Conversion of Methane Using Mo–MFI Zeolite Catalyst

Abstract

HZSM-5 (Si/Al = 30), silikalit dan Mo-MFI dengan kepekatan logam molibdenum yang berbeza telah disintesis secara kaedah langsung. Sampel-sampel mangkin ini dicirikan dengan menggunakan teknik pembelauan sinar-X (XRD), Spektroskopi Inframerah Fourier Transformasi (FTIR) dan penjerapan suhu teraturcara bagi Ammonia (TPD-NH₃). Prestasi pemangkinan sampel-sampel ini dijalankan di dalam reaktor aliran berterusan lapisan terpadat mikro. Kesan kandungan logam dalam mangkin terhadap penukaran metana dan kadar kepilihan terhadap produk dikaji. Hasil pencirian menunjukkan bahawa sampel-sampel tersebut adalah mempunyai struktur seperti MFI-zeolit dan logam molibdenum yang hadir berkemungkinan besar terletak di tapak cacat zeolit. Ubahsuaian zeolit dengan logam memberi kesan kepada peningkatan aktiviti pemangkinan. Keputusan eksperimen yang menggunakan Mo(0.1)-MFI menunjukkan kepilihan C₁-oksigenat yang tinggi. Walau bagaimanapun, mangkin Mo-MFI didapati tidak sesuai untuk penghasilan gasolin. Kata kunci: MO-MFI, sintesis langsung, XRD, FTIR, TPD-NH HZSM-5 (Si/Al = 30), silicalite and Mo-MFI with different molybdenum concentrations were synthesized by direct synthesis method. The catalyst samples were characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy and Temperature Programmed Desorption of Ammonia (TPD-NH₃) techniques. The catalytic performance of the samples was evaluated in a continuous micro packed-bed reactor. The effects of metal content on methane conversion and products selectivity were investigated. Characterization results revealed that the samples were MFI-zeolite catalysts and the molybdenum metal most probably occluded in the defect sites of the zeolite. Modification of zeolite with metal resulted in the enhancement of catalytic activation. The experimental results using Mo(0.1)-MFI demonstrated a high selectivity of C₁-oxygenates. However, Mo-MFI catalyst was found not suitable for gasoline production. Key words: MO-MFI, direct synthesis, XRD, FTIR, TPD-NH