EFFECT OF WORKING GASES ON THERMAL PLASMA WASTE TREATMENT

An electric are melter used for waste treatment processing is numerica lly studied. The effects of different plasma working gases are studied by using a laboratory scale test reactor. A two-dimensional finite di fference approximation is used to solve the set of governing equations . The Navier-Stokes equations coupled with the combined Maxwell's equa tion for the electromagnetic fields is used to obtain the temperature and flow fields in the are melter. It is found that the energy efficie ncy of the air plasma is lower than that of an argon plasma. However, the melted soil volumes are larger using the air plasma than those usi ng the argon plasma. The overall energy efficiency increases as the ga p between the cathode and the soil surface decreases. More uniform gas temperatures are found for the air plasma than that for the argon pla sma. Result obtained from the laboratory-scale are melter is used as a n input of the energy absorbed into the soil for the USBM are melter s imulation. Results show a maximum temperature of 2195 K at the center of the hear generation and a molten soil exit temperature of 1600 K.