟，从微观角度研究SS和CS协同效应的机理。从而表明混燃有利于 SS 的处置。未来，将通过更全面的实验结合工艺参数模拟，从微观角度研究SS和CS协同效应的机理。