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Study of micro-plastics separation from sea water with electro-magnetic force
Naoki Nomura,Fumihito Mishima,Shigehiro Nishijima 한국초전도저온공학회 2021 초전도와 저온공학 Vol.23 No.3
The method of removing micro-plastics from sea water has been developed using electro-magnetic force. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. The Lorentz force was generated in simulated sea water and its reaction force was applied to the micro-plastic to control their motion. Lorentz force was generated downward and the reaction force to the plastics was upward. The plastic used in the experiment was polystyrene with a diameter of 6 mm, and the density was 1.07 g/cm3. The polystyrene sphere levitated at the current density of 0.83 A/cm2 and the external field of 0.87T. The particle trajectory calculation was also made to design separation system using superconducting magnet.
Study of micro-plastics separation from sea water with electro-magnetic force
Nomura, Naoki,Mishima, Fumihito,Nishijima, Shigehiro The Korean Society of Superconductivity and Cryoge 2021 한국초전도저온공학회논문지 Vol.23 No.3
The method of removing micro-plastics from sea water has been developed using electro-magnetic force. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. The Lorentz force was generated in simulated sea water and its reaction force was applied to the micro-plastic to control their motion. Lorentz force was generated downward and the reaction force to the plastics was upward. The plastic used in the experiment was polystyrene with a diameter of 6 mm, and the density was 1.07 g/cm<sup>3</sup>. The polystyrene sphere levitated at the current density of 0.83 A/cm<sup>2</sup> and the external field of 0.87T. The particle trajectory calculation was also made to design separation system using superconducting magnet.
Research and development of new magnetic filter for high gradient magnetic separation
Shigehiro Nishijima,Naoki Nomura,Fumihito Mishima 한국초전도저온학회 2023 한국초전도저온공학회논문지 Vol.25 No.3
We have been developing a new magnetic filter so that small sized paramagnetic substances can be separated even in a low magnetic field (lower than 2T). The developed filter is a packed ferromagnetic filament with a triangular cross section. The filament has a diameter of 120 μm and a length of 3 mm, and is mechanically packed with a volume ratio of 17.6%. Using this filter, a magnetic separation experiment of hematite was carried out using a superconducting magnet at the field of 2T. Similarly, magnetic separation was performed using a conventional magnetic filter. It became clear that the separation efficiency of newly developed filter is high as that of conventional mesh filter. The smaller sized hematite (<3μm) could be separated though conventional mesh filter could not separate.
Development of volume reduction method of cesium contaminated soil with magnetic separation
Yukumatsu, Kazuki,Nomura, Naoki,Mishima, Fumihito,Akiyama, Yoko,Nishijima, Shigehiro The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.1
In this study, we developed a new volume reduction technique for cesium contaminated soil by magnetic separation. Cs in soil is mainly adsorbed on clay which is the smallest particle constituent in the soil, especially on paramagnetic 2:1 type clay minerals which strongly adsorb and fix Cs. Thus selective separation of 2:1 type clay with a superconducting magnet could enable to reduce the volume of Cs contaminated soil. The 2:1 type clay particles exist in various particle sizes in the soil, which leads that magnetic force and Cs adsorption quantity depend on their particle size. Accordingly, we examined magnetic separation conditions for efficient separation of 2:1 type clay considering their particle size distribution. First, the separation rate of 2:1 type clay for each particle size was calculated by particle trajectory simulation, because magnetic separation rate largely depends on the objective size. According to the calculation, 73 and 89 % of 2:1 type clay could be separated at 2 and 7 T, respectively. Moreover we calculated dose reduction rate on the basis of the result of particle trajectory simulation. It was indicated that 17 and 51 % of dose reduction would be possible at 2 and 7 T, respectively. The difference of dose reduction rate at 2 T and 7 T was found to be separated a fine particle. It was shown that magnetic separation considering particle size distribution would contribute to the volume reduction of contaminated soil.
Shibatani, Saori,Nakanishi, Motohiro,Mizuno, Nobumi,Mishima, Fumihito,Akiyama, Yoko,Okada, Hidehiko,Hirota, Noriyuki,Matsuura, Hideki,Maeda, Tatsumi,Shigemoto, Naoya,Nishijima, Shigehiro The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.1
A Superconducting High Gradient Magnetic Separation (HGMS) system is proposed for treatment of feed-water in thermal power plant [1]. This is a method to remove the iron scale from feed-water utilizing magnetic force. One of the issues for practical use of HGMS system is to extend continuous operation period. In this study, we designed the magnetic filters by particle trajectory simulation and HGMS experiments in order to solve this problem. As a result, the quantity of magnetite captured by each filter was equalized and filter blockage was prevented. A design method of the magnetic filter was proposed which is suitable for the long-term continuous scale removal in the feed-water system of the thermal power plant.
Yamamoto, Junya,Mori, Tatsuya,Hiramatsu, Mami,Akiyama, Yoko,Okada, Hidehiko,Hirota, Noriyuki,Matsuura, Hideki,Namba, Seitoku,Sekine, Tomokazu,Mishima, Fumihito,Nishijim, Sigehiro The Korea Institute of Applied Superconductivity a 2018 한국초전도저온공학회논문지 Vol.20 No.2
Removal of iron oxide scale from feed-water in thermal power plant can improve power generation efficiency. We have proposed a novel scale removal system utilizing High Gradient Magnetic Separation (HGMS). This system can be applied to high temperature and pressure area. We have conducted the lab-scale model experiments using ${\varphi}50mm$ filters and it demonstrated high removal efficiency in HGMS, but scale-up of the system is required toward practical use. In this study, we conducted a large scale mock-up HGMS experiment. We used the superconducting solenoidal magnet with ${\varphi}400mm$ bore and demonstrated that our HGMS system can achieve sufficient scale removal capacity that is required to introduce into both off-line and on-line system.
Junya Yamamoto,Tatsuya Mori,Mami Hiramatsu,Yoko AKIYAMA,Hidehiko Okada,Noriyuki Hirota,Hideki Matsuura,Seitoku Namba,Tomokazu Sekine,Fumihito Mishima,Sigehiro Nishijima 한국초전도.저온공학회 2018 한국초전도저온공학회논문지 Vol.20 No.2
Removal of iron oxide scale from feed-water in thermal power plant can improve power generation efficiency. We have proposed a novel scale removal system utilizing High Gradient Magnetic Separation (HGMS). This system can be applied to high temperature and pressure area. We have conducted the lab-scale model experiments using φ50 mm filters and it demonstrated high removal efficiency in HGMS, but scale-up of the system is required toward practical use. In this study, we conducted a large scale mock-up HGMS experiment. We used the superconducting solenoidal magnet with φ400 mm bore and demonstrated that our HGMS system can achieve sufficient scale removal capacity that is required to introduce into both off-line and on-line system.
Yoko Akiyama,Suqin Li,Koshiro Akiyama,Tatsuya Mori,Hidehiko Okada,Noriyuki Hirota,Tsuyoshi Yamaji,Hideki Matsuura,Seitoku Namba,Tomokazu Sekine,Fumihito Mishima,Shigehiro Nishijima 한국초전도저온공학회 2021 초전도와 저온공학 Vol.23 No.3
The reduction of carbon dioxide emissions becomes a global issue, the main source of carbon dioxide emissions in the Asian region is the energy conversion sector, especially coal-fired power plants. We are working to develop technologies that will at least limit the increase in carbon dioxide emissions from the thermal power plants as one way to reduce carbon dioxide emissions. Our research aims to reduce carbon dioxide emissions by removing iron oxide scale from the feedwater system of thermal power plants using a superconducting high-gradient magnetic separation (HGMS) system, thereby reducing the loss of power generation efficiency. In this paper, the background of thermal power plants in Asia is outlined, followed by a case study of the introduction of a chemical cleaning line at an actual thermal power plant in Japan, and the possibility of introducing it into the thermal power plants in China based on the results.