Kaolin as a fuel additive: Influence on gaseous and particulate matter emissions in an industrial-scale biomass CHP unit

Biomass combustion for carbon-neutral heat and electricity can provide baseload power independent of fluctuations typical for other energy systems (e.g., wind and solar). However, EU emission regulations for biomass-fired CHP units are strict and will likely become more challenging. Fuel-related measures for emission reduction thus complement primary and secondary measures while also addressing corrosion and slagging. Kaolin, a kaolinite-rich aluminosilicate additive, binds alkali metals such as K to form stable potassium aluminosilicates. This reduces gas-phase K compounds that contribute to particulate matter formation, inhibit CO oxidation, and corrosion in flue gas pathways. Lab and small-scale experiments show substantial total particulate matter (TPM) and CO mitigation during kaolin-additivated combustion tests, though large-scale CHP studies remain limited. This study presents results from field trials in a 26 MW<inf>th</inf> grate-fired biomass CHP using untreated wood chips from residual forest wood and short rotation coppice. Despite variations in fuel input and plant conditions within the measurement campaigns, trials with kaolin dosing of up to 1.0 wt%, showed up to 73% lower K amounts in the flue gas, 91% lower CO, and 39% lower TPM emissions.

Subjects

(Fuel) additivation

Aluminosilicate

Biomass CHP

Carbon monoxide

Grate firing

Particulate matter

DDC Class

628: Sanitary; Municipal

Funding(s)

Untersuchung einer automatisierten Aluminiumsilikat-basierten Brennstoffadditivierung von Holzhackschnitzeln zur Emissionsminderung von Biomasseheizkraftwerken

Lizenz

https://creativecommons.org/licenses/by/4.0/

Publication version

publishedVersion

Name

1-s2.0-S037838202600189X-main-1.pdf

Type

Main Article

Size

1.17 MB

Format

Adobe PDF

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Kaolin as a fuel additive: Influence on gaseous and particulate matter emissions in an industrial-scale biomass CHP unit