Faculty Profiles - NORINAGA Koyo

Papers - NORINAGA Koyo

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Efficient CO<sub>2</sub> Electrochemical Reduction by a Robust Electrocatalyst Fabricated by Electrodeposition of Indium and Zinc over Copper Foam Reviewed

Sirisomboonchai, S; Machida, H; Tran, KVB; Kawasumi, M; Norinaga, K

ACS APPLIED ENERGY MATERIALS Vol. 5 ( 8 ) page： 9846 - 9857 2022.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ACS Applied Energy Materials

Electrochemical reduction of CO2comprising the CO2reduction reactuib (CO2RR) and oxygen evolution reaction (OER) is one of the most promising technologies for electrification of the chemical process industry. Here, the performance of a electrocatalyst with a three-dimensional structure of InZnCu on Cu foam (CF) is presented. This electrocatalyst was fabricated by electrodeposition of In and Zn over Cu and exhibited a superior reduction of CO2to CO at a Faradaic efficiency of 93.7% at -0.7 V and an excellently long duration of 100 h. Due to the synergy of the thin In layer, the Zn nanosheets provided a high surface-active area and strong mechanical robustness during the reaction. Additionally, a two-electrode system was constructed based on the CF-modified surface, which provided valuable guidelines on the overall CO2RR-OER system for further evolution. Furthermore, due to the facile synthesis, the bimetal-layer double hydroxide (LDH) exhibited high conductivity and high OER performance. Hence, the two-electrode system assembled excellent electrocatalysts for the CO2RR-OER (InZnCu/CF||Cu(OH)2NWs@NiCo-LDH/CF) with high conversions of CO2to CO of 67% and 88% at 2 and 50 mA cm-2, respectively. Notably, the CO2RR-OER system exhibited excellent stability in a 40 h CO2conversion with a constant current density of 2 mA cm-2at an ultralow voltage of 1.59 V. Moreover, the calculation of the energy input converting CO per ton of CO2resulted in a low energy input range for further development in scalability. This overall CO2RR-OER proposes development in electrochemical CO2reduction for industrial applications.

DOI： 10.1021/acsaem.2c01564

Selective hydrogenation of furfural to tetrahydrofurfuryl alcohol in 2-butanol over an equimolar Ni-Cu-Al catalyst prepared by the co-precipitation method Reviewed

Rao, TU; Suchada, S; Choi, C; Machida, H; Huo, ZB; Norinaga, K

ENERGY CONVERSION AND MANAGEMENT Vol. 265 2022.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Energy Conversion and Management

In order to upgrade biomass-derived platform chemicals to high value-added chemicals and liquid fuels, it is highly advantageous and desirable to synthesize suitable non-precious bimetallic catalysts that are efficient and versatile in chemical reactions. Equal moles of Ni and Cu were dispersed on varying mole ratios of Al by the co-precipitation method to synthesize Ni-Cu alloy particles to obtain a maximum yield of tetrahydrofurfuryl alcohol (THFA) by the liquid phase hydrogenation of furfural. The nickel species were active for both the furan ring (C=C) and carbonyl group (C=O) of furfural molecule, while Cu species were highly active for only the carbonyl group of furfural molecule. Systematic characterization of the prepared catalysts by XRD, TPR, STEM-EDS, and XPS analysis revealed the formation of highly active Ni-Cu alloys and near-equal Ni/Cu surface contents were achieved for the equimolar catalyst, which showcased a maximum of 98 mol% yield of THFA at 140 °C, 30 bar, 4 h. The reaction pressure and temperature showed a substantial effect on the product yield. The solvent selection also influenced the product selectivity, particularly with 2-butanol, which promoted the reaction with its hydrogen donor capacity and supported the ring hydrogenation of FAL to THFA. Moreover, the reduced Ni1Cu1-Al1 catalyst displayed good recyclability for three runs and an equal activity to that of a fresh catalyst after the regeneration.

DOI： 10.1016/j.enconman.2022.115736

Understanding the involved chemistry and physics toward numerically simulating the reactors for carbon resources and carbon dioxide conversions Reviewed

NORINAGA Koyo

Proceedings of the Annual Conference of The Japan Institute of Energy Vol. 31 ( 0 ) page： xviii - xix 2022.7

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Institute of Energy

<p>The recent approaches by the author and co-workers in understanding the involved chemistry and physics toward numerically simulating the chemical reactors are presented. The processes will include the gasification of solid fuels, coal tar reforming, and Sabatier reaction for producing carbon neutral synthetic methane.</p>

DOI： 10.20550/jietaikaiyoushi.31.0_xviii

CFD simulation of the Sabatier process in a shell-and-tube reactor under local thermal non-equilibrium conditions: Parameter sensitivity and reaction mechanism analysis Reviewed

Lin, YX; Zhang, W; Machida, H; Norinaga, K

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY Vol. 47 ( 34 ) page： 15254 - 15269 2022.4

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Hydrogen Energy

The Sabatier process is a competitive technology applied for carbon capture and utilization. This process increases the risk of carbon deposition and catalyst thermal degradation because of its exothermic property. In this study, a CFD model verified through existing experimental data was established to systematically investigate the Sabatier process in a shell-and-tube reactor. The effects arising from several operating parameters (e.g., gas flow rate, feed gas composition, the thermal conductivity of catalyst pellet, the inlet temperature of cooling phase, as well as phase change refrigeration) on temperature profile and reaction performance were studied. Moreover, a mechanism of three reactions was investigated, including CO2 methanation, CO methanation, as well as RWGS reaction. Furthermore, the competition between CO2 methanation and RWGS reaction was explored. According to the further sensitivity analysis, increasing the thermal conductivity of the catalyst particles would be effective to inhibit hot spots, while keeping the carbon conversion rate unchanged.

DOI： 10.1016/j.ijhydene.2022.03.029

Catalytic transfer hydrogenation of ethyl levulinate into γ-valerolactone over air-stable skeletal cobalt catalyst Reviewed

Ren, DZ; Zhao, C; Zhang, NH; Norinaga, K; Zeng, X; Huo, ZB

JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING Vol. 10 ( 2 ) 2022.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Environmental Chemical Engineering

A fast and easy handled batch air diffusion method (BA) was developed to obtain a non-pyrophoric, air-stable skeletal Co catalyst (A-SCo) for catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) into γ-valerolactone (GVL). A batch air diffusion method (BA) consumed the active adsorbed H2 on the surface of skeletal Co (SCo) but maintained structure catalyst and avoided excessive oxidation of metallic Co, Ni and Al. The 96% yield of GVL was obtained over the A-SCo and HZSM-5 at 140 °C. Further study of CTH process shows that metallic state of A-SCo provides important active sites for dehydrogenation of i-PrOH, which is critical step for hydrogenation of EL. This study provides a simple, efficient method to prepare an air-stable skeletal metal catalyst for CTH and hydrogenation process.

DOI： 10.1016/j.jece.2022.107188

A review of thermal catalytic and electrochemical hydrogenation approaches for converting biomass-derived compounds to high-value chemicals and fuels Reviewed

Zhang, LJ; Rao, TU; Wang, JY; Ren, DZ; Sirisommboonchai, S; Choi, C; Machida, H; Huo, ZB; Norinaga, K

FUEL PROCESSING TECHNOLOGY Vol. 226 2022.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Fuel Processing Technology

Major global issues such as greenhouse gas emissions and the excessive use of fossil fuels lead to looking for sustainable and clean energy resources. Lignocellulosic biomass is a prospective resource for sustainable carbon-based energy. The production of petroleum-based green fuels, chemicals, and solvents from biomass-derived products has garnered much attention in the recent past. The study of biomass derivatives hydrogenation improves the efficiency of generating high-value chemicals and provides much-needed insights into the primary reaction mechanism for the effective utilization of raw constituents or biomass. However, the existing thermochemical conversions of biomass and biomass-derived products such as thermal catalytic hydrogenation (TCH) involve energy-intensive and expensive processes. In this regard, sustainable energy generation attracts alternative conversion technologies, including electrochemical conversion (ECC), electrocatalytic hydrogenation (ECH), and photocatalytic conversions that can be directly integrated with renewable wind/solar technologies and operated at ambient or lower temperatures. The role of electrocatalyst and electrolyte is pivotal to achieve efficient and selective ECH of biomass organics. This review paper summarizes the utilization of TCH and ECH processes on cellulose/hemicellulose, lignin, and their derivatives/model compounds, including catalyst types, reaction conditions, hydrogenation efficiency, and technical limitations. The advantages and disadvantages of the two technologies for biomass utilization have also been compared, which provides a more favourable knowledge base and theoretical basis for the subsequent research work.

DOI： 10.1016/j.fuproc.2021.107097

Durability and fire-hazardous-risk evaluation of unique phase separation solvent using high-boiling-point amine and ether Reviewed

Maeda, N; Kishimoto, A; Machida, H; Yamaguchi, T; Yanase, K; Norinaga, K

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol. 114 2022.2

Language：English Publishing type：Research paper (scientific journal) Publisher：International Journal of Greenhouse Gas Control

Durability and fire hazard risk evaluations were conducted to determine the process feasibility of a unique phase separation solvent with a low regeneration temperature (90 °C) consisting of an amine, ether, and a small amount of water. The results are as follows. I) The amine degradation rate of the phase separation solvent was determined to be less than 1/10 of that of monoethanolamine, which was attributed to the high oxidative resistance and low regeneration temperature of the former. II) The composition of the gas that formed in the absorber was completely out of the combustible range during the treatment of 6% oxygen-containing gas on a dry basis. Therefore, we believe that this phase separation solvent is applicable to the treatment of exhaust gas from coal-fired thermal power plants and can realize stable operation with a small amount of amine required for replenishment.

DOI： 10.1016/j.ijggc.2021.103532

Fluctuation in diethylene glycol diethyl ether/water mixtures near the lower critical solution temperature studied by small- and wide-angle x-ray scattering and thermodynamic calculation Reviewed

Yanase, K; Tran, KVB; Yamaguchi, T; Machida, H; Norinaga, K

JOURNAL OF MOLECULAR LIQUIDS Vol. 346 2022.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Molecular Liquids

We studied local structure of diethylene glycol diethyl ether (DEGDEE)-water mixtures near the lower critical solution temperature (LCST) by means of simultaneous small- and wide-angle x-ray scattering measurement and thermodynamic calculation based on the activity coefficient model. Long-wavelength limits of structure factors SNN(0), SCC(0), and SNC(0), which respectively represent mean square fluctuations in the particle number, the concentration, and their cross correlation, are determined from scattering intensity extrapolated to the zero scattering vector and thermodynamic quantities according to the Bhatia and Thornton formula. SNN(0) and SCC(0) exhibit maxima near critical concentration. We found that difference between partial molar volumes of water and DEGDEE essentially results in SNN(0) values being one order of magnitude larger than SCC(0) values. Further, we determined Kirkwood-Buff (KB) integrals to clarify a mixing state of the solution from a mesoscopic point of view. The KB integrals also exhibit extrema near critical concentration. These results demonstrate self-segregations of both DEGDEE and water in a nanometer length scale even at homogeneous solution states, which can be regarded as a precursor of the macroscopic phase separation. Concentration dependence of the wide-angle scattering curve suggests that the short-range structure, whose length scale is sub-nanometer, moderately changes between the intrinsic bulk structures of DEGDEE and water. Comparison of the KB integrals with those determined by the activity coefficient model using non-random two-liquid equation is presented and effects of the fluctuation on the phase behavior are discussed.

DOI： 10.1016/j.molliq.2021.117830

Modeling the Chemical Structures of Coals with Different Classifications Using Mean Molecular Weights

Hata Yuki, Hayashizaki Hideyuki, Takanohashi Toshimasa, Takahashi Takafumi, Kanehashi Koji, Norinaga Koyo

ISIJ International Vol. 62 ( 5 ) page： 948 - 956 2022

Language：English Publishing type：Research paper (scientific journal) Publisher：The Iron and Steel Institute of Japan

<p>The chemical structure models for the extractions and residues of two types of bituminous coals, A and B, were constructed. The molecular weights of the extractions were determined via gel permeation chromatography (GPC). New standard materials with structures similar to those of coal extraction (<i>i.e.</i>, 9, 10- diphenylanthracene, 5,6,11,12-tetraphenylnaphthracene, and chemical compounds A (Mw = 811) and B (Mw = 1135), which were synthesized using the coupling reaction) were adopted for GPC in order to obtain more accurate mean molecular weights than those in literature. Furthermore, a support program for constructing chemical structure models based on <sup>1</sup>H nuclear magnetic resonance (NMR) spectra was adopted. The coal models constructed suitably indicate the differences between the types of coal. In particular, it is found that a high pyridine-insoluble fraction extracted rate, which accounts for the most significant difference between the total extracted rates for coals A and B, enhance the coking property of coal A. In addition, the cluster size in the magic solvent-insoluble fraction might affect the softening property of coal.</p>

DOI： 10.2355/isijinternational.ISIJINT-2021-459

Determination of Kinetic Parameters for CO<sub>2</sub> Methanation (Sabatier Reaction) over Ni/ZrO<sub>2</sub> at a Stoichiometric Feed-Gas Composition under Elevated Pressure Reviewed

Choi, C; Khuenpetch, A; Zhang, W; Yasuda, S; Lin, YX; Machida, H; Takano, H; Izumiya, K; Kawajiri, Y; Norinaga, K

ENERGY & FUELS Vol. 35 ( 24 ) page： 20216 - 20223 2021.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Energy and Fuels

Methanation of CO2 using H2 obtained by renewable energy sources has been gaining attention as one of the promising options for utilizing captured CO2 and surplus power obtained when intermittent power sources such as solar and wind energy are used. Herein, kinetics of CO2 methanation over Ni/ZrO2 was studied using a tubular quartz reactor at 0.9 MPa. The Sabatier reaction (CO2 + 4H2 = CH4 + 2H2O, ΔHr298K = – 165 kJ mol–1) was carried out under stoichiometric gas feeding (CO2/H2 = 1/4 v/v to CH4/H2O = 1/2 v/v), and its reaction rate was determined. The exothermic nature of CO2 methanation and extremely high catalytic activities increased the reaction temperature to 400–600 °C even when the feed-gas temperature was as low as 250–400 °C, and the gas hourly space velocity was as high as 3 × 106 h–1. Nonlinear regression analyses based on one- and multistep kinetic models were used to investigate the reaction rates to estimate the kinetic parameters. Both models with optimized parameters can reproduce the experimentally obtained CH4 formation rates for the entire range of the feed-gas conversion with a coefficient of determination (R2) of over 0.98.

DOI： 10.1021/acs.energyfuels.1c01534

An Alternative CO<sub>2</sub> Capture with a Pressure Swing Amine Process Driven by Cryogenic Pumping with the Unused Cold Energy of Liquefied Natural Gas Reviewed

Machida, H; Hashiride, R; Niinomi, R; Yanase, K; Hirayama, M; Umeda, Y; Norinaga, K

ACS SUSTAINABLE CHEMISTRY & ENGINEERING Vol. 9 ( 47 ) page： 15908 - 15914 2021.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Sustainable Chemistry and Engineering

This paper presents an alternative concept of CO2 capture that can substantially reduce the energy required for CO2 capture by utilizing unused cold energy. The heat of vaporization of liquefied natural gas (LNG), of which the boiling point is 110 K, is a possible candidate for unused cold energy. This technology is based on a pressure swing amine process combined with a sublimation tank to cool CO2 released from a desorber into dry ice by exchanging the LNG cold energy. The feature of this technology is that pure CO2 is recovered mostly by a pressure swing that decreases the pressure in the desorber utilizing a cryogenic pump with CO2 sublimation instead of a mechanical pump. We developed an amine-based absorbent that can realize the proposed process for exhaust gas from a fossil fuel-fired power plant. A process simulation indicated that the required energy is as low as 0.25 GJ/ton CO2 when both the absorber and the desorber are operated at around 313 K, the desorber pressure is reduced to 1 kPa, and the sublimation tank is operated at 150 K.

DOI： 10.1021/acssuschemeng.1c05892

The effects of nitrogen functional groups and narrow micropore sizes on CO<sub>2</sub> adsorption onto N-doped biomass-based porous carbon under different pressure Reviewed

Luo, JY; Liu, BG; Shi, R; Guo, Y; Feng, QG; Liu, Z; Li, LQ; Norinaga, K

MICROPOROUS AND MESOPOROUS MATERIALS Vol. 327 2021.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Microporous and Mesoporous Materials

The biomass-derived N-doped porous carbons have been proved promising adsorbent material, due to their good CO2/N2 selectivity and excellent CO2 adsorption performance. However, many researchers simply studied the effect of nitrogen groups or narrow micropores (less than 0.7 nm) on CO2 uptake at 1 bar and ignored the role of different pressures. In this study, a promising porous carbon derived from eucalyptus bark with high CO2 adsorption capacity was prepared by urea-assisted hydrothermal and KOH activation. The obtained porous carbons were found to be mainly microporous and showed rich nitrogen content. Among the materials, at 1 bar, NPC700 exhibits high CO2 adsorption of 4.20 mmol/g and 6.98 mmol/g at 25 °C and 0 °C, respectively. Based on Grand canonical Monte Carlo (GCMC) simulation, the adsorption density and adsorption energy on graphite slit pore with different pore sizes (0.6–2.0 nm) and N-doped functional groups (pyridinic-N, pyrrole-N and graphitic-N) were calculated. And the results showed that the nitrogen functional groups played a crucial contribution on CO2 adsorption capacity at relative low pressure (0–0.16 bar). In the case of relative high pressure (0.16–1 bar), the narrow micropores volume determined the CO2 uptake capacity.

DOI： 10.1016/j.micromeso.2021.111404

Inhibition of temperature runaway phenomenon in the Sabatier process using bed dilution structure: LBM-DEM simulation Reviewed

Lin, YX; Yang, C; Choi, C; Zhang, W; Fukumoto, K; Machida, H; Norinaga, K

AICHE JOURNAL Vol. 67 ( 10 ) 2021.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AIChE Journal

The Sabatier process is promising for carbon dioxide utilization and energy storage. However, the serious problem that limits more comprehensive industrial applications is catalyst deactivation due to the temperature runaway phenomenon. The inert particle dilution approach, including the mixing dilution method and layered dilution method is applied to solve this problem. Based on the lattice kinetic scheme-lattice Boltzmann method (LKS-LBM), the effects of three parameters in bed dilution structure reconstructed by the discrete element method (DEM) on temperature distribution and carbon conversion rate were discussed, so as to investigate the relationship between packing structure and temperature distribution. Furthermore, numerical results indicated that an optimal bed dilution structure, which not only can control the peak temperature below the critical temperature to avoid coking and sintering of catalyst, but also can improve the conversion rate by almost 18% compared with the structure without dilution under the same circumstance.

DOI： 10.1002/aic.17304

Comprehensive Compositional Analysis of Heavy Oil Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and a New Data Analysis Protocol Reviewed

Katano, K; Teratani, S; Suzuki, T; Tanaka, R; Kato, H; Norinaga, K

ENERGY & FUELS Vol. 35 ( 17 ) page： 13687 - 13699 2021.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Energy and Fuels

A sequential method that deterministically estimates the molecular composition of heavy oil is reported. A sample of vacuum residua is preseparated into seven fractions: saturated (Sa), aromatic fractions containing one, two, and three or more rings (1A, 2A, and 3A+, respectively), polar and polyaromatic (Po and PA, respectively) resins, and asphaltene (As). The analysis by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) uses one of three different ionization methods depending on the type of structure. Paraffinic species in Sa are ionized by Ag cationization and laser desorption. Aromatic species in 1A, 2A, 3A+, and Po are ionized by atmospheric pressure photoionization. Poorly volatile and condensed aromatic species in PA and As are ionized by laser desorption ionization. Collision-induced dissociation (CID) is used by the FT-ICR MS instrument to determine the structural building blocks. A new data analysis protocol developed to represent petroleum molecules named the composition and structure analyzer (CSA) requires data obtained before and after CID as inputs. The CSA provides juxtaposed attributes for chemical-structure description (JACDs). Structural information based on JACDs can be used to predict physical and chemical properties such as boiling and melting points and solubility parameters and build attribute-based reaction models, to optimize heavy oil upgrading processes.

DOI： 10.1021/acs.energyfuels.1c01429

Density and Viscosity Calculation of a Quaternary System of Amine Absorbents before and after Carbon Dioxide Absorption Reviewed

Tran, KVB; Sato, M; Yanase, K; Yamaguchi, T; Machida, H; Norinaga, K

JOURNAL OF CHEMICAL AND ENGINEERING DATA Vol. 66 ( 8 ) page： 3057 - 3071 2021.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Chemical and Engineering Data

Viscosity and density of amine absorbents affect directly their flow, which is involved in the process design and simulation of carbon dioxide capture. A mixture of 2-(ethyl amino) ethanol (EAE), diethylene glycol diethyl ether (DEGDEE), and water changes its phase from homogeneous to two-liquid ones on CO2 absorption. It is difficult to calculate the viscosity and density of this phase separation solution, especially those of quaternary-component phases. In this research, models to calculate the density and viscosity of the quaternary-component system of EAE/DEGDEE/water/carbamate were suggested based on nonrandom two-liquid (NRTL)-DVOL and NRTL-DVIS models. Given the component concentrations, these models can replicate well the viscosity and density of the solutions. A good calculation result with a few numbers of parameters makes the models simple and easy to use.

DOI： 10.1021/acs.jced.1c00195

Production of light hydrocarbons from organosolv lignin through catalytic hydrogenation and subsequent fast pyrolysis Reviewed

Zhang, LJ; Choi, C; Machida, H; Norinaga, K

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS Vol. 156 2021.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Analytical and Applied Pyrolysis

Valorization and utilization of lignin have been drawing increasing attention recently. Hydroprocess is one of the main technologies, which can reduce organic compounds and partially depolymerize the macromolecular structure of lignin. The mechanism of lignin hydroprocess has been extensively discussed focusing on hydrogenolysis. In contrast, the solid residue regarded as unreacted or depolymerized lignin has drawn less attention so far. This study proposes an integrated process that consists of catalytic hydrogenation and subsequent fast pyrolysis for valorizing lignin. The results showed that 48−87 wt.% of solid product could be recovered as hydrogenated lignin (H-EOL) after hydrogenation at 200–250 ℃ for 1−7 h. Chemical structure of H-EOL was comprehensively investigated by means of elemental analysis, FTIR, 13C & 1H NMR, and TGA. Furthermore, behavior of fast pyrolysis of H-EOL was detected here for the first time. H-EOL has higher hydrogen to carbon atomic effective ratio(H/Ceff ratio) and achieves the increasing reactivity of thermal decomposition. H-EOL yields light olefins double as much as raw ethanol organosolv lignin (EOL). And the formation of alkanes (C1-C4), benzene, and toluene was promoted to various degrees, while the yield of carbon monoxide, carbon dioxide, and vapor decreased. A novel and efficient pretreatment method has been provided to valorize lignin, which is instructive for subsequent research.

DOI： 10.1016/j.jaap.2021.105096

An Approach to Simulate Vapor Phase Reactions of Coal Volatiles in a Reducing Section of the Two Stage Entrained Flow Gasifier with a Detailed Chemical Kinetic Model

Choi Cheolyong, Adachi Nozomi, Zhang Wei, Machida Hiroshi, Hayashi Jun-ichiro, Watanabe Hiroaki, Norinaga Koyo

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN Vol. 54 ( 6 ) page： 334 - 343 2021.6

Language：English Publishing type：Research paper (scientific journal) Publisher：The Society of Chemical Engineers, Japan

<p>The present study further develops an approach in predicting reactions undergone by coal volatiles in a reducing section (reductor) of an air-blown two-stage entrained flow gasifier toward designing a better gasification process. A detailed chemical kinetic model was first applied to simulate chemical reactions of a complex molecular mixture of the coal volatiles evolved due to rapid pyrolysis of coal fed into the reductor. The composition of volatiles was determined based on pyrolysis-gas chromatography experiments, where 22 compounds including inorganic gases (H<sub>2</sub>, H<sub>2</sub>O, CO and CO<sub>2</sub>), light hydrocarbon gases (C<sub>1</sub>–C<sub>4</sub>) and aromatic hydrocarbons (benzene to pyrene) were identified. Gas composition at the reductor inlet was estimated by integrating the information on the experimentally obtained molecular composition of the volatiles, and the thermodynamically calculated composition of inorganic gases generated from the combustor and the coal feeding rates into reductor and combustor. Concentration profiles of the individual chemical species, as well as soot particles along with the flow direction of the reductor, were revealed by using an extended detailed chemical kinetic model involving 202 species, 1,351 gas-phase reactions and 101 surface reactions for soot formation and growth. The simulation highlighted that near-complete decomposition of tar (<1.5 mg/Nm<sup>3</sup>) regarded as a set of all aromatic hydrocarbons is likely to require operation temperature of the reductor at temperatures as high as 1,200°C, when the combustor is operated at 1,800°C.</p>

DOI： 10.1252/jcej.20we171

A Review on Detailed Kinetic Modeling and Computational Fluid Dynamics of Thermochemical Processes of Solid Fuels Reviewed

Choi, C; Zhang, W; Fukumoto, K; Machida, H; Norinaga, K

ENERGY & FUELS Vol. 35 ( 7 ) page： 5479 - 5494 2021.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Energy and Fuels

This review presents the recent advances in computational approaches to understand thermochemical reactions of solid fuels with minimized empirical factors. It includes studies on kinetic modeling of gas-phase reactions of multicomponent molecular mixtures of volatiles derived from primary pyrolysis of solid fuels using a database for elementary reactions. Mechanistic studies to model the devolatilization of biomass and coal upon heating are also mentioned. The efforts to integrate the kinetic model with computational fluid dynamics to understand the flow and heat transfer behavior of industrial reactors for solid fuel conversions, including gasification and combustion, are reviewed. These advances are primarily based on the conventional forward analysis that provides a deeper understanding of chemically reacting flows of fuels undergoing thermochemical reactions. For the further development of the thermochemical conversion technology, it can be expected to develop alternative approaches such as inverse analysis to determine the optimal reactor design and operating conditions.

DOI： 10.1021/acs.energyfuels.0c04052

Catalytic hydrotreatment of alkaline lignin and its consequent influences on fast pyrolysis Reviewed

Zhang, LJ; Choi, C; Machida, H; Huo, ZB; Norinaga, K

CARBON RESOURCES CONVERSION Vol. 4 page： 219 - 229 2021

Authorship：Last author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Carbon Resources Conversion

The current state of lignin has been characterized by these three: (1) as one of the main components in lignocellulosic biomass with an abundant amount; (2) not be taken seriously but treated as a waste product; (3) underutilized due to a complex and stubborn structure. However, lignin can be a rich source for hydrocarbons and aromatic compounds when gives appropriate utilization. In this work, we have studied the hydrotreatment of alkaline lignin (AL) under relatively mild conditions and further investigated the characterization of hydrogenated lignin (HL), especially the behavior during fast pyrolysis. The recovery of the HL decreased with increasing reaction temperature from 60 wt.% to 41 wt.% in the range of 150–250 ℃. The hydrotreated products were analyzed using Elemental Analysis, FTIR (for HL) and GC–MS (for bio-oil). The HL samples were found to have a higher hydrogen/carbon atomic effective ratio (H/Ceff ratio) and a higher degree of saturation than AL. Compared to the internal structure of the lignin before and after hydrotreatment, the side chain groups were removed from AL during the process. After that, from the fast pyrolysis of HL, it was observed that more light hydrocarbons and aromatic compounds were formed than that of AL. Furthermore, fast pyrolysis in the hydrogen atmosphere revealed that more volatile fractions were released compared to the Helium atmosphere. The total olefins yield was increased for HL compared AL from 1.02 wt.% to 3.1 wt.% at 250 ℃ for 7 hours. This study of HL is instructive to some extent for the industrial utilization of lignin.

DOI： 10.1016/j.crcon.2021.09.001

A comprehensive study on butanolysis of furfuryl alcohol to butyl levulinate using tungstated zirconia and sulfonated carbon catalysts Reviewed

Thuppati, UR; Choi, C; Machida, H; Norinaga, K

CARBON RESOURCES CONVERSION Vol. 4 page： 111 - 121 2021

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Carbon Resources Conversion

This work presents the formation of butyl levulinate, a potential fuel additive, and an excellent renewable chemical obtained by the butanolysis of furfuryl alcohol (FAL) over a solid acid catalyst. The butanolysis of furfuryl alcohol reaction is a strong function of acidity for which tungstated zirconia (WO3-ZrO2), a robust solid acid catalyst, and a sulfonated carbon catalyst were employed to produce high yields of butyl levulinate targeting a lower initial molar ratio of butanol to FAL. A maximum of 28 mol% yield of butyl levulinate was obtained with tungstated zirconia catalyst. Easily prepared sulfonated carbon catalyst at high reaction temperatures facilitated the complete conversion of reaction intermediate, 2-butoxymethylfuran (2-BMF) through which butyl levulinate was formed, and as high as 80 mol% of butyl levulinate yield was produced at an initial mole ratio of 8.5:1 of butanol to FAL. The better results of sulfonated carbon catalyst could be attributed to the presence of -SO3H, carboxylic acid, and phenolic OH groups on the carbon surface.

DOI： 10.1016/j.crcon.2021.03.003

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