Experimental evaluation of chemical systems for CO2 capture by CaO in eutectic CaF2-CaCl2

AIMS Energy

Espen Olsen¹  Heidi S. Nygård¹  Maria Hansen¹  Yasen Alhaj-Saleh¹  Piotr Palimąka²  Stanisław Pietrzyk² 

[1] 1 Faculty of Science and Technology, Norwegian University of Life Sciences (NMBU), N-1432 Ås, Norway;2 AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Kraków, Poland;

关键词: co₂ capture;    calcium looping;    molten salts;    phase diagram;    viscosity;   

DOI  :  10.3934/energy.2019.5.619

来源: DOAJ

【 摘 要 】

CO₂ capture by CaO in molten salts is a variant of calcium looping in which the active substances (CaO/CaCO₃) are dissolved or in a slurry with inorganic molten salts. One of the main advantages is the nonexistence of degradation in the reactivity between the active material and CO₂. Previous research has revealed good absorption and desorption characteristics with CaO contents up to 20 wt% in eutectic CaF₂-CaCl₂. The hypothesis is that the formed CaCO₃ continuously dissolves in the melt, leaving highly reactive CaO readily available for the incoming CO₂. In the present study, the CaO content is increased to 40 wt%, and the absorption characteristics is investigated with focus on the sorption capacity and CO₂ removal rate. The chemical system is also evaluated experimentally with regards to viscosity and solubility of the formed CaCO₃ during CO₂ absorption, with the aim of determining chemical upscaling limitations. The results show that the practical CaO content limit is 30 wt%, in which a sorption capacity of 20 g CO₂/100 g sorbent is observed, without any deterioration of the reaction kinetics. For 40 wt% CaO, the sorption capacity is higher, but on the expense of the CO₂ removal rate and CaO conversion. This is attributed to a significant increase in viscosity and the solubility limit of CaCO₃ being exceeded.

【 授权许可】

Unknown