The Rapid Decay of CO₂ Capture Capacity of CaO Derived from Ca(OH)₂

Abstract

In this article, the rapid decay of the CO₂ capture capacity of calcined powders derived from Ca(OH)₂ is presented. The observed decay is closely related to the calcination conditions of Ca(OH)₂. By increasing calcinaion time, the CO₂ capture capacity decreases significantly. At 973 K, the decay can cause a 27.3% of CO₂ capture capacity loss by 2.5 min increase of calcination time. A higher calcination temperature will decrease the observed decay. In order to well understand the decay process, the characteristics of calcined powders derived from Ca(OH)₂, such as pore structure and basicity, were investigated. During the process of CO₂ capture of calcined powders from shorter Ca(OH)₂ calcination time, a carbonation reaction and Ca(OH)₂ decomposition occur simultaneously. Therefore, the diffusion and transportation of steam from the Ca(OH)₂ decomposition helps to prevent the formation of an exterior CaCO₃ layer, which can result in more thorough carbonation reactions. Furthermore, a preliminary attempt to overcome the observed decay was also studied.

Keywords:

• basicity
• CaO
• Ca(OH)₂
• CO₂ capture
• pore structure

Additional information

Funding

The financial support from the National Science Foundation of China (No. 50876062) and U.S.-China Clean Energy Research Center-Advanced Coal Technologies Consortium (CERC-ACTC) (No. 2010DFA72730-401,402) are gratefully acknowledged.