Study On The Modification Of Ca-based Composite CO₂ Sorbents By Pore-forming

As global climate change caused mainly by CO2 threatens the future of human survival, the reduction of CO2 emission has attracted great attention of people all around the world. Power plant is one of the main source for the emissions of CO2, thus it is urgent to control the CO2 emission of power plant. The cyclic carbonation calcination based on Ca-based sorbents is a promising CO2 capture technology, but the rapidly decay of its cyclic performance limited its application. The idea of pore-forming composite sorbent is a new thinking for the synthesis of a new cheap Ca-based sorbent with good performance.The thesis explored the differences between the Ca O from different precursors, it was found that the cyclic performance of Ca O from calcium acetate is better than those from calcium hydroxide or calcium carbonate, because H2 O and CO2 releasing separately from three stages during the process of calcination created better structure and pore. Mixing calcium hydroxide with aluminate cement achieved better performance, for the 1:1 sorbent kept a Ca O conversion of 56% after 20 cycles, and the Ca12Al14O33 is the answer. To further improve the performance of the composite sorbent, pore-forming was put forward.Pore-forming sorbent by pledget achieved great performance with a conversion of 80% after 20 cycles, while pore-forming by avicel worsened the performance.Moreover, the cyclic performance was also tested under different conditions.The result showed the composite sorbent after pore-forming achieves better cyclic performance under 650℃, and CO2 concentration beyond 15% has no effect on the sorbent, the performance of sorbents decreases rapidly under severe calcination conditions.