PECULIARITIES OF DIETHYLAMINE DISTILLATION PROCESS FROM CALCIUM CHLORIDE AQUEOUS SOLUTION

The research investigates the distillation process of diethylamine ((C₂H₅)₂NH) from aqueous solutions of calcium chloride, which is crucial in the potassium carbonate production process. Despite the significance of phase equilibria for the system CaCl₂ – (C₂H₅)₂NH – H₂O in optimizing distillation processes, the literature lacks comprehensive data, particularly at low pressures. This study aims to bridge that gap by examining the distillation kinetics at pressures of 47.996, 21.331, and 7.999 kPa. Experimental results show that when the calcium chloride content exceeds 27–28% by mass, the solution temperature increases, marking the transition from distillation to more energy-intensive processes due to the formation of hydrates like CaCl₂·12H₂O. The findings highlight that reducing pressure to 7.999 kPa nearly doubles the distillation rate compared to pressures above 21.331 kPa. A general kinetic model was developed, describing the relationship between evaporated water, diethylamine concentration, process time, and pressure. This model, derived from first-order kinetics, allows for accurate predictions of diethylamine content over time without directly accounting for pressure variations. Additionally, the research emphasizes that water evaporation kinetics are closely tied to the diethylamine content, as water evaporation accelerates significantly once the amine concentration drops below a certain threshold. These insights contribute to the development of efficient distillation strategies, minimizing reagent loss, and optimizing steam consumption. The derived equations and models are applicable not only for laboratory experiments but also for scaling up to industrial processes, offering practical tools for technological calculations and improving the sustainability of potassium carbonate production.