Myoung Jae Choi

Catalytic reforming of methane with carbon dioxide over pentasil zeolite-supported nickel catalyst

The reforming of methane with carbon dioxide was investigated over pentasil zeolite-supported nickel catalysts. These were prepared by solid-state reaction and exhibited high activity and stability for getting syngas having its ratio of unity. Moltening of nickel precursor together with potassium and calcium nitrates could enable the interaction with the aluminum and silicon species in pentasil-type zeolite having an alumina binder via solid-state reaction. This zeolite-supported catalyst has superior activity and stability in the CO 2 reforming of methane.

Characteristics of Carbon Dioxide Hydrogenation in a Fluidized Bed Reactor

Characteristics of CO2 hydrogenation were investigated in a fluidized bed reactor (0.052 m IDxl.5 m in height). Coprecipitated Fe-Cu-K-Al catalyst (dρ=75–90 Μm) was used as a fluidized solid phase. It was found that the CO2 conversion decreases but the CO selectivity increases, whereas the space-time-yield attains maximum values with increasing gas velocity. The CO2 conversion has increased, but CO selectivity has decreased with increasing hydrogenation temperature, pressure or H2/CO2 ratio in the fluidized bed reactor. Also, the CO, conversion and olefin selectivity appeared to be higher in the fluidized bed reactor than those of the fixed bed reactor.

Catalytic and thermal degradation of Korean food sludge

Korean food waste sludge was degraded by using a new thermal degradation method. In this system, radish contained waste food sludge as main portion was selected as a standard material. Products of thermal degradation were mainly composed of carbonized solid, small amounts of oil and methane. Total energy production was dependent on the reaction temperature. About 25–32% of solid in the radish was converted to carbonized solid in the thermal degradation of radish at 200°C. The heating values of the carbonized solid and the liquefied heavy oil were 4000–6000 cal/g and about 8000 cal/g respectively. Various catalysts were also examined to improve the carbonized solid used as energy source. Acid clay and MontmorilloniteKSF catalysts showed the best results among the catalysts tested. From the energy balance, this thermal degradation process operated at 200°C was a net energy producer.

Hydrodenitrogenation reaction of quinoline with nascent hydrogen generated from water gas shift reaction

The HDN of quinoline was investigated for the purpose of utilizing the hydrogen which could be generated from the water gas shift reaction (WGSR). The optimum concentration of hydrogen were produced under 1.5 of water to carbon monoxide mole ratio and 6 hr-1 of space velocity at 390°C of temperature during WGSR over Co-Mo/γ-Al2O3 catalyst. The HDN reactions were compared by using the pure hydrogen and the nascent hydrogen which was produced by a WGSR. The pure hydrogen gave much higher activity in the overall HDN reaction than the nascent hydrogen. However, kinetic study on the hydrogenation, hydrogenolysis and cracking reaction steps showed that only at the cracking reaction step the nascent hydrogen gave the superiority to the pure hydrogen. This inferiority of the nascent hydrogen in overall HDN reaction could be resulted from the negative effect of water which should be accompanied during WGSR. The conversion of the HDN reaction was maximized at the water pressure of 150 kpa.

Kinetic study on the hydrodesulfurization reaction of thiophene by water gas shift reaction

The in-situ hydrodesulfurization (HDS) reaction of thiophene was performed by using hydrogen which was generated by a water gas shift reaction (WGSR) in a same catalyst bed. The catalyst used was commercial CoMo/γ-Al2O3 and it was used after presulfiding. The activity in the conversion of thiophene by using hydrogen generated in-situ from a WGSR was inferior to that by the pure hydrogen. The lower efficiency in the in-situ HDS with WGSR was attributed to water, carbon monoxide and carbon dioxide which were mixed after WGSR. The following rate equation, which was revised from that of Satterfield, was proposed for this in-situ HDS reaction of thiophene with WGSR to explain the observed phenomena.