Selective Absorption Separation of NH_3 and CO_2 Mixture GasIII. Separation Investigation by Two Step Absorbers in Series

A selective absorption has been studied to separate the mixture gas of NH_3/CO_2=2(mol) by the two steps absorbers in series at high gas velocity, satisfactory separation was obtained. The export content of CO_2 for second step absorber has got to 0.909(mol fraction), and remainder ammonia mol fraction is only 0.091.The absorber recovered 96.7% of NH_3 and 33.1% of CO_2. The concentration of NH_3 in liquid phase reached 10.82mol/L, and the mol ratio of NH_3 to CO_2 is 5.85. It is concluded through the experiment that the concentration of NH_3 of first absorber, temperature of second step absorber and the gas velocity of nozzle are the main influence factors on remainder ammonia content. And the main influence factors on the total absorptivity of CO_2 are concentration of NH_3 in outlet solution and gas velocity of nozzle.