Reaction‐Crystallization of Struvite in a Continuous Liquid Jet‐Pump DTM MSMPR Crystallizer with Upward Circulation of Suspension in a Mixing Chamber – an SDG Kinetic Approach

Abstract

The experimental results concerning kinetic aspects of struvite precipitation in a continuous DTM-type crystallizer with internal circulation of suspension forced by a liquid jet-pump are presented and discussed. Nucleation and crystal growth rates of struvite during reaction-crystallization processes in diluted water solutions of magnesium, ammonium, and phosphate ions were identified. Kinetic parameters were calculated on the basis of population density distributions adopting a simplified model of the mass crystallization process in a MSMPR crystallizer taking under consideration size-dependent growth (SDG) mechanism. The Rojkowski hyperbolic SDG model has proved to be the equation best statistically fitted to our own data set.

Continuous Reaction Crystallization of Struvite in a DTM Type Crystallizer With Jet Pump of Ascending Suspension Flow in a Mixing Chamber–Kinetic Approach of the Process

“…Process temperature, pH and inlet/outlet flows (feed solution/product crystal magma) were strictly controlled with PC computer driven by IKA Labworldsoft software. For effective enough internal circulation of suspension, minimal value of unit power of a jet pump feed, P eu = 0.15 W/kg, was assumed [13]. Feeding nozzle diameter enabled one to use a possibly minimal feed value, however sufficient enough for continuous Continuous reaction crystallization of struvite ran through 5 (starting from the moment of stabilization of the assumed steady-state process parameter values).…”

“…This makes estimation of fundamental kinetic parameter values of the process based on product's CSD possible [12]. Experimental results concerning reaction crystallization of struvite from diluted water solutions of phosphate(V) ions in a continuous DTM type crystallizer with internal circulation of suspension driven by liquid jet pump providing ascending flow of suspension in a mixing chamber are presented [5,13]. From the product CSDs fundamental process kinetic parameter values were estimated.…”

Estimation of Kinetics for Batch Cooling Crystallization by Focused‐Beam Reflectance Measurements

“…In the process of producing pharmaceutical substances, crystal size distribution (CSD) needs to be regulated because the quality of products is remarkably affected by CSD , . CSD can be determined according to a balance between nucleation and growth of crystals , . In this study, numerical simulation of the seeded batch cooling crystallization process of active pharmaceutical ingredients (APIs) was performed.…”

Effects of Solution Composition and Polymer Additive on the Crystallization of Struvite

“…The discovery of such strategies requires a comprehensive understanding of the crystallization mechanism and behavior of struvite under different conditions, as well as the effects of certain operation parameters on the product properties. Much research has been done on the thermodynamics of the struvitewater system, the mechanisms of struvite nucleation and crystal growth [3,[9][10][11][12][13][14][15], as well as on the effects of impurities such as calcium chloride and potassium chloride on the crystallization of struvite [15,16]. However, few works have focused on the effects of the N/P molar ratio and polymer additives on the properties of struvite crystallized from the reject water system.…”