Plasma Cracking

Steam Plasma Source

For destruction of fluorinated compounds such as is CFCs, a special plasma source is needed. Plasma generators for noble gases and gases like nitrogen are well known and often used because of little erosion and a long lifetime for the electrodes.

The cracking process is a high-temperature pyrolysis process. It needs OH-radicals cracking CFCs and produces hydrogen fluoride and hydrogen chloride as stabile compounds. Therefore it is not helpful to use standard plasma technologies for the destruction of CFCs. The design of a plasma-chemical reactor depends on the physico-chemical characteristics of a specific disposal process and the requirements concerning the properties of the resulting products. The problem was solved by developing a special high-temperature pyrolysis process by steam plasma in which the CFC molecules are cracked by heat and OH-radicals into smaller units, in order to obtain hydrofluoric acid and hydrochloric acid for recovery as valuable chemicals. Depending on the halogen carbon ratio, it may be necessary to add an oxygen or hydrogen carrier to achieve full conversion to the desired products

The development of the highly sophisticated plasma source is based on long term experience in plasma systems for space station applications. The plasma generator is of linear design with the cathode in the center and a with a water-cooled anode. For the destruction of ODS material a steam plasma torch is used. The plasma torch is constructed to achieve a low erosion rate.