Removal of Magnetite from Closed Loop Heating and Cooling System Using Magnetic Dirt Filtration Technology

Swati Sharma1, Neil Watson2, Katie Wagenfuhr 1

1 Water Engineering, Mead, Nebraska, USA,

2ADEY, England, United Kingdom

Abstract

Magnetite, also known as black iron oxide, is one of the main causes of boilers and cooling towers damage. Most of the systems suffers from black iron oxide contamination creating thick sludge deposits. This deposits as result of corrosion along with water hardness scales and other unwanted contaminants can lead to system failure. A patented design using magnetic dirt filtration technology was studied for the removal of magnetite in the hydronics systems. The filters use individually removable neodymium magnetic rods making it easy and safe to maintain. The study showed more than 95% removal of magnetite from the system resulting in low iron levels.

Project

A condensate system in a steam generation plant had constant issue of high levels of iron coming into the system thereby affecting the reusability of the condensate return into the hydronic system. Due to the old systems in place throughout the facility, a good number of these equipment consistently brought in at times more than 20 ppm of iron back to the condensate receiver. As a result, the facility was losing reusability of the condensate as well as increased expenses of makeup water.

Methodology

To reduce the high levels of iron in the hydronics system, the user leveraged ADEY’s MagnaClean Commercial®, magnetic dirt filter range that removes damaging iron oxide sludge through magnetic filtration technology.

Two 4” MagnaClean Commercial filters were installed in parallel at the facility to reduce the iron sludge from the condensate system before going into the receiver tank and then to the deaerator tank. The installed filters are shown in figure 1.

Figure 1. ADEY MagnaClean Commercial.

Results and discussion

The system was installed, and data were collected to test for iron levels before and after the ADEY MagnaClean Commercial filters. The data shown in figure 2 shows decrease in iron levels from the condensate sample in a period of 60 days dated from August 2020 to October 2020. The initial concentration of iron in the beginning of filter installation was 9 ppm. Over the period of 60 days, the iron levels decreased to less than 1 ppm. Another data recorded from January 2020 until October 2020 presented in figure 3 shows consistent high iron levels of more than 20 ppm until the installation of the MagnaClean Commercial filters and a gradual decrease in the iron levels post installation.

From the data presented above, it was evident that the iron present in the condensate sample was mainly magnetic in nature and therefore could be attracted by the magnets in the filter. The remaining non-magnetic and dissolved iron levels were low in concentration and were treated by satellite feed of neutralizing amine. What sets ADEY’s technology apart from other traditional magnetic filtration technologies is its patented design ensuring low pressure loss. The filter forces system water to pass through the central magnetic core, where iron oxide is drawn out by powerful magnetic rods.

Conclusion

ADEY’s patented magnetic dirt filtration technology successfully removed more than 95% of the particulate magnetic iron oxide from the condensate return in a period of 60 days thereby achieving –

• Lower iron levels

• Low pressure drop