## 3 Results and Discussion
### Thermal Characteristics of the Plasma-Chemical Reactor  
As mentioned above, when the reactor is in the operating regime, the recycled feedback is decomposed, all organic materials and their harmful compounds are decomposed and removed from the reactor in gaseous form, and inert materials with a high melting point accumulate on the anode surface. The melt layer grows along the entire distance between the reactors' surfaces, starts to work as an anode, and decreases the plasma column dimensions. However, the exhaust gas temperature increased until \(x=25\) mm and remained constant. The exhaust gas temperature measured at a distance of 5 mm from the exhaust nozzle significantly depended on the nature of the waste (Figure 6). For the experiments, two different substances (without additional materials), clay and zeolites, were chosen to establish such dependence. Clay and zeolites were selected owing to their well-investigated chemical compositions. After the melt was released, the arc voltage increased accordingly. According to the results presented in Figure 6, it may be noted that the exhaust gas temperature drops significantly compared with the gas temperature inside the reactor. At an axial distance of up to 30 mm, the behavior of the temperature profiles also depends on the PT operating time because the thermal energy flow rate increases insignificantly, and the temperature of the reactor walls increases. When the axial distance exceeded 25 mm and the reactor wall temperature stabilized, the exhaust gas temperature depended mainly on the arc current. The essential difference between the case of clay and zeolite is that the gas enthalpy of melted clay particles is much larger than that of zeolites. It was also observed that the exhaust gas flow temperature suddenly decreased because of the decrease in its full pressure and density. This phenomenon is absent in high-temperature flows, as the flow expansion possibility towards the axis counterbalances the total pressure decrease. When the surrounding gas leaves the reactor, its exhaust nozzle generates large eddy movement interacting with the surrounding gas. Thus, the processes of increasing turbulence and drawing in the surrounding flow are interrelated. During the experiments, it was noticed that the profiles of the temperatures and enthalpies in the flow direction became nearly symmetrical. This implies that the additional flow is injected into the main two-phase flow from the surrounding layers in inverse proportion to its density. Because of the large amplitudes and durations of the eddies, considerable density fluctuations and transversal mass transfer occur. From the experimental results of thermal characteristics, it can be seen that it is also possible to establish the dependence of exhaust gas temperature on arc current and length. Figure 6: Radial distribution of gas temperature leaving the plasma-chemical reactor. White dots—when working with zeolites; black dots—with clay. The air flow through the plasma torch was 1 g/s, and the protective gas was 2.63 g/s. It was found that the PT thermal stability was reached with increasing arc current or arc length only at a distance of \(x>30\) mm. In this case, the region appears where the arc power is inversely proportional to the arc current. Temperature measurements (Figure 6) of the gas leaving the reactor showed that the temperature difference between the emission gases during the processing of both zeolites and clay was not high and reached approximately 200 \({}^{\circ}\)C (Figure 7). During the experiments, the plasma torch power was 41 kW in both cases, and the air flow was 3.63 g/s. More gas is released when only clay is used than when zeolites are used. This can also be seen by observing the flue gas flowing out of the reactor (Figure 7). The chemical composition of clay includes various metal oxides and salts (K, Mg, Na, Fe, etc.) that react with plasma gas during the treatment process and affect the color of the flame.