Issue 7, 2011

Reaction calorimetric analysis of batch cooling crystallization processes: studies of urea in supersaturated water–methanol solutions

Abstract

A thermal energy balance model is developed for the monitoring of batch cooling crystallization processes and applied to the analysis of the crystallization of urea from an 80% methanol and 20% water solution using a 2-litre batch reaction calorimeter operating over a range of cooling rate from 0.1 °C min−1 to 0.5 °C min−1. Detailed calibrations and measurements to determine the parameters needed for the energy and material balance calculation of crystallization reveal the overall heat transfer coefficient, the solution heat capacity, the solubility, the metastable zone width, and the molar enthalpy of crystallization. The instantaneous enthalpy evolved as a result of nucleation and subsequent crystal growth are determined via applying the energy balance model. The rates of the nucleation and crystal growth and the solution supersaturation during the crystallization processes are subsequently calculated. For a typical crystallization process at 0.25 °C min−1 cooling rate, the peak value of crystallization rate mainly due to the nucleation was approximately 30 g min−1, and thereafter the growth rate slowly decreased from 7 g min−1 and 3 g min−1 following the change of solution supersaturation. The influence of seeding is also analyzed and the generic appliables of this approach is discussed.

Graphical abstract: Reaction calorimetric analysis of batch cooling crystallization processes: studies of urea in supersaturated water–methanol solutions

Article information

Article type
Paper
Submitted
28 Oct 2010
Accepted
17 Jan 2011
First published
03 Feb 2011

CrystEngComm, 2011,13, 2505-2510

Reaction calorimetric analysis of batch cooling crystallization processes: studies of urea in supersaturated water–methanol solutions

X. Lai, K. J. Roberts, J. Svensson and G. White, CrystEngComm, 2011, 13, 2505 DOI: 10.1039/C0CE00786B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements