水溶性吸收剂对甲苯废气的吸收性能

液体吸收法应用于处理工业有机废气涉及到2个关键因素,即吸收剂的选择与吸收液的再生处理. 选择8种水溶性吸收剂——2种氟碳表面活性剂(FSO100和FSN100)、2种非离子表面活性剂〔TW80(吐温80)和SP20(斯盘20)〕、2种阴离子表面活性剂〔脂肪醇聚氧乙烯醚硫酸钠(AES)和脂肪醇聚氧乙烯醚羧酸钠(AEC)〕及2种类表面活性剂〔β-CD(β-环糊精)和SA(乙酸钠), 对模拟甲苯废气进行了动力学吸收试验,研究吸收性能和加热蒸馏法对甲苯回收与吸收剂溶液再生的可行性. 结果表明:吸收剂类型是影响甲苯吸收能力的最主要因素. 2种氟碳表面活性剂吸收液的甲苯吸收能力最强,其次是SP20与AES,而其他4种吸收剂溶液对甲苯的吸收能力很弱. 上述3类吸收剂对甲苯的初始去除率分别为80%～90%、75%左右与60%～70%,甲苯饱和吸收浓度(以w计)分别为0.58～3.45、0.38～1.44与0.14～1.01 mg/g. 除TW80吸收液热稳定性差、不宜采用加热蒸馏方法再生外, 其他吸收剂溶液经5次重复使用,甲苯回收率可达70%～85%,并能保持其原有吸收性能. 甲苯分配系数计算结果表明,FSO100和FSN100分别为0.41、0.62, SP20和AES分别为0.76、0.95, 其他4种吸收剂溶液在1.12～3.54之间；甲苯分配系数与饱和吸收浓度呈负相关、与体积传质系数呈正相关. 因此,2种氟碳表面活性剂吸收液对甲苯的吸收能力强,加热蒸馏法回收甲苯与再生吸收液具有经济性,用于处理甲苯废气具有广泛的应用前景. 

Toluene Absorption Performance of Typical Water Soluble Absorbents

The liquid absorption method applied to treat industrial organic waste gases includes two key aspects:absorbent choice and its regeneration. Eight water-soluble absorbents were selected, including two fluorosurfactants:FSO100 and FSN100; two non-ionic surfactants:Tween 80 (TW80) and Span 20 (SP20); two cationic surfactants:fatty alcohol polyoxyethylene ether sodium sulfate (AES) and fatty alcohol polyoxyethylene ether carboxylate (AEC); and two pseudo-surfactants:cyclodextrin (β-CD) and sodium acetate (SA). A dynamic absorption experiment and the heating distillation method were used to investigate their absorption capabilities to gaseous toluene, and the possibility to recover toluene from the absorbent solutions and regenerate them. The result showed that the property of the absorbent is greatly important to the toluene absorption efficiency. Among the eight absorbent solutions, the two fluorosurfactants presented the best performance, SP20 and AES were secondary, and the other four absorbent solutions had an obviously lower absorption capacity. The initial removal rates of toluene were 80%-90%, about 75% and 60%-70% respectively, and toluene saturation absorption concentrations were 0.58-3.45,0.38-1.44 and 0.14-1.01 mg/g respectively. Except for TW 80, which has a weak thermal stability and is unsuitable to be regenerated by distillation, the other absorbent solutions could keep their initial toluene absorption capacities during reuse, with a toluene recovery rate as high as 70%-85%. The partition coefficients of the eight absorbent solutions (calculated at an inlet toluene concentration of 3.0 g/m3) were quite different:0.41 and 0.62 for FSN100 and FSO100 respectively, 0.76 and 0.95 for SP20 and AES respectively, and between 1.12-3.54 for the other four absorbent solutions. The partition coefficient presented a negative correlation with the saturation absorption concentration, but a positive correlation with the volume mass transfer coefficient. In conclusion, the two fluorosurfactants have a practical potential to be applied to treat waste gas loaded with toluene, since they have a greater toluene absorption capacity, and heating distillation method is economical for the regeneration and toluene recovery.