超临界水活化褐煤制取活性炭

Activated carbon production from lignite in supercritical water

以超临界水(SCW)活化褐煤制取活性炭为目的,在半连续SCW反应装置上,研究了活化温度(600℃～700℃)、压力(0.1MPa～30MPa)和KOH添加量(质量分数为0%～15%)对小龙潭褐煤所制活性炭吸附性能和孔结构的影响。结果表明:升高活化温度有利于煤转化率、活性炭BET比表面和碘吸附值的增加,同时中孔比例也明显升高。与相同温度下常压水蒸气活化相比,SCW活化反应有利于活性炭的吸附性能和中孔比例的升高。650℃时活化压力由0.1MPa升至25MPa,活性炭BET比表面增加74%,中孔所占比例增加38%左右。煤中添加质量分数10%KOH可进一步促进孔隙生成,活性炭BET比表面可达825m2/g。此外,KOH还可与煤中的矿物质发生反应,通过酸洗脱除活性炭中的灰分至质量分数2%以下。

Conversion of Xiaolongtan lignite to activated carbon was conducted in a semi-continuous supercritical water （SCW） reactor. The effects of temperature （600-700℃）, pressure （0.1-30MPa） and KOH loading （ mass fraction 0 %-15 % ） were investigated. The coal conversion, iodine number and BET surface area of the activated carbon increase with temperature, and the meso-pore formation is also enhanced at relatively higher temperatures. Compared with steam activation at ambient pressure at the same temperature, SCW activation yields activated carbon with an excellent adsorption and develops mesopores. When the activation pressure increase from 0.1 MPa to 25 MPa at 650 ℃, the BET surface area and meso-pore ratio increase by 74 % and 38 %, respectively. The activated carbon has a BET surface area of 825 m^2/g with the addition of mass fraction 10 % KOH in lignite as catalyst. Moreover, the ash content of the activated carbon is lower than mass fraction 2 % after washing with dilute HCI.