CHEMICA: Jurnal Teknik Kimia

Acid-Catalysed Furfural Conversion: Enhanced Kinetic Insights into Formic Acid and Humin

2025-12-01T02:50:15+00:00

Furfural is a key platform molecule derived from lignocellulosic biomass and an essential precursor for biofuels, chemicals, and polymer materials. Its stability under acidic hydrothermal conditions critically affects biomass conversion efficiency. While numerous studies have explored furfural formation and xylose conversion, a comprehensive kinetic model that quantitatively captures furfural degradation pathways—particularly to formic acid and humins—and their interactions remains limited. This study addresses this gap by evaluating multiple kinetic models to identify the most accurate representation of furfural conversion behavior and by determining detailed kinetic parameters. Experiments were performed by reacting furfural with sulfuric acid at 140-180 C using furfural concentrations of 0.05–0.63 M and acid concentrations of 0.05-1.00 M. Among the tested models, Model 3 showed the highest predictive accuracy, with R² values of 98.04% for furfural conversion and 90.35% for formic acid formation. The estimated activation energies (Ea1 = 107.84 ± 0.53 kJ mol^-1, Ea2 = 81.75 ± 0.76 kJ mol^-1, and Ea4 = 117.07 ± 0.96 kJ mol^-1) indicate that humin formation has the lowest energetic barrier. In contrast, the autocatalytic formation of formic acid becomes significant only at elevated temperatures. Reaction orders of 0.81 for furfural, 0.62 for sulfuric acid, and 1.49 for formic acid reveal that both catalytic acidity and autocatalysis govern the overall reaction rate. Operational conditions strongly influence product selectivity: higher acid and furfural concentrations accelerate reactions but promote humin formation, whereas lower concentrations favor formic acid production. Overall, this study provides a holistic kinetic framework that accurately predicts the behavior of key species, offering valuable insights for reactor design and process optimization in furfural-based biorefineries.

Prioritizing Alternative Fuels for Co-firing in an Indonesian Cement Plant: A Techno-Economic Analysis Using Integrated AHP-TOPSIS

2025-12-18T10:19:57+00:00

The cement industry faces a dual challenge stemming from global decarbonization requirements and fossil fuel price volatility. Increasing environmental regulatory pressure and sustainability targets compel cement producers to accelerate the energy transition through the substitution of alternative fuels (co-firing). This study aims to identify the factors influencing alternative fuel selection for cement production, determine the optimal fuel option for PT Semen ABC, West Java, and establish a ranking of the best alternative fuels by balancing technical and economic considerations. Using an MCDM framework, this research integrates the AHP to weight decision criteria and the TOPSIS method to rank the alternatives. Six materials were evaluated: rice husk, sawdust, wood chips, rice husk pellets, carbon rubber, and RDF. The AHP results indicate that technical quality dominates decision preferences at 56.5% (calorific value weight: 28.26%; moisture content weight: 28.16%), exceeding the influence of material price, transportation cost, supplier capacity, and number of suppliers. Based on the TOPSIS analysis, carbon rubber ranks first as the most ideal solution, achieving the highest preference value (V = 0.7266), with a calorific value of 6.363 kcal/kg and a moisture content of 2.44%. The subsequent ranking is: rice husk pellets, rice husk, RDF, wood chips, and sawdust, with sawdust identified as the least-recommended fuel. This study concludes that kiln operational stability, which is strongly affected by material quality, constitutes the primary priority compared with procurement cost and supplier capability. Empirical research on integrated AHP–TOPSIS MCDM using techno-economic assessments based on operational data from Indonesian cement plants remains scarce. Most prior studies emphasize co-firing in power plants, making this application to the cement sector a key novel contribution.

Optimization of Neutralization in the Integrated Refining of Red Palm Oil: Effects on Free Fatty Acids and Water Content

2025-11-22T08:01:06+00:00

Red Palm Oil (RPO) is widely recognized for its high provitamin A content, especially carotenoids, and its abundance of natural antioxidants such as tocopherols and tocotrienols. These compounds make RPO a valuable functional food ingredient with significant nutritional and health benefits. However, refining RPO remains challenging because improvements in oil quality must be achieved without causing substantial losses of these bioactive compounds. This study evaluated an integrated refining sequence consisting of degumming, bleaching, neutralization, and deodorization applied to crude palm oil under moderate temperature conditions to maintain nutritional quality. The effects of NaOH concentration (14–18 Be) and reaction time (10–20 minutes) were investigated as the main variables influencing free fatty acid (FFA) reduction and water content stability. The results showed that the neutralization step was the most decisive stage, achieving an FFA reduction of nearly 60%, substantially higher than the reductions obtained during degumming–bleaching (28%) and deodorization (17%). The optimum operating condition was observed at 15 minutes with an appropriate NaOH concentration, where FFA reached its lowest level while water content remained relatively stable. In contrast, extending the reaction time beyond the optimum increased FFA levels, likely due to reverse hydrolysis caused by excess water formation during the process. Overall, this study defines an effective processing window for refining RPO under mild conditions and identifies neutralization as the critical control step. Further work is recommended to evaluate carotenoid retention and antioxidant stability throughout the refining sequence.

Rapid Source Attribution of Illegal Crude Oil Dumping Using GC–FID Fingerprinting and Multivariate Analysis in the Rokan Field

2025-12-17T06:21:13+00:00

Illegal crude oil dumping constitutes a significant environmental offense that threatens ecosystem integrity and necessitates reliable forensic methodologies for accurate source attribution. This study proposes a rapid, practical, and cost-effective forensic framework that integrates routine gas chromatography–flame ionization detection (GC–FID) fingerprinting with multivariate statistical analysis using MALCOM software. The developed approach is intended to provide a scientifically defensible method for source correlation in operational oil fields, where timely identification of contamination sources is critically important. Soil and water samples were collected from two suspected dumping sites, designated Spot A and Mud Pit B, and compared with crude oil samples obtained from three reference wells: Wells 3D, 4D, and 1E. Source attribution was evaluated through comparative chromatographic fingerprint analysis, diagnostic biomarker ratios (Pr/Ph, Pr/n-C17, and Ph/n-C18), hierarchical clustering via dendrogram analysis, and cosine similarity to quantify chemical relationships among samples. The results revealed that the soil sample from Spot A exhibited an exceptionally high cosine similarity value (>0.999) and clustered closely with crude oil from Wells 3D and 4D, strongly indicating a common origin and supporting evidence of illegal discharge from these sources. In contrast, samples from Mud Pit B displayed distinct chromatographic characteristics and lower similarity values (<0.997), suggesting a different source and/or significant weathering. These findings demonstrate that integrating widely accessible GC–FID data with multivariate statistical tools offers a rapid, robust, and economically feasible approach for environmental forensic investigations and source attribution of illegal crude oil dumping incidents.