Study on characteristics of crystallization kinetics of carbon capture by mixed absorbent contained aqua ammonia and ethyl alcohol

In response of problems existing in current research of carbon capture by ammonia, this paper presents a process of carbon capture by ammonia of low concentration with reinforced crystallization and lower energy consumption, using a new kind of absorbent which is the mixture of aqueous ammonia and ethanol. The effect of residual time on the crystallization was studied through a semi-continuous bubbling reaction system. It is found that as the extension of the residence time, the size distribution of the crystal product improves gradually, the average particle size grows with a certain rate in the first 30 min, crystal morphology tends to finish, and caking problem can be solved to some extent. All things considered, the relatively appropriate residence time is 30~40 min in this experimental condition. The preliminary exploration of the crystallization kinetics was also conducted. The crystal growth mechanism in this experiment was determined to be size independent growth, and the growth kinetics model of the crystal nucleation rate and growth rate was given as follows: B⁰=4.172 × 10⁶ G^1.090. This can provide basic data and reference for the further study of this new technology and has important significance for the development and improvement of the actual technology.