Effects of Organic Additives on Calcium Sulfate Scaling in Pipes

Tung A. Hoang; H. Ming Ang; Andrew L. Rohl

doi:10.1071/CH08464

RESEARCH ARTICLE

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Effects of Organic Additives on Calcium Sulfate Scaling in Pipes

Tung A. Hoang ^A ^B ^D , H. Ming Ang ^A ^B and Andrew L. Rohl ^B ^C

+ Author Affiliations

- Author Affiliations

^A Department of Chemical Engineering, Curtin University of Technology, PO Box U 1987, Perth, WA 6845, Australia.

^B AJ Parker CRC for Hydrometallurgy, Perth, WA 6152, Australia.

^C Interactive Virtual Environments Centre (IVEC), Technology Park, Kensington, WA 6151, Australia.

^D Corresponding author. Email: hoanganhtung@hotmail.com; thoang@unimelb.edu.au

Australian Journal of Chemistry 62(8) 927-933 https://doi.org/10.1071/CH08464
Submitted: 27 October 2008 Accepted: 4 April 2009 Published: 13 August 2009

Abstract

A comprehensive study of the effects of nine organic additives on the formation of calcium sulfate scale in a pipe system was conducted using a multiple pipe flow system. Several factors that influence the inhibitory capability of phosphonic and carboxylic additives such as their chemical structure, their concentration, and the run time were closely scrutinized. Results showed that the organic additives influence the deposition of calcium sulfate on the walls of a pipe flow system at various levels. The superiority of the phosphonic additives, especially N,N,N′,N′-ethylenediaminetetramethylenephosphonic acid (EDTP) and nitrilotrimethylenephosphonic acid (NTMP), to other organic compounds with respect to scale prevention is discussed thoroughly. For the first time, it was demonstrated that a solution with a given concentration of inhibitor that is continuously refreshed in a pipe reactor becomes less effective over time. The morphology of the scales formed in the presence of different additives is also studied, using scanning electron microscopy.

Acknowledgements

The authors express their high appreciation to Dr Franca Jones, School of Applied Chemistry, Curtin University of Technology, Western Australia, for her assistance with supplying special chemicals used in experiments.

References

Effects of Organic Additives on Calcium Sulfate Scaling in Pipes

Abstract

Acknowledgements

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