In Japan, energy and natural resources are imported by the maritime transport. It is, therefore, necessary to consider both procurement of overseas energy resources and risk management of resource transportation under the situation where international geopolitical structure faces a big change. In this paper, we consider both country risk and transportation risk including chokepoint risk and marine peril. In this analysis, we evaluate risks using two mathematical models. The objective of the former model is minimization of a country risk using portfolio theory. The objective of the latter model is minimization of a transportation risk using binomial distribution. We use import experience calculated by ship movement database and sea lane network as input data. Using mathematical programming solver, we show that there are export countries and transportation which make both country risk and transportation risk decrease without additional transport cost.
A new effective method for fabricating adsorbents using woody biomass in order to reduce bio-waste must be developed. This paper discusses the chemical treatment of woody biomass and reports a new adsorbent with high metal adsorption ability. This adsorbent was prepared by performing three treatments. The first was potassium loading onto woody biomass through impregnation using a potassium carbonate solution. The second was heat treatment at 250°C to increase the number of metal-capturing groups. The third was nitric acid treatment to remove potassium species. The metal adsorption ability of the resulting adsorbent, measured as the nickel loading, was as high as approximately 8.3 wt%. This adsorbent was heated at 600°C after nickel loading and it was found that the nickel particles were approximately 3.5 nm in size and highly dispersed in the char. This indicated that the nickel-loaded char had potential to show high activity for biomass tar reforming.
Titania coating of mesoporous silicas (MSs) with different pore size was performed several times under thoroughly dried circumstances. When the pore size was 3 nm, the pore-plugging took place by only one time coating. On the other hand, for the pore size of 7 nm, a uniform coating with titania layer could be achieved until three time coating, and for that of 10 nm, the uniform coating without pore-plugging was obtained even after five time coating. These observations could be explained by the difference in the curvature of the silica pore walls. From various analyses and characterization, it was found that the titania coating was uniform and that three time coating was needed to coat all the silica walls and then possible coating mechanism was proposed. The MSs coated with titania were applied as the support of Mo catalyst for hydrodesulfurization (HDS) of sulfur-containing aromatics. The effect of titania coating on the dibenzothiophene HDS was not significant, but positive increase in activity was observed for 4,6-dimethyldibenzothiophene HDS. This increase was due to the enhancement of hydrogenation ability, in agreement with the results from the naphthalene hydrogenation. Moreover, it was found the formation of three-dimensional pores is very useful to increase the HDS activity.
Millichannel reactor designed for continuous reaction of transesterification has been studied in recent years and also attracted the focus of scientists for its capability to produce high quality biodiesel yield. The millichannel reactor exhibits many advantages, one of which includes great improvement in reaction rate, product yield, energy efficiency as well as mass and heat transfer. Therefore, the millichannel reactor has a high potential to be used for biodiesel production. In this study, transesterification of refined palm oil was carried out by using a teflon tube with an internal diameter of 1.0 mm at 21:1 methanol to oil molar ratio and 60°C to investigate the effects of potassium hydroxide catalyst concentration (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 wt%), and residence time (60, 120, and 180 s) on the oil conversion and fatty acid methyl ester (FAME) yield. The transesterification using a batch reactor was also performed to compare with the millichannel reactor at conditions: 21:1 methanol to oil molar ratio, temperature of 60°C and 0.5 wt% potassium hydroxide concentration. Besides that, the process time has been varied in the ranges of 60, 120, and 180 s. In this study, the best FAME yield was obtained at 4.5 wt% catalyst concentration and residence time of 180 s. As a result, the millichannel reactor revealed a higher oil conversion and FAME yield compared to the batch reactor.
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