Since fiscal year 2011 the New Energy and Industrial Technology Development Organization (NEDO) has carried out feasibility studies to promote the international diffusion of high-efficiency clean coal technology (CCT) in order to stabilize energy supply and demand and address global environmental issues. This paper presents an overview of good examples for strengthening Japan's global competitiveness and support for system exports in twenty feasibility studies that were conducted in fiscal years 2011 and 2012. Highlights of the paper include Japan's high efficiency and low failure rate in long-term operation and maintenance, matching the needs of counterpart countries by reducing environmental load using carbon dioxide capture and storage (CCS) technology, and optimizing facilities, layout, etc. Although CO₂ emission reduction measures and the application of high-efficiency CCT such as ultrasupercritical (USC) technology to replace old existing power stations is effective, improved generation efficiency and the introduction of CCS should also be strategically developed in the near future. Through these activities, NEDO is contributing to the realization of a low carbon society.

View full abstract

Jet fuel synthesis from biomass syngas via Fischer-Tropsch synthesis was firstly conducted using Co/ZrO₂-SiO₂ bimodal catalyst in a slurry-phase reaction process. To break the limitation of classic ASF distribution law, a part of olefin was added into the reaction with the syngas to enhance the selectivity of C₈-C₁₆ selectivity, suppressing the formation rate of lighter hydrocarbons. The employed bimodal catalyst exhibited higher activity and higher selectivity than the uni-modal catalyst. It was clarified that the mesopores of the bimodal catalyst accelerated the mass transfer efficiency because the reactants and products here were heavier than those in conventional slurry-phase Fischer-Tropsch synthesis. Simultaneously, micropores of the bimodal catalyst realized the high dispersion of the supported cobalt particles, tuning the balance between dispersion and reduction degree of the supported cobalt. ZrO₂ acted as not only building blocks for the micropores of the bimodal spatial structure, but also as a promoter for Co/SiO₂ Fischer-Tropsch synthesis catalyst chemically. The comprehensive effect derived from bimodal spatial effect and ZrO₂ promoter effect realized the high activity of the Co/ZrO₂-SiO₂ bimodal catalyst. With the aid of the added 1-decene, new C-C bond formation was initiated and more carbene was connected to 1-decene, resulting in the boosted C₈-C₁₆ selectivity.

View full abstract

Hydrothermal t reatment of sludge was carried out, and the effect of hydrothermal conditions such as treatment temperature and treatment period on the filtration performance of the treated sludge was evaluated. The properties of the treated sludge were also analyzed by particle size distribution measurements, pH, and ζ potential, in order to understand the physical filtration mechanism. An increase in treatment temperature significantly improved the filtration capability of the treated sludge. The length of the treatment period also affected the filtration performance; the filtration rate of the sludge subjected to a longer treatment period was increased. Despite a decrease in the particle size of the treated sludge during high-temperature hydrolysis treatment, the filtration capability improved with an increase in the hydrothermal treatment temperature. Significant agglomeration of the treated sludge was not observed, and the agglomeration effect on the filtration performance was fairly small. In addition, the slurry concentration related to the decomposition of organic substances exhibited a significant influence on filtration resistance.

View full abstract