Some of hazardous liquid organic wastes, radioactive or not, are waiting from outlet to be destroyed. The ELIPSE process is a new technology of organic liquid destruction, involving a thermal plasma working under a water column, which ensures the cooling, the filtration and the scrubbing of the gases coming from the degradation. This study deals with the ability of the ELIPSE process to destroy the pure organic liquids and then to reduce the amount of organic matter remaining in the aqueous solution by means of the thermal or radiative properties of plasma. Preliminary test have shown how efficient the process is for the destruction of the organic liquids when they are directly fed in the plasma hearth. Extensive researches have been performed to assess the ability of the submerged plasma to destroy the remaining organic matters either by reinjecting them with the aqueous solution into the plasma or by using the UV ray coming from the plasma itself. A comparison of the experimental results obtained with various mechanisms proposed by the work carried out highlighted that this UV radiation could, by excitation of water molecules, produce radicals OH° which may either dimerise to produce hydrogen peroxide H 2 O 2 , or react with organic substances present. The calculation of an activation energy of 8.5 ± 0.9kJ.mol-1 during the experiments shows that these radicals OH° act directly after having been formed which explains a low H 2 O 2 content stability when the solution contains organic compounds. Thus, this photooxidation taking place in the water column could be used to improve the destruction of residual organic matter in the solution by maintaining the plasma after processing a given amount of organic liquids.
This work deals with incineration of organic liquid wastes using an oxygen thermal plasma jet, submerged in water. The results presented here concern incineration of trichloroethylene (TCE). During a trial run, the CO 2 and CO content in the exhaust gas is continuously measured; samples taken periodically from the solution are analyzed by appropriate methods: total organic carbon and chlorine content are measured. Process efficiency during tests with a few L/h of TCE is given by the mineralization rate. The trapping rate of chlorine as HCl is near 100 %. The TCE destruction and removal efficiency, measured by MS/GC, is better than 99.9999 %. A simplified kinetic model of gas quenching was constructed from a single-phase plug-flow reactor model taking into account 14 species and 34 reactions. It satisfies the requirements of heat balance and major components analysis, and reveals the major role of the OH radical on the concentrations of CO as well as HCl and/or Cl 2 in the off-gas stream.
The CEA is studying the development of processes with a sufficiently large operating range in order to propose a general treatment system and make it possible to absorb a significant quantity of radioactive liquid stocks awaiting treatment around the world. A solution may be the use of submerged plasma into which the organic liquids would be injected. Current research has demonstrated that such a technique may enable the instantaneous and complete destruction of liquids with a wide variety of constituants, such as chlorine, fluorine or phosphorus. The ELIPSE process was designed based on the results of this research. In this process, an arc plasma torch is submerged in the core of an aqueous solution. The submersion solution offers many advantages: quenching and cleaning of combustion gases; filtering of the particles they contain; and cooling maintained for the entire process, which guarantees excellent corrosion control. An advantage of this type of design is that the gas treatment system can be reduced to a demister-condenser followed by a simple safety filter, thereby offering the additional advantage of an extremely compact treatment system. This design also allows the ELIPSE process to become by this way an embeddable process if required. The present paper will first describe the state-of-the-art concerning this concept and secondly research currently conducted using the ELIPSE process to destroy a wide variety of liquids such as TBP, trichloroethylene and perfluoropolyether with an efficiency of over 99% at rates of several liters per hour. The apparent absence of any corrosion observed in the treatment system would indicate that, following optimization, a universal and compact process may soon be available, which may be transportable and dedicated to the treatment of orphan waste products awaiting treatment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.