Yasuhiko Urabe

Natural gas storage in activated carbon pellets without a binder

Abstract Activated carbon pellets without a binder from cellulose microcrystals as a raw material were investigated. After compression of the raw materials, the thus obtained raw material pellets were slowly carbonized to 1073 K under nitrogen. To activate them, the carbon pellets were heated to 1173 K under carbon dioxide. The activated carbon pellet shape, after heat treatment, was columnar by using the previous employed compression of the raw material. The total surface area, pore volume, and average pore diameter for all the samples were evaluated from the analysis of N2 adsorption isotherm data. The total surface area and the pore volume were decreased with an increase in compression pressure under the same heat treatment conditions. On the contrary, the bulk densities of the activated carbon pellets were increased. However, these properties can be easily controlled by changing the sintering temperature and time. The bulk density of sample pellet was 0.56 g/cm3. It is 2.3 times higher than activated carbon powder, which was made without the compression process. The total methane storage capacity at 298 K reached 164 cm3 in 1 cm3 volume of activated carbon pellets at 3.5 MPa.

Pore-width-dependent preferential interaction of sp 2 carbon atoms in cyclohexene with graphitic slit pores by GCMC simulation

The adsorption of cyclohexene with two sp2 and four sp3 carbon atoms in graphitic slit pores was studied by performing grand canonical Monte Carlo simulation. The molecular arrangement of the cyclohexene on the graphitic carbon wall depends on the pore width. The distribution peak of the sp2 carbon is closer to the pore wall than that of the sp3 carbon except for the pore width of 0.7 nm, even though the Lennard-Jones size of the sp2 carbon is larger than that of the sp3 carbon. Thus, the difference in the interactions of the sp2 and sp3 carbon atoms of cyclohexene with the carbon pore walls is clearly observed in this study. The preferential interaction of sp2 carbon gives rise to a slight tilting of the cyclohexene molecule against the graphitic wall. This is suggestive of a π-π interaction between the sp2 carbon in the cyclohexene molecule and graphitic carbon.

Gas Supply Infrastructure

In 2012, Japan imported 87 million tons of LNG or 36.2 % of total worldwide LNG imports of 239 million tons. The main sources, accounting for over 70 % of the total, are Asia-Pacific countries such as Australia, Malaysia, Russia, and Brunei. LNG production is dispersed more widely around the world, making it less exposed to geopolitical risk than oil. LNG can be transported in several ways, such as tank lorries and tank containers, to satellite bases for distribution. Gas pipelines are the primary means in Japan, where there are two kinds of gas pipelines. One is for transport of natural gas produced in domestic gas fields; the other is for transport of city gas produced in LNG terminals to areas of demand. For metering gas consumption at customer sites, there is an increasing need for remote meter reading. Furthermore, it is believed that demand will increase for services that emphasize security and safety or for those facilitating monitoring of senior citizens or those living alone via their gas use. Energy saving is another important consideration. To meet all these expectations, a smart gas meter is being developed.