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    Solubility effect of deep eutectic solvent and ethanol concentration on corncob lignin extraction
    (2024-12-01) ;
    Marom, Phakasinee
    ;
    Silpradit, Warunya
    This research investigates the solubility effect of deep eutectic solvent (DES) mass ratio and ethanol–water solution concentration on corncob lignin extraction. The objective is to propose a solubility matching technique based on like-dissolves-like theory to optimize lignin extraction conditions. The choline chloride (ChCl):lactic acid (LA) mass ratio that maximized lignin extraction was determined by varying DES mass ratio between 1:2 and 1:5, and ethanol–water solution (5–95 % (v/v)) was added to precipitate lignin. By using the solubility matching technique, the maximum lignin extraction was achieved at 1:4 ChCl:LA mass ratio, and 70 % (v/v) ethanol–water concentration yielded the highest lignin precipitation. Lignin is highly soluble where the solubility (δ-values) of lignin, DES, and precipitant are similar. Unlike conventional trial-and-error methods, the solubility matching technique relies on δ-values calculated by the Hildebrand and Scott equation. The proposed technique can also be applied to optimize the extraction conditions of other biomass materials.
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    Modelling and Process Simulation of Indirect Internal Reforming Solid Oxide Fuel Cell Fueled by Glycerol
    (2023-01-01) ;
    Kongkapan, Punyawee
    ;
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    Saebea, Dang
    This work applied Aspen Plus V9 simulator to study the performance of indirect internal reforming solid oxide fuel cell (SOFC) fueled by glycerol. The optimal operating conditions of the SOFC that can provide the maximum SOFC efficiency or the maximum syngas production were examined. This information can be a guideline for an SOFC operation in which wider range of operating conditions can be adjusted, depending on the target of use. If the maximum efficiency is required, an SOFC should be operated at fuel utilization of 0.85, SOFC temperature of 800-900°C and S/G molar ratio of 1. Under these operating conditions, the IIR-SOFC had an electrical efficiency between 63% and 67%. Considering the maximum syngas production, it was found that the anode exhaust gas consisting of 78% H<inf>2</inf> and 22% CO can be obtained at fuel utilization of 0.1, SOFC temperature of 700°C and S/G molar ratio of 5. In addition, the results indicated that the S/G ratio is a main parameter used for adjusting the H<inf>2</inf>/CO ratio in the syngas.
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    Hydrothermal reaction of cellulose in ionic liquid catalyzed by Er(OTf)3
    (2022-12-01) ;
    Wongkam, Nattajak
    This research explores the potential of ionic liquid to improve lactic acid yield of the hydrothermal reaction of cellulose. The research premise was that ionic liquid dissolved cellulose and water into liquid phase, which would facilitate the formation of glucose and lactic acid using water-tolerant catalyst Erbium (III) trifluoromethanesulfonate (Er(OTf)<inf>3</inf>). Contrary to the research premise, the experiment revealed that dissolving cellulose in ionic liquid prior to hydrothermal reaction lowered lactic acid yield while increasing hydroxymethylfurfural (HMF) yield. The phenomenon could be attributed to dissociation of water and ionic liquid to give hydronium ion and chloride ion, which subsequently formed hydrochloric acid (HCl). HCl catalyzed cellulose into HMF, in addition to lactic acid. Pressure and pressurized gas had minimal impact on the yield of lactic acid, while the hydrothermal reaction was affected by type of cation and anion of ionic liquid. The highest lactic acid yield of 54.26% was achieved by using 1-butyl-3 methylimidazolium chloride ionic liquid, with 190 °C, 30-min, 10 bar CO<inf>2</inf> initial pressure, and Er(OTf)<inf>3</inf> 50 wt% cellulose. Meanwhile, the highest HMF yield of 66.06% was realized with 1-butyl-3-methylimidazolium hydrogen sulfate in the absence of Er(OTf)<inf>3</inf>.
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    Optimization and kinetics modeling of phenolics extraction from coffee silverskin in deep eutectic solvent using ultrasound-assisted extraction
    (2023-07-01)
    Taweekayujan, Supawat
    ;
    Somngam, Supitcha
    ;
    This research investigates the effect of extraction parameters on total phenolic content (TPC) and the antioxidant capacity of coffee silverskin (CS) extract using ultrasound-assisted extraction (UAE) in deep eutectic solvent (DES). The optimization was carried out in two stages: (i) the optimization of the UAE condition with the highest TPC; and (ii) a four-factor Box-Behnken design (BBD) to optimize the UAE condition with the optimal TPC; 2,2 diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity; and ferric reducing antioxidant power (FRAP). The results showed that the optimal UAE condition with the highest TPC was 150–250 μm CS particle size; 1,6-hexanediol as hydrogen bond donor (HBD); 1:7 HBA:HBD molar ratio; and 30% (w/w) water content, given choline chloride (ChCl) as hydrogen bond acceptor (HBA), 30 min extraction time and 30 ° C extraction temperature. The BBD-based optimal UAE condition was 30% w/w water content, 45 mL/g liquid/solid ratio, 90 min extraction time and 85 ° C extraction temperature, given the CS particle size of 150–250 μm and the HBA:HBD molar ratio of 1 (ChCl): 7 (1,6 hexanediol), achieving 19.19 ± 0.20 mg GAE/g CS for TPC, 24.06 ± 1.77 mg TE/g CS for DPPH radical scavenging capacity, and 59.13 ± 4.55 mg Fe (II)/g CS for FRAP. The experimental results were in good agreement with the BBD-based predicted results (22.40 mg GAE/g CS for TPC, 24.09 mg TE/g CS for DPPH, and 59.43 mg Fe(II)/g CS for FRAP). The two-site kinetics model best fitted the experimental data, with R<sup>2</sup> of 0.991–0.999.
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    Biodiesel production from unrefined krating (Calophyllum Inophyllum) seed oil using supercritical methanol
    (2017-10-01)
    Tipachan, Chuenkhwan
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    Kajorncheappunngam, Somjai
    This study investigated the feasibility of biodiesel production from unrefined Krating (Calophyllum inophyllum) seed oil using supercritical methanol transesterification reaction. The experiments were conducted under various conditions of reaction temperature (200, 240, 260, 300, and 350°C), pressure (8, 12, 14, 16, and 18 MPa), and oil-to-methanol molar ratio (1:20, 1:40, and 1:60). All reactions were run at a constant reaction time of 10 minutes. Results showed that oil-to-methanol molar ratio, temperature, pressure, and their interactions significantly affected fatty acid methyl ester (FAME) yield. The highest FAME yield of 90.4% by weight was achieved at 260°C, 16 MPa, and an oil-to-methanol molar ratio of 1:40. This study also showed a significant decrease in acid value of Krating seed oil from 29 mg to 0.3 mg KOH per gram of oil compared to its biodiesel product. Moreover, most physical properties (kinematic viscosity, density, iodine number, flash point and water content) of our biodiesel product were comparable to the standard biodiesel EN14214.
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    Development and thermal performance of a portable solar cooker using glycerol-erythritol phase change material
    (2026-07-01) ;
    Tetthong, Areena
    ;
    Chaumsuk, Benya
    This study presents a portable and thermally efficient solar cooking system that employs a 25 wt% glycerol-erythritol mixture as phase change material (PCM) for thermal energy storage. The solar cooker utilizes a box-type solar collector to absorb solar radiation and store energy in the PCM. A two-dimensional transient heat transfer model was developed to analyze temperature profiles during cooking. The simulation results showed good agreement with laboratory experimental data and guided the design of a solar cooker capable of preparing meals for two people. Because erythritol's relatively high melting point limits its ability to fully absorb solar energy under typical solar radiation, glycerol was introduced to reduce the melting point. A prototype solar rice cooker accommodating two servings was fabricated and tested under three conditions: (i) direct solar energy without PCM, (ii) sun-exposed pre-melted 25 wt% glycerol-erythritol PCM with non-solar cooking, and (iii) sun-exposed pre-melted 25 wt% glycerol-erythritol PCM with solar cooking. MATLAB simulations were used to model transient heat transfer and temperature distribution during cooking. Experimental results indicated that condition 3 was the most effective cooking method. Under condition 1, rice was fully cooked in approximately 240 minutes, while condition 2 produced undercooked rice due to incomplete PCM melting. Overall, this study demonstrates the feasibility of integrating PCM with solar energy to improve cooking efficiency, contributing to the advancement of sustainable, off-grid cooking technologies.