Reactivation Properties of Carbide Slag as a CO2 Sorbent during Calcination/Carbonation Cycles

摘要

The carbide slag from polyvinyl chloride production as industry hazardous wastes was proposed as CO2 sorbent at high temperature in calcium looping cycle. The cyclic CO2 capture behavior and the microstructure characteristics of the carbide slag as one of the typical calcium-based industrial wastes during the multiple calcination/carbonation cycles.Also, the comparisons between the carbide slag and the natural limestone in cyclic CO2 capture behavior were made.XRD analysis demonstrates that the predominating constituent of the carbide slag is Ca (OH)2. The carbonation temperature ranging from 650℃ to 700℃ is favourable to cyclic carbonation of the carbide slag. The cyclic carbonation conversions of the carbide slag is lower than that of the limestone before a certain time,but the situation is converse after that time in a thermogravimetric analyzer. The carbide slag has better cyclic CO2 capture capacity. The carbonation conversion of the carbide slag retains 0.28 after 100 calcination/carbonation cycles,while the two limestones achieve 0.08 and 0.14 respectively at the same reaction conditions in a dual fixed-bed reactor. The microstructure of the carbide slag by SEM reveals the reason why it possesses better CO2 capture capacity.