PSI - Issue 77

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Michal Holubčík et al. / Procedia Structural Integrity 77 (2026) 413– 423 "Michal Holubčík" / Structural Integrity Procedia 00 (2026) 000 – 000

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Figure 1 presents a combustion efficiency plot based on the Air to Fuel Ratio that presents unique zone control options.

Figure 1 : Combustion efficiency plot

1.3. Challenges in Small-Scale Boiler Operation Although biomass boilers are increasingly promoted as renewable heating systems, small-scale units face several operational challenges that directly affect combustion quality, efficiency, and emissions. Unlike large plants, domestic boilers often lack adva nced automation and rely on simplified control strategies that cannot adapt to fluctuating conditions. Key challenges include: 1. Fuel variability: Moisture content (10–30%), density, and composition strongly influence combustion.

2. Limited automation: Many units lack precise control of air and fuel flow. 3. Dynamic load changes: Rapid shifts in heating demand reduce stability. 4. Emission control gaps: Particulate matter and CO often exceed regulatory limits. 5. User behavior: Irregular maintenance and operation practices further reduce performance.

MC. Backa et al. (2025) demonstrated that the combustion of various biomass pellets in small -scale boilers leads to distinct differences in heat output, emission levels, and ash behavior, proving that fuel selection is a decisive factor in boiler performance [2]. Čajová Kantová et al. (2022) concluded that pellets from spruce sawdust, bark, and pine cones display significant variation in energy content and durability, reinforcing that raw material composition critically determines fuel quality [3] These operational challenges highlight the absence of advanced control and monitoring systems in small-scale boilers. Without automation and smart regulation, the air–fuel ratio remains unstable, emissions rise above acceptable levels, and efficiency drops under variable load conditions. Intelligent technologies— such as sensor networks, predictive algorithms, and IoT platforms—offer solutions by adapting combustion in real time. Bridging these gaps is essential to align domestic heating systems with modern efficiency and emission reduction goals.

Table 2 : Challenges and consequences in traditional small-scale biomass combustion

Challenge

Effect on Performance Incomplete combustion, fluctuating flame

Consequence

Fuel variability (moisture, size)

Higher CO and PM emissions