Systematic design of supersaturation controlled crystallization processes for shaping the crystal size distribution using an analytical estimator

Study of the influence of the reaction parameters on nutrients recovering from digestate by struvite crystallisation

Struvite production by crystallisation is one of the most promising methods of phosphorus recovering from wastewater or livestock waste. Lab-scale batch experiments were carried out to study the effect of supersaturation, magnesium and phosphorous concentration, pH value and temperature on struvite crystallisation reaction using pig manure digestate from an anaerobic digestion plant as raw material. Taguchi methodology has been used as method to define the design of experiments and to analyse the results. In the design of experiments, three levels of each parameter have been studied: Mg/P ratio (1.0-2.0), N/P ratio (4.0-12.0), pH (9.0-12.0) and temperature (20-40 °C). The morphology of the crystals obtained was observed by scanning electron microscopy. The results show that the optimal values of Mg/P ratio, N/P ratio, pH and temperature for struvite crystallisation are 1.5; 4.0; 10.5 and 30 °C, respectively. High supersaturation levels should be avoided to obtain high yields in the process.

Application of PAT-Based Feedback Control Approaches in Pharmaceutical Crystallization

Crystallization is one of the important unit operations for the separation and purification of solid products in the chemical, pharmaceutical, and pesticide industries, especially for realizing high-end, high-value solid products. The precise control of the solution crystallization process determines the polymorph, crystal shape, size, and size distribution of the crystal product, which is of great significance to improve product quality and production efficiency. In order to develop the crystallization process in a scientific method that is based on process parameters and data, process analysis technology (PAT) has become an important enabling platform. In this paper, we review the development of PAT in the field of crystallization in recent years. Based on the current research status of drug crystallization process control, the monitoring methods and control strategies of feedback control in the crystallization process were systematically summarized. The focus is on the application of model-free feedback control strategies based on the solution and solid information collected by various online monitoring equipment in product engineering, including improving particle size distribution, achieving polymorphic control, and improving purity. In this paper, the challenges of feedback control strategy in the crystallization process are also discussed, and the development trend of the feedback control strategy has been prospected.

Revealing the roles of solvation in D-mannitol's polymorphic nucleation

Using the different solvating powers of solvents, molecular distribution within solutions can be changed, leading to distinct solvation patterns that ultimately affect polymorphic outcomes.