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Affiliation |
Graduate School of Engineering Science Department of Materials Science Applied Chemistry Course |
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Date of Birth |
1995 |
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Mail Address |
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REN JIE
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Research Interests 【 display / non-display 】
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Efficient utilizing of carbonaceous resources; Carbon dioxide capture, storage and utilization
Graduating School 【 display / non-display 】
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2013.09-2017.06
Huazhong University of Science and Technology Energy and power engineering Graduated
Graduate School 【 display / non-display 】
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2020.04-2023.03
Kyoto University Graduate School,Division of Engineering Doctor's Degree Program Completed
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2018.04-2020.03
Kyoto University Graduate School,Division of Engineering Master's Degree Program Completed
Campus Career 【 display / non-display 】
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2023.04-Now
Akita University Graduate School of Engineering Science Department of Materials Science Applied Chemistry Course Assistant Professor
Research Areas 【 display / non-display 】
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Energy Engineering / Earth resource engineering, Energy sciences
Thesis for a degree 【 display / non-display 】
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Development of depolymerization methods of carbonaceous resources utilizing reduction reactions by formic acid
Ren Jie
2023.03
Single author
Research Achievements 【 display / non-display 】
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Jie Ren, Tomoka Fujita , Hirokazu Okawa , Takahiro Kato
Japanese Journal of Applied Physics ( IOPscience ) 63 ( 03SP47 ) 1 - 8 2024.02 [Refereed]
Research paper (journal) Single author
Ultrasound can effectively desorb CO2 from dissolved CO2 gas [CO2 (aq)] in solution at low temperatures. In this study, three various classes (primary, secondary, and tertiary) of amine solutions were used as a CO2 absorbent for loading CO2 under 0.1 MPa and 0.5 MPa. The effectiveness of ultrasound irradiation and stirring to desorb CO2 from CO2-loaded amine solution was evaluated at around 25 oC. The ultrasound had better desorption results than stirring for all three amines. Among the three classes of amine, tertiary amine triethanolamine (TEA) with low pKa achieved the highest CO2 desorption ratio of 43.2 % and 61.8 % after CO2 loaded under 0.1 and 0.5 MPa by ultrasound. It was considered that amine with low pKa and strong sterically hindered structure can promote the balance of the rate-determining reaction of H+ transferred from amine cation to HCO3- and form CO2 (aq) after initial CO2 (aq) was desorbed by ultrasound.
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Development of a Novel Mild Depolymerization Method of Coal by Combining Oxygen Oxidation and Formic Acid Reduction Reactions
Jie Ren, Ryuichi Ashida, Motoaki Kawase, Koji Sakai, and Noriyuki Okuyama
ACS OMEGA ( American Chemical Society ) ８ 2531 - 2537 2023.01 [Refereed]
Research paper (journal) Domestic Co-author
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1-05 Preparation of humic acid by hydrothermal treatment of biomass
MIURA Shintaro, KATO Takahiro, IWAO Yuya, YOKOTA Saki, REN Jie, OKAWA Hirokazu, SUGAWARA Katsuyasu
Proceedings of Conference on Coal Science ( The Japan Institute of Energy ) 61 ( 0 ) 10 - 11 2024.10
◆Original paper【 display / non-display 】
◆Other【 display / non-display 】
Presentations 【 display / non-display 】
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CO2 desorption using ultrasound at low temperature from CO2-loaded amine solution under pressure conditions
Jie Ren, Tomoka Fujita, Hirokazu Okawa* and Takahiro Kato
The 44 Symposium on Ultrasonic Electronics (Toyama International Conference Center) 2023.11 - 2023.11 USE 2023 Organizing Committee Insitute for Ultrasonic Electronics
As the main greenhouse gas, carbon dioxide (CO2) in the atmosphere would rise the global temperature, causing extreme weather and disasters. To reduce the concentration of atmospheric CO2 and achieve the “carbon-neutral” goal, CCS (carbon dioxide capture and storage) technology which could recover pure CO2 selectively from the exhaust gas of power plants and store it underground was gathering more attention. The chemical absorption method using amine solution as CO2 absorbent is mainly applied for CO2 recovery from exhaust gas in CCS process for low cost. Conventional chemical absorption method chose monoethanolamine (MEA) as the absorbent 1). Reaction formulas of CO2 absorption in MEA solution are shown below:
2RNH2 + CO2 → RNH3+ + RNHCOO- (1)
RNH2 + CO2 +H2O → RNH3+ + HCO3- (2)
(R: C2H5O, RNH2: MEA)
CO2 is absorbed as both carbamate ion (RNHCOO-) and bicarbonate ion (HCO3-). The CO2 absorption rate and capacity are high for MEA, however, high temperature (> 110 oC) is necessary for desorbing the absorbed CO2 from 4.9 M of MEA solution 2), which resulted in approximately 70-80 % of the operating cost for a CCS process 3), and more CO2 generation for producing the extra heat energy. Therefore, a new method that could desorb CO2 from CO2-absorbed amine solution at low temperature must be developed.
In this research, desorbing CO2 from CO2-absorbed amine solution by ultrasound at low temperature (20-25 oC) was studied. Ultrasound can desorb CO2 (aq) as CO2 (g) from amine solution from our previous studies4). Thus, increasing the CO2 (aq) state in CO2-absorbed amine solution can enhance the CO2 desorption efficiency of ultrasound. The equilibrium equation of CO2 in solution is shown below:
HCO3- + H+→ H2CO3 → CO2 (aq) + H2O (3)
HCO3- can transform to CO2 (aq) easily by changing the solution pH, and when pH < 8.2, CO2 (aq) would be the main species of CO2 in solution 5). Thus, increasing the bicarbonate ion concentration and reducing the solution pH was effective for increasing CO2 (aq) in solution, and then CO2 (g) can be desorbed continuously under ultrasound.
Tertiary amine, which only forms bicarbonate ion during CO2 absorption, was chosen as the candidate sorbent in this research. The CO2 absorption reaction formula of tertiary amine is shown below:
R1R2R3N + CO2 +H2O → R1R2R3NH+ + HCO3- (4)
To decrease solution pH for increasing the state of CO2 (aq) after CO2 absorption, a tertiary amine, triethanolamine (TEA), which has low pKa (7.85) was chosen. Moreover, CO2 absorption under CO2 pressure conditions of 0.1 and 0.5 MPa was applied to increase the CO2 absorption amount to reduce the solution pH after absorption. And then, the CO2 desorption ability of both MEA and TEA solution under low temperatures by ultrasound or stirring was evaluated and compared. To decide the best conditions for ultrasound CO2 desorption, the relationships between ultrasound output power and CO2 desorption amount were investigated. The desorption results were investigated when reached ultrasound power was 17 W in amine solution measured by calorimetric method here, and more detailed information will be shown in the presentation. -
Development of a method for reducing the molecular weight of coal under mild conditions using formic acid
Ren Jie, Ryuichi Ashida, Motoaki Kawase, Koji Sakai, Noriyuki Okuyama
MMIJ Fall Meeting 2023, Matsuyama (Ehime University Johoku Campus) 2023.09 - 2023.09 General Social Corporation: The Mining and Materials Processing Institute of Japan
Since high-grade coal (bituminous coal), which is a raw material for carbon materials such as coke, is expected to be depleted, it is desirable to make effective use of low-grade coal (sub-bituminous coal and lignite) with abundant recoverable reserves in the future. On the other hand, low-grade coal cannot be used as a raw material for carbon materials because it has poor low molecular weight components and almost no thermal softening meltability. In order to effectively use coal not only as a fuel but also as a raw material for high value-added carbon materials, the key is to reduce the molecular weight of coal. Since the cost of energy and equipment is enormous due to the adoption of harsh conditions such as high temperature and high pressure in the conventional coal small molecule method, it is desirable to develop a method for reducing the molecular weight of coal under mild conditions.
In this study, we proposed for the first time a low-molecularization method for coal using formic acid (HCOOH), which provides hydrogen radicals to coal even under mild conditions, and demonstrated its effectiveness. By stabilizing the original radicals of coal under the conditions of 60 °C-,1 atm and preventing polymerization by the crosslinking reaction of the radicals during heat treatment, both the thermal softening melting of the coal and the strength of the produced coke were increased. In addition, the low molecular weight component of coal was successfully increased to 29 wt.% by a treatment method that combined the breaking of chemical bonds of coal molecules by air oxidation reaction and the stabilization of coal radicals with formic acid under the condition of 90 °C-,1 atm. -
Depolymerization of Coal Under Mild Conditions Via Redox Reactions by Oxygen and Formic Acid
Jie Ren, Ryuichi Ashida, Motoaki Kawase, Koji Sakai, Noriyuki Okuyama
Pittsburgh Coal Conference 2022 (Online) 2022.09 - 2022.09 University of Pittsburgh