Numerical and experimental methods in investigating measures for achieving low pollutant combustion in the residential appliances

ABSTRACT

In this work, the effects of proposed measures for improving environmental footprint of woody and non-woody biomass combustion in residential appliances, comprising partial insulation of combustion chamber and inclusion of combustion intensifier are numerically and experimentally evaluated. In the numerical part, a simplified modeling approach for wood pellets, based on Finite-Rate and Eddy-Dissipation model, is presented and the obtained combustion reaction maps are extensively discussed. The accompanying experiments with wood and agropellets are performed in a multi-fuel boiler equipped with rotary pellet burner. It is found that significant reductions in pollutant emissions are obtained (CO – 31 to 78%, PM – 28 to 56 mg/Nm³ at standardized oxygen content). The results also show that by combining both measures, CO emissions below 1000 mg/Nm³ at the standardized oxygen content (limitation for Class 4 according to EN 303–5:2021), without a significant drop in combustion efficiency (approx. 2%), can be expected for agropellets. The optimal combustion conditions can be achieved with lower excess air ratio, whereby a slight reduction in NO_x emissions can be accomplished.

KEYWORDS:

• Pollutant emission reduction
• wood pellets
• agropellets
• combustion intensifier
• combustion chamber chamotte insulation

Disclosure statement

No potential conflict of interest was reported by the author(s).

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