Enhanced glycerol dry reforming over Ni/SBA-15 synthesized from palm oil ash: Effect of GHSV

Abstract

The current research investigated the effect of gas hourly space velocity toward the GDR reaction using Ni/ SBA-15 catalyst derived from palm oil ash (P). The SBA-15(P) was prepared by hydrothermal technique and loaded with 3 % Ni via ultrasonic-assisted impregnation technique. The physio-chemical features of the unloaded and loaded Ni on the SBA-15(P) were characterized via BET, FTIR, XRD, H2 TPR, and TEM. In a vertical reactor made up of stainless steel operating at 800 °C, 1 atm, with various gas hourly space velocities (18000, 24000, 30000, and 36000 mL/g-1 s−1), the catalytic performance of the Ni/SBA-15(P) was investigated. The exceptional inclusion of active Ni particles with the SBA-15(P) support and strong Ni-O-Si interaction were demonstrated by FTIR, H2 TPR, and TEM, respectively. The highest catalytic activity (glycerol conversion = 43.24 %, H2 yield = 30.60 % and CO yield = 59.76 %) of Ni/SBA-15(P) was achieved at 24000 mL/g-1s−1. The higher the GHSV (30000 and 36000 mL/g-1s−1), the lower the syngas yield (H2 and CO) and glycerol conversion due to the less CO2 and glycerol molecules adsorbed on the active centers of the Ni/SBA-15(P) catalyst. Moreover, shorter contact time interaction between reactant molecules and the active site would build up the pressure inside the reactor system and favor carbon plugging during the catalytic process. Meanwhile, Ni loaded on SBA-15(P) at lower GHSV (20000 mL/g-1s−1) was low catalytic activity due to the limitation of existing molecules interacting with catalyst active sites. At lower GHSV (20000 mL/g-1s−1), Ni/SBA-15(P) exhibited poor catalytic performance because of the limited ability of molecules to interact with the catalyst active sites.