Recycling with 500 kW 3 phase AC plasma torch

Abstract

Experiments for gas destruction with the help of the new three phase AC plasma generator were performed. Advantages of the new type plasma generator were studied. It was shown that this generator can be successfully used for destruction of hazardous waste. Tests of methane, freon and malathion destruction were performed. Results of the tests shows complete destruction of the injected gases. INTRODUCTION Plasma treatment of hazardous waste appears to be one of the most promising methods of waste destruction which will be available on the market in the next few years. The introduction of plasma into a combustion system reduces the ignition delay time and increases the burning rate and completeness of burn out waste mixtures. All these features are very important for treatment of a hazardous waste. It is already recognized that plasma can be successfully used for nerve gas, freons and PCB destruction. All these components have highly stable chlorine and fluorine bonds and require temperatures higher then 2000 K. On the other hand plasma combustion can be used for treatment of the other types of waste. One such application of the plasma combustion technique can be drug destruction. Plasma treatment allows to create fast, portable and complete method for destruction of the stockpiles of the confiscated drugs. In this paper characteristics and capabilities of the pilot unit for such destruction are discussed. Almost all known plasma generators are DC type systems. Their technology now is rather advanced but still they have several weak points. Usually DC plasma systems require a very rather complicated and expensive power supply. To increase the lifetime of electrodes and improve heat transfer, special magnetic rotation systems usually installed on the torch. All this makes a DC plasma system very complicated, expensive and not dependable. Another disadvantage of many DC plasma torches is that to achieve more or less reasonable lifetimes of the electrodes, one must use noble gases as working gas. The three phase AC plasma system described in thispaper has non of these disadvantages. But its characteristics differ from conventional DC torches. This research was done to prove the possibility of application of the plasma torch under consideration to the destruction of drugs. THREE PHASE AC PLASMA GENERATOR The SUI Plasmatron is an AC plasma generator that takes advantage of the inherent efficiency and cost effectiveness of AC plasma systems without the usual AC instability. The plasmatron operates efficiently on almost any working gas or aerosol and has an efficiency above 90%. The plasma temperature in the torch is above 6000 K with the power variable from 225 kW to 1 MW. Three J -shaped electrodes are mounted in a single discharge chamber hi a Y configuration (Fig.l). Near the center of the Y, a high voltage oscillator directs a flow of ionized gases across the electrode junction. This allows an arc to form between the electrodes at line voltage because the ionization lowers the resistance across the Copyright 01996 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.