SO2 and HF emitted from coal-combustion is a serious problem of indoor air pollution in China. Powdery coal mixed with Ca(OH)2, which is called coal-briquette, was suggested to control SO2 and HF emissions from coal combustion, but it is thought that desulfurization and defluorination occur at the same time during the combustion of coal-briquette. The objective of this study is to clarify the interaction of desulfurization and defluorination reactions during the coal-briquette combustion. This research work focuses on the removal of SO2 and HF from coal combustion. Carbonaceous graphite, muscovite and FeS2 are used to make simulated briquettes, as carbonaceous graphite provides carbon, muscovite contains fluorine and FeS2 contains sulfur. Ca(OH)2 is used as an additive to the simulated coal-briquettes to remove SO2 and HF. As the result, it was found that HF generation is a first-order reaction and that existing sulfur in the simulated coal-briquettes has an influence on defluorination efficiency. The experimental result showed that the emitted SO2 concentration increased with an increase of fluoride content in the simulated coal-briquettes. Further, our data showed that if pyrolysis of fluoride (muscovite) proceeds in the simulated coal-briquettes combustion, desulfurization efficiency decreases.
The 5th Strategic Energy Plan indicates that the introduction of cogeneration will be promoted. When cogeneration is introduced widely, it is desirable to disseminate it at a level aligned with the energy demand and potential capacity of a given region. The objective of this study is to estimate the potential capacity for both achieving energy conservation and securing the electric power necessary for business continuity in the commercial sector using cogeneration. Further, this study attempts to estimate by region the potential capacity contributing to improvement in electrical system power flow in general gas provider supply areas. Building energy demand and cogeneration energy conservation performance were analyzed using “BEST”, a comprehensive building energy simulation tool, referring to standard building specifications in FY2013 and based on analysis results in energy conservation plans submitted to administrative agencies with jurisdiction. It is possible to estimate the usage and the total floor area of buildings located in a given region, and to determine location information by using a geographic information system (GIS). Further, by using the GIS, it is possible to determine general gas provider supply areas and the regions where cogeneration can contribute to improvement in electrical system power flow when distributed power is introduced. As a result of the estimation, the potential capacity for both achieving energy conservation and securing the electric power necessary for business continuity is approximately 24.8 GW in the business sector nationwide, and approximately 14.9 GW potential capacity will contribute to improvements in electrical system power flow in general gas provider supply areas.
Hydrogen (H2) receives much attention to mitigate climate change and strengthen energy security. This study analyzed the economic viability of H2 energy with a focus on the electricity and transport sectors, employing a spatially-disaggregated global energy system model. The simulated period is from 2015 to 2050. The results suggest that, in addition to strict CO2 regulation policies, significant cost reductions of H2 production technologies would be prerequisite to accelerate H2-fueled power generation globally. By contrast, deployment of fuel-cell vehicle appears more sensitive to vehicle price, rather than the H2 supply costs. Among H2 production processes, gasification of coal and reformation of natural gas, combined with carbon capture and storage, are estimated to be cost-efficient, implying opportunities for H2 trade between coal and gas resource countries and energy consumers. Yet, again, improved economics are necessary for maritime H2 transportation, including liquefied H2; otherwise, H2 trade would be limited to pipeline. If maritime H2 trade becomes economically viable, natural gas and coal in Australia could be competitive feedstock for Japan. Long-term policies to support research and development are crucial to commercialize H2 supply system.