## 1 Introduction
In [18], the plasma ignition of highly reactive lignite dust particles in a flat flame burner was studied using a high-voltage DC plasma torch with a rod electrode. The calculations indicated that the coal ignition delay time decreased by 0.8-3.5 ms, depending on the ambient temperature, which ranged from 1200 K to 1800 K. The study examined the effects of both chemical and thermal factors on coal ignition, revealing that the thermal effect dominates. Experimental results showed that as the ambient temperature increased from 1200 K to 1800 K, the ignition delay time reduced from 2.9 ms to 1.2 ms, which aligns with the calculated predictions. In [19], the plasma ignition of coal using an alternating current (AC) plasma torch was tested to reduce fuel oil consumption in a pulverized coal boiler at a power plant. Experiments were conducted to evaluate the electrode service life of the AC plasma torch, with the operating life of the electrodes determined to be 530 h. The plasma burner was specifically designed to ignite low-ash, low-quality coal through the staged combustion principle. To assess the impact on combustion characteristics such as plasma torch power, combustion temperature, and carbon burnout rate, the power was varied between 150 kW and 300 kW. At 300 kW plasma torch power, a flame temperature of 940 \({}^{\circ}\)C and a carbon burnout rate of 52.2% were achieved with a coal torch length of 6.3 m. These results confirmed the effectiveness of igniting low-quality coal using an oil-free AC plasma torch. In [20], the FLOREAN program for CFD modeling was used to compare two combustion modes in a pulverized coal boiler with a steam capacity of 160 t/h: conventional combustion of low-quality coal (30% ash content) using eight tangential burners arranged in two levels, and combustion with plasma fuel systems installed in two opposite burners on the lower level. The calculations provided temperature, velocity, and concentration fields for carbon oxides (CO) and nitrogen oxides (NO) in the boiler furnace. The study demonstrated that plasma combustion systems can effectively reduce harmful CO and NO emissions when burning low-quality coal. It is important to note that plasma combustion technology is primarily studied through numerical-theoretical methods and laboratory-scale experimental research. Plasma combustion technology has been widely adopted in thermal power plants by the Chinese company LY Power, located in Yantai city, Shandong Province, China, which, by 2020, had implemented this technology in 862 power units, including 31 units across the Republic of Korea, Russia, Southeast Asia, Europe, and Africa [21]. These units have a total installed capacity exceeding 370 GW. LY Power also developed the world's first oil-free thermal power plant using plasma combustion technology. This system eliminates the need for fuel oil in both boiler start-up and the stabilization of the pulverized coal flame. However, a limitation of LY Power's plasma combustion technology is that the ash content of the coal being burned must not exceed 30%. The reviewed articles indicate that, in laboratory, pilot, and industrial-scale applications, plasma was produced through electric arcs generated by AC (alternating current) or DC (direct current) technologies. However, a common limitation noted for both methods is the relatively short service life of the electrodes. In this regard, a novel burner design employing plasma combustion technology, based on the ionization of air using microwave energy to produce plasma, is proposed in this study as a replacement for traditional auxiliary burners. The proposed burner features an internal combustion system and multi-stage ignition process to enhance flame stability, improve combustion efficiency, and enable more controlled coal burning within the plasma. To determine the optimal operating parameters of the novel auxiliary burner, a test setup was established in Unit-1 22 MW\({}_{e}\) of the Soma A Thermal Power Plant, and integrated into a newly designed pulverized coal storage system.