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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.
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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−1, and H2/oil (v/v) of 1000 cm3/cm3 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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Bioresources and biofuels—From classical to perspectives and trends
(2022-01-01)
Kiatkittipong, Worapon
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Pongsiriyakul, Kanokthip
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Lim, Jun Wei
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Kiatkittipong, Kunlanan
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Wongsurakul, Peerawat
This chapter provides perspective on “Bioresources and Biofuels” based on three platforms of bioresource feedstock, i.e., amorphous sugar, lipid, and lignocellulosics. A comprehensive scheme of various possibilities of biofuel production in the three platforms of feedstock that are already commercialized or under development is proposed. At present, only lipid platform dominates the production of “drop-in” biofuel in large volume. However, a coming electric vehicle revolution, disruptive technology, could be a threat to biofuel industries either electricity is produced from renewable energy or having carbon capture and sequestration (CCS) or not. Different alleviation approaches are discussed, for examples (1) shifting from ethanol to “Alcohol to jet, AtJ” or “Direct sugar to hydrocarbon, DSHC” in the amorphous sugar platform; (2) shifting from biodiesel or even bio-hydrotreated diesel (BHD) (also called Hydrogenated Esters and Fatty Acids, HEFA) to HEFA—Synthetic Paraffinic Kerosene (HEFA-SPK) in the lipid platform; and (3) shifting from Fischer-Tropsch (FT) to FT-Synthetic Paraffinic Kerosene (FT-SPK) and FT-SPK with Aromatics (FT-SPK/A) in the lignocellulosic biomass platform. Another interesting choice is on biofuel allocation to produce hydrogen and hydrogen carrier fuel for state-of-the-art fuel cell vehicle application. Last but not least, by using biorefinery concept, lipid/oleochemical biorefinery is specially emphasized and some current typical technologies such as fatty acid methyl ester biodiesel as well as coproduct glycerol should be shifted to more valuable oleochemicals are also mentioned in this chapter. Obviously, economic viability for biofuels and oleochemicals production is still a challenge today. Process intensification which aims to improve process performance substantially (with respect to equipment size, time, energy, etc.) is encouraged and illustrated as an example along the chapter.
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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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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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Kiatkittipong, Kunlanan
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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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