PROCESS FOR REDUCING THE CONTENT OF NOx AND N2O FROM A TAIL GAS OF A NITRIC ACID PROCESS

A process for reducing the content of NOx and N2O from an input tail gas of a nitric acid process, said input tail gas having a temperature lower than 400° C., the process comprising:

• an abatement stage including at least a stage of catalytic N2O decomposition (deN2O) over an iron-loaded zeolite catalyst and a stage of catalytic NOx reduction (deNOx), said abatement stage providing a conditioned tail gas having a temperature greater than the input tail gas, wherein:
• prior to submission to said abatement stage, said input tail gas is pre-heated to a temperature of at least 400° C. by indirect heat exchange with at least a portion of said conditioned gas;
• said deN2O and deNOx stages being carried out in separated catalytic beds and said deNOx stage being carried out over at least one of:
• a vanadium catalyst, a copper-loaded zeolite catalyst, or an iron-loaded zeolite catalyst.

A system for reducing the content of NOx and N2O from a tail gas of a nitric acid process, the system comprising:

• a tail gas pre-heater, which provides a pre-heated tail gas;
• a catalytic reactor, receiving said pre-heated tail gas and carrying out catalytic N2O decomposition (deN2O) and catalytic NOx reduction (deNOx), thereby providing a conditioned gas;
• a flow line arranged to recycle at least a portion of said conditioned gas to said tail gas pre-heater, wherein said conditioned gas acts as hot heat exchange medium;
• wherein said catalytic reactor includes at least one catalytic bed wherein deN2O is carried out and at least one catalytic bed wherein deNOx is carried out.