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    Catalytic Hydrotreating of Crude Pongamia pinnata Oil to Bio-Hydrogenated Diesel over Sulfided NiMo Catalyst
    (2022-02-01)
    Plaola, Yuwadee
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    Leangsiri, Wanwipa
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    Pongsiriyakul, Kanokthip
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    Kiatkittipong, Worapon
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    Srifa, Atthapon
    This work studied the catalytic activity and stability of Ni-MoS2 supported on γ-Al2O3, SiO2, and TiO2 toward deoxygenation of different feedstocks, i.e., crude Pongamia pinnata oil (PPO) and refined palm olein (RPO). PPO was used as a renewable feedstock for bio-hydrogenated diesel production via catalytic hydrotreating under a temperature of 330 °C, H2 pressure of 50 bar, WHSV of 1.5 h<sup>−1</sup>, and H2/oil (v/v) of 1000 cm<sup>3</sup>/cm<sup>3</sup> under continuous operation. The oil yield from a Soxhlet extraction of PPO was up to 26 wt.% on a dry basis, mainly consisting of C18 fatty acids. The catalytic activity in terms of conversion and diesel yield was in the same trend as increasing in the order of NiMo/γ-Al2O3 > NiMo/TiO2 > NiMo/SiO2. The hydrodeoxygenation (HDO) activity was more favorable over the sulfided NiMo supported on γ-Al2O3 and TiO2, while a high DCO was observed over the sulfided NiMo/SiO2 catalyst, which related to the properties of the support material and the intensity of metal–support interaction. The deactivation of NiMo/SiO2 and NiMo/TiO2 occurred in a short period, due to the phosphorus and alkali impurities in PPO which were not found in the case of RPO. NiMo/γ-Al2O3 exhibited the high resistance of impure feedstock with excellent stabil-ity. This indicates that the catalytic performance is influenced by the purity of the feedstock as well as the characteristics of the catalysts.
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    Alternative Hydrocarbon Biofuel Production via Hydrotreating under a Synthesis Gas Atmosphere
    (2017-11-16)
    Pongsiriyakul, Kanokthip
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    Kiatkittipong, Worapon
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    Laosiripojana, Navadol
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    Faungnawakij, Kajornsak
    Direct use of syngas, a cheaper hydrogen-rich gas, instead of pure hydrogen, as a deoxygenating agent for biohydrogenated diesel (BHD) production is presented in this study. Low-cost palm fatty acid distillate (PFAD), an inedible byproduct from refining palm oil, is used as a feedstock in the presence of a Pd/C catalyst. The results indicate that syngas can be effectively used in BHD production, while the achieved BHD yield is slightly lower than that obtained from pure hydrogen. The liquid products contain mostly n-C<inf>15</inf> and n-C<inf>17</inf>, which fall into a diesel range. Decarbonylation is a prominent pathway under both hydrogen and syngas atmospheres. It was found that CO in syngas can act as a reducing agent, which can remove an oxygen atom from fatty acid molecules to form alkenol that could be further reduced to alkene and then cyclized to cycloparaffins. After reactivation, the activity of the catalyst could be fully recovered for at least 4 reused cycles. Reaction pathways for the catalytic deoxygenation under syngas are also proposed with the underlying mechanism on the role of CO.
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    Hydrogen production from catalytic supercritical water reforming of glycerol with cobalt-based catalysts
    (2013-04-15)
    Pairojpiriyakul, Thirasak
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    Croiset, Eric
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    Kiatkittipong, Worapon
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    Arpornwichanop, Amornchai
    Glycerol reforming under catalytic supercritical water at temperatures in the range of 723-848 K using Co catalyst deposited on various supports including ZrO<inf>2</inf>, yttria-stabilized zirconia (YSZ), La<inf>2</inf>O<inf>3</inf>, γ-Al<inf>2</inf>O<inf>3</inf>, and α-Al<inf>2</inf>O<inf>3</inf> was investigated. An increase in operating temperature promoted the continued increase in glycerol conversion; however, carbon formation causing system operation failure was observed for γ-Al<inf>2</inf>O<inf>3</inf> and α-Al<inf>2</inf>O<inf>3</inf> at high operating temperatures (i.e. 748-798 K). Co supported on YSZ provided the most efficient performance for hydrogen production. 10 wt.% Co loading on YSZ support was an optimum amount to enhance the reaction. The increase in glycerol conversion and reduction of the amount of liquid products were observed for lower weight hourly space velocity (WHSV), higher operating temperature or higher cobalt loading. On Co/YSZ catalyst, glycerol conversion of 0.94 and hydrogen yield of 3.72 was obtained with WHSV of 6.45 h<sup>-1</sup>at 773 K. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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    Green pathway in utilizing CO2 via cycloaddition reaction with epoxide-A mini review
    (2020-05-01) ;
    Shukri, Muhammad Amirul Amin Mohamad
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    Kiatkittipong, Worapon
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    Lim, Jun Wei
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    Show, Pau Loke
    Carbon dioxide (CO<inf>2</inf>) has been anticipated as an ideal carbon building block for organic synthesis due to the noble properties of CO<inf>2</inf>, which are abundant renewable carbon feedstock, non-toxic nature, and contributing to a more sustainable use of resources. Several green and proficient routes have been established for chemical CO<inf>2</inf> fixation. Among the prominent routes, this review epitomizes the reactions involving cycloaddition of epoxides with CO<inf>2</inf> in producing cyclic carbonate. Cyclic carbonate has been widely used as a polar aprotic solvent, as an electrolyte in Li-ion batteries, and as precursors for various forms of chemical synthesis such as polycarbonates and polyurethanes. This review provides an overview in terms of the reaction mechanistic pathway and recent advances in the development of several classes of catalysts, including homogeneous organocatalysts (e.g., organic salt, ionic liquid, deep eutectic solvents), organometallic (e.g., mono-, bi-, and tri-metal salen complexes and non-salen complexes) and heterogeneous supported catalysts, and metal organic framework (MOF). Selection of effective catalysts for various epoxide substrates is very important in determining the cycloaddition operating condition. Under their catalytic systems, all classes of these catalysts, with regard to recent developments, can exhibit CO<inf>2</inf> cycloaddition of terminal epoxide substrates at ambient temperatures and low CO<inf>2</inf> pressure. Although highly desired conversion can be achieved for internal epoxide substrates, higher temperature and pressure are normally required. This includes fatty acid-derived terminal epoxides for oleochemical carbonate production. The production of fully renewable resources by employment of bio-based epoxy with biorefinery concept and potential enhancement of cycloaddition reactions are pointed out as well.
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    Oil extracted from spent coffee grounds for bio-hydrotreated diesel production
    (2016-10-15)
    Phimsen, Songphon
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    Kiatkittipong, Worapon
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    Yamada, Hiroshi
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    Tagawa, Tomohiko
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    Oil extracted from spent coffee grounds is utilized as a renewable source for bio-hydrotreated fuel production. In the present work, oil yield up to 13% can be obtained by Soxhlet extraction with hexane as a solvent. As the extracted oil contained high content of free fatty acids (6.14%), therefore one step alkali-catalyzed for ester based biodiesel production is impractical. Hydrotreating of extracted oil was performed over two catalysts i.e. NiMo/γ-Al<inf>2</inf>O<inf>3</inf> and Pd/C with different operating parameters i.e. reaction time, operating temperature, and H<inf>2</inf>/oil. It was found that the reaction time of 2 h and the reaction temperature of 400 °C are favorable operating conditions. The liquid products mostly consisted of n-pentadecane and n-heptadecane, which contain one carbon atom shorter than the corresponding fatty acid (C<inf>n−1</inf>) i.e. palmitic and stearic acid, respectively. Unfavorable cracking of diesel product is pronounced at high temperature and prolonged reaction time. In addition, although increased H<inf>2</inf>/oil promoted overall reaction and hydrodeoxygenation activity (C<inf>n−1</inf>/C<inf>n</inf> decreased) for both catalysts, hydrocracking is enhanced over Pd/C, leading to significant increase in gasoline yield. Moreover, Pd/C gave higher olefin content in liquid product (22.3 wt%) than NiMo/γ-Al<inf>2</inf>O<inf>3</inf> (4.8 wt%). However, NiMo/γ-Al<inf>2</inf>O<inf>3</inf> shows higher isomerization activity. The amount of isoparaffins catalyzed by NiMo/γ-Al<inf>2</inf>O<inf>3</inf> and Pd/C were 10.8 and 1.7 wt%, respectively. Physiochemical analysis of the diesel fraction exhibit satisfactory properties. The density and kinematic viscosity were consistent with the specification of commercial bio-hydrogenated diesel, NExBTL, while the cetane index was much higher than conventional diesel.
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    Mechanism of CaO catalyst deactivation with unconventional monitoring method for glycerol carbonate production via transesterification of glycerol with dimethyl carbonate
    (2022-02-01)
    Praikaew, Wanichaya
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    Kiatkittipong, Worapon
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    Aiouache, Farid
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    Najdanovic-Visak, Vesna
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    Termtanun, Mutsee
    Glycerol carbonate (GC) was synthesized by transesterification of glycerol with dimethyl carbonate (DMC) using calcium oxide (CaO) derived from eggshell as a catalyst. The best results of 96% glycerol conversion and 94% GC yield were achieved under the following reaction conditions: 0.08 mole ratio of CaO to glycerol, 1:2.5 mole ratio of glycerol to DMC, 60°C reaction temperature, and 3 hours reaction time. As expected, CaO showed deteriorated catalytic performance when recycling as observed by a rapid decrease in GC yield. This research showed that the active CaO phase first was converted to calcium methoxide (Ca[OCH<inf>3</inf>]<inf>2</inf>) and calcium diglyceroxide (Ca[C<inf>3</inf>H<inf>7</inf>O<inf>3</inf>]<inf>2</inf>) and finally to carbonate phase (CaCO<inf>3</inf>) which can be confirmed by XRD patterns. According to the phase transformation, the basicity decreased from 0.482 mmol/g to 0.023 mmol/g, and basic strength altered from strong basic strength (15.0 < H_ < 18.4) to weak basic strength (7.2 < H_ < 9.8), resulting in the lower catalytic activity of the consecutive runs. Despite the fact that the GC selectivity was almost 100%, the reaction products (methanol and GC) were not obtained in their stoichiometric ratio and their extents corresponded with that of the catalyst phase transformation to CaCO<inf>3</inf>. The mechanism of CaO catalyzed transesterification based on the condensation reaction of glycerol and catalyst was proposed, and in situ formation of water-derivative species was hypothesized as a cause of CaO transformation. CaO could react with DMC and water, generating methanol and CaCO<inf>3</inf>. This enabled unconventional monitoring of catalyst deactivation by checking if the mole ratio of methanol to GC was higher than 2:1 of its reaction stoichiometric ratio. It was also demonstrated that calcination of post-run catalyst at 900°C to CaO exhibited almost constant catalytic activity, and the mole ratio of methanol to GC was constant at its reaction stoichiometry (2:1) for at least 4 times use.
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    Effective Cu/Re promoted Ni-supported γ-Al2O3 catalyst for upgrading algae bio-crude oil produced by hydrothermal liquefaction
    (2021-06-01)
    Pongsiriyakul, Kanokthip
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    Kiatkittipong, Worapon
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    Adhikari, Sushil
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    Lim, Jun Wei
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    Lam, Su Shiung
    Catalytic hydrotreating of algae bio-crude oil from hydrothermal liquefaction (HTL) of Nannochloropsis sp. was performed. Different Ni-based catalysts, including Ni/γ-Al<inf>2</inf>O<inf>3</inf>, Ni-Cu/γ-Al<inf>2</inf>O<inf>3,</inf> Ni-Re/γ-Al<inf>2</inf>O<inf>3,</inf> and Ni-Cu-Re/γ-Al<inf>2</inf>O<inf>3,</inf> (10%Ni, 5%Cu, 2.5%Re) were used in upgrading of the bio-crude oil. Most catalytic systems could effectively eliminate S and decrease the N and O contents, and enhance more than 20% improvement in the higher heating value (HHV) of the bio-oil (34 to 41–45 MJ/kg). Introducing only Cu could enhance the C[dbnd]O hydrogenation resulting in higher aromatic and alcohol compounds. While the addition of Re is effective for hydrodeoxygenation, it lowers denitrogenation due to amination reaction. Ni-Cu-Re/γ-Al<inf>2</inf>O<inf>3</inf> ternary alloy offered the best results on the overall performance, achieving the highest upgraded bio-oil yield of 58 wt% and the highest energy recovery in the upgrading process (ER<inf>upgrade</inf>) of 64.6%. As ER in HTL process (ER<inf>HTL</inf>) was ca. 71.8%, the overall ER (ER<inf>overall</inf>) from algae biomass to upgraded bio-oil of 46.4% can be achieved for Ni-Cu-Re/γ-Al<inf>2</inf>O<inf>3</inf> catalyst. Carbon efficiency approx. 47.7% can be attained as the carbon in the algae biomass feedstock was retained in the upgraded bio-oil. In addition, reaction pathways for the formation of different hydrotreated products catalyzed by mono-, bi-, and tri- metallic Ni-Cu-Re have been proposed.
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    Process and energy intensification of glycerol carbonate production from glycerol and dimethyl carbonate in the presence of eggshell-derived cao heterogeneous catalyst
    (2021-07-02)
    Praikaew, Wanichaya
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    Kiatkittipong, Worapon
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    Aiouache, Farid
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    Najdanovic-Visak, Vesna
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    Ngaosuwan, Kanokwan
    The process and energy intensifications for the synthesis of glycerol carbonate (GC) from glycerol and dimethyl carbonate (DMC) using an eggshell-derived CaO heterogeneous catalyst were investigated. The transesterification reaction between glycerol and DMC was typically limited by mass transfer because of the immiscible nature of the reactants. By varying the stirring speed, it was observed that the mass transfer limitation could be neglected at 800 rpm. The presence of the CaO solid catalyst made the mass transport-limited reaction process more prominent. Mass transfer intensification using a simple kitchen countertop blender as an alternative to overcome the external mass transfer limitation of a typical magnetic stirrer was demonstrated. A lower amount of the catalyst and a shorter reaction time were required to achieve 93% glycerol conversion or 91% GC yield, and the turnover frequency (TOF) increased almost 5 times from 1.5 to 7.2 min<sup>−1</sup> when using a conventional magnetic stirrer and countertop blender, respectively. In addition, using a simple kitchen countertop blender with 7200 rpm, the reaction temperature of 60<sup>◦</sup>C could be reached within approximately 3 min without the need of a heating unit. This was the result of the self-frictional heat generated by the high-shear blender. This was considered to be heat transfer intensification, as heat was generated locally (in situ), offering a higher homogeneity distribution. Meanwhile, the trend toward energy intensification was promising as the yield efficiency increased from 0.064 to 2.391 g/kJ. A comparison among other process intensification techniques, e.g., microwave reactor, ultrasonic reactor, and reactive distillation was also rationalized.
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    Liquid-Liquid Phase Equilibria of Aqueous Biphasic Systems Based on Glycerol Formal: Application on Tetracycline Recovery from Water
    (2019-11-14)
    Praikaew, Wanichaya
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    Kiatkittipong, Worapon
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    Assabumrungrat, Suttichai
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    Aiouache, Farid
    Biopharmaceuticals are commonly present in relatively low concentrations in aqueous solutions, making their detection and purification detrimental. In this work, we used novel aqueous biphasic systems based on glycerol formal (GF) to extract an important antibiotic-tetracycline. We report cloud points (solubility curve) and tie-lines for three ternary systems, containing GF, water, and inorganic salt (either K<inf>3</inf>PO<inf>4</inf>, K<inf>2</inf>HPO<inf>4</inf>, or K<inf>2</inf>CO<inf>3</inf>) at constant temperature of 298 K and at 0.1 MPa. The tie-line data of these ternary systems were correlated using the nonrandom two-liquid model, and binary interaction parameters of activity coefficients were estimated. The experimental and correlated tie-line data were compared in terms of average root-mean-square deviation and showed satisfactory agreements. The partition coefficients of tetracycline between two phases were measured, and corresponding extraction efficiencies were calculated. The maximum value of partition coefficient was 1551 for the system containing K<inf>3</inf>PO<inf>4</inf>, followed by values of 1145 and 927 for systems containing K<inf>2</inf>CO<inf>3</inf> and K<inf>2</inf>HPO<inf>4</inf>, respectively. The calculated extraction efficiencies were very high-greater than 98.8%, demonstrating high potential for using aqueous biphasic systems based on GF for separation and purification processes.
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    Biofuel upgrading via catalytic deoxygenation in trickle bed reactor: Crucial issue in selection of pressure regulator type
    (2024-01-01)
    Pongsiriyakul, Kanokthip
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    Kiatkittipong, Worapon
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    Lim, Jun Wei
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    Najdanovic-Visak, Vesna
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    Wongsakulphasatch, Suwimol
    Trickle bed reactors (TBRs) are commonly used in various chemical and associated processes. The selection of a proper back pressure regulator (BPR) is crucial for maintaining the system's upstream pressure. In this study, we investigate the impact of BPR selection on deoxygenation reaction in a TBR with two typical types of BPR, including gas-phase type back pressure regulator (Gas-BPR) and multiphase type back pressure regulator (Multi-BPR). Notably, Gas-BPR introduces interruptions and pressure drops during the sampling step, impacting the hydrogen flow rate, while Multi-BPR ensures more consistent hydrogen flow. To examine the performance of BPR systems, hydrotreating experiments were conducted at 330 °C, 50 bar of hydrogen over Ni/γ-Al<inf>2</inf>O<inf>3</inf> catalyst using crude Pongamia pinnata oil as a feedstock and refined palm olein as a benchmark. Insignificant difference in the reaction performance between Multi-BPR and Gas-BPR systems was observed when using refined palm olein. Interestingly, there was a significant difference between the two systems when feeding with crude Pongamia pinnata oil. The multi-BPR system demonstrated superior performance, achieving 100% conversion of the feedstock over a prolonged period compared to the interrupted hydrogen flow in the Gas-BPR system. Further characterization of fresh and spent catalysts using N<inf>2</inf> sorption, XRD, SEM-EDS and TGA-DTG-DSC techniques revealed that a gum and coke formation was a reason for the rapid catalyst deactivation. Furthermore, the interrupted flow in the Gas-BPR system led to substantial gum production, ultimately causing a blockage in the reactor bed. Consequently, for feedstocks with high impurities, a robust continuous flow of hydrogen is essential. Thus, the study strongly recommends selecting Multi-BPR for continuous operation in TBRs to enhance efficiency and avoid catalyst deactivation.