市政污泥水热法制备高值固体燃料研究

Study on preparation of high-quality solid fuel by hydrothermal conversion of municipal sludge

以市政污泥为原料进行水热碳化制备固体燃料水热炭,研究不同温度、时间对水热炭产率、热解和燃烧性能及其动力学特性影响规律。在不同升温速率(10℃·min^(-1)、20℃·min^(-1)、40℃·min^(-1))下采用热重分析法分析污泥水热炭的燃烧特性,利用Coasts-Redfern法探究水热炭燃烧的动力学特性,并分析燃烧反应机理。结果表明:市政污泥水热炭燃料特性明显改善,且受碳化温度影响较为显著。水热碳化温度240℃制备的水热炭热值达到最大为12.67 MJ·kg^(-1),碳含量最高为36.55%。与污泥相比,水热炭的着火温度和燃尽温度都整体降低;同时水热炭的着火指数整体大于原污泥,其中碳化温度200℃制备的水热炭着火性能最好。动力学分析结果表明:活化能主要分布于51.23~61.38 kJ·mol^(-1)。

Hydrothermal carbonization(HTC)of sewage sludge for solid fuel production was performed.The effects of temperature and time on the hydrochar yield,pyrolysis and combustion characteristics,and kinetic analysis were investigated.The combustion characteristics of hydrochar was analyzed using thermogravimetric analysis at different heating rates(10℃·min^(-1),20℃·min^(-1),40℃·min^(-1)).Further,the Coasts-Redfern method was applied to investigate the kinetic properties of hydrochar,and the combus-tion reaction mechanism was analyzed.The results showed that the fuel performance of hydrochar was significantly improved,and the fuel characteristics of hydrochar were significantly affected by HTC temperature.A maximum calorific value of 12.67 MJ·kg^(-1)and maximum carbon content of 36.55%was obtained at temperature of 240 C.Both ignition and burnout temperatures of hydrochars decreased compared with that of sludge.Besides,the ignition index of hydrochars was generally higher than that of sludge.Notably,the hydrochar prepared with the HTC temperature of 200 ℃ has the best ignition performance.The kinetic analysis results showed that the activation energy mainly distributed between 51.23 and 61.38 kJ·mol^(-1).