Preliminary measurements on microwave plasma flame for gasification

Abstract

In this paper, the effects of plasma power and plasma gas flow rate on the geometrical dimensions, the shape of plasma flame and temperature distribution in gasification reactor have been investigated. The effects of plasma power and plasma gas flow rate on the geometrical dimensions, shape of plasma flame and temperature distribution in gasification reactor are presented. The plasma pictures at a variety of plasma power ranging from 300 to 4200 W with the range of plasma gas which is air from 50 to 100 L/min are presented. As expected, an increase in power causes the generation of intensive plasma with enhancement of the plasma flame volume. On the other hand, air flow rate is inversely proportional to the volume of the plasma flame. It is observed that both power and air flow rate has a significant effect on plasma flame shape. The spreading shape of plasma flame is observed at low powers. However, the shape of flame is pointed toward its end with an increase in plasma power. Meanwhile, reducing air flow rate causes a change in shape at lower power levels. The interactive influence of air flow rate and plasma power is confirmation of different plasma flow regimes. The temperature measurements confirm the effects of air flow rate and power on plasma flame regime from 1800 to 6000 W power. Increasing power level causes increment in the reactor temperature. The average temperature in the reactor is increased from 480 °C at 1800 W power to 1018 °C at 6000 W power. The flow rate has a reverse effect on magnitude of the temperature. The average temperature in the reactor is reduced from 480 to 348 °C at 1800 W power and 1018 to 918 °C at 6000 W power when the flow rate is increased from 50 to 100 L/min. However, the temperature distribution is more uniform in higher flow rates. It is also related with the shape of plasma. While the magnitude of temperature and its gradient is high in pointed end plasma, the effects are reversed in spreading shape plasma.