大粒径厨余垃圾水热碳化制备炭燃料

Hydrochar production from hydrothermal carbonization of large particle kitchen waste for fuel

开展了不同温度条件(150~300℃)下大粒径(>2 cm)厨余垃圾水热碳化实验,研究了水热炭的理化性质、燃烧特性和关键元素迁移规律.实验结果表明,当水热温度过低,厨余垃圾颗粒尺寸影响水热碳化效果;大粒径厨余垃圾碳化需更高的水热温度;水热温度250~300℃产生的水热炭具有高热值(24.48~26.9 MJ·kg^(-1))、高燃料比(0.44~0.56)、高含碳量(59.6%~65.6%)和低含灰量(8.51%~4.35%)的特点.随着水热温度提高,水热炭中碳含量升高、灰含量下降;水热炭的着火温度、燃烬温度、挥发分释放特性指数VI、可燃性指数CI和综合燃烧特性指数CP均上升,提高了燃烧稳定性;同时水热炭中K、Na浓度降低,有利于降低水热炭燃烧结焦;N、S在水热炭中分布比例下降,这将减少水热炭燃烧的烟气污染物排放.因此,水热碳化能实现大粒径厨余垃圾的燃料化利用.

Hydrothermal carbonization(HTC)of large particles(>2 cm)of kitchen waste was conducted at different temperatures between 150~300 ℃.Physicochemical characteristics,combustion characteristics,and migration regularity of key elements within hydrochar were studied from these experiments.The results show that when the hydrothermal temperature is low,the large particle size of kitchen waste becomes a hindrance to HTC.The carbonization was improved with the increase of hydrothermal temperature,which may increase carbon content in hydrochar,and decrease the ash content.At 250~300 ℃,the obtained hydrochar has the best properties,with high heating value(HHV)of 24.48~26.9 MJ·kg^(-1),a high fuel ratio of0.44~0.56,high carbon content at 59.6%~65.6%,and low ash content(8.51%~4.35%).Results also showed that ignition temperature,burnout temperature,volatile characteristic index(VI),combustion index(CI),and combustion performance(CP)of hydrochar increased with the rising HTc temperature,indicating an improving stability of combustion.Increasing HTC temperature also decrease K and Na concentration in hydrochar,which is beneficial in reducing coking in hydrochar combustion.Increasing temperature decrease The distribution ratio of N and S in hydrochar,which reduces the emission of pollutants in flue gas from hydrochar combustion.Therefore,hydrothermal carbonization is a potential method for fuel utilization of large particle sized kitchen waste.