METHOD FOR SEPARATING THE NON-CLEAR GASES OF XENON AND KRYPTON FROM EXHAUST GAS FROM NUCLEAR TECHNICAL PLANTS

摘要

Process for separating the noble fission gases xenon and krypton from a prepurified waste gas from a nuclear plant. The prepurified waste gas is brought into contact with liquid Cl2CF2 as an absorption agent in a first column at an operating pressure which is less than or equal to normal pressure, whereby Xe, Kr, N2O, CO2, O2 and N2 are absorbed by the agent. Subsequently, the liquid absorption agent containing the absorbed gases is heated to substantially the boiling temperature of Cl2CF2 at the operating pressure for vaporizing part of the liquid absorption agent and desorbing the absorbed Kr, N2 and O2 to thereby separate the Kr and Xe from one another. The desorbed Kr, N2 and O2 gases are separated from the vaporized absorption agent. The liquid absorption agent which has not been vaporized is treated to recover Xe, N2O and CO2. Waste gas containing Kr, N2 and O2 from the head of the first column is brought into contact with liquid Cl2CF2 as an absorption agent in a second column, at an operating pressure which is less than or equal to normal pressure, whereby Kr, N2 and O2 are absorbed. Subsequently, the liquid absorption agent in the second column containing the absorbed Kr, N2 and O2 is heated to substantially the boiling temperature of the Cl2CF2 at the operating pressure for vaporizing part of the liquid absorption agent and desorbing the absorbed N2 and O2. The liquid Cl2CF2 which has not been vaporized is treated to recover Kr. An apparatus is provided for performing the process.