Reactivity enhancement of calcium based sorbents by doped with metal oxides through the sol-gel process

The calcium-based sorbents are considered to be promising candidates for capturing CO2 from fossil fuel power plants and how to improve the CO2 capture and sintering-resistant performance of the sorbents during the cycling is a challenge for researchers. To improve the CO2 capture capacity and sintering resistant of the sorbents, CaO sorbents were synthesized by the sol-gel process with different precursors. Test matrices considering the important factors, such as dopant, doping amount, HNO3 addition and water addition in solvent were designed to investigate effects of synthesis conditions on reactivity of sorbents and to obtain an appropriate process for synthesizing sorbents for CO2 capture. The structural properties of the resulting sorbents were characterized by N2 physisorption and X-ray diffraction (XRD) techniques, showing that the sorbents prepared by the sol-gel process possessed wonderful microstructure as well as uniform distribution of CaO and MgO, MnO2 and TiO2. These features result in excellent reactivity enhancement and strong sintering resistant of sorbents compared with pure CaO, which give rise to high carbonation conversion, especially for CaO sorbents doped with MgO and MnO2, of 0.79 and 0.76 after 50 cycles under severe calcination condition, respectively. It demonstrates the excellent performance of sorbents synthesized by the sol-gel process.