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활성탄 담지 몰리브덴 촉매를 이용한 합성가스 직접 메탄화 반응
김성수,이승재,박성열,김진걸 한국수소및신에너지학회 2020 한국수소 및 신에너지학회논문집 Vol.31 No.5
The kinetics of direct methanation over activated charcoal-supported molybdenum catalyst at 30 bar was studied in a cylindrical fixed-bed reactor. When the temperature was not higher than 400℃, the CO conversion increased with increasing temperature according to the Arrhenius law of reaction kinetics. While XRD and Raman analysis showed that Mo was present as Mo oxides after reduction or methanation, TEM and XPS analysis showed that Mo2C was formed after methanation depending on the loading of Mo precursor. When the temperature was as high as 500℃, the CO conversion was dependent not only on the Arrhenius law but also on the catalyzed reaction by nanoparticles, which came off from the reactor and thermocouple by metal dusting. These nanoparticles were made of Ni, Fe, Cr and alloy, and attributed to the formation of carbon deposit on the wall of the reactor and on the surface of the thermocouple. The carbon deposit consisted of amorphous and disordered carbon filaments.
반응기촉매 교체작업시 최적 환기조건에 대한 수치해석적 연구
윤장근,임용순,신미수 한국산업보건학회 2018 한국산업보건학회지 Vol.28 No.2
Objectives: The purpose of this case study is to assess the current airflow and find the ideal ventilation conditions in tank reactors for minimizing the possibility of exposure respiratory dusts(size of 2.5 ㎛, 10 ㎛) when workers exchange catalysts in the tank reactors. Methods: A Numerical study was performed to determine ideal ventilation conditions, We considered two sizes of airborne respiratory particles(2.5 ㎛, 10 ㎛) at 12points from the bottom of tank reactor. We changed input & output ventilation conditions and analyzed the particle motion in the tank reactor. The star-ccm+, computational fluid dynamics tool was used to predict air & particle flow patterns in the tank reactor and a numerical simulation was achieved by applying the realized κ-ε turbulence model and the Lagrangian particle tracking method. Results: From the results, the increase of recirculation air had a significant impact on removing dusts because they are removed by HEPA filter. To the contrary, Increasing the clean air quantity or changing the input position of clean air is not good for workers because it causes the exit of respiratory dusts through workers’ entrance or cause it to remail suspended in the air in the workplace tank.