Optimal Quality Control of Industrial Crystallizers

Publication Reference: 
Author Last Name: 
J B Rawlings
Report Type: 
Research Area: 
Particle Formation
Publication Year: 
Publication Month: 
United States

This report summarizes the research activities for the project “Optimal Quality Control of Industrial Crystallizers,” ARR 32 - 01, during the period 1 September 1996 to 31 August 1997. The goal of this project is to develop on-line measurement technology and predictive crystallization models so that advanced on-line crystallizer control can be implemented to enhance precise control of crystal size and shape.

During the current year, we have demonstrated model identification and control strategies to improve filtration of a problematic photochemical of industrial interest. In order to analyze crystal shape as well as size, we have purchased and installed an Olympus BX60 microscope, image capturing hardware, and Image Pro Plus image analysis software. We have further developed our stochastic modelling capabilities so that models with new and complex crystallization mechanisms can be simulated quickly and accurately. We currently can simulate the following mechanisms: size dependent nucleation, size dependent growth, growth rate and nucleation rate fluctuations, growth rate dispersion, and size dependent agglomeration.

Plans for the next year are to test and commission the new image analysis equipment on a relatively simple system, and identify a model chemical system that is particularly relevant to industrial practice, for which improvements in particle size and shape measurement and control would provide large potential benefit. We will construct a flow cell and circulation loop to monitor the crystal size and shape in real time during crystallization experiments.