Doped lithium orthosilicate for absorption of CO_2 at steam atmosphere with low CO_2 partial pressure

摘要

Calcium and lithium containing oxides are regarded as options for the capture of CO_2 insorption-enhanced steam reforming of methane (SEMSR) system. Among the latter, lithiumorthosilicate (Li_4SiO_4) is considered as one of the most potential materials due to its largecapacity, high selectivity and good cycle performance. Improved properties can be obtained byappropriately doping different elements into Li_4SiO_4. In this study, the best amount of dopingelements (K, Fe) into Li_4SiO_4 were calculated by Factsage 5.5. Therefore, different lithiumorthosilicate based absorbents, potassium doped and iron doped lithium orthosilicate according tothe calculated results from Factsage 5.5 were prepared and characterized by XRD, SEM. For thestudy of practical applicability in SESMR, the absorption ability was investigated by TGA underlow CO_2 partial pressure (5%～20%) influenced by different steam atmosphere (5%～30%). Inaddition, the cyclic absorption/desorption performance of different absorbents were alsoinvestigated. The results show that potassium and iron can enhance the absorption capacity at lowCO_2 partial pressure and cyclic ability respectively and the best absorbent with suitable amount ofpotassium and iron was acquired.