抄録
The effect of temperature and O2 concentration on the product distribution of the CaO-SO2 reaction was thermogravimettically studied. The accompanied changes in pore characteristics (specific surface area and pore volume) with reaction temperature, time and O2 concentration were also investigated. Among the sulfation products, CaSO3 was found to be thermally stable at temperatures below about 973 and 1015 K with and without O2, respectively.
Within CaSO3 stability limits, O2 presence increased the initial sulfation rate, but virtually suppressed SO2-sorption capacity. On the other hand, at temperatures beyond CaSO3 stability limits, O2 presence improved the initial sulfation rate as well as SO2-sorption capacity, and the reaction order with respect to SO2 was determined to be around unity independent of O2 presence.
Regardless of O2 presence, the reaction order with respect to SO2 was found to increase from 0.5 to 1.1 with temperature increase from 823 to 1123 K. No influence of O2 concentration on the initial reaction rates and sorption capacities were observed above 2 vol% O2 in the tested temperature range (823–1123 K). The temperature dependency of the CaO-SO2 reaction system was correlated with an activation energy, E, ranging between 31 and 51 kJ·mol–1.
