Bruce I. Dvorak
Date of this Version
Al-Sharji, F.(2020). "MAGNETIC WATER TREATMENT FOR SCALE PREVENTION ON WATER HEATER ELEMENTS". Thesis presented to the University of Nebraska - Lincoln in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering.
Calcium carbonates is one of the main components of scale that is commonly found in industrial equipment such as hot water systems. Scale formation on heater elements may lead to reduce heat efficiency and shorten the heat service life. Ion exchange softened water are used to reduce the scale formation, but excess salt during regeneration discharged to the wastewater stream, limits the reuse of wastewater for industrial purposes. As a result, non-salt alternative devices would provide consumers with the ability to reduce the impacts of ion exchange softened water without creating negative salinity impacts on wastewater stream. Magnetic water treatment device involves passing a hard water though a magnetic field. This method reduces amount of scale and favors the precipitations of aragonite, a softer type of scale rather than a hard scale, calcite.
A water heater system was constructed to quantify the scale formation with tap water by using one proprietary magnetic water treatment device, AkwaMag device, and compare it to untreated tap water at 60°C in systems with a tank with 70.4 in2 of exposed iron and with a tank with little exposure of iron. Accelerated scale formation teste were performed on tanks with and without the magnetic device tested at 30 °C and 60 °C. Scale were collected and characterized by x-ray diffraction (XRD), and scanning electron microscopy (SEM) analysis.
The water heater simulation study from the experiment with a tank with little exposure of iron showed that the mass of scale was reduced on the magnetically treated water heater element. Aragonite was formed on both untreated and magnetically treated water heating elements, but the weight percentage of aragonite increased on the magnetically treated water heating elements based on the results obtained from XRD. Other compounds were also detected with XRD found in both heating elements. SEM of both heating elements showed the presence of calcium carbonate polymorphs. In accelerated scale study, the weight percentage of aragonite was higher than calcite at 60 °C and 30 °C. However, calcite was reduced in the magnetically treated water heater elements, which indicates the effects of magnetic fields on reducing calcite formation.
Advisor: Bruce I. Dvorak