| Crystallization supersaturation or concentration measurement, measurement’s accuracy can influence the study of crystallization kinetics, in order to get an effective method of concentration measurement for D-Pantolactone crystallization process,this paper respectively use three methods:pressure-difference,density and spectrometry to get concentration,and obtaining a comparison compared to the concentration measured by drying method, the result shows:the accuracy of using the spectrometry of measuring is higher than the others; the density method is convenient,and also has high accuracy;pressure-difference gets great errors. And the conclusion is that the density method is more suitable than the others for some concentration measures in crystallization processes,which need numerous and quick determination,like the research on kinetics of dynamic crystallization.The metastable region measurement,using a laser monitoring dynamic measurement method,establishing the measurement device.Measuring the solubility curve,heating at6℃/h,and the supersolubility curve,cooling at9℃/h,under200r/min stirring rate. The research on Kinetics.According to the Randolph-Larson general-population balance and the McCabe’s delta L law,parameters which need to measure are determined.Establishing a continuous steady-state crystallizer(MSMPR),the crystal size distribution(CSD)are measured by sieving method and other necessary parameters are also measured.Finally,the growth rate G and nucleation rate B°of D-Pantolactone crystallization are obtained by using the nonlinear L-M algorithm:rowth rate:G=443×10-6exp(RT/-6860.054)△C0.4612(R2=0.7327)Nucleation rate:B°=9.168×105MT/0.01△C0.93(R2=0.8947)... |
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