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The optimal operating conditions for a fluidized-bed reactor (FBR) capable of simultaneous and continuous production of both hydrogen and carbon materials via direct decomposition of methane, employing a transition-metal-based catalyst, were determined. The nickel-based catalyst was synthesized via the sol–gel method and the catalyst particles, classified as Geldart group B, were used in the FBR. As the first step, the optimal reaction temperature and flow rate for the catalysis were determined by using a lab-scale FBR with an internal diameter of 28 mm. Using the data obtained in the lab-scale FBR experiments, the appropriate operating conditions were established for a bench-scale FBR with an internal diameter of 76.2 mm. The system was operated in a continuous manner, in which hydrogen and solid carbon with catalyst particles were simultaneously and continuously discharged and the catalyst was periodically fed into the reactor. Approximately 5 h stable operation and performance were confirmed at an average temperature of 710 °C and a pressure of 2 bar in the fluidized bed. The maximum carbon production rate observed was 5 kg/day, and the hydrogen production rate was 1.66 kg/day with the bench-scale reactor. The quality of the carbon products, in the form of multiwalled carbon nanotubes, was characterized and evaluated using transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy.

The carbon anode material for lithium-ion battery was prepared by pyrolysis fuel oil and waste polyethylene terephthalate (PET) additive. The pitch was synthesized as a medium material for carbon anode by heat treatment. The waste PET additive improved the softening point and thermal stability of the pitch. Laand Lcof the anode material (heat-treated pitch) increased at higher treatment temperature but decreased by waste PET additive. The electric capacity was evaluated based on effects of defective cavity and developed graphite interlayer, respectively. When the Laand Lcof the anode material decreased, the electric capacity by cavity increased based on defective graphite structure. Therefore, the addition of waste PET causes the improved capacity by the cavity. The anode material which has a high efficiency (over 95%) and C-rate (95%, 2 C/0.1 C) was obtained by controlling the process of heat treatment and PET addition. The mechanism of lithium-ion insertion was discussed based on effects of defective cavity and developed graphite interlayer.

Fly ash consists of various metal oxides which can remove SO2gas by the catalyst effect. When fly ash is added in the preparation process of pitch-based activated carbon, the pitch particles aggregate and fly ash is embedded in the activated carbon. To increase SO2gas removal performance, activated carbon was prepared by surface-treated fly ash and petroleum-based pitch. Carboxyl groups were introduced into the fly ash by malic acid treatment. The introduced carboxyl groups acted as an activation agent to create micropore around the fly ash, and created micropores were exposed to the fly ash outside of the activated carbon. The exposed fly ash increased removal amount of SO2gas by a catalytic effect of the metal oxides. The SO2gas removal performance improved by 34% because of the catalyst effect of the exposed fly ash and improvement in the micropore structure in the activated carbon.

In the present study, carbon molded bodies were prepared by using graphite/coke fillers and petroleum-based binder pitch with various softening points, and the thermal properties of the prepared carbon molded bodies were investigated. The ratio of a binder affects the molded body preparation: no molded body was prepared at a low binder pitch content, and swelling occurred during the thermal treatment at a high binder pitch content. The binder pitch thermal treatment yield was the highest at 41 wt% at the softening point of 150 °C and the lowest at 23 wt% at the softening point of 78 °C. A significant mass reduction was found in the range of 150 to 300 °C in the petroleum-based binder pitch, and in the range of 300 to 475 °C in the coal-based binder pitch. The molecular weight of the binder pitch was analyzed through the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) method. The molecular weight ratio within the interval showing the highest binder pitch molecular weight (178 to 712 m/z) was the highest at 66.4% in the coal-based binder pitch (softening point 115 °C) and the lowest at 46.0% in the petroleum-based binder pitch (softening point 116 °C). When the petroleum-based binder pitch was applied, as the softening point was increased, the voids decreased and thus the thermal conductivity increased. The highest thermal conductivity was 99.5 W/mK for the carbon molded bodies prepared using the coal-based binder pitch and 102.8 W/mK for those prepared by using the petroleum-based binder pitch. The results showed that the thermal properties were similar between the coal-based binder pitch (softening point 115 °C) and the petroleum-based binder pitch (softening point 150 °C).