Seong Uk Jeong

Tar-formation kinetics and adsorption characteristics of pyrolyzed waste lubricating oil

Abstract Pyrolysis is now considered an appropriate technology in dealing with waste problems, such as waste plastics and lubricating oil. An important advantage of pyrolysis is that it produces less air and water pollution. However, pyrolyzed oil includes enough excess unsaturated hydrocarbons to form tar, which can cause the nozzle of engines to plug when pyrolyzed oil is used as fuel. In this study, pyrolysis of waste lubricating oil was carried out to obtain pyrolyzed oil. Then, the formation kinetics and adsorption characteristics of tar have been studied experimentally. A power-law kinetic model was assumed for the mechanism of tar formation. The fastest formation time of tar was 5 days after pyrolysis of waste lubricating oil. An adsorption isotherm experiment was done to select the best adsorbents for 5 days. Activated carbon was proven to have prominent adsorption capability among the other adsorbents that were mainly composed of carbon. The experiment of tar adsorption using activated carbon showed that activated carbon improved the optical intensity of pyrolyzed oil and decreased oxygen compounds in the pyrolyzed oil. The experimental results of elemental analysis supported improvement of pyrolyzed oil quality.

Hydrogen Storage and Release Properties for Compacted Ti-Mn Alloy

Received 12 January, 2017 Revised 23 February, 2017 Accepted 28 February, 2017 Abstract >> Hydrogen forms metal hydrides with some metals and alloys leading to solid-state storage under moderate temperature and pressure that gives them the safety advantage over the gas and liquid storage methods. However, it has disadvantages of slow hydrogen adsorption-desorption time and low thermal conductivity. To improve characteristics of metal hydrides, it is important that activation and thermal conductivity of metal hydrides are improved. In this study, we have been investigated hydrogen storage properties of Hydralloy C among Ti-Mn alloys. Also, the characteristics of activation and thermal conductivity of Hydralloy C were enhanced to improve kinetics of hydrogen adsorption-desorption. As physical activation method, PHEM (planetary high energy mill) was performed in Ar or H2 atmosphere. Hydralloy C was also activated by TiCl3 catalyst. To improve thermal conductivity, various types of ENG (expanded natural graphite) were used. The prepared samples were compacted at pressure of 500 bar. As a result, the activation properties of H2 PHEM treated Hydralloy C was better than the other activation methods. Also, the amounts of hydrogen storage showed up to 1.6 wt%. When flake type ENG was added to Hydralloy C, thermal conductivity and hydrogen storage properties were improved.