Volume: 5, 2026
5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: T003
DOI: https://doi.org/10.24326/ICDSUPL5.T003
Published online: 22 April 2026
Exhaust gas emissions during combustion of off-grade pellets in a low-power burner with a fixed combustion chamber
Jacek Gładysz*, Grzegorz Zając and Joanna Szyszlak-Bargłowicz
Department of Power Engineering and Transportation, University of Life Sciences in Lublin, 13 Akademicka St., 20-950 Lublin, Poland
* Corresponding author: jacek.gladysz@up.edu.pl
Boilers with automatic burners burning pellet fuel are rapidly gaining popularity in single-family homes due to tightening exhaust emission standards. Furthermore, the fuel’s high availability and operational flexibility are contributing to their growing demand. Biofuel in pellet form has several advantages, including ease of storage and low susceptibility to soiling the rooms in which it is stored and burned. However, exhaust gas and dust emissions remain significant concerns. Pellet combustion is one of the cleanest solid fuels, but to ensure safe and efficient operation, the fuel must meet certain requirements, including chemical composition, ash content, and moisture content. Unfortunately, these parameters are often overlooked when choosing solid fuel for a home. For those heating their own home, the most important criterion is fuel price. One way to reduce heating costs is to purchase off-grade fuel, which does not have a quality certificate. The price of non-classified pellets is half that of the highest-quality A1 class pellets. Burners designed to burn 6 mm diameter A1 class wood pellets are suitable for burning other types of pellets, including 8 mm diameter A2 class and even 8 mm diameter B class pellets, but require specialized adjustment of burner control parameters and frequent servicing and cleaning. Failure to do so can cause changes in the combustion process, and therefore impact boiler emissions. The aim of the study was to determine CO, CO2, NOx, and dust emissions during the combustion of 8 mm diameter sunflower husk pellets and 6 mm diameter non-certified wood pellets in a low-power burner with a fixed burner.
The burner was factory-set for burning 6 mm diameter A1 class wood pellets. The study was conducted on a test bench equipped with an SKG DELTA automatic central heating pellet boiler with a rated power of 10 kW and an automatic burner with a fixed burner. A Testo 320-2 LL exhaust gas analyzer was used to analyze exhaust emissions (CO, CO2, NOx), and a Testo 380 dust emission analyzer was used to evaluate dust emissions. The reference fuel was class A1 wood pellets with a diameter of 6 mm, meeting the PN-EN ISO 17225-2:2014 standard. The second fuel was wood pellets of an unspecified class with a diameter of 6 mm. The third fuel was a mixture of uncertified wood pellets with a diameter of 6 mm (with Class B sunflower husk pellets with a diameter of 8 mm) in a 1:1 mass ratio. In the three tests, the boiler operated while maintaining the same burner operating parameters. Burners with a fixed combustion chamber, using the factory burner settings, are capable of burning non-certified pellets and their mixture, but they do not meet current exhaust emission standards. The test results showed that when burning a mixture of sunflower husk pellets and wood pellets, the current exhaust emission standards were exceeded: for CO by 2.4 times, for NOx by 1.5 times, and for dust by 1.7 times.
Keywords: automatic pellet burner; biomass; emissions
How to cite
Gładysz J., Zając G, Szyszlak-Bargłowicz J., 2026. Exhaust gas emissions during combustion of off-grade pellets in a low-power burner with a fixed combustion chamber. In: 5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL5.T003