混合气体直接吸附分离回收过程研究

以精密陶瓷制造过程中排放的甲苯和异丙醇混合气体为目标气体,采用4段活性炭吸附柱串联吸附实验方式研究了混合组分气体直接吸附分离回收的可行性.结果表明,异丙醇和甲苯这2种物性具有一定差异的物质在吸附床的长度方向存在明显的分层吸附现象.在表观气速0.42 m·s-1、异丙醇与甲苯入口浓度分别为477 mg·m-3和746 mg·m-3、吸附柱总长为26cm条件下,通气吸附798 min时,0～10 cm长度段炭层吸附甲苯量为184.5 mg·g-1,吸附异丙醇量为0 mg·g-1,而21～26 cm长度段炭层吸附甲苯量为0.92 mg·g-1,吸附异丙醇量为91.2 mg·g-1,通过分段再生回收分别得到了纯度99%以上的甲苯和异丙醇回收液.弱吸附质异丙醇在吸附过程中存在气相浓度增浓现象,该现象导致实验条件下部分活性炭层区域对异丙醇的吸附量提高了27%以上.通过多段串联吸附、分段再生回收的方式可以实现混合气体的直接吸附分离回收.

Process of Adsorption and Separating Recovery Solvents from Vapor Mixture Directly

Experiment on process feasibility of adsorption and separating recovery of organic compounds directly from waste gas was conducted with the activated carbon column train consists of 4 units in serial. Isopropyl alcohol and toluene vapor mixture was used as target gas, which are the common constituents of the gas emitted from fine ceramic manufacture. The experimental results showed obvious adsorption stratification phenomena alone the activated carbon column length for the vapor mixture. Under the condition of superficial gas velocity of 0.42 m·s^-1, inlet concentration of 477 mg·m^-3and 746 mg·m^-3 for isopropyl alcohol and toluene respectively, 26 cm total carbon packing length of the four column serial train, when the adsorption time reached 798 min, the adsorption capacities for toluene and isopropyl alcohol are 184.5 mg·g^-1 and 0 mg·g^-1 respectively in 0-10 cm section, and 0.92 mg·g^-1 and 91.2 mg·g^-1 respectively in 21-26 cm section, liquids with over 99% purity of isopropyl alcohol and toluene were recovered separately from the two end columns of the carbon column train. There is a gaseous concentration amplifier zone in the carbon column for the weaker adsorbate, isopropyl alcohol, which make the adsorption capacity of isopropyl alcohol increase over 27% in part of the down flow zone in this experiment. It is possible to directly recover the pure solvent liquid separately from the vapor mixture by the way of a serial adsorption column with separating stage recovering.