Intensification of catalytic conversion for production of fuel-additive

Abstract

A novel nano-photocatalyst has been prepared using hydroxyapatite (HAp) derived from waste fish scale and fly ash derived aluminosilicate (SiO2-Al2O3) grafted with zirconium oxide (ZrO2) active sites by innovative photo-hydrothermal protocol. The physio-chemical properties of the prepared photocatalyst have been characterized by different analyses like XRD, FTIR, XPS, UV-VIS-NIR, BET, NH3-TPD, HRTEM, DLS and TGA. The optimal catalyst has Zr loading of 20 wt% and has a low bandgap energy of 2.15 eV as confirmed by UV-VIS-NIR spectroscopy. The optimal catalyst also depicted a high acidity of 1.52 mmol NH3/g and a specific surface area of 62.872 m²/g. Owing to the high acidity, specific surface area and low band gap energy the photocatalyst has led to achieve a yield of 76.6% levulinic acid (LA) from glucose in hybrid radiation reactor (HRR) deploying UV and FIR irradiation at appreciably low temperature and reaction time of 115℃ and 2h respectively. Under the same reaction conditions, the conventionally heated reactor (CHR) gave a very low yield of 23.7 %. Individual radiation effects on LA yield evinced the synergistic advantageous effect of hybrid radiation technique. The catalyst reusability and regenerative study confirmed the high stability of the prepared catalyst. Also, a comparative LCI study has been conducted between HRR and CHR systems which revealed that HRR is more environmentally sustainable than CHR. HRR based process demonstrated a 59% lower global warming potential, 65% lower terrestrial ecotoxicity while being 120% more energy efficient than CHR based reaction making HRR more environmentally sustainable as well as economically feasible. This study also focused on the synthesis of ethyl levulinate (EL) from glucose in ethanol medium, utilizing various catalytic systems. To replace conventional heating, a hybrid radiation system combining UV and IR was implemented. The optimization of key reaction parameters, such as reaction temperature (140 ℃), reaction time (45 mins), catalyst loading (30 wt%), and glucose-to-ethanol molar ratio (90), was achieved using a Taguchi L9 orthogonal design. At the optimized conditions, the maximum EL yield of 76.08% with 100% selectivity was obtained using an Amberlyst-36 + TiO2 (2:1) catalytic system. Furthermore, the synthesized EL was blended with biodiesel and commercial diesel at different ratios to evaluate engine performance and emission quality. The B7E3 blend exhibited favorable results, demonstrating a significant reduction of 19% and 18.86% in hydrocarbon (HC) and carbon monoxide (CO) emissions, respectively, compared to the other blends. Additionally, the B7E3 blend showcased lower brake specific fuel consumption (BSFC) and higher brake thermal efficiency (BTE). Furthermore, a life cycle assessment (LCA) was performed to evaluate the environmental impacts of EL production. in a conventional reactor (ELCH) in comparison to a hybrid radiation reactor (ELHR). The findings revealed that the ELHR significantly reduced global warming potential (GWP) by 48.86% compared to the ELCH, while also exhibiting a five-fold reduction in energy consumption. Overall, this study provides a comprehensive analysis of EL synthesis, engine performance, emission characteristics, and environmental implications, emphasizing the advantages of the hybrid radiation system over conventional heating methods.