Double chamber linear circuit plasma torch experimental investigation and choosing its optimal technological parameters

Abstract

The article presents the results of experimental studies dual-chamber DC arc plasma torch of linear circuit in bench and industrial conditions. Arc plasma torch of linear circuit VORTEX-200 rated power of 200 kW is designed for plasma ignition of pulverized coal flame, its stabilization and fuel oil free start up boilers of thermal power plants. Plasma torch of linear circuit comprises two water-cooled cases, insulated from one another, one of which is mounted a hollow cylindrical electrode - a cathode, both ends of which are located swirlers of plasma gas, while in another case the output electrode - the anode diffuser having a channel with a cylindrical section beginning and an outlet nozzle at the end of a diffuser. Power of the plasma torch according to the process parameters can vary from 80 to 230 kW. The plasma torch is characterized by stable high power air plasma torch. Tests of these plasma torches showed their high reliability and the possibility of their use in difficult conditions of thermal power plants (increased dust and humidity, high temperatures near the boiler). The measured current-voltage characteristics of the plasma torch allowed determining the area of sustainable arc 350-475 A. The parameters of the plasma torch at its rated capacity of 200 kW and a plasma gas flow of 1000 l/min are achieved at currents less than 450 A. Use of a mechanical ignition of the plasma torch with a needle of a refractory material, instead of the breakdown of the electrode gap using oscillator increased the reliability of its operation. A device axial scanning binding cathode spot, allowing multiply the surface of cathode erosion. Application of the azimuthal and axial scanning cathode spot plasma torch can increase the life of the cathode up to 200 hours at a resource of the massive anode more than 500 hours.