Influence of inorganic additives on ash adhesion to a metal mesh during bamboo powder combustion

Abstract

If the high melting point oxides added to the bamboo powder, the ash adhesion on the metal mesh during combustion was counterproductive in some cases, but effective in others. For SiO₂ addition, although the shrinkage temperature (SHT) and part fusion temperature (PFT) were higher than that for only bamboo combustion due to the formed KAlSiO₄ whose melting temperature was 1750 °C, the amount of ash on the metal mesh decreased in some cases or increased in others with the additive mass percentage of SiO₂. Because there was the ratio distribution of K₂O to SiO₂ in the bamboo ash which decided the minimum melting point, the amount of adhered ash had a large variation. For CaO addition, although the SHT and PFT were higher than that for only bamboo combustion, whether ash deposition was enhanced or reduced could be determined by the distribution of char present in the combusted ash, resulting in the adhesion on the Inconel mesh. Because the ash for only bamboo combustion had 13.6% char, not only CaCO₃ but also Ca(OH)₂ with a lower melting point than that of CaO were formed during combustion. On the other hand, for MgO powder addition, as the ash formed that could be adhered by MgO particles was fluffy, the adhesion mass decreased with the additive mass percentage. Then all fusion temperatures of SHT, PFT, and the full fusion temperature (FFT) for MgO addition were higher than that for only bamboo combustion.

Keywords:

• Ash fusion
• bamboo powder combustion
• fusion temperature
• inorganic oxide addition
• shrinkage temperature

Acknowledgement

The authors would like to give special thanks to Ms. Kanna Hirao for conducting the experiments of the bamboo powder combustion.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number 21H03664 and the research grant for the new industrial innovation research workshop 2020 by the Chugoku Regional Innovation Research Center.