An arc discharge, one of the most common forms of electric gas discharge, occurs when a high-density electric current (usually of the order of 100-1000 A/cm²) passes between metal electrodes. In an arc plasma, due to the high current density and high pressure, the number of collisions of electrons with heavy particles is large, as a result of which there is an effective exchange of energy between electrons and the rest of the plasma components and, as a consequence, the same temperature of electrons and gas is established. This temperature is quite high – depending on the discharge conditions, it ranges from 4500K to 8000K.
Non-equilibrium plasma chemical systems for Hydrogen production
In recent years, numerous attempts have been made to use non-equilibrium plasma of pulsed spark discharges, barrier, corona, microwave, in order to mainly reduce energy consumption for heating gas to initiate chemical reactions, which in quasi-equilibrium arc plasma is at least 40 %. Below is an attempt to analyze the current state of problems of applied non-equilibrium plasma chemistry of atmospheric pressure with the prospect of its use in large tonnage production. In recent decades a great attention has been paid to the production of hydrogen, including in non-equilibrium plasma chemical systems. This is due to the tasks of hydrogen energy development with the use of fuel cells providing direct conversion of chemical energy of fuel into electrical energy with maximum efficiency and minimum environmental pollution, which requires increasing industrial production of hydrogen.
Electric Arc Vapor Plasma
Water as a plasma forming medium has a special place. This substance is widely distributed in nature and plays a huge role in it, providing a variety of chemical reactions and physical processes. The subject of discussion is water vapor of near-atmospheric pressure with temperatures up to several tens of thousands of degrees. The so-called water vapor plasma is one of the most chemically active media, and steam is an extremely cheap plasma gas. Water vapor plasma is not only a coolant, but also an active reagent in physical and chemical reactions. Due to its unique properties of enthalpy, environmental friendliness, non-explosion safety, wide availability, water vapor plasma is promising in technological processes of metallurgy, power engineering, mechanical engineering, plasma chemistry. The advantage of steam-water plasma is the absence of harmful nitrogen oxides when plasmatron operates on water vapor. To date, the main contribution to the development of plasma-chemical processes of pyrolysis and oxidative conversion of hydrocarbons have received in the quasi -equilibrium arc plasma.