煤沥青预处理工艺对活性炭孔结构的影响

EFFECTS OF PRETREATMENT PROCESSES OF COAL PITCH ON PORE STRUCTURE OF ACTIVE CARBON

煤沥青属热塑性高含碳材料 ,因其软化点低 ,制备活性炭前需要进行不溶不熔处理 .实验采用热聚合与空气氧化聚合两种工艺分别对沥青进行预处理 ,发现原料预处理工艺对所制备前驱体的组成、结构和性能影响很大 ,由此导致制备的活性炭比表面积与孔结构同样存在显著差异 .根据变化规律 ,可从中找出制备高比表面积活性炭适宜的工艺条件 :对热聚合方法预处理条件为 45 0℃恒温 4h～ 6h,挥发分 1 6.7%～ 2 6.4% .对氧化聚合方法预处理条件为 :42 0℃前升温速度为 2℃ /min～ 3℃ /min,挥发分 2 0 .2 %～ 2 2 .7% .在同样条件下分别采用 KOH炭化、活化 ,其比表面积前者为 :1 1 0 0 m2 /g～ 1 30 0 m2 /g,后者为 :1 40 0 m2 /g～ 1 5 5 0 m2 /g.

Coal pitch is a kind of thermoplastic carbon material.It need be treated into thawless and infusible material before be prepared into active carbon because of low softening point.Thermal polymerization and air blowing were carried to pretreat coal pitch in this experiment,we can find that it has great influence of pretreatment on composition,structure and properties of precursor,even influence on specific surface area and pore structure of active carbon.In as far as preparing high specific area active carbon,the fitting pretreatment condition listed as follows:to thermal polymerization pretreatment process,constant temperature 4 h-6 h under 450 ℃,volatile matter content is about 16.7%-26.4%;to air blowing pretreatment process,high heating rate is about 2 ℃/min-3 ℃/min before 420 ℃,volatile matter content is about 20.2%-22.7%.Then by carbonization and activation with KOH under the same condition,specific surface area of the former is about 1 100 m 2/g-1 300 m 2/g,while the latter is about 1 400 m 2/g-1 550 m 2/g.Thus,it can provide a gist for the further research of preparing active carbon from coal pitch.