## 5 Conclusions  
In this study, a novel microwave-assisted burner design based on plasma combustion technology was developed and tested for pulverized coal combustion applications. The experimental results obtained from the industrial-scale prototype demonstrated that plasma generated through microwave energy can effectively and reliably ignite pulverized coal, ensuring stable flame formation even at low ambient temperatures.  
The multi-stage internal combustion system of the burner allowed for controlled ignition and combustion of pulverized coal, achieving high flame stability and combustion efficiency. The experimental setup, integrated into the Soma A Thermal Power Plant's Unit-1, confirmed that at a secondary air flow rate of 500 \(\mathrm{Nm^{3}/h}\) and with a magnetron operating at 37.5 kW (50% of total capacity), a stable plasma flame was established. Furthermore, the system successfully ignited coal feed rates up to 3000 kg/h, where approximately 22% of the total coal was combusted directly within the plasma zone, initiating a stable and extended flame.  
The experimental data indicated that the plasma-assisted burner enabled efficient ignition of low-quality lignite coal with high ash and moisture content, commonly found in the Soma basin. The particle size distribution analysis confirmed that 61.14% of the pulverized coal was below 90 \(\mathrm{\upmu m}\), exceeding the plant's design specifications, which further facilitated the combustion process within the plasma flame. Additionally, the flame temperature was measured to range between 1200 \({}^{\circ}\)C and 1350 \({}^{\circ}\)C, demonstrating the burner's capability to create optimal combustion conditions without the need for conventional fossil fuels such as fuel oil or natural gas during start-up and flame stabilization.  
The specific microwave energy consumption was calculated to be approximately 0.055 \(\mathrm{kWh/kg}\) of coal, highlighting the system's energy efficiency. Importantly, this technology offers significant environmental and economic advantages by reducing auxiliary fuel consumption and associated emissions in coal-fired power plants.  
In conclusion, the proposed microwave-assisted plasma burner represents a promising alternative to conventional auxiliary burners, combining high efficiency, operational safety, and environmental sustainability. Future research will focus on long-term operational stability, scalability for larger units, and further optimization of microwave-plasma-coal interactions to enhance performance under varying coal qualities.  
This research has been supported by EUAS (Electricity Generation Company Ankara, Turkiye) and TKI (Turkish Coal Enterprises Ankara, Turkiye) and has been financed under the contract signed between these two institutions on 4 June 2016.  
**Institutional Review Board Statement**: Not applicable.  
**Informed Consent Statement**: The author declares data availability only upon request.  
**Data Availability Statement**: The original contributions presented in this study are included in the article. For further information, the author may be contacted.  
**Acknowledgments:** The author would like to thank the staff of the Soma A Thermal Power Plant for their technical support provided within the scope of this project.  
**Conflicts of Interest:** The authors declare no conflicts of interest.