Effect of ZSM-5 acid modification on aromatization performance of methanol

ZSM-5 zeolites were modified with tartaric acid, oxalic acid and nitric acid. The physicochemical properties of ZSM-5 zeolites, such as crystal structure, acid content, surface area and pore volume, were characterized by XRD, SEM, NH₃-TPD, XRF, ²⁷Al MAS NMR, pyridine adsorption infrared spectroscopy and N₂ adsorption-desorption isotherms. The catalytic activity of ZSM-5 zeolites were investigated under the condition of reaction temperature 422 ℃ and methanol mass space velocity of 4.74 h^-1. The specific surface area, acidity, pore volume and catalytic performance of the catalyst are affected by acid modification. The acid-modified zeolites show good catalytic activity in methanol aromatization (MTA) reaction, and oxalic acid modified catalyst shows higher catalytic activity and selectivity. The yield of aromatic hydrocarbons and BTX reaches 57.40% and 39.40% for reaction time at 8 h, respectively.