多层流化床中含氧水蒸汽活化法煤基活性炭的制备

Preparation of coal-based activated carbon using steam with oxygen in a multi-stage fluidized bed

为探究多层流化床用于粉状炭化料活化的可行性,采用多层流化床反应器,以大同煤的炭化料为原料,通过含氧水蒸汽活化法制备活性炭,考察操作条件对活性炭的吸附性能、孔结构特性及产率的影响。结果表明,与单层床和3层床相比,双层床活化满足生产高品质活性炭的需求,且能获得较高的活性炭产率。采用在第2层床供入部分氧气的分级供氧方法可提高活性炭的产率,并维持了较高的吸附能力和比表面积。在双层流化床第1层床和第2层床活化温度分别为890℃和870℃、活化剂中氧体积分数为8.9%、加料速率5 g/min、水碳比1.73的条件下,当第2层床供氧量占总氧量的体积分数为50%时,活性炭的收率达到46%,比表面积为877.1 m2/g,亚甲基蓝吸附值为226 mg/g,碘吸附值为1 025 mg/g,强度为92%,装填密度为334 kg/m3。因此,在双层流化床中采用分级供氧能确保同时实现煤基活性炭制备的高收率和高品质。

In order to explore the feasibility of powder carbonized material activation by multi-stage fluidized bed, a multi-stage fluidized bed was used to prepare activated carbon from carbonized material of Datong coal by activation in oxygen-containing steam. The influence of the operating conditions on adsorption property, pore structure and yield of activated carbon were investigated. The results show that comparing to single-stage fluidized bed and three-stage fluidized beds, the two-stage fluidized bed activation satisfy the need of high quality activated carbon production, and also gets high product yield. Supplying a part of the oxygen agent into the second stage further increases the yield of activated carbon, while adsorption ability and specific surface area of the activated carbon remaine high. When second stage oxygen against total oxygen is 50% in the two-stage fluidized bed, the yield of prepared activated carbon reaches 46%, which is possessed of the specific surface area of 877.1 m2/g, the methylene blue number of 226 mg/g, the iodine number of 1025 mg/g, hardness of 92% and apparent density of 334 kg/m3under the conditions of activation temperatures of 890 and 870 in the first stage and second stage, oxygen fraction of 8.9% in activating agent, raw material feeding rate of 5 g/min and steam to carbon ratio of 1.73. Consequently, activated carbon with both high yield and high quality can be produced via steam activation in a two-stage fluidized bed with staged-oxygen supply. © 2015, China Coal Society. All right reserved.