Chemical Decomposition and Pressure Rise in Gaseous and Liquid C2Cl3F3 Under Internal Arc Stress

Trichlorotrifluoroethane (C2C13F3) is a stablelemolecule up to a temperature of 700°C. Under internal arc stress C2C13F3 was decomposed and phosgene and other products were produced. The amount of produced phosgene depends on the energy per unit of gas mass and the presence of oxygen. At the ignition of an arc in liquid C2C13F3 a shock-wave with amplitudes of up to 1 MPa occurs dependent on arc current steepness at ignition. After the damping out of the shock-wave, the pressure rise in gaseous and liquid C2C13F3 is approximately similar and can be calculated with help of the electrical energy fed in. These results lead to the following requirements for technical applications: the enclosure of an C2C13F3 cooled and insulated power semi-conductor must withstand the shockwava ave at arc ignition and the pressure rise during the arcing time without any damage to prevent loss ofosphosgene. Therefore, pressure relief valves cannot be used for such applications. For a faster decomposition of produced phosgene within the enclosure substances like aniline, ammonia or soda lime are applicable.