Review of current practices in evaporator cleaning

Chemical cleaning still provides the most cost-effective method of cleaning the evaporators and heat exchangers in a sugar mill. However, operating procedures can have a profound impact on scaling propensity as well as cleaning effectiveness and efficiency. There has been little research into the characteristics of scale formation over the last 10 years, but recent developments in remediation, scale analysis and advancements in other chemical industries may allow new cleaning strategies for sugar mill evaporators to be developed and thereby improve cleaning performance. Some best practices used by sugar factories in the use of preventative and post-operation cleaning chemicals are reviewed. Recent experiences from several sugar factories in modifying evaporator cleaning procedures to improve the efficacy of scale removal are detailed. Recent research that has provided pointers for a step-change in the development of improved chemical-cleaning formulations is provided. Key words Scale, fouling, chemical cleaning, evaporators, heat exchanger