On-line Analysis For Quality Control In The Batch Reaction And Crystallization Process

With the development of industry and technology, the value added to chemicalsincreased, which, at the same time, promoted the demands in the qualities of chemicalproducts. Product quality control is the key to ensure the product quality. But in batch process,the main process of value-added chemicals production, it is seriously restricted by thenonlinearity, un-stabilization, uncertainty and multi-scale factors of the process. The processanalysis technology, including the variables on-line measurements and the analysis of theprocess, can improve the quality optimization control effectively.The solute concentration is one of the key factors in chemical process study. First,Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is coupledwith Partial least square (PLS) to provide a solute concentration calibration model，in whichthe IR absorbances constitute the predictor variables of PLS and the concentration as theoutput predictions．The accuracy of the model is studied by a multicomponent system，theesterification of ethylparaban．Results showed that the model is highly accurate and can givethe on-line solute concentration measurements reliably.Then the process of Glyphosate crystallization was studied, including the crystallizationthermodynamics measurements, the transfer from Chord Length Distribution (CLD) toParticle Size Distribution (PSD), and the crystallization kinetic modeling. Through thecrystallization kinetic model, the effect of the temperature, the supersaturation, the slurryconsistency and the stirring rate to the crystallization process are analyzed.All the process analysis work is done for the further product quality control.