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Development of Steam Plasma-Enhanced Coal Gasifier and Future Plan for Poly-Generation
Yongcheol Hong,Taihyeop Lho,Bongju Lee,Hansup Uhm 한국표면공학회 2009 한국표면공학회지 Vol.42 No.3
A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 ㎓ and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and r ight now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.
Effect of oxygen negative ions on electron energy distribution function
Park I. S.,Lho Taihyeop,Kang I. J.,Lee S. H.,Chung K.-S. 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.8
To study the effect of negative ions on the electron energy distribution function (EEDF) of plasma, the electron energies of pure argon and mixed gas (Ar + O2) plasmas were compared based on their EEDFs. An electric probe was used to measure EEDFs together with other plasma parameters such as electron temperature (Te), electron density (ne), ion density (ni ), negative ion density (N−), plasma potential (Φp), and floating potential (Φf). Negative ion plasma was generated by the discharge of Ar and O2 gas in a cubical chamber (24×24×24 cm3 ) with a direct-current (DC) hot-filament source under the following conditions: working pressure of~2× 10−4 Torr, bias voltage (Vb) of~90 V, ni in the range of 109 –1010 cm−3, and Te in the range of 1–2 eV. Both the EEDF and the Te values decreased, and the ne/ni decreased to O2 fow, while the N−/ni ratio showed an opposite tendency. Considering the thermal properties of the Ar+ O2 mixed plasma, the relation between electron temperature, plasma, and floating potential due to the negative ions, α( = e | | | Φp − Φf | | | / KBTe ) , did not remain constant; it slowly increased up to 2 sccm and then rapidly increased from 2 to 5 sccm.
Kang In Je,Bae Min-Keun,박인선,Woo Hyun-Jong,Lho Taihyeop,Ahn Jeong-Sun,Chang Doo-Hee,조순국,Choi Geun-Sik,Choi Heung-Gyun,Choi Yong-Sup,Chung Bo-Hyun,Chung Tae Hun,Do Jeong-Joon,Goo Bon-Cheol,Hong Sunghoon 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.8
Because a fusion edge plasma contains various atomic and molecular processes, along with various plasma–material interactions (PMIs) for post-mortem analyses, a linear plasma device can simulate divertor and scrape-off layer (SOL) plasmas with DC edge relevant parameters, although it cannot generate a high ion temperature and toroidicity with much less power density compared to toroidal devices. The Divertor Plasma Simulator-2 (DiPS-2), a linear device with an LaB6 DC cathode, has been used for a few fusion-relevant physics experiments, including edge localized mode (ELM) simulation and edge transport of diffusion and convection. An ELM simulation has been performed by modulating the magnetic field relevant to the pressure modulation of a toroidal device, and the diffusion coefficients of free and bound presheaths have been measured in simulations of divertor or limiter transport. Moreover, the convection of the filament or the bubble expansion to the first wall has also been analyzed. In addition to various atomic and molecular processes in SOL and divertor plasmas, PMIs must be analyzed both on and beneath the surface of the plasma-facing components (PFCs) because of surface modification. Using DiPS-2 and other linear devices along with Korea Superconducting Tokamak Advanced Research (KSTAR), PMIs have been analyzed in terms of the following elements or processes: (1) boronizations, both for dust interactions with the surface chamber (DiSC) and KSTAR device, are analyzed; (2) carbon damage by the dense heat flux of DiPS-2 is experimentally investigated; (3) the density profile of the lithium injection gettering of hydrogen and its transport experiments (LIGHT-1) device is analytically calculated; (4) the effect of nitrogen on the relaxation of the heat flux to the divertor tile is experimentally analyzed; and (5) tungsten as the divertor tile material is analyzed via laser ELM simulations in terms of dust generation and surface modification.
Hyun-Jong Woo,Kyu-Sun Chung,Roger McWilliams,Taihyeop Lho 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.II
Accurate measurements of the ion velocity distribution function (IVDF), the ion temperature, and the ion drift velocity by laser-induced fluorescence (LIF) are only possible if the accurate laser wavelength during the wavelength scan is known, yet an absolute calibration is not easily achievable because of the non-linear characteristics of the piezo-electric actuator in a diode laser, the small mode-hop free tuning region, and uncertainty of the wavemeter. The LIF system for the Diversified Plasma Simulator (DiPS), which is a simulator for the divertor and space plasmas, is calibrated both by absolute calibration of the wavemeter and by launching diode lasers in opposite directions. In addition, the first result on the measurement of the ion temperature and the flow velocity is given.