Water plasma generation under atmospheric pressure for HFC destruction

Hydrophobicity improvement of contaminated high temperature vulcanization (HTV) silicone rubber is of great significance to avoid risk of pollution flashover during wetting events. In the present investigation, low-temperature plasma jet produced by dielectric barrier discharge (DBD) under atmospheric pressure was used to quickly increase the hydrophobicity of contaminated HTV surface. Effects of the processing time, non-soluble deposit density (NSDD) and transfer time on the hydrophobicity improvement were studied and the long term stability of hydrophobicity was investigated. Experimental results proved that: hydrophobicity of contaminated HTV silicone rubber was significantly improved after a quick exposure to low-temperature plasma jet; and with the increase of exposure time, hydrophobicity transfer increased and a larger contact angle was obtained for the same transfer time. For the low discharge power plasma treatment, NSDD had a negative effect on hydrophobicity improvement and with the increase of the NSDD, increment of the contact angle decreased. In addition, hydrophobicity improvement had long term stability. Control experiment proved that interaction of plasma jet with silicone rubber played an important role in accelerating the transfer of low molecular weight (LMW) silane chains from the silicone rubber to the pollution layer, which finally resulted in the hydrophobicity improvement.

Hydrophobicity improvement of contaminated HTV silicone rubber by atmospheric plasma jet treatment

During two last decades, numerous technologies and approaches are presented for treating contaminants in liquids and solutions. Among them, thermal plasma has shown rapid kinetic and high destruction efficiencies due to very high temperature and highly active radicals. Hence, the use of thermal plasma for treatment of the contaminants in liquids and solutions has received a lot of attention in view of its low environmental impacts. This review focuses on thermal plasma, and it describes the current status of liquid and solution treatment using this technology. A comprehensive analysis of the available scientific and technical literature on liquid and solution plasma treatment is presented, including the treatment of a variety of contaminants in liquids and solutions via different kinds of thermal plasma. The principles of thermal plasma generation and the available plasma technologies with potential applications to generate valuable products from liquid waste are presented. In addition, the results of the thermal plasma processes for the treatment of specific contaminants are investigated. In light of the investigated literature, thermal plasma is found to have a significant potential to treat the liquid wastes.

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Liquid and solution treatment by thermal plasma: a review

..........................................................................................................................................iv ACKNOWLEDEGMENTS ............................................................................................................vi List of Figures .............................................................................................................................. xiii List of Tables.................................................................................................................................xix

Traitementde solutionscontaminÈescontenant de l 'acide carboxyliquepar plasma thermiquesubmergÈ Treatmentof contaminated solution containing carboxylic acidby submerged thermal plasma

Water Plasmas for Environmental Application

A plasma arcjet reactor has been constructed to study the fundamental reaction kinetics for decomposition of hazardous liquids. The temperature profile of the plasma jet was measured using an enthalpy probe, and the profile was used to model the arcjet as a nonisothermal tubular flow reactor. A surrogate liquid waste-1,2 dichloroethane-was injected into the plasma reactor, and the decomposition byproducts were monitored using a residual gas analyzer. The experimental results were compared to the predicted byproducts from the tubular reactor model and indicated that a photochemical dissociation process accounted for some of the decomposition of dichloroethane. This research also provided a more comprehensive understanding of the critical parameters associated with thermal plasma chemistry and the destruction of liquid waste.

Decomposition of dichloroethane in a plasma arcjet reactor: experiment and modeling

Summary form only given. A plasma arcjet reactor has been constructed to study the fundamental reaction kinetics for decomposition of hazardous liquids. The arcjet was operated at a power level of 1.5 kW and an argon flow rate of 17.5 LPM. The temperature profile of the plasma jet was measured using an enthalpy probe and the maximum temperature measured in the plasma jet was 1850/spl deg/C. A surrogate liquid waste, 1,2 dichloroethane, was injected into the plasma jet and the decomposition byproducts were monitored using a residual gas analyzer. A removal efficiency greater than 99% was obtained. The temperature profile was used to model the arcjet as a non-isothermal tubular now reactor.

C.B. Fleddermann

Papers

Decomposition of dichloroethane in a plasma arcjet reactor: experiment and modeling

Decomposition of dichloroethane in a plasma arcjet reactor: experiment and modeling