Concentration Control for Semi-batch pH-shift Reactive Crystallization of L-glutamic Acid

While major advances have been made in the control of cooling and antisolvent crystallizations, very little progress has been made for the much more challenging pH-shift reactive crystallizations that are also quite common in industry. This paper extends the concentration control strategy developed for cooling and antisolvent crystallization to pH-shift reactive crystallization of L-glutamic acid. The straightforward extension to semi-batch pH-shift reactive crystallization is not applicable, which motivates a variant that incorporates data-based models so as to better cope with process nonlinearity. Further analysis motivates the development of control strategies that directly incorporate measurements of the key product quality attributes.