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All Journal International Journal of Renewable Energy Development Bulletin of Chemical Reaction Engineering & Catalysis
Makertihartha, I Gusti Bagus Ngurah
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Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering

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Evaluation of the effects of fatty ester isomerization and turpentine-derived additive introduction on biodiesel cold flow properties and oxidation stability Indarto, Antonius; Pradana, Yano Surya; Kembara Alam, Alif; Makertihartha, I Gusti Bagus Ngurah; Prakoso, Tirto; Soerawidjaja, Tatang Hernas
International Journal of Renewable Energy Development Vol 15, No 3 (2026): May 2026
Publisher : Center of Biomass & Renewable Energy (CBIORE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61435/ijred.2026.61192

Abstract

Biodiesel is a cleaner and renewable combustion fuel that globally serves as an effective alternative to fossil diesel. The current application of this biofuel is still restricted to specific concentration due to its poor cold flow properties (CFPs) and low oxidation stability (OS). Later, isomerization process was offered to improve cold flow properties as well as oxidation stability. In this study, palm-biodiesel isomerization was carried out atmospherically using SO4/SnO2 catalyst, prepared via wet nitration method, in the stirred batch reactor at temperature of 200oC, catalyst loading of 10 wt%, stirring speed of 900 rpm, and under N2 flow. The performance of catalyst and the effect of fatty ester isomerization on CFPs and OS were investigated. For comparative study, the effect of bio-additive (turpentine oil and α-terpineol) introduction, at concentrations of 1−10 vol%, on CFPs and OS was also evaluated. The isomerization results demonstrated a conversion ratio of 12.54±0.60%, an isomerization selectivity of 75.92±5.79%, and an overall turnover frequency of 1.75×10−1±8.5×10−3 h−1. This reaction had a small reduction in pour point (ΔPP = ‒1oC), a minor elevation in cloud point (ΔCP = 0.50±0.15oC), and a slight improving effect in OS (ΔOS = 1.36 h). Furthermore, the optimum insertion of bio-additive was α-terpineol at concentration of 5 vol%, demonstrating a more significant enhancement in CFP parameters (ΔPP = ‒1oC; ΔCP = ‒1.75±0.15oC). Nevertheless, it significantly reduced OS level (ΔOS = ‒11 h), although the absolute value (OS = 10.36 h) remains compliant with international standards.
Comparative Assessment of Empirical Coke Deposition Models during n-Butanol Dehydration over a Zeolite-Y-Based Cracking Catalyst Adhi, Tri Partono; Subagjo, Subagjo; Makertihartha, I Gusti Bagus Ngurah; Nabilah, Azizah; Aulia, Hanief; Gunawan, Melia Laniwati
Bulletin of Chemical Reaction Engineering & Catalysis 2026: BCREC Volume 21 Issue 2 Year 2026 (August 2026) (Issue in Progress)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.20612

Abstract

The dehydration of n-butanol to butenes over zeolite-Y is accompanied by coke formation, which progressively deactivates the catalyst and affects reaction kinetics. In this study, dehydration was performed in an isothermal fixed-bed reactor at 400–500 °C using a commercial zeolite-Y composite catalyst. Coke deposition was quantified gravimetrically, while catalyst characterization showed a Si/Al ratio of 6, surface area of 353.9 m².g⁻¹, pore diameter of 57.2 Å, and pore volume of 0.602 cm³.g⁻¹, confirming a mesoporous structure. Coke accumulation data were analyzed using the Voorhies power-law model and analytical expressions derived from the Dumez–Froment empirical model. Model parameters were estimated by fitting experimental coke content data at different temperatures. The Voorhies model showed excellent agreement with experimental data (R² = 0.96–0.98). Among the Dumez–Froment-based expressions, only the logarithmic form accurately described coke deposition, while other forms resulted in poor fits. The results indicate that coke formation is progressively inhibited by accumulated coke, likely due to pore blockage and reduced accessibility of active sites. These findings identify suitable empirical models for predicting coke deposition and catalyst deactivation during n-butanol dehydration over zeolite-Y catalysts. Copyright © 2026 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
Co-Authors Adhi, Tri Partono Aulia, Hanief Indarto, Antonius Kembara Alam, Alif Melia Laniwati Gunawan Nabilah, Azizah Pradana, Yano Surya Subagjo Subagjo Tatang Hernas Soerawidjaja Tirto Prakoso