The price of caking coal, which is used in the production of metallurgical coke, has risen in recent years. Also of concern is the amount of CO2 emitted from steel industries, comprising approximately 15% of total CO2 emissions in Japan. Therefore, CO2 emissions from the ironmaking process should be reduced to avoid global warming. In this work, fundamental research is conducted on the effect of adding woody biomass to the properties of coke, with the aim of possibly using woody biomass, which is carbon neutral, as a raw material in coke-making. Experimental results showed that the connectivity between coal particles in the coke sample during carbonization and coke strength drastically decrease by adding woody biomass to caking coal. However, the coke properties of the coke sample with added woody biomass could be improved by removing the partly volatile matter of woody biomass before mixing with caking coal, and as a result, the possibility of using woody biomass as a raw material for coke-making with prior carbonization at temperatures of more than 500°C was found.

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“HyPr-RING” is a new H2 production process using carbonaceous fuels in which the fuel is reacted with subcritical steam and a calcium-based CO2 sorbent. We investigated the applicability of this process to organic matter by examining the performance of the process with fuels of differing volatility. The gasification rate and relative contributions of the volatile and “char” components to H2 production were investigated by using dried sewage sludge with a high volatile component concentration, coal with an intermediate volatile component concentration, and coal char with a low volatile component concentration. During the initial thermal decomposition, carbon in the fuels rapidly decreased with time and was converted to carbonaceous gas of CH4 and C2H6 in addition to H2. The amount of the decrease depended on the volatile content in the fuels. Following this initial rapid stage, the residual carbon appeared to become charlike, even for the high volatile content fuel. The gasification rate became slow, and the gasification shifted to favor H2 production in a molar ratio of H2 to CH4 that approximated the equilibrium composition for a char and steam reaction. NaOH catalytically promoted H2 production even for the sludge.