Vishwakarma Rakhi S, Gogate Parag R
Chemical Engineering Department, Institute of Chemical Technology, Matunga, Mumbai 400 019, India.
Chemical Engineering Department, Institute of Chemical Technology, Matunga, Mumbai 400 019, India.
Ultrason Sonochem. 2017 Nov;39:111-119. doi: 10.1016/j.ultsonch.2017.04.015. Epub 2017 Apr 12.
The present work reports the comparison of the effectiveness of ultrasonic bath and horn for intensifying the cooling crystallization of oxalic acid for the first time. The effect of various parameters such as temperature, crystallization time, irradiation time, ultrasonic frequency and ultrasonic power on the crystal characteristics has been investigated. The average particle size of oxalic acid crystals reduced with an increase in irradiation time and ultrasonic power dissipation. Comparison of crystal characteristics obtained in ultrasonic bath with that obtained in the ultrasonic horn under optimized parameters revealed that the average size in the case of ultrasonic horn and bath were only marginally different. The studies related to the effect of different cooling modes using ultrasonic horn revealed that a narrow size distribution and lower average size of 357.2µm was obtained for the cooling using ice cold water as compared to air cooling where observed mean size was 439.7µm. A narrow particle size distribution was also obtained in the scale-up studies using ultrasound horn with mean size of 96.70µm, which was significantly lower than 161.1µm obtained under conventional approach. Overall significant process intensification benefits have been established for the ultrasound assisted approach for cooling crystallization of oxalic acid.
本研究首次报道了超声浴和超声变幅杆在强化草酸冷却结晶效果方面的比较。研究了温度、结晶时间、辐照时间、超声频率和超声功率等各种参数对晶体特性的影响。草酸晶体的平均粒径随辐照时间和超声功率耗散的增加而减小。在优化参数下，将超声浴中获得的晶体特性与超声变幅杆中获得的晶体特性进行比较，结果表明，超声变幅杆和超声浴情况下的平均尺寸仅略有不同。使用超声变幅杆对不同冷却模式的效果进行的研究表明，与空气冷却相比，使用冰冷的水冷却时可获得窄尺寸分布且平均尺寸较低，为357.2µm，空气冷却时观察到的平均尺寸为439.7µm。在使用超声变幅杆的放大研究中也获得了窄粒度分布，平均尺寸为96.70µm，明显低于传统方法获得的161.1µm。总体而言，已确定超声辅助法对草酸冷却结晶具有显著的过程强化优势。
