Retention of S with Lignite Using Cedarnut Shell in the Co-combustion Process Performed in a Fluidized Bed Combustor

ABSTRACT

The mix of high-sulfur lignite with cedarnut shell of high K₂O content in ash was combusted in a fluidized bed reactor. When grain size distribution was identical, SO₂ emission was the same as in the case of lignite alone. Under the same conditions, co-combustion of bituminous coal with cedarnut shells showed a significant drop of the SO₂ emission. Reduction of SO₂ emission was obtained by increasing the lignite grain size in order to extend the process of its combustion. When the lignite grain size was three times larger than the biomass grain size, the SO₂ emission was 50% of the previous value, when six times larger it was 30%. This means that S retention takes place when SO₂ released during lignite combustion is in direct contact with the biomass mineral residues. The most significant SO₂ emission reduction occurred when lignite was combusted with biomass ash, not with raw biomass.

KEYWORDS:

• Cedarnut shell
• Co-combustion
• Lignite
• Sulfur dioxide emission

Acknowledgments

The authors would like to thank Mr. Jacek Pasierb and Mr. Piotr Mondkiewicz (AGH) for their technical assistance.

Additional information

Funding

This work was carried out with financial support from the AGH University of Science and Technology (D.S. No. 11.11.110.423/2016).