一种氨法脱碳氨水乙醇混合吸收剂结晶动力学特性研究

Study on Characteristics of Crystallization Kinetics of Carbon Capture by Mixed Absorbent Contained Aqua Ammonia and Ethyl Alcohol

针对目前氨法脱除二氧化碳研究中存在的问题，该文提出一种低浓度氨水强化结晶低能耗捕集 CO2的工艺，采用新型的氨水乙醇混合吸收液，利用半连续鼓泡反应系统考察停留时间对结晶的影响。发现随着停留时间的延长，晶体产物的粒径分布逐渐改善，平均粒径亦在前30 min 保持一定增长速率，晶体形貌趋于完整，且结块问题也可以得到一定程度的解决。综合考虑，该实验条件下较适宜的停留时间为30-40 min；同时对结晶动力学进行初步探索，确定了该实验中晶体的生长机制为粒度无关生长，并给出了晶体成核速率与生长速率的生长动力学模型为B0=4.172＆#215;106G1.090。为接下来新工艺的进一步研究提供基础数据和参考，并对实际工艺的发展和改善具有借鉴意义。

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 ＆#215; 106G1.090. 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.