Chemical Engineering Science, Vol.65, No.9, 2689-2699, 2010
Membrane assisted crystallization using reverse osmosis: Influence of solubility characteristics on experimental application and energy saving potential
Membrane assisted crystallization is a promising concept to improve control over the generation of supersaturation and to reduce energy consumption of conventional solvent evaporation. In this work both the practical and theoretical feasibility of membrane assisted crystallization using reverse osmosis (MaC-RO) is investigated with an emphasis on the influence of solubility characteristics. An experimental setup is presented tailored towards reduction of the two main sources of risk for the concept, which are concentration polarization and scaling on the membrane surface. The performance is investigated for two model systems with different solubility behaviour, which are ammonium sulphate and adipic acid both crystallized from water. The latter system shows a much better operational performance. In addition, a model of a continuously operated MaC-RO process is developed and optimized, and the energy consumption as function of solubility characteristics is systematically compared to that of conventional evaporative crystallization. Both the experimental and theoretical study show that MaC-RO has potential for many applications and is economically and practically most suitable for components with a moderate solubility, high molecular weight, and a strong dependency of solubility on temperature. (C) 2010 Elsevier Ltd. All rights reserved.