Hydroxyl radical-regulated crystallization of hierarchical H-ZSM-5 at low temperatures for palm oil conversion into high aromatic green gasoline

Abstract

Biofuel is a sustainable fuel that is more environmentally friendly. Common biofuel processing is pyrolysis, which requires high energy. The use of appropriate catalysts can reduce the activation energy and increase product selectivity. H-ZSM-5 has excellent characteristics as a catalyst. However, hierarchical H-ZSM-5 has better characteristics because catalyst deactivation can be minimized and substrate diffusion increased. Generally, the H-ZSM-5 crystallization rate is relatively slow; in this research, OH radicals (OH) have successfully increased the crystallization rate of hierarchical H-ZSM-5. A successful synthesis of H-ZSM-5 was confirmed based on FTIR spectra and XRD diffractogram, which showed characteristic peaks in H-ZSM-5 for both TR-3 (H-ZSM-5 synthesized using OH for three days) and TN-3 (H-ZSM-5 synthesized without OH for three days). The use of OH shows an increase in the rate constant up to 3 times, producing highly crystalline TR-3. The use of OH also affected the morphology of H-ZSM-5, where TR-3 crystals tended to be more spheric with a larger size than TN-3. Porosity analysis showed higher porosity and better mesoporous features, where SBET increased from 309 to 373 m2/g, and Sext increased from 226 to 237 m2/g. This gave good effects on the catalytic ability of TR-3 compared to TN-3 by increasing gasoline yield in palm oil cracking from 35.91 wt% to 38.82 wt%, while the enhancement of the mesoporous features successfully inhibiting coke formation on the catalyst from 3.23 wt% becomes 2.02 wt% so that catalyst deactivation can be minimized.