吸附法分离焦化甲苯中的吡啶类物质及吸附剂的再生

Separation of pyridines compounds from coking toluene and regeneration of adsorbents

采用气相吸附法以NaY分子筛作为吸附剂,对焦化甲苯进行精制脱氮,当吸附温度为115℃时,可以将焦化甲苯原料中吡啶和甲基吡啶的含量从5595μg/g和1633μg/g均降到500μg/g以下,NaY原粉和成型吸附剂的穿透处理量分别为12.44 g/g和5.94 g/g,对应的吸附量分别为0.90 mmol/g和0.44 mmol/g。热重分析(TGA)和核磁C谱(13C-NMR)的结果表明,采用250℃水蒸气再生的方法可以将吡啶和甲基吡啶脱附,但无法将积炭完全脱除。通过对比分子筛原粉和成型后吸附剂的吸附性能和再生性能,发现成型后的分子筛穿透处理量有所降低,但黏合剂的加入使其吸附性能更加稳定。并且在相同的吸附条件下,成型吸附剂比原粉吸附剂具有更强的深度脱氮能力。

Denitrogenation of coking toluene was studied via gas phase-adsorption and NaY zeolite was used as adsorbent.The contents of pyridine and methylpyridine in coking toluene could be reduced from 5595 μg/g and 1633 μg/g to below 500 μg/g,when temperature of adsorption was 115 ℃.The breakthrough treatment capacities for raw powder adsorbent and shaped adsorbent were 12.44 g/g and 5.94 g/g respectively corresponding to the adsorption amounts of 0.90 mmol/g and 0.44 mmol/g.The results of TGA and 13C-NMR indicated that pyridines compounds could desorbed with steam at 250 ℃,but carbon deposit could not be totally desorbed.The adsorption and desorption behavior comparison of raw powder adsorbent and shaped adsorbent showed that shaped adsorbent had lower treatment capacity but higher deep denitrogenation ability than raw powder adsorbent.