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Hydrocracking of vacuum residue using unsupported NiWS dispersed catalyst
허영걸,김찬훈,이관영 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
In the conventional oil refinery processes, metal-supported catalysts are generally used. (e.g. NiMo/Al<sub>2</sub>O<sub>3</sub>, CoMo/Al<sub>2</sub>O<sub>3</sub>). However, when supported catalysts are applied to the hydrocracking process of extraheavy oil, several problems arise. First problem of supported catalysts is a short life time, which is caused by the deactivation by sulfur or coke deposition. Secondly, problems related to mass transfer limitations occur because large size hydrocarbon molecules are too difficult to pass through micropores or mesopores in a catalyst. In this study, to overcome the problems associated with the use of supported catalysts, we used unsupported NiWS particles as a dispersed catalyst for the hydrocracking of vacuum residue (VR). We investigated the activities of NiWS dispersed catalysts in terms of total liquid and solid product yield, C<sub>5</sub>-asphaltene conversion and API gravity of the liquid product.
Catalytic upgrading of Vacuum residue using nano-sized tungsten carbide catalyst
김찬훈,허영걸,정광식,이관영 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1
In hydrotreating process of extra-heavy oil, coke induces deactivation of catalysts and blocks pores of supports so it decreases catalytic activity. The provision of protons by hydrogenation process could suppress formation of coke. Levy and Boudart reported tungsten carbide, composed of tungsten and carbon atoms, could provide similar catalytic activity with platinum. But unlike platinum, tungsten carbide has sulfur-resistance when it is exposed to sulfur at high temperature. In recent study, small cluster of tungsten carbide has outstanding performance in hydrogen dissociative adsorption even more than platinum. In this study, nano-sized tungsten carbide catalyst was synthesized via sol-gel method and analysed via XRD and TEM. Also, nano-sized tungsten carbide catalysts were applied in vacuum residue reaction.
Unsupported molybdenum sulfide catalysts for upgrading vacuum residue
정광식,허영걸,이관영,김찬훈 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Recent world oil demand gradually increase compare to supply of light oil. Since Oil shock hit the world wide, necessity of self-sufficiency in oil brings interest of non-conventional upgrading technology in petroleum industry. Even many catalysts developed nowadays, heavy oil upgrading technologies are facing lots of problems. Typical problems are mass transfer limitation, catalyst deactivation, and loosing valid carbon by coke form. Those problems are occurred by one main reason that heavy fraction in oil dramatically increased. Asphalthene and resin are large enough to block entrance of commercial supported catalysts and that bring mass transfer limitation and deactivation. To avoid issue of texture properties of support and sustain advantages of using support,colloidal dispersed catalysts are suitable. In this study, using general petroleum catalysts sources, molybdenum and cobalt molybdenum were used as dispersed colloidal catalysts.
Trayed 기포탑 반응기에서 높이에 따른 기포입자의 거동분석
양정훈(Yang, Jung Hoon),허영걸(Hur, Young Gul),양정일(Yang, Jung-Il),김학주(Kim, Hak-Joo),천동현(Chun, Dong Hyun),김병권(Kim, Byung Kwon),이호태(Lee, Ho-Tae),정헌(Jung, Heon) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05
슬러리 기포탑 반응기는 열 및 물질 전달의 용이성, 낮은 운전비용 및 장치의 간단성의 장점을 가지고 있어서 Fischer-Tropsch 반응, bio-reaction 등에 많이 응용되고 있다. 특히, 반응물은 기체 상태로 반응기에 투입이 되는데, 이 기포입자의 상승하는 힘을 바탕으로 기상/액상/고상이 균일하게 혼합되게 된다. 많은 연구자들이 이러한 기포탑 반응기의 성능을 개선하고자, 다양한 반응기 디자인에 대하여 보고하고 있다. 특히 반응기 내부에 tray를 설치함으로써, 기포 포집율을 증진시기고 액상의 역류를 최소화시키는 연구가 활발히 진행되고 있다. 본 연구에서는, 다양한 기공크기를 갖는 tray를 활용함으로써 높이에 따른 기포 포집율의 변화 및 반응기 내에 기포 입자의 거동 특성에 대하여 살펴보았다.
Effect of hydroxyapatite-doping in Na-W-Mn/SiO2 catalysts on oxidative coupling of methane
이병진,이재환,한근호,허영걸,이관영 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.9
Sodium-tungsten-manganese supported on silica (Na-W-Mn/SiO2) and hydroxyapatite (HAp) are representative catalysts for oxidative coupling of methane (OCM). In this work, the effect of the HAp doping in a Na-WMn/ SiO2 catalysts on the OCM performance was studied. To enhance the ethylene selectivity of the Na-W-Mn/SiO2 catalyst, silica supports were coated with HAp containing hydroxyl and phosphate groups as oxygen species. A series of Na-W-Mn/xHAp_SiO2 (x=1, 3, 5 and 7) catalysts with the different HAp coating cycles were prepared through the alternative soaking method, and X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that the amount of HAp doping was dependent on the HAp coating cycles. In addition, the change of oxygen species upon HAp doping was examined with X-ray photoelectron spectroscopy (XPS) and oxygen temperature-programmed desorption (O2-TPD) techniques. With HAp doping, the increase of oxygen species assigned to metal oxide responsible for selective oxidation of methane to ethylene was observed in O 1s XPS spectra. In addition, weakly bound oxygen species were observed with the introduction of HAp doping in O2-TPD profiles of prepared catalysts. The influence of these oxygen species on OCM catalytic performance was evaluated at an operating temperature of 775 oC and gas hourly space velocity of 18,000ml/gcat∙h. The amount of HAp doping provided reactive oxygen species for oxidative dehydrogenation of ethane, which resulted in as much as 120% increase in C2H4/C2H6 ratio over the Na-W-Mn/ 3HAp_SiO2 catalyst compared to the Na-W-Mn/SiO2 catalyst.