• 한국대기환경학회지
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• 제29권5호
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• pp.634-641
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• 2013

Condensing species behaviour downstream of a combustor was discussed with particle size distribution in this study. The effects of operating conditions in a biomass combustion facility, i.e. concentration of condensing species, temperature gradient, residence time and injection of adsorbents, on particle size distribution were investigated. Pyroligneous liquid which was completely vaporized at the temperature higher than $350^{\circ}C$ was used as a representative of condensing gaseous species. We found that particle size downstream of a combustor increased with increasing heating temperature (i.e. concentration of condensing species) and residence time. However, temperature gradient was not an important factor to control the particle size. The addition of $SiO_2$ precursor as an adsorbent could effectively prevent the particle formation by adsorbing condensing gaseous species on $SiO_2$ particles, and increased the particle size up to 300 nm, resulting in increasing particle removal efficiency in a conventional air pollution control device.

• 대한환경공학회지
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• 제37권5호
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• pp.285-292
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• 2015

본 연구에서는 바이오매스의 탄화공정 시 발생되는 목초액을 응축성 가스물질의 전구물질로 이용하여 발생되는 응축성 가스상 오염물질을 제거하기 위하여 액체상 흡착제중 실리카 전구물질인 HMDS의 주입조건에 따른 응축성물질의 입경분포 변화특성을 명확히 파악하고자 하였다. 응축성 가스상 물질을 입자화시켜 제거하기 위하여 액체상 흡착제인 HMDS를 이용할 경우, 흡착제의 주입량, 체류시간 및 가열온도, MFC 유량 등의 적절한 조절로써 입자화 크기를 조절할 수 있었다. 특히 실리카 전구물질을 도입시 끓는점, 밀도(비중), 분자량 등의 물리화학적 특성을 고려하면, 발생되는 응축성 물질을 효과적으로 입자화시켜 제어 가능할 것으로 판단된다.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.611-623
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• 2024

The ISP-47 TOSQAN experiment was analyzed with containmentFOAM which is an open-source CFD code based on OpenFOAM. The containment phenomena taking place during the experiment are gas mixing, stratification and wall condensation in a mixture composed of steam and non-condensable gas. The k-ω SST turbulence model was adopted with buoyancy turbulence models. The wall condensation model used is based on the diffusion layer approach. We have simulated the full TOSQAN experiment which had a duration 20000 s. Sensitivity studies were conducted for the buoyancy turbulence models with SGDH and GGDH and there were not significant differences. All the main features of the experiments namely pressure history, temperature, velocity and gas species evolution were well predicted by containemntFOAM. The simulation results confirmed the formation of two large flow stream circulations and a mixing zone resulting by the combined effects of the condensation flow and natural convection flow. It was found that the natural convection in lower region of the vessel devotes to maintain two large circulations and to be varied the height of the mixing zone as result of sensitivity analysis of non-condensing wall temperature. The computational results obtained with the 2D mesh grid approach were comparable to the experimental results.