污泥–秸秆衍生固体燃料燃烧特性

Combustion Characteristics of Sewage Sludge-straw Derived Fuel

污泥秸秆衍生燃料技术是一种有效的污泥无害化、资源化处理技术。研究了通过化学调质法制备的污泥秸秆衍生固体燃料的燃烧特性，为污泥衍生燃料的应用提供理论依据。在升温速率为20K／min、流量为70mL／min的空气介质中，实验研究了4种污泥秸秆衍生固体燃料的着火特性、燃尽特性及综合燃烧性能，并求出了相关动力学参数。结果表明：燃料的燃烧过程分为干燥脱水、第一类有机物分解挥发及燃烧、第二类有机物的分解挥发及燃烧和固定碳的燃烧4个阶段，其温度范围大致为295-475K、475-650K、660-840K和900-1000K，前3个阶段有相互交叉和重叠的现象；4种燃料燃烧的着火点均在490-515K内，燃尽指数Cb最小为5．10×0^-3min^-1，综合燃烧特性指数S最小为10．80×10^-10mg^2．min^-2．K^-3，1000K内可完全燃烧；第一类挥发份的燃烧是二级反应，而第二类挥发份及固定碳的燃烧为一级反应，反应的活化能最大为64．80kJ／mol，与污泥单烧及煤混烧相比，污泥固体燃料燃烧性能更好，可作替代燃料使用。

The sludge-straws derived fuel technology is an effective method to realize the harmlessness and recycling of sludge. At a 70mL/min air ambient with a heating rate of 20K and a temperature range of 293-1 173 K, this study characterized the combustion behaviors （ignition characteristic, burnout behavior and the integrative combustion performance） and obtained kinetic parameters of four kinds sludge-straw fuels derived by chemical conditioning, in order to provide theoretical basis for industrial application of these fuels. The results show that the combustion process of these fuels includes four stages, which are the fuel drying, combustion of the first type volatile, combustion of the second type volatile and combustion of fixed carbon. The corresponding temperature range is about 295.-475 K, 475-650 K, 660-840 K and 900- 1 000 K respectively. The first three stages are intersected and overlapping. The ignition temperature, bum out temperature, the least burnout index Cb and integrative combustion performance index S of these four kinds of fuels is about 490- 515K, 1 000K, 5.10×10^-3min^-land 10.80×10^-1mg^2.min^-2.K^-3 respectively. The dynamic analysis results show that the second stage could be expressed by the second-order reactions together with Arrhenius equation, while the combustion reactions of the third stage and fixed carbon stages are accordance with first-order reaction. The maximum activation energy of these stages is only 64.80 kJ/mol. The studies demonstrate that sludge-derived fuel has better combustion characteristics than single sludge or mixture of sludge and coal, and could be used as substituted fuel.