Corrosion inhibitors for acid cleaning of desalination heat exchangers: Progress, challenges and future perspectives

Heat exchangers represent vital equipment for the production and heat recovery in thermal desalination processes. However, with operation under scale control practices, scale growth reduces the performance and efficiency. To restore this performance, acid cleaning is the most adopted and efficient descaling method. Usually, strong mineral acids are used for acid cleaning and corrosion inhibitor addition represents a necessity to protect the underlying metal. Development of cost–effective and low toxic corrosion inhibitors for acid cleaning purpose has, therefore, becomes an essential area of research. In the present work, acid cleaning corrosion inhibitors research and development efforts reported in scientific publications and patent inventions over the last thirty years is reviewed. The review strictly considers works directly related to acid cleaning (descaling) publications rather than the usual acid corrosion inhibition of metals. Critical knowledge gaps are identified and future research perspectives are highlighted.