水热炭化温度对稻秆燃料特性影响的研究

Effect of Temperature of Hydrothermal Carbonization on Fuel Quality of Rice Straw

采用水热炭化法对稻秆进行预处理,用ICP-OES和元素分析的方法对固相产物(生物炭)的燃料特性进行表征。结果表明:相对于未处理的稻秆,150℃所得的生物炭中氮与硫元素含量分别降低了34%和33%,且生物炭的能量密度随反应温度的上升而升高,250℃所得的生物炭具有最高热值(21.14 MJ/kg)和最低的H/C(0.09)与O/C(0.76)。另外水热炭化可以有效去除稻秆中的主要成灰金属元素,100℃所得的生物炭中钠、钾、镁、钙和铁5种金属元素的去除率均可高达80%以上。同时,水热炭化处理能够明显减轻稻秆燃烧过程中存在的积灰和结渣现象,250℃时所得生物炭的结渣与积灰指数分别降至0.19和3.69。

Hydrothermal carbonization（HTC） was employed to upgrade rice straw. Fuel characteristics of biochar produced were characterized by ICP-OES and elemental analysis, and results indicated that the nitrogen and sulfur content of biochar decreased by 34% and 33%, respectively, when the reaction temperature increased to 150 ℃. The energy density of biochar increased with the increase of the reaction temperature, and the maximum heat value 21.14 MJ/kg and the lowest H/C 0.09 and O/C 0.76 were observed when the reaction temperature increased to 250 ℃. High fraction of major ash forming metals originally contained in rice straw were removed by HTC, up to 80% of sodium, potassium, magnesium, calcium and iron were removed during hydrothermal process at 100 ℃. In addition, the ash-related problems including slagging and fouling encountered during rice straw combustion were significantly mitigated, and the slagging and fouling indexes at 250 ℃ were0.19 and 3.69, respectively.