Microbubbles as Heterogeneous Nucleation Sites for Crystallization in Continuous Microfluidic Devices.
Microbubbles as Heterogeneous Nucleation Sites for Crystallization in Continuous Microfluidic Devices.
复制标题
微泡作为连续微流体装置中结晶的异质成核位点。
作者：
Naghmeh Fatemi;Zhengya Dong;T. Van Gerven;S. Kuhn
提出了在连续微流体装置中注入微泡流并由此引入异质界面以增强成核和控制颗粒形成。研究了不同气液流量下微气泡两相流的流型图，并确定了微气泡流动的最佳特性。随后，研究了微气泡对对乙酰氨基酚冷却结晶的影响。与无气泡操作相比，观察到增强的成核速率，并且微气泡的存在导致更多晶体的形成，这表明成核比无气泡操作中的成核更快，即，亚稳区宽度减小。确定晶体产率证实，在具有微泡的两相流中获得更大质量的晶体。此外，结果表明，微气泡的存在允许连续结晶而不会堵塞微反应器。
Injecting a stream of microbubbles and thereby introducing a heterogeneous interface is proposed for enhancing nucleation and controlling particle formation in continuous microfluidic devices. Different gas and liquid flow rates were investigated to establish the two-phase flow regime map and to identify the optimum characteristics for microbubble flow. Subsequently, the effect of microbubbles was studied for the cooling crystallization of paracetamol. An enhanced nucleation rate compared to that in the operation without bubbles was observed and the presence of microbubbles results in the formation of more crystals, which indicates that nucleation is faster than that in operation without bubbles, i.e., the metastable zone width is reduced. Determining the crystal yield confirmed that a larger mass of crystals is obtained in a two-phase flow with microbubbles. Furthermore, results showed that the presence of microbubbles allows crystallizing continuously without clogging of the microreactor.