DESIGN AND OPTIMIZATION OF A NITRIC-ACID RECOVERY PLANT FROM NITROUS WASTE GASES

The modelling of the multicomponent absorption with chemical reaction is not a trivial problem due to superposition of many driving forces - multicomponent diffusion, chemical interactions, convective flows, mu lticomponent thermodynamic interaction etc. Therefore, adequate theore tical description of multicomponent reactive systems calls for the app lication of the Maxwell-Stefan equations and for the use of matrix cou pled mass transfer equations together with the relevant reaction kinet ics. On this basis, a countercurrent absorption tower for chemisorptio n of nitrogen oxides (NOx) to nitric acid is considered and a general non-equilibrium stage model is developed for its design and optimizati on.