Aegir Impulse

Aegir Impulse - impulse generator for heat exchange systems

Heat exchange systems consisting of components such as boilers, heat exchangers, and cooling towers use water as the heat exchange medium. Suspended and dissolved minerals precipitate out of the water and accumulate as scale deposits on the surfaces of the heat exchange system components, restricting water flow, acting as insulation that hinders heat transfer from one surface to another, impeding equipment function, and increasing energy consumption as contaminated systems lose efficiency and struggle to meet operating parameters. 

Contaminated heat transfer systems must be descaled to recover lost productivity and reduce energy consumption, at a significant cost, not only in terms of the cost of cleaning system components but also in terms of lost productivity when the facility is out of operation while the contaminated heat transfer system is being descaled. 

Chemical treatment is a common way to control sediment, corrosion, algae, bacteria, and other biological contaminants in heat exchange systems and is also often used to remove suspended or dissolved solids from process water, makeup water, industrial stormwater, and wastewater. The use of chemicals is costly, requires storage, handling, and dosing of hazardous substances, and creates increasing environmental problems. 

When chemicals, minerals, and other contaminants accumulate in heat exchange systems, the water becomes unsuitable for further use, requiring a fresh water supply for such systems to operate continuously. Contaminants introduced into the water from such systems typically give rise to substantial additional discharge fees due to the need to treat the water to make it suitable for discharge into the environment.

In this study, the effect of electromagnetic fields (EMF) on membrane fouling and scale control during desalination of brackish groundwater using a pilot-scale reverse osmosis (RO) system was investigated. The groundwater consisted mainly of CaSO4 with a total dissolved solids concentration of 5850 mg/L and a hardness of 2500 mg/L as CaCO3. Two EMF devices were installed in the pipeline upstream of the cartridge filter and at the RO feed inlet to induce an electrical signal at ±150 kHz to the groundwater. 

The effect of EMF on membrane scaling was assessed under accelerated conditions, i.e., without pH adjustment and addition of an antiscalant. Two-phase experiments were conducted: phase 1 (376 hours) with EMF devices turned on after 150 hours of baseline operation and phase 2 (753 hours) with EMF devices turned on from the beginning of the study. 

EMF significantly reduced membrane fouling and improved RO performance by 38.3% and 14.3% in terms of normalized decline in water permeability after 150 hours and 370 hours of operation, respectively. The results of the autopsy of the membranes showed that the coating layer formed during EMF was loosely packed with low density and easily removable by hydraulic flushing.