The effects of particle size, O2 concentration, temperature, and sorbent type on sulfation of calcium sulfide were investigated at temperatures of 650 to 850°C Calcium sulfide particle is oxidized to CaSO4 through reaction: CaS + 2O2↑CaSO4 when reaction temperature is below 850°C. CaS particle with a diameter below 0.005 mm was found to achieve complete conversion to CaSO4. However, CaS particle with a diameter above 0.02 mm wasn't be completely converted to CaSO4 due to the pore blockage of sulfate product layer. A kinetic study of the sulfation reaction (CaS + 2O2 ↑CaSO4) has shown its activation energy to be 57.2 kJ/mol. A grain model has been developed to analyze the oxidation reaction within a CaS particle. The effects of temperature, O2 concentration, particle size and type of limestone on the reaction process were discussed.
In order to clarify the coke degradation mechanism in the lower part of blast furnace, several kinds of model experiment were conducted based on the conditions that are possible to occur in the above region by considering the reaction form, reaction temperature, reaction degree and impact energy with 15 kinds of coke having different strength and reactivity. In the above region, the control reaction affected more on the coke degradation and fine generation is CO2 gasification than contact to molten FeO or contact to molten metal. As coke is received CO2 gasification, fine (-1mm) is generated from the degraded part by abrasion. One property of coke with less fine generation is that having high cold strength (I 6001≥ 86%) and low reactivity (CRI≤25%), and the other is that having high cold strength and high reactivity (CRI≥45%). In the former coke, CO2 gasification is gathered only on the surface of particle, and in the latter coke, CO2 gasification is occurred in the whole area of particle. From now on, the coke breakage mechanism in the above region will be expected to be researched.
The proton magnetic resonance thermal analysis (PMRTA) method has been applied to the reaction of a bituminous coal with elemental sulfur (S8). From the non-isothermal PMRTA data including mobile and rigid hydrogen fractions, it is revealed that the dehydrogenation reactions are accelerated by S8 at temperature above 250°C The dehydrogenation reactions accompanied a decrease in mobile hydrogen and fusibility, resulting in an increase in the proportion of hydrogen that is rigid.