This paper describes the equilibrium compositions of the typical medical waste under high temperature pyrolysis by a steam plasma torch using the NASA CEA2 program. Various components from selected typical medical was...This paper describes the equilibrium compositions of the typical medical waste under high temperature pyrolysis by a steam plasma torch using the NASA CEA2 program. Various components from selected typical medical waste were input to the program along with the treatment temperature from 1000 K -4100 K. The program then performed the Gibbs free energy calculations and searched for the equilibrium composition with minimizing the total system Gibbs free energy. The calculation results indicate that, the equilibrium composition of a system C-H-O at C/O = 1 in the temperature range of 1400 K - 2000 K has demonstrated that gas composition are CO and H2 mainly, the other components （CO2, C2H4, C2H2, CH4 etc.） is less than 1% by volume and the degree of raw material transformation is about 100%. Comparison with air plasma, the steam plasma treatment will not produce nitrogen oxides, if the materials are free of nitrogen element.展开更多
Based on the Chapman-Enskog theory, we calculate the electrical conductivity of non-equilibrium air plasma in the two-temperature model. We consider different degrees of non-equilibrium, which is defined by the ratio ...Based on the Chapman-Enskog theory, we calculate the electrical conductivity of non-equilibrium air plasma in the two-temperature model. We consider different degrees of non-equilibrium, which is defined by the ratio of electronic temperature to heavy particles temperature. The method of computing the composition of air plasma is demonstrated. After calculating the electrical conductivity from electron temperature 1000 K to 15000K, the present result is compared with Murphy＇s study [Plasma Chem. Plasma Process 15 （1994） 279] for equilibrium case. All the calculation is completed at atmospheric pressure. The present results may have potential applications in numerical calculation of non-equilibrium air plasma.展开更多
Current-voltage （I-V） characteristics of a non-transferred DC arc plasma spray torch operated in argon at vacuum are reported. The arc voltage is of negative characteristics for a current below 200 A, fiat for a cur...Current-voltage （I-V） characteristics of a non-transferred DC arc plasma spray torch operated in argon at vacuum are reported. The arc voltage is of negative characteristics for a current below 200 A, fiat for a current between 200 A to 250 A and positive for a current beyond 250 A. The voltage increases slowly with the increase in carrier gas of arc. The rate of change in voltage with currents is about 3-4 V/100 A at a gas flow rate of about 1-1.5 V/10 standard liter per minute （slpm）. The I-V characteristics of the DC plasma torch are of a shape of hyperbola. Arc power increases with the argon flow rate. and the thermal efficiency of the torch acts in a similar way. The thermal efficiency of the non-transferred DC plasmatron is about 65-78%.展开更多
Decomposition of carbon tetrachloride was studied theoretically in the most commonly used thermal plasma atmosphere such as H2, N2, O2 and water steam. A code developed by the National Aeronautics and Space Administra...Decomposition of carbon tetrachloride was studied theoretically in the most commonly used thermal plasma atmosphere such as H2, N2, O2 and water steam. A code developed by the National Aeronautics and Space Administration （NASA） was adopted to calculate the chemical equilibrium distribution and energy consumption of the decomposition of CC;4 in the H2, N2, O2 and water steam atmosphere thermal plasma respectively, with a temperature range of 500 K to 5000 K. In the neutral condition （H2, N2, atmosphere） formation of solid carbon was observed and in the oxygen-atmosphere （O2 and water steam） solid carbon formation disappeared through controlling the ratio of C/O. This indicates that the formation of polycyclic aromatic hydrocarbons （PAHs） is impossible theoretically. The energy consumption in the N2 atmosphere was much higher than that in the H2, O2 and water steam atmosphere at 1500 K.展开更多
文摘This paper describes the equilibrium compositions of the typical medical waste under high temperature pyrolysis by a steam plasma torch using the NASA CEA2 program. Various components from selected typical medical waste were input to the program along with the treatment temperature from 1000 K -4100 K. The program then performed the Gibbs free energy calculations and searched for the equilibrium composition with minimizing the total system Gibbs free energy. The calculation results indicate that, the equilibrium composition of a system C-H-O at C/O = 1 in the temperature range of 1400 K - 2000 K has demonstrated that gas composition are CO and H2 mainly, the other components （CO2, C2H4, C2H2, CH4 etc.） is less than 1% by volume and the degree of raw material transformation is about 100%. Comparison with air plasma, the steam plasma treatment will not produce nitrogen oxides, if the materials are free of nitrogen element.
文摘Based on the Chapman-Enskog theory, we calculate the electrical conductivity of non-equilibrium air plasma in the two-temperature model. We consider different degrees of non-equilibrium, which is defined by the ratio of electronic temperature to heavy particles temperature. The method of computing the composition of air plasma is demonstrated. After calculating the electrical conductivity from electron temperature 1000 K to 15000K, the present result is compared with Murphy＇s study [Plasma Chem. Plasma Process 15 （1994） 279] for equilibrium case. All the calculation is completed at atmospheric pressure. The present results may have potential applications in numerical calculation of non-equilibrium air plasma.
文摘Current-voltage （I-V） characteristics of a non-transferred DC arc plasma spray torch operated in argon at vacuum are reported. The arc voltage is of negative characteristics for a current below 200 A, fiat for a current between 200 A to 250 A and positive for a current beyond 250 A. The voltage increases slowly with the increase in carrier gas of arc. The rate of change in voltage with currents is about 3-4 V/100 A at a gas flow rate of about 1-1.5 V/10 standard liter per minute （slpm）. The I-V characteristics of the DC plasma torch are of a shape of hyperbola. Arc power increases with the argon flow rate. and the thermal efficiency of the torch acts in a similar way. The thermal efficiency of the non-transferred DC plasmatron is about 65-78%.
文摘Decomposition of carbon tetrachloride was studied theoretically in the most commonly used thermal plasma atmosphere such as H2, N2, O2 and water steam. A code developed by the National Aeronautics and Space Administration （NASA） was adopted to calculate the chemical equilibrium distribution and energy consumption of the decomposition of CC;4 in the H2, N2, O2 and water steam atmosphere thermal plasma respectively, with a temperature range of 500 K to 5000 K. In the neutral condition （H2, N2, atmosphere） formation of solid carbon was observed and in the oxygen-atmosphere （O2 and water steam） solid carbon formation disappeared through controlling the ratio of C/O. This indicates that the formation of polycyclic aromatic hydrocarbons （PAHs） is impossible theoretically. The energy consumption in the N2 atmosphere was much higher than that in the H2, O2 and water steam atmosphere at 1500 K.
