Preparation of HZSM-5 zeolite assisted by glycerin and its catalytic performance for methane aromatization

HZSM-5 zeolite was synthesized under hydrothermal condition with TEOS as silicon source and glycerin as auxiliary agent. The effects of glycerol addition and crystallization time on the grain size, relative crystallinity and acidity of HZSM-5 molecular sieves and their catalytic performance for anaerobic aromatization of methane were investigated. XRD, SEM, NH₃-TPD and other analytical methods were used to characterize the HZSM-5 molecular sieve samples synthesized under different conditions. The results show that the relative crystallinity of HZSM-5 molecular sieve can be increased through adding certain amount of glycerol adjuvant and adjusting the crystallization time, meanwhile, the formation of amorphous SiO₂ can be suppressed and the acid content can be increased. The HZSM-5 prepared with glycerol assistance shows excellent catalytic performance in methane anaerobic aromatization. Compared with the HZSM-5 catalyst synthesized without the addition of glycerin, the methane conversion rate, benzene selectivity and aromatic selectivity are all greatly improved, and it has better stability and resistance to carbon deposition.