Improved knowledge of the spatial distribution of temperature inside a coal-fired boiler will allow tuning and validation of detailed models of combustion that are already operating at partial load and are performing significantly increased load following. One way this could be done is using pyrotechnic materials fed with pulverized coal that can react at a certain temperature and emit a detectable light signal that can provide the spatial temperature distribution inside the boiler. Given the reddish-yellow background in coal-fired boilers, the green color will yield a distinct signal. Barium containing materials, Ba(NO3)2, BaCO3, or Ba(ClO3)2, are well-known for their green color emission, and we here report pyrotechnic flame generation using barium chloride (BaCl2.2H2O) based compositions. For this work, different compositions containing BaCl2.2H2O and other components acting as oxidant, fuel, etc. were made and analyzed using TGA and burning tests. The flame intensity was captured using a photocell attached with a green color filter. It was observed that the decomposition behavior and the flame intensity were strongly influenced by the ratio of barium chloride to the oxidizer and by the particle size of the pyrotechnic composition powder. Compositions having a higher amount of oxidizer were found to decompose faster (shown in figure 1) and have a more intense flame color. This might be due to higher temperatures achieved by the oxidizer rich compositions allowing more BaCl2 to get into the gas phase forming BaCl specie needed to generate the green color emission.

Barium chloride based pyrotechnic compositions for green color emissions

ACS Fall 2020 Virtual Meeting

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