Heat transfer analysis on progressive freeze concentration of aqueous lysozyme solution

Abstract

In this study, operating conditions of progressive freeze concentration method were arranged to deal with heat transfer analysis. Progressive freeze concentration is also known as a method to remove water from the solution by freezing process. The aqueous solution of lysozyme needs a water removal technology system as the residual moisture content has a significant impact on the solid-state stability of this biopharmaceutical product. The process was carried out by a newly designed crystallizer called a multiple probe cryo-concentrator (MPCC) which is completely equipped with a controlled stirrer, adjustable cooling gas system, solution tank and a set of cooling probes. The operating condition involved in this system include operation time, t (20 to 60 min), coolant temperature, CT (-6 to -14 C) and stirrer speed, SS (200 to 400 rpm) at constant initial concentration of 10mg/ml. The result of overall heat transfer coefficient (Uo) at varied operating condition was analysed and obtained where coolant temperature of -8 °C, operation time of 20 min and stirrer speed of 350 rpm were found to give the highest Uo. All the operating conditions were found to contribute to the progress of ice development and removal of water in the MPCC system resulting in purity of ice and solution concentration accordingly.