Thursday 20 January 2022

What does a central heating boiler have to do with fluorescence?

Central heating boilers that burn on natural gas can be equipped with an aluminum heat exchanger or an exchanger made of a combination of silicon and aluminum. Not for nothing are these exchangers (as in this case) made from an aluminum-silicon alloy. This material has proven its value in boilers for decades. Aluminum gives the best heat conduction and in combination with silicon, it is very durable.

Due to exposure to the hot gas flames, the exchangers release an oxidation product which deposits on the exchanger on the side of the flame, while the material of the exchanger slowly wears off. Due to lack of maintenance, the exchanger can clog and cause consequential problems such as a decrease in the efficiency of heat transfer.

To clean the heat exchanger, the fins of the exchanger are sprayed with sulfur-containing oil. By then burning the central heating boiler again for a while, the deposition of oxidation products is loosened. Then there is further cleaning by hand.

Boiler deposit

During a regular service to a boiler, some loosened product was collected and placed under the fluorescence microscope. The reaction product, formed by burning with the sulfur-containing oil, could be a mixture of aluminum oxide, silicon oxide, and aluminum silicate (possibly with some sulfur in one form or another) Aluminum (metal) silicates are known for their fluorescent properties, as shown on the attached photos.



© www.willemsmicroscope.com

No comments:

Post a Comment