Review on descaling and anti-scaling technology of heat exchanger in high-salt wastewater thermal desalination

Abstract

Thermal desalination evaporation of high-salt wastewater has been widely used in industry because of the proposed concept of ‘zero liquid discharge’. However, due to the high content of Ca2+ and Mg2+ in high-salt wastewater, the heat exchanger, as the main treatment equipment, suffers from serious scaling problems. This review presents descaling and scale inhibition technologies of high-salt wastewater. The advantages and disadvantages of various technologies are summarized and analyzed to provide theoretical support for the research of descaling and anti-scaling of heat exchangers with high-salt wastewater. In future industrial development, the synergistic application of electromagnetic water treatment technology and scale inhibitors can significantly improve the anti-scaling effect, which can reach over 95% stably. Furthermore, the addition of a physical field can also expand the application range of scale inhibitors. HIGHLIGHTS Mechanisms and limitations of the descaling technology of heat exchangers are explained.; The mechanism of chemical anti-scaling technology is introduced.; The anti-scaling technology in use for high-salt wastewater desalination is reviewed.; The synergistic effects of scale inhibitors and physical fields are put forward.; Future development of anti-scaling technology should notice post-treatment of scales.;

Keywords

• anti-scaling
• descaling
• heat exchanger
• high-salt wastewater
• scale inhibitors
• scaling